Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
ProspectusDate	rr_ProspectusDate	Aug. 01, 2011
NASDAQ-100 Fund (First Prospectus Summary) | NASDAQ-100 Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return, Heading	rr_RiskReturnHeading	NASDAQ-100® FUND
Investment Objective, Heading	rr_ObjectiveHeading	INVESTMENT OBJECTIVE -
investment Objective, Primary	rr_ObjectivePrimaryTextBlock	The NASDAQ-100® Fund (the "Fund") seeks to provide investment results that correspond, before fees and expenses, to a benchmark for over-the-counter securities on a daily basis. The Fund's current benchmark is the NASDAQ-100 Index® (the "underlying index").
Expense, Heading	rr_ExpenseHeading	FEES AND EXPENSES OF THE FUND -
Expense, Narrative	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold Advisor Class Shares or Investor Class Shares of the Fund.
Shareholder Fees, Caption	rr_ShareholderFeesCaption	SHAREHOLDER FEES (fees paid directly from your investment) N/A
Operating Expenses, Caption	rr_OperatingExpensesCaption	ANNUAL FUND OPERATING EXPENSES (expenses that you pay each year as a percentage of the value of your investment)
Portfolio Turnover, Heading	rr_PortfolioTurnoverHeading	PORTFOLIO TURNOVER -
Portfolio Turnover	rr_PortfolioTurnoverTextBlock	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 highe taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Total 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 39% of the average value of its portfolio. However, the Fund's portfolio turnover rate is calculated without regard to cash instruments or derivatives. If such instruments were included, the Fund's portfolio turnover rate might be significantly higher.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	39.00%
Expense Example, Heading	rr_ExpenseExampleHeading	EXAMPLE -
Expense Example, Narrative	rr_ExpenseExampleNarrativeTextBlock	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 may be higher or lower, based on these assumptions your costs would be:
Investment Strategy, Heading	rr_StrategyHeading	PRINCIPAL INVESTMENT STRATEGIES -
Investment Strategy, Narrative	rr_StrategyNarrativeTextBlock	The Fund employs as its investment strategy a program of investing in the common stock of companies that are generally within the capitalization range of the underlying index and derivative instruments, which primarily consist of equity index swaps, futures contracts, and options on securities, futures contracts, and stock indices. Equity index swaps and futures and options contracts enable the Fund to pursue its objective without investing directly in the securities included in the underlying index or in the same proportion that those securities are represented in the underlying index. Under normal circumstances, the Fund will invest at least 80% of its net assets, plus any borrowings for investment purposes, in securities of companies in the underlying index and derivatives and other instruments whose performance is expected to correspond to that of the underlying index. The NASDAQ-100 Index® is a modified capitalization-weighted index composed of 100 of the largest non-financial companies listed on The Nasdaq Stock Market with capitalizations ranging from $4.46 billion to $317.24 billion as of June 30, 2011. Certain of the Fund's derivative investments may be traded in the over-the-counter ("OTC") market. On a day-to-day basis, the Fund may hold U.S. government securities or cash equivalents to collateralize its derivative positions. The Fund also may invest in American Depositary Receipts ("ADRs") to gain exposure to international companies included in the underlying index. In an effort to ensure that the Fund is fully invested on a day-to-day basis, the Fund may conduct any necessary trading activity at or just prior to the close of the U.S. financial markets. To the extent the Fund's underlying index is concentrated in a particular industry the Fund will necessarily be concentrated in that industry. Currently, the NASDAQ-100 Index® is concentrated in technology companies. The Fund is non-diversified and, therefore, may invest a greater percentage of its assets in a particular issuer in comparison to a diversified fund.
