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Investment Risks
Mar. 01, 2026
California Municipal Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
California Municipal Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
California Municipal Fund | Geographic Concentration Risk1 Member  
Prospectus [Line Items]  
Risk [Text Block] Geographic Concentration Risk. A fund that invests significant portions of its assets in municipal obligations and bonds in particular geographic areas (a particular state, such as California, or a particular country or region) has greater exposure than other funds to economic conditions and developments in those areas.
California Municipal Fund | High Yield Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] High Yield Securities Risk. High yield fixed-income securities (commonly referred to as “junk bonds”) are subject to greater credit quality risk than higher rated fixed-income securities and should be considered speculative.
California Municipal Fund | Industrial Revenue Bond Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Industrial Revenue Bond Risk. The Fund will be sensitive to, and its performance will depend to a greater extent on, the overall condition and performance of industrial revenue bonds. These revenue bonds are issued by or on behalf of public authorities to obtain funds to finance various public and/or privately operated facilities, including those for business and manufacturing, housing, sports, pollution control, airport, mass transit, port, and parking facilities. These bonds are normally secured only by the revenues from the project and not by state or local government tax payments. Consequently, the credit quality of these bonds is dependent upon the ability of the user of the facilities financed by the bonds and any guarantor to meet its financial obligations.
California Municipal Fund | Inverse Floating Rate Investments Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Inverse Floating Rate Investments Risk. Inverse floating rate investments are extremely sensitive to changes in interest rates and, in some cases, their market value may be extremely volatile.
California Municipal Fund | Leverage Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Leverage Risk. Leverage created by borrowing or certain types of transactions or investments may impair the Fund’s liquidity, cause it to liquidate positions at an unfavorable time, increase volatility of the Fund’s net asset value, or diminish the Fund’s performance.
California Municipal Fund | Municipal Obligations Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Municipal Obligations Risk. Principal and interest payments on municipal securities may not be guaranteed by the issuing body and may be payable only from a particular source. That source may not perform as expected, and payment obligations may not be made or made on time.
California Municipal Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
California Municipal Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
California Municipal Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
California Municipal Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Core Fixed Income Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Core Fixed Income Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Core Fixed Income Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Core Fixed Income Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Core Fixed Income Fund | Real Estate Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Real Estate Securities Risk. Investing in real estate securities subjects the fund to the risks associated with the real estate market (which are similar to the risks associated with direct ownership in real estate), including declines in real estate values, loss due to casualty or condemnation, property taxes, interest rate changes, increased expenses, cash flow of underlying real estate assets, regulatory changes (including zoning, land use, and rents), and environmental problems, as well as to the risks related to the management skill and creditworthiness of the issuer.
Core Fixed Income Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Core Fixed Income Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Core Fixed Income Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Core Fixed Income Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Core Fixed Income Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Core Plus Bond Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Core Plus Bond Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Core Plus Bond Fund | High Yield Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] High Yield Securities Risk. High yield fixed-income securities (commonly referred to as “junk bonds”) are subject to greater credit quality risk than higher rated fixed-income securities and should be considered speculative.
Core Plus Bond Fund | Leverage Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Leverage Risk. Leverage created by borrowing or certain types of transactions or investments may impair the Fund’s liquidity, cause it to liquidate positions at an unfavorable time, increase volatility of the Fund’s net asset value, or diminish the Fund’s performance.
Core Plus Bond Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Core Plus Bond Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Core Plus Bond Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Core Plus Bond Fund | Real Estate Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Real Estate Securities Risk. Investing in real estate securities subjects the fund to the risks associated with the real estate market (which are similar to the risks associated with direct ownership in real estate), including declines in real estate values, loss due to casualty or condemnation, property taxes, interest rate changes, increased expenses, cash flow of underlying real estate assets, regulatory changes (including zoning, land use, and rents), and environmental problems, as well as to the risks related to the management skill and creditworthiness of the issuer.
Core Plus Bond Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Core Plus Bond Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Core Plus Bond Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Core Plus Bond Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
•Futures and Swaps. These derivative instruments involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the fund and the price of the instruments; possible lack of a liquid secondary market for an instrument and the resulting inability to close it when desired; counterparty risk; and if the fund has insufficient cash, it may have to sell securities from its portfolio to meet any applicable daily variation margin requirements.
Core Plus Bond Fund | Derivatives Risk, Credit Default Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
Core Plus Bond Fund | Derivatives Risk, Futures And Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Futures and Swaps. These derivative instruments involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the fund and the price of the instruments; possible lack of a liquid secondary market for an instrument and the resulting inability to close it when desired; counterparty risk; and if the fund has insufficient cash, it may have to sell securities from its portfolio to meet any applicable daily variation margin requirements.
Core Plus Bond Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Core Plus Bond Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Core Plus Bond Fund | Hedging Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Hedging Risk. A fund that implements a hedging strategy using derivatives and/or securities could expose the fund to the risk that can arise when a change in the value of a hedge does not match a change in the value of the asset it hedges. In other words, the change in value of the hedge could move in a direction that does not match the change in value of the underlying asset, resulting in a risk of loss to the Fund.
Core Plus Bond Fund | High Portfolio Turnover Risk Member  
Prospectus [Line Items]  
Risk [Text Block] High Portfolio Turnover Risk. High portfolio turnover (more than 100%) caused by active and frequent trading of portfolio securities may result in accelerating the realization of taxable gains and losses, lower fund performance, and increased brokerage costs.
Core Plus Bond Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Core Plus Bond Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Diversified Income Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Diversified Income Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Diversified Income Fund | High Yield Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] High Yield Securities Risk. High yield fixed-income securities (commonly referred to as “junk bonds”) are subject to greater credit quality risk than higher rated fixed-income securities and should be considered speculative.
Diversified Income Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Diversified Income Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Diversified Income Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Diversified Income Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Diversified Income Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
•Currency Contracts. Derivatives related to currency contracts involve the specific risk of government action that would restrict the ability of the Fund to deliver or receive currency.
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Diversified Income Fund | Derivatives Risk, Credit Default Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
Diversified Income Fund | Derivatives Risk, Futures And Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Diversified Income Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Diversified Income Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Diversified Income Fund | Hedging Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Hedging Risk. A fund that implements a hedging strategy using derivatives and/or securities could expose the fund to the risk that can arise when a change in the value of a hedge does not match a change in the value of the asset it hedges. In other words, the change in value of the hedge could move in a direction that does not match the change in value of the underlying asset, resulting in a risk of loss to the Fund.
Diversified Income Fund | Asset Allocation Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Asset Allocation Risk. A fund’s selection and weighting of asset classes and allocation among sub-advisors may cause it to underperform other funds with a similar investment objective.
Diversified Income Fund | Bank Loans Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Bank Loans Risk. Changes in economic conditions are likely to cause issuers of bank loans (also known as senior floating rate interests) to be unable to meet their obligations. In addition, the value of the collateral securing the loan (if any) may decline, causing a loan to be substantially unsecured. Underlying credit agreements governing the bank loans, reliance on market makers, priority of repayment, and overall market volatility may harm the liquidity of loans.
Diversified Income Fund | Derivatives Risk, Currency Contracts Risk Member  
Prospectus [Line Items]  
Risk [Text Block] •Currency Contracts. Derivatives related to currency contracts involve the specific risk of government action that would restrict the ability of the Fund to deliver or receive currency.
Diversified Income Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Diversified Income Fund | Floating And Variable Rate Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Floating and Variable Rate Securities Risk. The market prices of securities with variable and floating interest rates are generally less sensitive to interest rate changes than are the market prices of securities of fixed interest rates. Floating and variable rate securities may decline in value if market interest rates or interest rates paid by them do not move as expected. Floating and variable rate securities may be subject to greater liquidity risk than other debt securities, meaning that there may be limitations on the Fund’s ability to sell the securities at any given time.
Diversified Income Fund | Index (Passive) Strategy Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Index (Passive) Strategy Risk. An index (passive) fund (or passive strategy that is part of a fund) has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between an index strategy’s performance and index performance may also be affected by the type of passive investment approach used (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of shares.
Diversified Income Fund | Preferred Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Preferred Securities Risk. Because preferred securities have a lower priority claim on assets or earnings than senior bonds and other debt instruments in a company’s capital structure, they are subject to greater credit and liquidation risk than more senior debt instruments. In addition, preferred securities are subject to other risks, such as limited or no voting rights, deferring or skipping distributions, interest rate risk, and redeeming the security prior to any stated maturity date.
