Label

Element

Value

Risk/Return:

rr_RiskReturnAbstract

Registrant Name

dei_EntityRegistrantName

PENN SERIES FUNDS INC

Prospectus Date

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May 01, 2015

Penn Series International Equity Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

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FUND SUMMARY:  INTERNATIONAL EQUITY FUND

Objective [Heading]

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Investment Objective

Objective, Primary [Text Block]

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The investment objective of the International Equity Fund (the “Fund”) is to achieve capital appreciation.

Expense [Heading]

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Fund Fees and Expenses

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. Additional fees and expenses will be applied at the variable contract level. Those fees and expenses are described in your variable contract prospectus. If the information below were to reflect the deduction of variable contract charges, fees and expenses would be higher.

Operating Expenses Caption [Text]

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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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The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover may indicate higher transaction costs. These costs, which are not reflected in the annual fund operating expenses or in the Example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 31% of the average value of its portfolio.

Portfolio Turnover, Rate

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31.00%

Expenses Restated to Reflect Current [Text]

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The expense information in the table has been restated to reflect an increase in the Fund’s Investment Advisory Fee approved by Fund shareholders on February 13, 2014 and effective May 1, 2014.

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. 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 and returns might be higher or lower, based on these assumptions your costs would be:

Strategy [Heading]

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Principal Investment Strategy

Strategy Narrative [Text Block]

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Under normal circumstances, the Fund invests at least 80% of its net assets, plus the amount of any borrowings for investment purposes, in equity securities, such as common stocks, preferred stocks, convertible bonds, and warrants. The Fund will invest primarily in companies operating in the countries in Europe and the Pacific Basin. The countries include the eleven Euro-zone countries (France, Germany, Italy, Spain, Portugal, Finland, Ireland, Belgium, the Netherlands, Luxembourg and Austria), the United Kingdom, Denmark, Sweden, Switzerland, Norway, Japan, Hong Kong, Australia, New Zealand and Singapore. The Sub-Adviser employs bottom-up stock and business analysis to identify high-quality growth companies. Typically, these companies tend to be well managed with the following attributes: consistent operating histories and financial performance; favorable long-term economic prospects; free cash flow generation; and competent management that can be counted on to use cash flow wisely, and channel the reward from the business back to its shareholders. The Sub-Adviser's goal is to construct a portfolio of high-quality growth companies in the developed markets of Europe and the Pacific Basin. With approximately 40-70 stocks, the Fund seeks to be well diversified and will have investments in at least 10 countries and 5 sectors at all times. The Fund may invest in securities of companies in emerging and developing markets. The Fund may, but is not required to, undertake hedging activities and may invest in certain instruments, such as forward currency exchange contracts, and may use certain techniques to hedge currency risks associated with the purchase of individual securities denominated in a foreign currency.

Risk [Heading]

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Principal Risks of Investing

Risk Narrative [Text Block]

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Convertible Securities Risk.  The possibility that the value of the Fund’s investments in convertible securities may be adversely affected by changes in interest rates, the credit of the issuer and the value of the underlying common stock. The market values of convertible securities tend to decline as interest rates increase and, conversely, to increase as interest rates decline. In addition, as the market price of the underlying common stock declines below the conversion price, the price of the convertible security tends to be increasingly influenced by the yield of the convertible security.

Currency Risk.  The possibility that the value of the Fund’s assets may be affected favorably or unfavorably by currency exchange rates, currency exchange control regulations, and restrictions or prohibitions on the repatriation of foreign currencies.

Derivatives Risk.  The possibility that the Fund’s use of derivatives, such as futures, options and swap agreements, may lead to losses, including those magnified by leverage, particularly when derivatives are used to enhance return rather than mitigate risk. Certain derivative instruments may be difficult to sell when the Sub-Adviser believes it would be appropriate to do so, difficult to value if the instrument becomes illiquid, or the other party to a derivative contract may be unwilling or unable to fulfill its contractual obligations.

Emerging Markets Risk.  The possibility that the stocks of companies located in emerging markets may be more volatile, and less liquid, than the stocks of companies located in the U.S. and developed foreign markets due to political, economic, or regulatory conditions within emerging market countries. In addition, emerging market countries may experience more volatile interest and currency exchange rates, higher levels of inflation and less efficient trading and settlement systems.

Foreign Investment Risk.  The possibility that the Fund’s investments in foreign securities may be adversely affected by political, social, and economic conditions affecting foreign issuers, greater volatility, reduced liquidity, or decreases in foreign currency values relative to the U.S. dollar.

Investment Style Risk.  The possibility that the Fund could underperform if the Fund’s investment style shifts out of favor based on changing market sentiment and conditions.

Liquidity Risk.  The possibility that the market for certain of the Fund’s investments may become illiquid under adverse or volatile market or economic conditions, making those investments difficult to sell at an advantageous price. The market price of certain investments may fall dramatically if there is no liquid trading market for the investments. It also may be difficult for the Fund to purchase a desired investment at an advantageous price under such circumstances.