Risk, Heading	rr_RiskHeading	PRINCIPAL RISKS -
Risk, Narrative	rr_RiskNarrativeTextBlock	As with all mutual funds, a shareholder is subject to the risk that his or her investment could lose money. In addition to this risk, the Fund is subject to a number of additional risks that may affect the value of its shares, including: Active Trading Risk - Active trading, also called "high portfolio turnover," may result in higher brokerage costs or mark-up charges, which may negatively affect Fund performance and result in short-term capital gains, which have a negative tax effect. Large movements of assets into and out of the Fund due to active trading also may adversely affect the Fund's ability to achieve its investment objective. Counterparty Credit Risk - The Fund may make investments in financial instruments involving counterparties that attempt to gain exposure to a particular group of securities, index or asset class without actually purchasing those securities or investments, or to hedge a position. The Fund's use of such financial instruments, including swap agreements, involves risks that are different from those associated with ordinary portfolio securities transactions. For example, if a swap agreement counterparty defaults on its payment obligations to the Fund, this default will cause the value of your investment in the Fund to decrease. Swap agreements also may be considered to be illiquid. Depositary Receipt Risk - The Fund may hold the securities of non-U.S. companies in the form of ADRs. The underlying securities of the ADRs in the Fund's portfolio are subject to fluctuations in foreign currency exchange rates that may affect the value of the Fund's portfolio. In addition, the value of the securities underlying the ADRs may change materially when the U.S. markets are not open for trading. Investments in the underlying foreign securities also involve political and economic risks distinct from those associated with investing in the securities of U.S. issuers. Derivatives Risk - The Fund's investments in derivatives may pose risks in addition to those associated with investing directly in securities or other investments, including illiquidity of the derivatives, imperfect correlations with underlying investments or the Fund's other portfolio holdings, lack of availability and counterparty risk. Early Closing Risk - The Fund is subject to the risk that unanticipated early closings of securities exchanges and other financial markets may result in the Fund's inability to buy or sell securities or other financial instruments on that day and may cause the Fund to incur substantial trading losses. Foreign Issuer Exposure Risk - The Fund may invest in securities of foreign companies directly, or in financial instruments, such as ADRs, that are indirectly linked to the performance of foreign issuers. Foreign securities markets generally have less trading volume and less liquidity than U.S. markets, and prices in some foreign markets may fluctuate more than those of securities traded on U.S. markets. Industry and Technology Sector Concentration Risk - The risk of concentrating Fund investments in a limited number of issuers conducting business in the same industry or group of industries is that the Fund will be more susceptible to the risks associated with that industry or group of industries than a fund that does not concentrate its investments. To the extent that the Fund's investments are concentrated in issuers conducting business in the technology sector, the Fund is subject to the risk that the securities of such issuers will underperform the market as a whole due to legislative or regulatory changes, adverse market conditions and/or increased competition affecting that economic sector. The prices of the securities of technology companies also may fluctuate widely in response to such events. Large-Capitalization Securities Risk - The Fund is subject to the risk that large-capitalization stocks may underperform other segments of the equity market or the equity market as a whole. Market Risk - The Fund's investments in securities and derivatives, in general, are subject to market risks that may cause their prices, and therefore the Fund's value, to fluctuate over time. An investment in the Fund may lose money. Non-Diversification Risk - The Fund is considered non-diversified and can invest a greater portion of its assets in securities of individual issuers than a diversified fund. As a result, changes in the market value of a single security could cause greater fluctuations in the value of Fund shares than would occur in a diversified fund. OTC Trading Risk - Certain of the derivatives in which the Fund may invest may be traded (and privately negotiated) in the OTC market. While the OTC derivatives market is the primary trading venue for many derivatives, it is largely unregulated. As a result and similar to other privately negotiated contracts, the Fund is subject to counterparty credit risk with respect to such derivative contracts. Passive Investment Risk - The Fund is not actively managed and the Advisor does not attempt to take defensive positions in declining markets. Therefore, the Fund may be subject to greater losses in a declining market than a fund that is actively managed. Tracking Error Risk - The Advisor may not be able to cause the Fund's performance to correspond to that of the Fund's benchmark, either on a daily or aggregate basis. Factors such as Fund expenses, imperfect correlation between the Fund's investments and those of the underlying index, rounding of share prices, changes to the composition of the underlying index, regulatory policies, and high portfolio turnover rate all contribute to tracking error. Tracking error may cause the Fund's performance to be less than you expect. Trading Halt Risk - If a trading halt occurs, the Fund may temporarily be unable to purchase or sell securities, options or futures contracts. Such a trading halt near the time the Fund prices its shares may limit the Fund's ability to use leverage and may prevent the Fund from achieving its investment objective.
Risk, Lose Money	rr_RiskLoseMoney	As with all mutual funds, a shareholder is subject to the risk that his or her investment could lose money.
Risk, Nondiversified Status	rr_RiskNondiversifiedStatus	The Fund is considered non-diversified and can invest a greater portion of its assets in securities of individual issuers than a diversified fund. As a result, changes in the market value of a single security could cause greater fluctuations in the value of Fund shares than would occur in a diversified fund.
Bar Chart and Performance Table, Heading	rr_BarChartAndPerformanceTableHeading	PERFORMANCE INFORMATION -
Performance, Narrative	rr_PerformanceNarrativeTextBlock	The following bar chart shows the performance of the Investor Class Shares of the Fund from year to year. The variability of performance over time provides an indication of the risks of investing in the Fund. The following table shows the performance of the Investor Class Shares and Advisor Class Shares of the Fund as an average over different periods of time in comparison to the performance of a broad-based market index. The figures in the bar chart and table assume the reinvestment of dividends and capital gains distributions. Of course, this past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future. Updated performance information is available on the Fund's website at www.rydex-sgi.com or by calling Rydex|SGI Client Services at 800-820-0888.