Diversified Income Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Diversified Income Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Diversified International Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Diversified International Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Diversified International Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Diversified International Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Diversified International Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Diversified International Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Diversified International Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Diversified International Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Diversified International Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Diversified International Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Equity Income Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Equity Income Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Equity Income Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Equity Income Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Equity Income Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Equity Income Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Equity Income Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Finisterre Emerging Markets Total Return Bond Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Finisterre Emerging Markets Total Return Bond Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Finisterre Emerging Markets Total Return Bond Fund | High Yield Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] High Yield Securities Risk. High yield fixed-income securities (commonly referred to as “junk bonds”) are subject to greater credit quality risk than higher rated fixed-income securities and should be considered speculative.
Finisterre Emerging Markets Total Return Bond Fund | Leverage Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Leverage Risk. Leverage created by borrowing or certain types of transactions or investments may impair the Fund’s liquidity, cause it to liquidate positions at an unfavorable time, increase volatility of the Fund’s net asset value, or diminish the Fund’s performance.
Finisterre Emerging Markets Total Return Bond Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Finisterre Emerging Markets Total Return Bond Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Finisterre Emerging Markets Total Return Bond Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Finisterre Emerging Markets Total Return Bond Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Finisterre Emerging Markets Total Return Bond Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Finisterre Emerging Markets Total Return Bond Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Currency Contracts. Derivatives related to currency contracts involve the specific risk of government action that would restrict the ability of the Fund to deliver or receive currency.
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Finisterre Emerging Markets Total Return Bond Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
•Defensive Strategy Risk. Because emerging market debt markets are particularly susceptible to adverse market, economic, political, and other conditions, the Fund is more prone to take a defensive position and invest a significant portion of its assets in cash and cash equivalents in response to abnormal market conditions. In taking a large cash position, the Fund’s performance may be adversely affected as the Fund may not be able to benefit from an upswing in the market. Further, the Fund may be unable to pursue or achieve its investment objective when employing such a defensive strategy.
•Frontier Markets Risk. Frontier markets are emerging markets, but generally have small economies or less mature capital markets than more developed emerging markets, and, as a result, the risks of investing in emerging markets are magnified in frontier markets. Frontier markets typically have low trading volumes and the potential for extreme price volatility and illiquidity.
Finisterre Emerging Markets Total Return Bond Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Finisterre Emerging Markets Total Return Bond Fund | Hedging Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Hedging Risk. A fund that implements a hedging strategy using derivatives and/or securities could expose the fund to the risk that can arise when a change in the value of a hedge does not match a change in the value of the asset it hedges. In other words, the change in value of the hedge could move in a direction that does not match the change in value of the underlying asset, resulting in a risk of loss to the Fund.
Finisterre Emerging Markets Total Return Bond Fund | High Portfolio Turnover Risk Member  
Prospectus [Line Items]  
Risk [Text Block] High Portfolio Turnover Risk. High portfolio turnover (more than 100%) caused by active and frequent trading of portfolio securities may result in accelerating the realization of taxable gains and losses, lower fund performance, and increased brokerage costs.
Finisterre Emerging Markets Total Return Bond Fund | Derivatives Risk, Currency Contracts Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Currency Contracts. Derivatives related to currency contracts involve the specific risk of government action that would restrict the ability of the Fund to deliver or receive currency.
Finisterre Emerging Markets Total Return Bond Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Finisterre Emerging Markets Total Return Bond Fund | Convertible Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Convertible Securities Risk. Convertible securities are securities that are convertible into common stock. Convertible securities are subject to credit and interest rate risks associated with fixed-income securities and to stock market risk associated with equity securities.
Finisterre Emerging Markets Total Return Bond Fund | Derivatives Risk, Forward Contracts, Futures, And Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Finisterre Emerging Markets Total Return Bond Fund | Distressed Investments Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Distressed Investments Risk. A fund’s investment in instruments involving loans, loan participations, bonds, notes, non-performing and sub-performing mortgage loans, many of which are not publicly traded, may involve a substantial degree of risk for the following reasons. These instruments may become illiquid and the prices of such instruments may be extremely volatile. Valuing such instruments may be difficult and a fund may lose all of its investment, or it may be required to accept cash or securities with a value less than the fund’s original investment. Issuers of distressed securities are typically in a weak financial condition and may default, in which case the fund may lose its entire investment.
Finisterre Emerging Markets Total Return Bond Fund | Emerging Markets Risk, Defensive Strategy Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Defensive Strategy Risk. Because emerging market debt markets are particularly susceptible to adverse market, economic, political, and other conditions, the Fund is more prone to take a defensive position and invest a significant portion of its assets in cash and cash equivalents in response to abnormal market conditions. In taking a large cash position, the Fund’s performance may be adversely affected as the Fund may not be able to benefit from an upswing in the market. Further, the Fund may be unable to pursue or achieve its investment objective when employing such a defensive strategy.
Finisterre Emerging Markets Total Return Bond Fund | Emerging Markets Risk, Frontier Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Frontier Markets Risk. Frontier markets are emerging markets, but generally have small economies or less mature capital markets than more developed emerging markets, and, as a result, the risks of investing in emerging markets are magnified in frontier markets. Frontier markets typically have low trading volumes and the potential for extreme price volatility and illiquidity.
Finisterre Emerging Markets Total Return Bond Fund | Volatility Mitigation Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Volatility Mitigation Risk. Volatility mitigation strategies may increase the Fund’s transaction costs, which could increase losses or reduce gains. These strategies may not protect the Fund from market declines and may reduce the Fund’s participation in market gains.
Finisterre Emerging Markets Total Return Bond Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Finisterre Emerging Markets Total Return Bond Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Global Emerging Markets Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Global Emerging Markets Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Global Emerging Markets Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
•China Investment Risk. The Fund invests a significant portion of its assets in securities of issuers located or operating in China and its administrative and other districts such as Hong Kong and Macau. Investing in China involves certain heightened risks and considerations, including, among others: frequent trading suspensions and government interventions (including by nationalizing assets); currency exchange rate fluctuations or blockages; limits on using brokers and on foreign ownership; different financial reporting standards; higher dependence on exports and international trade; political and social instability; infectious disease outbreaks; regional and global conflicts; increased trade tariffs, embargoes, and other trade limitations; custody and other risks associated with programs used to access Chinese securities; and uncertainties in tax rules that could result in unexpected tax liabilities for the Fund. Significant portions of the Chinese securities markets may become rapidly illiquid, as Chinese issuers have the ability to suspend the trading of their equity securities. Moreover, actions by the U.S. government, such as delisting of certain Chinese companies from U.S. securities exchanges or otherwise restricting their operations in the U.S., may negatively impact the value of such securities held by the Fund.
Global Emerging Markets Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Global Emerging Markets Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Global Emerging Markets Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Global Emerging Markets Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Global Emerging Markets Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Global Emerging Markets Fund | Emerging Markets Risk, China Investment Risk Member  
Prospectus [Line Items]  
Risk [Text Block] •China Investment Risk. The Fund invests a significant portion of its assets in securities of issuers located or operating in China and its administrative and other districts such as Hong Kong and Macau. Investing in China involves certain heightened risks and considerations, including, among others: frequent trading suspensions and government interventions (including by nationalizing assets); currency exchange rate fluctuations or blockages; limits on using brokers and on foreign ownership; different financial reporting standards; higher dependence on exports and international trade; political and social instability; infectious disease outbreaks; regional and global conflicts; increased trade tariffs, embargoes, and other trade limitations; custody and other risks associated with programs used to access Chinese securities; and uncertainties in tax rules that could result in unexpected tax liabilities for the Fund. Significant portions of the Chinese securities markets may become rapidly illiquid, as Chinese issuers have the ability to suspend the trading of their equity securities. Moreover, actions by the U.S. government, such as delisting of certain Chinese companies from U.S. securities exchanges or otherwise restricting their operations in the U.S., may negatively impact the value of such securities held by the Fund.
Global Emerging Markets Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Global Emerging Markets Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Global Real Estate Securities Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Global Real Estate Securities Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Global Real Estate Securities Fund | Real Estate Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Real Estate Securities Risk. Investing in real estate securities subjects the fund to the risks associated with the real estate market (which are similar to the risks associated with direct ownership in real estate), including declines in real estate values, loss due to casualty or condemnation, property taxes, interest rate changes, increased expenses, cash flow of underlying real estate assets, regulatory changes (including zoning, land use, and rents), and environmental problems, as well as to the risks related to the management skill and creditworthiness of the issuer.
