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.

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]

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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]

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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]

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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 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]

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

Performance Availability Phone [Text]

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1-800-222-5852

Performance Availability Website Address [Text]

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www.principal.com

Performance Past Does Not Indicate Future [Text]

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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:

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Trading Symbol

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PEDGX

Shareholder Fee, Other

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none

Management Fees (as a percentage of Assets)

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0.75%

Other Expenses (as a percentage of Assets):

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0.05%

^[1]

Expenses (as a percentage of Assets)

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0.80%

Fee Waiver or Reimbursement

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none

^[2]

Net Expenses (as a percentage of Assets)

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0.80%

Fee Waiver or Reimbursement over Assets, Date of Termination

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December 30, 2016

Expense Example, with Redemption, 1 Year

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$ 82

Expense Example, with Redemption, 3 Years

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$ 255

[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.