The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. This is a new Fund and does not yet have a portfolio turnover rate to disclose.

Other Expenses, New Fund, Based on Estimates [Text]

rr_OtherExpensesNewFundBasedOnEstimates

Based on estimated amounts for the current fiscal year.

Expense Example [Heading]

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Example

Expense Example Narrative [Text Block]

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This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

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Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

Under normal circumstances, the Fund invests at least 80% of its net assets, plus any borrowings for investment purposes, in equity securities of companies with medium market capitalizations at the time of each purchase. For this Fund, companies with medium market capitalizations are those with market capitalizations within the range of companies comprising the Russell Midcap® Index (as of December 31, 2014, this range was between approximately $275.0 million and $33.5 billion). The Fund invests in real estate investment trust securities. The Fund invests in foreign securities.

The Fund invests in equity securities with value and/or growth characteristics and constructs an investment portfolio that has a "blend" of equity securities with these characteristics. Investing in value equity securities is an investment strategy that emphasizes buying equity securities that appear to be undervalued. The growth orientation selection emphasizes buying equity securities of companies whose potential for growth of capital and earnings is expected to be above average. The Fund does not have a policy of preferring one of these categories over the other.

Risk [Heading]

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Principal Risks

Risk Narrative [Text Block]

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The value of your investment in the Fund changes with the value of the Fund's investments. Many factors affect that value, and it is possible to lose money by investing in the Fund. 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. The principal risks of investing in the Fund, in alphabetical order, are:

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.

Equity Securities Risk. The value of equity securities could decline if the issuer’s financial condition declines or in response to overall market and economic conditions. A fund's principal market segment(s), such as large cap, mid cap or small cap stocks, or growth or value stocks, may underperform other market segments or the equity markets as a whole. Investments in smaller companies and mid-size companies may involve greater risk and price volatility than investments in larger, more mature companies.

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).

Growth Stock Risk. If growth companies do not increase their earnings at a rate expected by investors, the market price of the 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 Investment Trusts (“REITs”) Risk. A REIT could fail to qualify for tax-free pass-through of income under the Internal Revenue Code, and fund shareholders will indirectly bear their proportionate share of the expenses of REITs in which the fund invests.

Real Estate Securities Risk. Real estate securities are subject to the risks associated with direct ownership of real estate, including declines in value, adverse economic conditions, increases in expenses, regulatory changes and environmental problems. Investing in securities of companies in the real estate industry, subjects a fund to the special risks associated with the real estate market including factors such as loss to casualty or condemnation, changes in real estate values, property taxes, interest rates, cash flow of underlying real estate assets, occupancy rates, government regulations affecting zoning, land use and rents, and the management skill and creditworthiness of the issuer.

Risk of Being an Underlying Fund. A fund is subject to the risk of being an underlying fund to the extent that a fund of funds invests in the fund. An underlying fund of a fund of funds may experience relatively large redemptions or investments as the fund of funds periodically reallocates or rebalances its assets. These transactions may cause the underlying fund to sell portfolio securities to meet such redemptions, or to invest cash from such investments, at times it would not otherwise do so, and may as a result increase transaction costs and adversely affect underlying fund performance.

Value Stock Risk. The market may not recognize the intrinsic value of value stocks for a long time, or they may be appropriately priced at the time of purchase.

Risk Lose Money [Text]

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Many factors affect that value, and it is possible to lose money by investing in the Fund.

Risk Not Insured Depository Institution [Text]

rr_RiskNotInsuredDepositoryInstitution

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.

Bar Chart and Performance Table [Heading]

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Performance

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

No performance information is shown because the Fund has not yet had a calendar year of performance. The Fund's performance is benchmarked against the Russell Midcap® Index. Performance information provides an indication of the risks of investing in the Fund. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. You may get updated performance information by calling 1-800-222-5852 or online at:


•	For Institutional Class - www.principal.com.

Performance One Year or Less [Text]

rr_PerformanceOneYearOrLess

No performance information is shown because the Fund has not yet had a calendar year of performance.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

1-800-222-5852

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.principal.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

EDGE MidCap Fund | Institutional Class

Prospectus:

rr_ProspectusTable

Trading Symbol

dei_TradingSymbol

PEDGX

Shareholder Fee, Other

rr_ShareholderFeeOther

none

Management Fees (as a percentage of Assets)

rr_ManagementFeesOverAssets

0.75%

Other Expenses (as a percentage of Assets):

^[1]

rr_OtherExpensesOverAssets

0.05%

Expenses (as a percentage of Assets)

rr_ExpensesOverAssets

0.80%

Fee Waiver or Reimbursement

^[2]

rr_FeeWaiverOrReimbursementOverAssets

none

Net Expenses (as a percentage of Assets)

rr_NetExpensesOverAssets

0.80%

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

December 30, 2016

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 82

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

$ 255

Real Estate Debt Income Fund

Prospectus:

rr_ProspectusTable

Risk/Return [Heading]

rr_RiskReturnHeading

REAL ESTATE DEBT INCOME FUND

Objective [Heading]

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Objective:

Objective, Primary [Text Block]

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The Fund seeks to provide current income.

Expense [Heading]

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Fees and Expenses of the Fund

Expense Narrative [Text Block]

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This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees Caption [Text]

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Shareholder Fees (fees paid directly from your investment):

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Heading]

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Portfolio Turnover

Portfolio Turnover [Text Block]

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Other Expenses, New Fund, Based on Estimates [Text]

rr_OtherExpensesNewFundBasedOnEstimates

Based on estimated amounts for the current fiscal year.