Global Real Estate Securities Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Global Real Estate Securities Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Global Real Estate Securities Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Global Real Estate Securities Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Global Real Estate Securities Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Global Real Estate Securities Fund | Industry Concentration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Industry Concentration Risk. A fund that concentrates investments in a particular industry or group of industries has greater exposure than other funds to market, economic, and other factors affecting that industry or group of industries.
•Real Estate. A fund concentrating in the real estate industry is subject to the risks associated with direct ownership of real estate, securities of companies in the real estate industry, and/or real estate investment trusts. These risks are explained more fully below in Real Estate Investment Trusts (REITs) Risk and Real Estate Securities Risk.
Global Real Estate Securities Fund | Industry Concentration Risk, Real Estate Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Real Estate. A fund concentrating in the real estate industry is subject to the risks associated with direct ownership of real estate, securities of companies in the real estate industry, and/or real estate investment trusts. These risks are explained more fully below in Real Estate Investment Trusts (REITs) Risk and Real Estate Securities Risk.
Global Real Estate Securities Fund | Real Estate Investment Trusts ("REITs") Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Real Estate Investment Trusts (“REITs”) Risk. In addition to risks associated with investing in real estate securities, REITs are dependent upon management skills, are not diversified, and are subject to heavy cash flow dependency, risks of default by borrowers, and self-liquidation. Investment in REITs also involves risks similar to risks of investing in small market capitalization companies, such as limited financial resources, less frequent and limited volume trading, and may be subject to more abrupt or erratic price movements than larger company securities. A REIT could fail to qualify for tax-free pass-through of income under the Internal Revenue Code. Fund shareholders will indirectly bear their proportionate share of the expenses of REITs in which the fund invests.
Global Real Estate Securities Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Global Real Estate Securities Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Government & High Quality Bond Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Government & High Quality Bond Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Government & High Quality Bond Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Government & High Quality Bond Fund | Real Estate Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Real Estate Securities Risk. Investing in real estate securities subjects the fund to the risks associated with the real estate market (which are similar to the risks associated with direct ownership in real estate), including declines in real estate values, loss due to casualty or condemnation, property taxes, interest rate changes, increased expenses, cash flow of underlying real estate assets, regulatory changes (including zoning, land use, and rents), and environmental problems, as well as to the risks related to the management skill and creditworthiness of the issuer.
Government & High Quality Bond Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk). With respect to securities that are delivered in TBA transactions, there is a risk that the actual securities received by the Fund may be less favorable than what was anticipated when entering into the transaction.
Government & High Quality Bond Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Government & High Quality Bond Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Government & High Quality Bond Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Government & High Quality Bond Fund | High Portfolio Turnover Risk Member  
Prospectus [Line Items]  
Risk [Text Block] High Portfolio Turnover Risk. High portfolio turnover (more than 100%) caused by active and frequent trading of portfolio securities may result in accelerating the realization of taxable gains and losses, lower fund performance, and increased brokerage costs.
Government & High Quality Bond Fund | Derivatives Risk, Futures Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Government & High Quality Bond Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Government & High Quality Bond Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Government Money Market Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Government Money Market Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Government Money Market Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Government Money Market Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Government Money Market Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Government Money Market Fund | Floating And Variable Rate Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Floating and Variable Rate Securities Risk. The market prices of securities with variable and floating interest rates are generally less sensitive to interest rate changes than are the market prices of securities of fixed interest rates. Floating and variable rate securities may decline in value if market interest rates or interest rates paid by them do not move as expected. Floating and variable rate securities may be subject to greater liquidity risk than other debt securities, meaning that there may be limitations on the Fund’s ability to sell the securities at any given time.
Government Money Market Fund | Investment Company Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Investment Company Securities Risk. A fund that invests in another investment company (for example, another fund or an exchange-traded fund (or ETF)) is subject to the risks associated with direct ownership of the securities in which such investment company invests. Fund shareholders indirectly bear their proportionate share of the expenses of each such investment company.
Government Money Market Fund | Repurchase Agreement Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Repurchase Agreement Risk. If the other party to a repurchase agreement defaults on its obligation under the agreement, the Fund may suffer delays and incur costs or lose money in exercising its rights under the agreement. If the seller fails to repurchase the security and the market value of the security declines, the Fund may lose money.
Government Money Market Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money by investing in the Fund.
Government Money Market Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a bank account and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
High Yield Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
High Yield Fund | High Yield Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] High Yield Securities Risk. High yield fixed-income securities (commonly referred to as “junk bonds”) are subject to greater credit quality risk than higher rated fixed-income securities and should be considered speculative.
High Yield Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
High Yield Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
High Yield Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
High Yield Fund | Bank Loans Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Bank Loans Risk. Changes in economic conditions are likely to cause issuers of bank loans (also known as senior floating rate interests) to be unable to meet their obligations. In addition, the value of the collateral securing the loan (if any) may decline, causing a loan to be substantially unsecured. Underlying credit agreements governing the bank loans, reliance on market makers, priority of repayment, and overall market volatility may harm the liquidity of loans.
High Yield Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
High Yield Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Inflation Protection Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Inflation Protection Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Inflation Protection Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Inflation Protection Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Inflation Protection Fund | High Portfolio Turnover Risk Member  
Prospectus [Line Items]  
Risk [Text Block] High Portfolio Turnover Risk. High portfolio turnover (more than 100%) caused by active and frequent trading of portfolio securities may result in accelerating the realization of taxable gains and losses, lower fund performance, and increased brokerage costs.
Inflation Protection Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Inflation Protection Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Inflation Protection Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
International Bond Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
International Bond Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
International Bond Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
International Bond Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
International Bond Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
International Bond Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
•Currency Contracts. Derivatives related to currency contracts involve the specific risk of government action that would restrict the ability of the Fund to deliver or receive currency.
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
International Bond Fund | Derivatives Risk, Credit Default Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
International Bond Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
•China Investment Risk. The Fund invests a significant portion of its assets in securities of issuers located or operating in China. Investing in China involves certain heightened risks and considerations, including, among others: frequent trading suspensions and government interventions (including by nationalizing assets); currency exchange rate fluctuations or blockages; limits on using brokers and on foreign ownership; different financial reporting standards; higher dependence on exports and international trade; political and social instability; infectious disease outbreaks; regional and global conflicts; increased trade tariffs, embargoes, and other trade limitations; custody and other risks associated with programs used to access Chinese securities; and uncertainties in tax rules that could result in unexpected tax liabilities for the Fund. Significant portions of the Chinese securities markets may become rapidly illiquid, as Chinese issuers have the ability to suspend the trading of their equity securities. Moreover, actions by the U.S. government, such as delisting of certain Chinese companies from U.S. securities exchanges or otherwise restricting their operations in the U.S., may negatively impact the value of such securities held by the Fund.
International Bond Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
International Bond Fund | Hedging Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Hedging Risk. A fund that implements a hedging strategy using derivatives and/or securities could expose the fund to the risk that can arise when a change in the value of a hedge does not match a change in the value of the asset it hedges. In other words, the change in value of the hedge could move in a direction that does not match the change in value of the underlying asset, resulting in a risk of loss to the Fund.
International Bond Fund | Derivatives Risk, Currency Contracts Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Currency Contracts. Derivatives related to currency contracts involve the specific risk of government action that would restrict the ability of the Fund to deliver or receive currency.
International Bond Fund | Derivatives Risk, Forward Contracts, Futures, And Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
International Bond Fund | Emerging Markets Risk, China Investment Risk Member  
Prospectus [Line Items]  
Risk [Text Block] China Investment Risk. The Fund invests a significant portion of its assets in securities of issuers located or operating in China. Investing in China involves certain heightened risks and considerations, including, among others: frequent trading suspensions and government interventions (including by nationalizing assets); currency exchange rate fluctuations or blockages; limits on using brokers and on foreign ownership; different financial reporting standards; higher dependence on exports and international trade; political and social instability; infectious disease outbreaks; regional and global conflicts; increased trade tariffs, embargoes, and other trade limitations; custody and other risks associated with programs used to access Chinese securities; and uncertainties in tax rules that could result in unexpected tax liabilities for the Fund. Significant portions of the Chinese securities markets may become rapidly illiquid, as Chinese issuers have the ability to suspend the trading of their equity securities. Moreover, actions by the U.S. government, such as delisting of certain Chinese companies from U.S. securities exchanges or otherwise restricting their operations in the U.S., may negatively impact the value of such securities held by the Fund.
International Bond Fund | Frequent Trading Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Frequent Trading Risk. Active and frequent trading of portfolio assets may result in accelerating the realization of taxable gains and losses, lower Fund performance, and increased transaction costs.