Performance, Information Illustrates Variability of Returns	rr_PerformanceInformationIllustratesVariabilityOfReturns	The variability of performance over time provides an indication of the risks of investing in the Fund.
Performance, Availability Phone Number	rr_PerformanceAvailabilityPhone	800-820-0888
Performance, Availability Website Address	rr_PerformanceAvailabilityWebSiteAddress	www.rydex-sgi.com
Performance, Past Does Not Indicate Future	rr_PerformancePastDoesNotIndicateFuture	Of course, this past performance (before and after taxes) does not necessarily indicate how the Fund will perform in the future.
Bar Chart, Narrative	rr_BarChartNarrativeTextBlock	The performance information shown below for Investor Class Shares is based on a calendar year. The year-to-date return for the period from January 1, 2011 through June 30, 2011 is 4.70%.
Bar Chart, Closing	rr_BarChartClosingTextBlock	Highest Quarter Return Lowest Quarter Return (quarter ended 12/31/2001) 34.43% (quarter ended 9/30/2001) -36.77%
Index No Deduction for Fees, Expenses, Taxes	rr_IndexNoDeductionForFeesExpensesTaxes	reflects no deduction for fees, expenses or taxes
Performance Table, Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes.
Performance Table, Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold shares of the Fund through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Performance Table, Narrative	rr_PerformanceTableNarrativeTextBlock	The after-tax returns presented in the table below are calculated using highest historical individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Your actual after-tax returns will depend on your specific tax situation and may differ from those shown below. After-tax returns are not relevant to investors who hold shares of the Fund through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts.
Average Annual Returns, Caption	rr_AverageAnnualReturnCaption	AVERAGE ANNUAL TOTAL RETURN (for periods ended December 31, 2010)
NASDAQ-100 Fund (First Prospectus Summary) | NASDAQ-100 Fund | Investor
Risk/Return:	rr_RiskReturnAbstract
Year to Date Return, Label	rr_YearToDateReturnLabel	The year-to-date return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2011
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	4.70%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest Quarter Return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2001
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	34.43%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest Quarter Return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2001
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(36.77%)
NASDAQ-100 Fund | NASDAQ-100 Index®
Risk/Return:	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	NASDAQ-100 Index® (reflects no deduction for fees, expenses or taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	19.22%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	6.16%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(0.54%)
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	6.62%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Mar. 31, 2004
Average Annual Returns, Since Inception Secondary	ck0000899148_AverageAnnualReturnSinceInceptionSecondary	2.90%
Average Annual Returns, Inception Date Secondary	ck0000899148_AverageAnnualReturnInceptionDateSecondary	Mar. 26, 2001
NASDAQ-100 Fund | Advisor
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.75%
Distribution (12b-1) and/or Shareholder Service Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.80%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.80%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	183
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	566
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	975
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	2,116
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Return Before Taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	17.98%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	5.12%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(2.02%)
NASDAQ-100 Fund | Advisor | After Taxes on Distributions
Risk/Return:	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Return After Taxes on Distributions
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	17.98%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	5.12%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(2.03%)
NASDAQ-100 Fund | Advisor | After Taxes on Distributions and Sales
Risk/Return:	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	11.69%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	4.41%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(1.70%)
NASDAQ-100 Fund | Investor
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.75%
Distribution (12b-1) and/or Shareholder Service Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.56%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.31%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	133
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	415
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	718
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	1,579
Annual Return 2001	rr_AnnualReturn2001	(34.65%)
Annual Return 2002	rr_AnnualReturn2002	(38.55%)
Annual Return 2003	rr_AnnualReturn2003	46.24%
Annual Return 2004	rr_AnnualReturn2004	9.67%
Annual Return 2005	rr_AnnualReturn2005	1.33%
Annual Return 2006	rr_AnnualReturn2006	6.27%
Annual Return 2007	rr_AnnualReturn2007	18.05%
Annual Return 2008	rr_AnnualReturn2008	(41.88%)
Annual Return 2009	rr_AnnualReturn2009	52.24%
Annual Return 2010	rr_AnnualReturn2010	18.51%
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Return Before Taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	18.51%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	5.64%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(1.51%)
NASDAQ-100 Fund | Investor | After Taxes on Distributions
Risk/Return:	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Return After Taxes on Distributions
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	18.51%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	5.64%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(1.53%)
NASDAQ-100 Fund | Investor | After Taxes on Distributions and Sales
Risk/Return:	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Return After Taxes on Distributions and Sale of Fund Shares
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	12.03%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	4.87%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(1.28%)