Market Risk.  The possibility that the values of, and/or the income generated by, securities held by the Fund may decline, sometimes unpredictably, due to general market conditions or other factors, including those directly involving the issuers of such securities. Security markets are volatile and may decline significantly in response to adverse issuer, regulatory, political, or economic developments. Different sectors of the market and different security types may react differently to such developments.

Preferred Stock Risk.  The possibility that the value of the Fund’s investments in preferred stock may decline if stock prices fall or interest rates rise. In the event of a liquidation, the rights of a company’s preferred stock to the distribution of company assets are generally subordinate to the rights of a company’s debt securities.

Warrants Risk.  The possibility that the Fund’s investments in warrants are subject to greater price volatility than the warrants’ underlying securities. Warrants offer greater potential for profit or loss than an equivalent investment in the underlying security. A warrant generally ceases to have value if it is not exercised prior to its expiration date.

An investment in the Fund may be appropriate for investors who are willing to accept the risks and uncertainties of international investing in the hope of realizing capital appreciation while diversifying their investment portfolio.

Bar Chart and Performance Table [Heading]

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Performance Information

Performance Narrative [Text Block]

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The bar chart and table below show the performance of the Fund both year-by-year and as an average over different periods of time. The bar chart and table demonstrate the variability of performance over time and provide an indication of the risks and volatility of an investment in the Fund by showing how the Fund’s average annual total returns for various periods compare with those of a broad-based securities market index and one additional index, the MSCI ACWI (All Country World Index) ex-U.S. Index. The foregoing indices, when considered together, may provide investors with a useful comparison of the Fund’s overall performance. Past performance does not necessarily indicate how the Fund will perform in the future. This performance information does not include the impact of any charges deducted under your variable contract. If it did, returns would be lower.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The bar chart and table below show the performance of the Fund both year-by-year and as an average over different periods of time. The bar chart and table demonstrate the variability of performance over time and provide an indication of the risks and volatility of an investment in the Fund by showing how the Fund’s average annual total returns for various periods compare with those of a broad-based securities market index and one additional index, the MSCI ACWI (All Country World Index) ex-U.S. Index.

Performance Additional Market Index [Text]

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The bar chart and table demonstrate the variability of performance over time and provide an indication of the risks and volatility of an investment in the Fund by showing how the Fund’s average annual total returns for various periods compare with those of a broad-based securities market index and one additional index, the MSCI ACWI (All Country World Index) ex-U.S. Index. The foregoing indices, when considered together, may provide investors with a useful comparison of the Fund’s overall performance.

Performance Past Does Not Indicate Future [Text]

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Past performance does not necessarily indicate how the Fund will perform in the future.

Bar Chart Does Not Reflect Sales Loads [Text]

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This performance information does not include the impact of any charges deducted under your variable contract. If it did, returns would be lower.

Bar Chart Closing [Text Block]

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Best Quarter	Worst Quarter
18.48%	-19.10%
6/30/2009	9/30/2008

Performance Table Heading

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Average Annual Total Return (for Periods Ended December 31, 2014)

Penn Series International Equity Fund | International Equity Fund

Risk/Return:

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Investment Advisory Fees

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0.85%

^[1]

Distribution (12b-1) Fees

rr_DistributionAndService12b1FeesOverAssets

none

Other Expenses

rr_OtherExpensesOverAssets

0.30%

Total Annual Fund Operating Expenses

rr_ExpensesOverAssets

1.15%

^[1]

1 Year

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117

3 Years

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365

5 Years

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633

10 Years

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1,398

2005

rr_AnnualReturn2005

16.77%

2006

rr_AnnualReturn2006

30.34%

2007

rr_AnnualReturn2007

20.05%

2008

rr_AnnualReturn2008

(41.28%)

2009

rr_AnnualReturn2009

21.74%

2010

rr_AnnualReturn2010

11.08%

2011

rr_AnnualReturn2011

0.91%

2012

rr_AnnualReturn2012

21.06%

2013

rr_AnnualReturn2013

5.97%

2014

rr_AnnualReturn2014

2.95%

Highest Quarterly Return, Label

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Best Quarter

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2009

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

18.48%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst Quarter

Lowest Quarterly Return, Date

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Sep. 30, 2008

Lowest Quarterly Return

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(19.10%)

1 Year

rr_AverageAnnualReturnYear01

2.95%

5 Years

rr_AverageAnnualReturnYear05

8.16%

10 Years

rr_AverageAnnualReturnYear10

6.82%

Penn Series International Equity Fund | MSCI EAFE Index (reflects no deduction for expenses and taxes and is gross of withholding taxes on foreign dividends)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(4.48%)

5 Years

rr_AverageAnnualReturnYear05

5.81%

10 Years

rr_AverageAnnualReturnYear10

4.91%

Penn Series International Equity Fund | MSCI ACWI ex-U.S. Index (reflects no deduction for expenses and taxes and is gross of withholding taxes on foreign dividends)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(3.44%)

5 Years

rr_AverageAnnualReturnYear05

4.89%

10 Years

rr_AverageAnnualReturnYear10

5.59%

[1] The expense information in the table has been restated to reflect an increase in the Fund's Investment Advisory Fee approved by Fund shareholders on February 13, 2014 and effective May 1, 2014.