International Bond Fund | Sovereign Debt Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Sovereign Debt Risk. Sovereign debt instruments are subject to the risk that a governmental entity may delay or refuse to pay interest or repay principal on its sovereign debt, due, for example, to cash flow problems, insufficient foreign currency reserves, political considerations, the relative size of the governmental entity’s debt position in relation to the economy, or the failure to put in place economic reforms required by the International Monetary Fund or other multilateral agencies.
International Bond Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
International Bond Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
International Equity Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
International Equity Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
International Equity Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
•China Investment Risk. The Fund invests a significant portion of its assets in securities of issuers located or operating in China. Investing in China involves certain heightened risks and considerations, including, among others: frequent trading suspensions and government interventions (including by nationalizing assets); currency exchange rate fluctuations or blockages; limits on using brokers and on foreign ownership; different financial reporting standards; higher dependence on exports and international trade; political and social instability; infectious disease outbreaks; regional and global conflicts; increased trade tariffs, embargoes, and other trade limitations; custody and other risks associated with programs used to access Chinese securities; and uncertainties in tax rules that could result in unexpected tax liabilities for the Fund. Significant portions of the Chinese securities markets may become rapidly illiquid, as Chinese issuers have the ability to suspend the trading of their equity securities. Moreover, actions by the U.S. government, such as delisting of certain Chinese companies from U.S. securities exchanges or otherwise restricting their operations in the U.S., may negatively impact the value of such securities held by the Fund.
International Equity Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
International Equity Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
International Equity Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
International Equity Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
International Equity Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
International Equity Fund | Emerging Markets Risk, China Investment Risk Member  
Prospectus [Line Items]  
Risk [Text Block] China Investment Risk. The Fund invests a significant portion of its assets in securities of issuers located or operating in China. Investing in China involves certain heightened risks and considerations, including, among others: frequent trading suspensions and government interventions (including by nationalizing assets); currency exchange rate fluctuations or blockages; limits on using brokers and on foreign ownership; different financial reporting standards; higher dependence on exports and international trade; political and social instability; infectious disease outbreaks; regional and global conflicts; increased trade tariffs, embargoes, and other trade limitations; custody and other risks associated with programs used to access Chinese securities; and uncertainties in tax rules that could result in unexpected tax liabilities for the Fund. Significant portions of the Chinese securities markets may become rapidly illiquid, as Chinese issuers have the ability to suspend the trading of their equity securities. Moreover, actions by the U.S. government, such as delisting of certain Chinese companies from U.S. securities exchanges or otherwise restricting their operations in the U.S., may negatively impact the value of such securities held by the Fund.
International Equity Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
International Equity Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
LargeCap Growth Fund I | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
LargeCap Growth Fund I | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.

•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
LargeCap Growth Fund I | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
LargeCap Growth Fund I | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
LargeCap Growth Fund I | Passive Strategy Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Passive Strategy Risk. A portion of the Fund seeks to match the performance of a specified index. However, the correlation between the performance of this portion of the Fund and index performance may be affected by many factors, such as Fund expenses, the timing of cash flows into and out of the Fund, changes in securities markets, and changes in the composition of the index.
LargeCap Growth Fund I | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
LargeCap Growth Fund I | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
LargeCap Growth Fund I | Risk Nondiversified Status [Member]  
Prospectus [Line Items]  
Risk [Text Block]
Non-Diversification Risk. A non-diversified fund may invest a high percentage of its assets in the securities of a small number of issuers and is more likely than diversified funds to be significantly affected by a specific security’s poor performance.
LargeCap S&P 500 Index Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
LargeCap S&P 500 Index Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
LargeCap S&P 500 Index Fund | Industry Concentration Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Industry Concentration Risk. A fund that concentrates investments in a particular industry or group of industries has greater exposure than other funds to market, economic, and other factors affecting that industry or group of industries.
LargeCap S&P 500 Index Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
LargeCap S&P 500 Index Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
LargeCap S&P 500 Index Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
LargeCap S&P 500 Index Fund | Risk Nondiversified Status [Member]  
Prospectus [Line Items]  
Risk [Text Block]
Non-Diversification Risk. From time to time, the Fund may operate as a non-diversified fund under the 1940 Act, solely as a result of a change in relative market capitalization or index weighting of one or more constituents of the Fund’s Index. A non-diversified fund may invest a high percentage of its assets in the securities of a small number of issuers and is more likely than diversified funds to be significantly affected by a specific security’s poor performance.
LargeCap Value Fund III | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
LargeCap Value Fund III | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
LargeCap Value Fund III | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
LargeCap Value Fund III | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
LargeCap Value Fund III | Investment Company Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Investment Company Securities Risk. A fund that invests in another investment company (for example, another fund or an exchange-traded fund (or ETF)) is subject to the risks associated with direct ownership of the securities in which such investment company invests. Fund shareholders indirectly bear their proportionate share of the expenses of each such investment company.
LargeCap Value Fund III | Passive Strategy Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Passive Strategy Risk. A portion of the Fund seeks to match the performance of a specified index. However, the correlation between the performance of this portion of the Fund and index performance may be affected by many factors, such as Fund expenses, the timing of cash flows into and out of the Fund, changes in securities markets, and changes in the composition of the index.
LargeCap Value Fund III | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
LargeCap Value Fund III | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
MidCap Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
MidCap Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
MidCap Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
MidCap Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
MidCap Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
MidCap Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
MidCap S&P 400 Index Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
MidCap S&P 400 Index Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
MidCap S&P 400 Index Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
MidCap S&P 400 Index Fund | Industry Concentration Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Industry Concentration Risk. A fund that concentrates investments in a particular industry or group of industries has greater exposure than other funds to market, economic, and other factors affecting that industry or group of industries.
MidCap S&P 400 Index Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
MidCap S&P 400 Index Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
MidCap S&P 400 Index Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
MidCap Value Fund I | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
MidCap Value Fund I | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
MidCap Value Fund I | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
MidCap Value Fund I | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
MidCap Value Fund I | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
MidCap Value Fund I | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Money Market Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Money Market Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Money Market Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Money Market Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Money Market Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Money Market Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Money Market Fund | Repurchase Agreement Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Repurchase Agreement Risk. If the other party to a repurchase agreement defaults on its obligation under the agreement, the Fund may suffer delays and incur costs or lose money in exercising its rights under the agreement. If the seller fails to repurchase the security and the market value of the security declines, the Fund may lose money.
Money Market Fund | Commercial Paper Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Commercial Paper Risk. The value of the Fund’s investment in commercial paper, which is generally unsecured, is susceptible to changes in interest rates and the issuer’s financial condition or credit quality. Commercial paper is usually repaid at maturity by the issuer from the proceeds of the issuance of new commercial paper. As a result, investments in commercial paper are subject to the risk that the issuer cannot issue enough new commercial paper to satisfy its outstanding obligations. In addition, under certain circumstances commercial paper may become illiquid or may suffer from reduced liquidity.
Money Market Fund | Discretionary Liquidity Fee Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Discretionary Liquidity Fee Risk. The Fund may charge a liquidity fee of up to 2% of the value of shares redeemed if the Fund’s Board of Directors (or PGI, in accordance with Board-approved guidelines) determines that doing so is in the best interests of the Fund. Accordingly, your redemptions from the Fund may be subject to a liquidity fee when you sell your shares at certain times.
Money Market Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] You could lose money by investing in the Fund.
Money Market Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a bank account and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Overseas Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Overseas Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies). The Schedule of Investments included in the Fund’s annual and semi-annual reports identify the countries in which the Fund had invested, as of the date of the reports; to the extent a Fund has significant investments in issuers or securities tied to a certain country or region, it will be particularly susceptible to economic, political, regulatory or other events or conditions affecting such country or region.
Overseas Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Overseas Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Overseas Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Overseas Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Overseas Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Overseas Fund | Passive Strategy Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Passive Strategy Risk. A portion of the Fund seeks to match the performance of a specified index. However, the correlation between the performance of this portion of the Fund and index performance may be affected by many factors, such as Fund expenses, the timing of cash flows into and out of the Fund, changes in securities markets, and changes in the composition of the index.