Expense Example [Heading]

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Example

Expense Example Narrative [Text Block]

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This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.

Expense Example by, Year, Caption [Text]

rr_ExpenseExampleByYearCaption

The Example assumes that you invest $10,000 in the Fund for the time periods indicated. The Example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

Under normal circumstances, the Fund invests at least 80% of its net assets, plus any borrowings for investment purposes, in debt securities of U.S. companies principally engaged in the real estate industry at the time of purchase. A real estate company has at least 50% of its assets, income or profits derived from products or services related to the real estate industry. Real estate companies include real estate investment trusts ("REITs") and companies with substantial real estate holdings such as paper, lumber, hotel and entertainment companies as well as those whose products and services relate to the real estate industry include building supply manufacturers, mortgage lenders and mortgage servicing companies. The Fund will invest in commercial mortgage-backed securities (“CMBS”), which are bonds that are secured by first mortgages on commercial real estate. The Fund will also invest in debt and preferreds issued by REITs. REITs are pooled investment vehicles that invest in income producing real estate, real estate related loans, or other types of real estate interests. REITs are corporations or business trusts that are permitted to eliminate corporate level federal income taxes by meeting certain requirements of the Internal Revenue Code.

The Fund concentrates its investments (invest more than 25% of its net assets) in securities in the real estate industry.

The Fund is considered non-diversified, which means it can invest a higher percentage of assets in securities of individual issuers than a diversified fund. As a result, changes in the value of a single investment could cause greater fluctuations in the Fund's share price than would occur in a more diversified fund.

Strategy Portfolio Concentration [Text]

rr_StrategyPortfolioConcentration

The Fund concentrates its investments (invest more than 25% of its net assets) in securities in the real estate industry.

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

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Fixed-Income Securities Risk. Fixed-income securities are subject to interest rate risk and credit quality risk. The market value of fixed-income securities generally declines when interest rates rise, and an issuer of fixed-income securities could default on its payment obligations.

Industry Concentration Risk (Real Estate). 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. A fund concentrating in the real estate industry can be 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.

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.

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.

Preferred Securities Risk. Preferred securities are securities with a lower priority claim on assets or earnings than bonds and other debt instruments in a company's capital structure, and therefore can be 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 the stated maturity date.

Prepayment Risk. Unscheduled prepayments on mortgage-backed and asset-backed securities 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).

Risk Lose Money [Text]

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Many factors affect that value, and it is possible to lose money by investing in the Fund.

Risk Nondiversified Status [Text]

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Risk Not Insured Depository Institution [Text]

rr_RiskNotInsuredDepositoryInstitution

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.

Bar Chart and Performance Table [Heading]

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Performance

Performance Narrative [Text Block]

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No performance information is shown below because the Fund has not yet had a calendar year of performance. The Fund's performance is benchmarked against the Barclays CMBS ERISA-Eligible Index. Performance information provides an indication of the risks of investing in the Fund. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. You may get updated performance information by calling 1-800-222-5852 or online at:


•	For Class P - www.principalfunds.com

Performance One Year or Less [Text]

rr_PerformanceOneYearOrLess

No performance information is shown below because the Fund has not yet had a calendar year of performance.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

1-800-222-5852

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

www.principalfunds.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

Real Estate Debt Income Fund | Class P

Prospectus:

rr_ProspectusTable

Trading Symbol

dei_TradingSymbol

PDIFX

Shareholder Fee, Other

rr_ShareholderFeeOther

none

Management Fees (as a percentage of Assets)

rr_ManagementFeesOverAssets

0.55%

Other Expenses (as a percentage of Assets):

^[3]

rr_OtherExpensesOverAssets

0.34%

Expenses (as a percentage of Assets)

rr_ExpensesOverAssets

0.89%

Fee Waiver or Reimbursement

^[4]

rr_FeeWaiverOrReimbursementOverAssets

(0.14%)

Net Expenses (as a percentage of Assets)

rr_NetExpensesOverAssets

0.75%

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

December 30, 2016

Expense Example, with Redemption, 1 Year

rr_ExpenseExampleYear01

$ 77

Expense Example, with Redemption, 3 Years

rr_ExpenseExampleYear03

$ 263

[1]	Based on estimated amounts for the current fiscal year.
[2]	Principal Management Corporation ("Principal"), the investment advisor, has contractually agreed to limit the Fund’s expenses by paying, if necessary, expenses normally payable by the Fund, (excluding interest expense, expenses related to fund investments, acquired fund fees and expenses, and other extraordinary expenses) to maintain a total level of operating expenses (expressed as a percent of average net assets on an annualized basis) not to exceed 0.90% for Institutional shares. It is expected that the expense limit will continue through the period ending December 30, 2016; however, Principal Funds, Inc. and Principal, the parties to the agreement, may mutually agree to terminate the expense limit prior to the end of the period.
[3]	Based on estimated amounts for the current fiscal year.
[4]	Principal Management Corporation ("Principal"), the investment advisor, has contractually agreed to limit the Fund’s expenses by paying, if necessary, expenses normally payable by the Fund, (excluding interest expense, expenses related to fund investments, acquired fund fees and expenses, and other extraordinary expenses) to maintain "Other Expenses" (expressed as a percent of average net assets on an annualized basis) not to exceed 0.20% for Class P shares. It is expected that the expense limit will continue through the period ending December 30, 2016; however, Principal Funds, Inc. and Principal, the parties to the agreement, may mutually agree to terminate the expense limit prior to the end of the period.