Overseas Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Overseas Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal Capital Appreciation Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal Capital Appreciation Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Principal Capital Appreciation Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Principal Capital Appreciation Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal Capital Appreciation Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime Strategic Income Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime Strategic Income Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime Strategic Income Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime Strategic Income Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime Strategic Income Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime Strategic Income Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Principal LifeTime Strategic Income Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Principal LifeTime Strategic Income Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Principal LifeTime Strategic Income Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Strategic Income Fund | Derivatives Risk, Credit Default Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
Principal LifeTime Strategic Income Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime Strategic Income Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Strategic Income Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Strategic Income Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime Strategic Income Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Strategic Income Fund | Derivatives Risk, Forward Contracts, Futures, And Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime Strategic Income Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime Strategic Income Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime Strategic Income Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime Strategic Income Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime 2015 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime 2015 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime 2015 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime 2015 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime 2015 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime 2015 Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Principal LifeTime 2015 Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Principal LifeTime 2015 Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Principal LifeTime 2015 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2015 Fund | Derivatives Risk, Credit Default Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
Principal LifeTime 2015 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime 2015 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block] •Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2015 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2015 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime 2015 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2015 Fund | Derivatives Risk, Forward Contracts, Futures, And Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime 2015 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime 2015 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime 2015 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime 2015 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime 2020 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime 2020 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime 2020 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime 2020 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime 2020 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime 2020 Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Principal LifeTime 2020 Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Principal LifeTime 2020 Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Principal LifeTime 2020 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2020 Fund | Derivatives Risk, Credit Default Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
Principal LifeTime 2020 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime 2020 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2020 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2020 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime 2020 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2020 Fund | Derivatives Risk, Forward Contracts, Futures, And Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime 2020 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime 2020 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime 2020 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime 2020 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime 2025 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime 2025 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime 2025 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime 2025 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime 2025 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime 2025 Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Principal LifeTime 2025 Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Principal LifeTime 2025 Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Principal LifeTime 2025 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2025 Fund | Derivatives Risk, Credit Default Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
Principal LifeTime 2025 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime 2025 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2025 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2025 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime 2025 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2025 Fund | Derivatives Risk, Forward Contracts, Futures, And Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime 2025 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime 2025 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime 2025 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime 2025 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime 2030 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime 2030 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime 2030 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime 2030 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime 2030 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime 2030 Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Principal LifeTime 2030 Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Principal LifeTime 2030 Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Principal LifeTime 2030 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2030 Fund | Derivatives Risk, Credit Default Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
Principal LifeTime 2030 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime 2030 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2030 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2030 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime 2030 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2030 Fund | Derivatives Risk, Forward Contracts, Futures, And Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime 2030 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime 2030 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime 2030 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime 2030 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime 2030 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime 2035 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime 2035 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime 2035 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime 2035 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime 2035 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime 2035 Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Principal LifeTime 2035 Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Principal LifeTime 2035 Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Principal LifeTime 2035 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2035 Fund | Derivatives Risk, Credit Default Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
Principal LifeTime 2035 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime 2035 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2035 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2035 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime 2035 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2035 Fund | Derivatives Risk, Forward Contracts, Futures, And Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime 2035 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime 2035 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime 2035 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime 2035 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime 2035 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime 2040 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime 2040 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime 2040 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime 2040 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime 2040 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime 2040 Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Principal LifeTime 2040 Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Principal LifeTime 2040 Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Principal LifeTime 2040 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2040 Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Principal LifeTime 2040 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime 2040 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2040 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2040 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime 2040 Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Principal LifeTime 2040 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2040 Fund | Derivatives Risk, Futures Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime 2040 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime 2040 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime 2040 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime 2040 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime 2040 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime 2045 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime 2045 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime 2045 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime 2045 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime 2045 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime 2045 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2045 Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Principal LifeTime 2045 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime 2045 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2045 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2045 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime 2045 Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Principal LifeTime 2045 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2045 Fund | Derivatives Risk, Futures Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime 2045 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime 2045 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime 2045 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime 2045 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime 2045 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime 2050 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime 2050 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime 2050 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime 2050 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime 2050 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime 2050 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2050 Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Principal LifeTime 2050 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime 2050 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2050 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2050 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime 2050 Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Principal LifeTime 2050 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2050 Fund | Derivatives Risk, Futures Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime 2050 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime 2050 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime 2050 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime 2050 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime 2050 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime 2055 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime 2055 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime 2055 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime 2055 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime 2055 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime 2055 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2055 Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Principal LifeTime 2055 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime 2055 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2055 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2055 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime 2055 Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Principal LifeTime 2055 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2055 Fund | Derivatives Risk, Futures Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime 2055 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime 2055 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime 2055 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime 2055 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime 2055 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime 2060 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime 2060 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime 2060 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime 2060 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime 2060 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime 2060 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2060 Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Principal LifeTime 2060 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime 2060 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2060 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2060 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime 2060 Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Principal LifeTime 2060 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2060 Fund | Derivatives Risk, Futures Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime 2060 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime 2060 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime 2060 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime 2060 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime 2060 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime 2065 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime 2065 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime 2065 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime 2065 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime 2065 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime 2065 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2065 Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Principal LifeTime 2065 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime 2065 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2065 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2065 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime 2065 Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Principal LifeTime 2065 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2065 Fund | Derivatives Risk, Futures Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime 2065 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime 2065 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime 2065 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime 2065 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime 2065 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime 2070 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime 2070 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime 2070 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime 2070 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime 2070 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime 2070 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2070 Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Principal LifeTime 2070 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime 2070 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block] •Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime 2070 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2070 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime 2070 Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Principal LifeTime 2070 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime 2070 Fund | Derivatives Risk, Futures Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime 2070 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime 2070 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime 2070 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime 2070 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime 2070 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime Hybrid Income Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime Hybrid Income Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime Hybrid Income Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime Hybrid Income Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime Hybrid Income Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime Hybrid Income Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Principal LifeTime Hybrid Income Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Principal LifeTime Hybrid Income Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Principal LifeTime Hybrid Income Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid Income Fund | Derivatives Risk, Credit Default Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
Principal LifeTime Hybrid Income Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime Hybrid Income Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid Income Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid Income Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime Hybrid Income Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid Income Fund | Derivatives Risk, Forward Contracts, Futures, And Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime Hybrid Income Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime Hybrid Income Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime Hybrid Income Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime Hybrid Income Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime Hybrid Income Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime Hybrid 2015 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime Hybrid 2015 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime Hybrid 2015 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime Hybrid 2015 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime Hybrid 2015 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime Hybrid 2015 Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Principal LifeTime Hybrid 2015 Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Principal LifeTime Hybrid 2015 Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Principal LifeTime Hybrid 2015 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2015 Fund | Derivatives Risk, Credit Default Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
Principal LifeTime Hybrid 2015 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime Hybrid 2015 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2015 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2015 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime Hybrid 2015 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2015 Fund | Derivatives Risk, Forward Contracts, Futures, And Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime Hybrid 2015 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime Hybrid 2015 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime Hybrid 2015 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime Hybrid 2015 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime Hybrid 2015 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime Hybrid 2020 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime Hybrid 2020 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime Hybrid 2020 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime Hybrid 2020 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime Hybrid 2020 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime Hybrid 2020 Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Principal LifeTime Hybrid 2020 Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Principal LifeTime Hybrid 2020 Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Principal LifeTime Hybrid 2020 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2020 Fund | Derivatives Risk, Credit Default Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
Principal LifeTime Hybrid 2020 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime Hybrid 2020 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2020 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2020 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime Hybrid 2020 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2020 Fund | Derivatives Risk, Forward Contracts, Futures, And Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime Hybrid 2020 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime Hybrid 2020 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime Hybrid 2020 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime Hybrid 2020 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime Hybrid 2020 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime Hybrid 2025 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime Hybrid 2025 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime Hybrid 2025 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime Hybrid 2025 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime Hybrid 2025 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime Hybrid 2025 Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Principal LifeTime Hybrid 2025 Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Principal LifeTime Hybrid 2025 Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Principal LifeTime Hybrid 2025 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2025 Fund | Derivatives Risk, Credit Default Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
Principal LifeTime Hybrid 2025 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime Hybrid 2025 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2025 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2025 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime Hybrid 2025 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2025 Fund | Derivatives Risk, Forward Contracts, Futures, And Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime Hybrid 2025 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime Hybrid 2025 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime Hybrid 2025 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime Hybrid 2025 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime Hybrid 2025 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime Hybrid 2030 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime Hybrid 2030 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime Hybrid 2030 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime Hybrid 2030 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime Hybrid 2030 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime Hybrid 2030 Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Principal LifeTime Hybrid 2030 Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Principal LifeTime Hybrid 2030 Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Principal LifeTime Hybrid 2030 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2030 Fund | Derivatives Risk, Credit Default Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block] •Credit Default Swaps. Credit default swaps involve special risks in addition to those associated with swaps generally because they are difficult to value, are highly susceptible to liquidity and credit risk, and generally pay a return to the party that has paid the premium only in the event of an actual default by the issuer of the underlying obligation (as opposed to a credit downgrade or other indication of financial difficulty). The protection “buyer” in a credit default contract may be obligated to pay the protection “seller” an up-front payment or a periodic stream of payments over the term of the contract, provided, generally, that no credit event on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (i.e., full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. The Fund may be either the buyer or seller in the transaction.
Principal LifeTime Hybrid 2030 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime Hybrid 2030 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2030 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2030 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime Hybrid 2030 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2030 Fund | Derivatives Risk, Forward Contracts, Futures, And Swaps Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Forward Contracts, Futures, and Swaps. Forward contracts, futures, and swaps involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the forward contract, future, or swap; possible lack of a liquid secondary market for a forward contract, future, or swap and the resulting inability to close a forward contract, future, or swap when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime Hybrid 2030 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime Hybrid 2030 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime Hybrid 2030 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime Hybrid 2030 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime Hybrid 2030 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime Hybrid 2035 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime Hybrid 2035 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime Hybrid 2035 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime Hybrid 2035 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime Hybrid 2035 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime Hybrid 2035 Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Principal LifeTime Hybrid 2035 Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Principal LifeTime Hybrid 2035 Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Principal LifeTime Hybrid 2035 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2035 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime Hybrid 2035 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2035 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2035 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime Hybrid 2035 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2035 Fund | Derivatives Risk, Futures Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime Hybrid 2035 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime Hybrid 2035 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime Hybrid 2035 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime Hybrid 2035 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime Hybrid 2035 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime Hybrid 2040 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime Hybrid 2040 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime Hybrid 2040 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime Hybrid 2040 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime Hybrid 2040 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime Hybrid 2040 Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Principal LifeTime Hybrid 2040 Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Principal LifeTime Hybrid 2040 Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Principal LifeTime Hybrid 2040 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2040 Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Principal LifeTime Hybrid 2040 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime Hybrid 2040 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2040 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2040 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime Hybrid 2040 Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Principal LifeTime Hybrid 2040 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2040 Fund | Derivatives Risk, Futures Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime Hybrid 2040 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime Hybrid 2040 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime Hybrid 2040 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime Hybrid 2040 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime Hybrid 2040 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime Hybrid 2045 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime Hybrid 2045 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime Hybrid 2045 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime Hybrid 2045 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime Hybrid 2045 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime Hybrid 2045 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2045 Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Principal LifeTime Hybrid 2045 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime Hybrid 2045 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2045 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2045 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime Hybrid 2045 Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Principal LifeTime Hybrid 2045 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2045 Fund | Derivatives Risk, Futures Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime Hybrid 2045 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime Hybrid 2045 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime Hybrid 2045 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime Hybrid 2045 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime Hybrid 2045 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime Hybrid 2050 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime Hybrid 2050 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime Hybrid 2050 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime Hybrid 2050 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime Hybrid 2050 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime Hybrid 2050 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2050 Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Principal LifeTime Hybrid 2050 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime Hybrid 2050 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2050 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2050 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime Hybrid 2050 Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Principal LifeTime Hybrid 2050 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2050 Fund | Derivatives Risk, Futures Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime Hybrid 2050 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime Hybrid 2050 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime Hybrid 2050 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime Hybrid 2050 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime Hybrid 2050 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime Hybrid 2055 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime Hybrid 2055 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime Hybrid 2055 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime Hybrid 2055 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime Hybrid 2055 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime Hybrid 2055 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2055 Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Principal LifeTime Hybrid 2055 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime Hybrid 2055 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2055 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2055 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime Hybrid 2055 Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Principal LifeTime Hybrid 2055 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2055 Fund | Derivatives Risk, Futures Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime Hybrid 2055 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime Hybrid 2055 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime Hybrid 2055 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime Hybrid 2055 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime Hybrid 2055 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime Hybrid 2060 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime Hybrid 2060 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime Hybrid 2060 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime Hybrid 2060 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime Hybrid 2060 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime Hybrid 2060 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2060 Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Principal LifeTime Hybrid 2060 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime Hybrid 2060 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2060 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2060 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime Hybrid 2060 Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Principal LifeTime Hybrid 2060 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2060 Fund | Derivatives Risk, Futures Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime Hybrid 2060 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime Hybrid 2060 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime Hybrid 2060 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime Hybrid 2060 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime Hybrid 2060 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime Hybrid 2065 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime Hybrid 2065 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime Hybrid 2065 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime Hybrid 2065 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime Hybrid 2065 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime Hybrid 2065 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2065 Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Principal LifeTime Hybrid 2065 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime Hybrid 2065 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2065 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2065 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime Hybrid 2065 Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Principal LifeTime Hybrid 2065 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2065 Fund | Derivatives Risk, Futures Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime Hybrid 2065 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime Hybrid 2065 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime Hybrid 2065 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime Hybrid 2065 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime Hybrid 2065 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Principal LifeTime Hybrid 2070 Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Principal LifeTime Hybrid 2070 Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Principal LifeTime Hybrid 2070 Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Principal LifeTime Hybrid 2070 Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Principal LifeTime Hybrid 2070 Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Principal LifeTime Hybrid 2070 Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2070 Fund | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Principal LifeTime Hybrid 2070 Fund | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Principal LifeTime Hybrid 2070 Fund | Derivatives Risk, Options Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Options. Options involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the options; counterparty risk; difference in trading hours for the options markets and the markets for the underlying securities (rate movements can take place in the underlying markets that cannot be reflected in the options markets); and an insufficient liquid secondary market for particular options.
Principal LifeTime Hybrid 2070 Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2070 Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Principal LifeTime Hybrid 2070 Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Principal LifeTime Hybrid 2070 Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Principal LifeTime Hybrid 2070 Fund | Derivatives Risk, Futures Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Principal LifeTime Hybrid 2070 Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
Principal LifeTime Hybrid 2070 Fund | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Principal LifeTime Hybrid 2070 Fund | Target Date Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Target Date Fund Risk. A target date fund should not be selected based solely on age or retirement date because there is no guarantee that this Fund will provide adequate income at or through retirement.
Principal LifeTime Hybrid 2070 Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Principal LifeTime Hybrid 2070 Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Real Estate Securities Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Real Estate Securities Fund | Real Estate Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Real Estate Securities Risk. Investing in real estate securities subjects the fund to the risks associated with the real estate market (which are similar to the risks associated with direct ownership in real estate), including declines in real estate values, loss due to casualty or condemnation, property taxes, interest rate changes, increased expenses, cash flow of underlying real estate assets, regulatory changes (including zoning, land use, and rents), and environmental problems, as well as to the risks related to the management skill and creditworthiness of the issuer.
Real Estate Securities Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Real Estate Securities Fund | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Real Estate Securities Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Real Estate Securities Fund | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Real Estate Securities Fund | Industry Concentration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Industry Concentration Risk. A fund that concentrates investments in a particular industry or group of industries has greater exposure than other funds to market, economic, and other factors affecting that industry or group of industries.
•Real Estate. A fund concentrating in the real estate industry is subject to the risks associated with direct ownership of real estate, securities of companies in the real estate industry, and/or real estate investment trusts. These risks are explained more fully below in Real Estate Investment Trusts (REITs) Risk and Real Estate Securities Risk.
Real Estate Securities Fund | Industry Concentration Risk, Real Estate Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Real Estate. A fund concentrating in the real estate industry is subject to the risks associated with direct ownership of real estate, securities of companies in the real estate industry, and/or real estate investment trusts. These risks are explained more fully below in Real Estate Investment Trusts (REITs) Risk and Real Estate Securities Risk.
Real Estate Securities Fund | Real Estate Investment Trusts ("REITs") Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Real Estate Investment Trusts (“REITs”) Risk. In addition to risks associated with investing in real estate securities, REITs are dependent upon management skills, are not diversified, and are subject to heavy cash flow dependency, risks of default by borrowers, and self-liquidation. Investment in REITs also involves risks similar to risks of investing in small market capitalization companies, such as limited financial resources, less frequent and limited volume trading, and may be subject to more abrupt or erratic price movements than larger company securities. A REIT could fail to qualify for tax-free pass-through of income under the Internal Revenue Code. Fund shareholders will indirectly bear their proportionate share of the expenses of REITs in which the fund invests.
Real Estate Securities Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Real Estate Securities Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Real Estate Securities Fund | Risk Nondiversified Status [Member]  
Prospectus [Line Items]  
Risk [Text Block]
Non-Diversification Risk. A non-diversified fund may invest a high percentage of its assets in the securities of a small number of issuers and is more likely than diversified funds to be significantly affected by a specific security’s poor performance.
Strategic Asset Management Balanced Portfolio | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Strategic Asset Management Balanced Portfolio | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Strategic Asset Management Balanced Portfolio | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Strategic Asset Management Balanced Portfolio | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Strategic Asset Management Balanced Portfolio | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Strategic Asset Management Balanced Portfolio | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Strategic Asset Management Balanced Portfolio | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Strategic Asset Management Balanced Portfolio | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Strategic Asset Management Balanced Portfolio | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Strategic Asset Management Balanced Portfolio | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Strategic Asset Management Balanced Portfolio | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Strategic Asset Management Balanced Portfolio | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Strategic Asset Management Balanced Portfolio | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Strategic Asset Management Conservative Balanced Portfolio | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Strategic Asset Management Conservative Balanced Portfolio | High Yield Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
High Yield Securities Risk. High yield fixed-income securities (commonly referred to as “junk bonds”) are subject to greater credit quality risk than higher rated fixed-income securities and should be considered speculative.
Strategic Asset Management Conservative Balanced Portfolio | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Strategic Asset Management Conservative Balanced Portfolio | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Strategic Asset Management Conservative Balanced Portfolio | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Strategic Asset Management Conservative Balanced Portfolio | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Strategic Asset Management Conservative Balanced Portfolio | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Strategic Asset Management Conservative Balanced Portfolio | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Strategic Asset Management Conservative Balanced Portfolio | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Strategic Asset Management Conservative Balanced Portfolio | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Strategic Asset Management Conservative Balanced Portfolio | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Strategic Asset Management Conservative Balanced Portfolio | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Strategic Asset Management Conservative Balanced Portfolio | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Strategic Asset Management Conservative Balanced Portfolio | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Strategic Asset Management Conservative Balanced Portfolio | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Strategic Asset Management Conservative Growth Portfolio | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Strategic Asset Management Conservative Growth Portfolio | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Strategic Asset Management Conservative Growth Portfolio | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Strategic Asset Management Conservative Growth Portfolio | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Strategic Asset Management Conservative Growth Portfolio | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Strategic Asset Management Conservative Growth Portfolio | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Strategic Asset Management Conservative Growth Portfolio | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Strategic Asset Management Conservative Growth Portfolio | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Strategic Asset Management Conservative Growth Portfolio | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Strategic Asset Management Conservative Growth Portfolio | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Strategic Asset Management Conservative Growth Portfolio | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Strategic Asset Management Conservative Growth Portfolio | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Strategic Asset Management Conservative Growth Portfolio | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Strategic Asset Management Flexible Income Portfolio | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Strategic Asset Management Flexible Income Portfolio | High Yield Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
High Yield Securities Risk. High yield fixed-income securities (commonly referred to as “junk bonds”) are subject to greater credit quality risk than higher rated fixed-income securities and should be considered speculative.
Strategic Asset Management Flexible Income Portfolio | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Strategic Asset Management Flexible Income Portfolio | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Strategic Asset Management Flexible Income Portfolio | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Strategic Asset Management Flexible Income Portfolio | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Strategic Asset Management Flexible Income Portfolio | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Strategic Asset Management Flexible Income Portfolio | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Strategic Asset Management Flexible Income Portfolio | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Strategic Asset Management Flexible Income Portfolio | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Strategic Asset Management Flexible Income Portfolio | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Strategic Asset Management Flexible Income Portfolio | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Strategic Asset Management Flexible Income Portfolio | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Strategic Asset Management Flexible Income Portfolio | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Strategic Asset Management Flexible Income Portfolio | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Strategic Asset Management Flexible Income Portfolio | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Strategic Asset Management Strategic Growth Portfolio | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Strategic Asset Management Strategic Growth Portfolio | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Strategic Asset Management Strategic Growth Portfolio | Emerging Markets Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Emerging Markets Risk. Investments in emerging markets may have more risk than those in developed markets because the emerging markets are less developed and more illiquid. Emerging markets can also be subject to increased social, economic, regulatory, and political uncertainties and can be extremely volatile. The U.S. Securities and Exchange Commission, the U.S. Department of Justice, and other U.S. authorities may be limited in their ability to pursue bad actors in emerging markets, including with respect to fraud.
Strategic Asset Management Strategic Growth Portfolio | Foreign Currency Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Currency Risk. Risks of investing in securities denominated in, or that trade in, foreign (non-U.S.) currencies include changes in foreign exchange rates and foreign exchange restrictions.
Strategic Asset Management Strategic Growth Portfolio | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Strategic Asset Management Strategic Growth Portfolio | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
Strategic Asset Management Strategic Growth Portfolio | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
Strategic Asset Management Strategic Growth Portfolio | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
Strategic Asset Management Strategic Growth Portfolio | Fund Of Funds Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Fund of Funds Risk. Fund shareholders bear indirectly their proportionate share of the expenses of other investment companies (for example, other mutual funds or exchange-traded funds) in which the Fund invests (“underlying funds”). The Fund’s selection and weighting of asset classes and allocation of investments in underlying funds may cause it to underperform other funds with a similar investment objective. The Fund’s performance and risks correspond directly to the performance and risks of the underlying funds in which it invests, proportionately in accordance with the weightings of such investments, and there is no assurance that the underlying funds will achieve their investment objectives. Management of the Fund entails potential conflicts of interest: the Fund invests in affiliated underlying funds; and PGI and its affiliates may earn different fees from different underlying funds and may have an incentive to allocate more Fund assets to underlying funds from which they receive higher fees.
Strategic Asset Management Strategic Growth Portfolio | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Strategic Asset Management Strategic Growth Portfolio | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Short-Term Income Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Short-Term Income Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Short-Term Income Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Short-Term Income Fund | Foreign Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Foreign Securities Risk. The risks of foreign securities include loss of value as a result of: political or economic instability; nationalization, expropriation, or confiscatory taxation; settlement delays; and limited government regulation (including less stringent reporting, accounting, and disclosure standards than are required of U.S. companies).
Short-Term Income Fund | Real Estate Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Real Estate Securities Risk. Investing in real estate securities subjects the fund to the risks associated with the real estate market (which are similar to the risks associated with direct ownership in real estate), including declines in real estate values, loss due to casualty or condemnation, property taxes, interest rate changes, increased expenses, cash flow of underlying real estate assets, regulatory changes (including zoning, land use, and rents), and environmental problems, as well as to the risks related to the management skill and creditworthiness of the issuer.
Short-Term Income Fund | Securitized Products Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Securitized Products Risk. Investments in securitized products are subject to risks similar to traditional fixed-income securities, such as credit, interest rate, liquidity, prepayment, extension, and default risk, as well as additional risks associated with the nature of the assets and the servicing of those assets. Unscheduled prepayments on securitized products may have to be reinvested at lower rates. A reduction in prepayments may increase the effective maturities of these securities, exposing them to the risk of decline in market value over time (extension risk).
Short-Term Income Fund | U.S. Government Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government Securities Risk. Yields available from U.S. government securities are generally lower than yields from many other fixed-income securities. The value of U.S. government securities may be adversely impacted by changes in interest rates, changes in the credit rating of the U.S. government, or a default by the U.S. government.
Short-Term Income Fund | U.S. Government-Sponsored Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
U.S. Government-Sponsored Securities Risk. Securities issued by U.S. government-sponsored enterprises such as the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association, and the Federal Home Loan Banks are not issued or guaranteed by the U.S. government.
Short-Term Income Fund | Derivatives Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Derivatives Risk. Derivatives may not move in the direction anticipated by the portfolio manager. Transactions in derivatives may increase volatility, cause the liquidation of portfolio positions when not advantageous to do so, and result in disproportionate losses that may be substantially greater than a fund’s initial investment.
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Short-Term Income Fund | Derivatives Risk, Futures Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Futures. Futures contracts involve specific risks, including: the imperfect correlation between the change in market value of the instruments held by the Fund and the price of the futures contract; possible lack of a liquid secondary market for a futures contract and the resulting inability to close a futures contract when desired; counterparty risk; and if the Fund has insufficient cash, it may have to sell securities from its portfolio to meet daily variation margin requirements.
Short-Term Income Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Short-Term Income Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
SmallCap Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
SmallCap Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
SmallCap Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
SmallCap Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
SmallCap Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
SmallCap Growth Fund I | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
SmallCap Growth Fund I | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
SmallCap Growth Fund I | Equity Securities Risk, Growth Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Growth Style Risk. Growth investing entails the risk that if growth companies do not increase their earnings at a rate expected by investors, the market price of their stock may decline significantly, even if earnings show an absolute increase. Growth company stocks also typically lack the dividend yield that can lessen price declines in market downturns.
SmallCap Growth Fund I | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
SmallCap Growth Fund I | Passive Strategy Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Passive Strategy Risk. A portion of the Fund seeks to match the performance of a specified index. However, the correlation between the performance of this portion of the Fund and index performance may be affected by many factors, such as Fund expenses, the timing of cash flows into and out of the Fund, changes in securities markets, and changes in the composition of the index.
SmallCap Growth Fund I | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
SmallCap Growth Fund I | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
SmallCap S&P 600 Index Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
SmallCap S&P 600 Index Fund | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
SmallCap S&P 600 Index Fund | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
SmallCap S&P 600 Index Fund | Industry Concentration Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Industry Concentration Risk. A fund that concentrates investments in a particular industry or group of industries has greater exposure than other funds to market, economic, and other factors affecting that industry or group of industries.
SmallCap S&P 600 Index Fund | Index Fund Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Index Fund Risk. Index funds use a passive investment approach and generally do not attempt to manage market volatility, use defensive strategies, or reduce the effect of any long-term periods of poor investment performance. Therefore, the Fund may hold securities that present risks that an investment advisor researching individual securities might seek to avoid. An index fund has operating and other expenses while an index does not. As a result, over time, index funds tend to underperform the index. The correlation between fund performance and index performance may also be affected by the type of passive investment approach used by a fund (sampling or replication), changes in securities markets, changes in the composition of the index, and the timing of purchases and sales of fund shares. Errors or delays in compiling or rebalancing the Index may impact the performance of the Fund and increase transaction costs.
SmallCap S&P 600 Index Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
SmallCap S&P 600 Index Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
SmallCap Value Fund II | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
SmallCap Value Fund II | Real Estate Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
SmallCap Value Fund II | Equity Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Equity Securities Risk. A variety of factors can negatively impact the value of equity securities held by a fund, including a decline in the issuer’s financial condition, unfavorable performance of the issuer’s sector or industry, or changes in response to overall market and economic conditions. A fund’s principal market segment(s) (such as market capitalization or style) may underperform other market segments or the equity markets as a whole.
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
SmallCap Value Fund II | Equity Securities Risk, Smaller Companies Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Smaller Companies Risk. Investments in smaller companies may involve greater risk and price volatility than investments in larger, more mature companies. Smaller companies may have limited product lines, markets, or financial resources; lack the competitive strength of larger companies; have less experienced managers; or depend on a few key employees. Their securities often are less widely held and trade less frequently and in lesser quantities, and their market prices often fluctuate more, than securities of larger companies.
SmallCap Value Fund II | Equity Securities Risk, Value Style Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
•Value Style Risk. Value investing entails the risk that value stocks may continue to be undervalued by the market for extended periods, including the entire period during which the stock is held by a fund, or the events that would cause the stock price to increase may not occur as anticipated or at all. Moreover, a stock that appears to be undervalued actually may be appropriately priced at a low level and, therefore, would not be profitable for the fund.
SmallCap Value Fund II | Passive Strategy Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Passive Strategy Risk. A portion of the Fund seeks to match the performance of a specified index. However, the correlation between the performance of this portion of the Fund and index performance may be affected by many factors, such as Fund expenses, the timing of cash flows into and out of the Fund, changes in securities markets, and changes in the composition of the index.
SmallCap Value Fund II | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
SmallCap Value Fund II | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.
Tax-Exempt Bond Fund | Counterparty Risk Member  
Prospectus [Line Items]  
Risk [Text Block] Counterparty Risk. Counterparty risk is the risk that the counterparty to a contract or other obligation will be unable or unwilling to honor its obligations.
Tax-Exempt Bond Fund | Fixed-Income Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate, credit quality, and liquidity risks. The market value of fixed-income securities generally declines when interest rates rise, and increased interest rates may adversely affect the liquidity of certain fixed-income securities. Moreover, an issuer of fixed-income securities could default on its payment obligations due to increased interest rates or for other reasons.
Tax-Exempt Bond Fund | Geographic Concentration Risk1 Member  
Prospectus [Line Items]  
Risk [Text Block]
Geographic Concentration Risk. A fund that invests significant portions of its assets in municipal obligations and bonds in particular geographic areas (a particular state, such as California, or a particular country or region) has greater exposure than other funds to economic conditions and developments in those areas.
Tax-Exempt Bond Fund | High Yield Securities Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
High Yield Securities Risk. High yield fixed-income securities (commonly referred to as “junk bonds”) are subject to greater credit quality risk than higher rated fixed-income securities and should be considered speculative.
Tax-Exempt Bond Fund | Industrial Revenue Bond Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Industrial Revenue Bond Risk. The Fund will be sensitive to, and its performance will depend to a greater extent on, the overall condition and performance of industrial revenue bonds. These revenue bonds are issued by or on behalf of public authorities to obtain funds to finance various public and/or privately operated facilities, including those for business and manufacturing, housing, sports, pollution control, airport, mass transit, port, and parking facilities. These bonds are normally secured only by the revenues from the project and not by state or local government tax payments. Consequently, the credit quality of these bonds is dependent upon the ability of the user of the facilities financed by the bonds and any guarantor to meet its financial obligations.
Tax-Exempt Bond Fund | Inverse Floating Rate Investments Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Inverse Floating Rate Investments Risk. Inverse floating rate investments are extremely sensitive to changes in interest rates and, in some cases, their market value may be extremely volatile.
Tax-Exempt Bond Fund | Leverage Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Leverage Risk. Leverage created by borrowing or certain types of transactions or investments may impair the Fund’s liquidity, cause it to liquidate positions at an unfavorable time, increase volatility of the Fund’s net asset value, or diminish the Fund’s performance.
Tax-Exempt Bond Fund | Municipal Obligations Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Municipal Obligations Risk. Principal and interest payments on municipal securities may not be guaranteed by the issuing body and may be payable only from a particular source. That source may not perform as expected, and payment obligations may not be made or made on time.
Tax-Exempt Bond Fund | Portfolio Duration Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Portfolio Duration Risk. Portfolio duration is a measure of the expected life of a fixed-income security and its sensitivity to changes in interest rates. The longer a fund’s average portfolio duration, the more sensitive the fund will be to changes in interest rates, which means funds with longer average portfolio durations may be more volatile than those with shorter durations.
Tax-Exempt Bond Fund | Redemption And Large Transaction Risk Member  
Prospectus [Line Items]  
Risk [Text Block]
Redemption and Large Transaction Risk. Ownership of the Fund’s shares may be concentrated in one or a few large investors (such as funds of funds, institutional investors, and asset allocation programs) that may redeem or purchase shares in large quantities. These transactions may cause the Fund to sell securities to meet redemptions or to invest additional cash at times it would not otherwise do so, which may result in increased transaction costs, increased expenses, changes to expense ratios, and adverse effects to Fund performance. Such transactions may also accelerate the realization of taxable income if sales of portfolio securities result in gains. Moreover, reallocations by large shareholders among share classes of a fund may result in changes to the expense ratios of affected classes, which may increase the expenses paid by shareholders of the class that experienced the redemption.
Tax-Exempt Bond Fund | Risk Lose Money [Member]  
Prospectus [Line Items]  
Risk [Text Block] Many factors affect that value, and it is possible to lose money by investing in the Fund.
Tax-Exempt Bond Fund | Risk Not Insured Depository Institution [Member]  
Prospectus [Line Items]  
Risk [Text Block] An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.