Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
ProspectusDate	rr_ProspectusDate	Aug. 01, 2011
Utilities Fund (First Prospectus Summary) | Utilities Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return, Heading	rr_RiskReturnHeading	UTILITIES FUND
Investment Objective, Heading	rr_ObjectiveHeading	INVESTMENT OBJECTIVE -
investment Objective, Primary	rr_ObjectivePrimaryTextBlock	The Utilities Fund (the "Fund") seeks to provide capital appreciation by investing in companies that operate public utilities ("Utilities Companies").
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 higher 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 800% 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	800.00%
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	Under normal circumstances, the Fund invests substantially all (at least 80%) of its net assets in equity securities of Utilities Companies that are traded in the United States and in derivatives which primarily consist of futures contracts and options on securities, futures contracts, and stock indices. In addition, the Fund will invest to a significant extent in the securities of Utilities Companies that have small to mid-sized capitalizations. Utilities Companies may include companies involved in the manufacturing, production, generation, transmission, distribution or sales of gas or electric energy; water supply, waste and sewage disposal; and companies that receive a majority of their revenues from their public utility operations. The Fund may also purchase American Depositary Receipts ("ADRs") to gain exposure to foreign Utilities Companies and U.S. government securities. 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. The Fund invests in the securities of a limited number of issuers conducting business in the utilities sector and therefore may be concentrated in an industry or group of industries within the utilities sector. 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. 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. Investment Technique Risk - The Advisor does not engage in temporary defensive investing, keeping the Fund fully invested in all market environments. This means that, based on market and economic conditions, the Fund's performance could be lower than other types of mutual funds that may actively shift their portfolio assets to lessen the impact of a market decline. 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. Mid-Capitalization Securities Risk - The Fund is subject to the risk that medium-capitalization stocks may underperform other segments of the equity market or the equity market as a whole. 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. Small-Capitalization Securities Risk - The Fund is subject to the risk that small-capitalization stocks may underperform other segments of the equity market or the equity market as a whole. 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. Utilities Sector Concentration Risk - To the extent that the Fund's investments are concentrated in issuers conducting business in the utilities 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 Utilities Companies also may fluctuate widely in response to such events.
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 10.74%.
Bar Chart, Closing	rr_BarChartClosingTextBlock	Highest Quarter Return Lowest Quarter Return (quarter ended 6/30/2003) 20.39% (quarter ended 9/30/2002) -23.13%
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)
Utilities Fund (First Prospectus Summary) | Utilities Fund | Investor
Risk/Return:	rr_RiskReturnAbstract
Year to Date Return, Label	rr_YearToDateReturnLabel	The year-to-date return for the period
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2011
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	10.74%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Highest Quarter Return
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2003
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	20.39%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Lowest Quarter Return
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2002
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(23.13%)
Utilities Fund | S&P 500® Index
Risk/Return:	rr_RiskReturnAbstract
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	S&P 500® Index (reflects no deduction for fees, expenses or taxes)
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	15.06%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	2.29%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	1.41%
Average Annual Returns, Since Inception	rr_AverageAnnualReturnSinceInception	4.17%
Average Annual Returns, Inception Date	rr_AverageAnnualReturnInceptionDate	Sep. 01, 2004
Average Annual Returns, Since Inception Secondary	ck0000899148_AverageAnnualReturnSinceInceptionSecondary	1.97%
Average Annual Returns, Inception Date Secondary	ck0000899148_AverageAnnualReturnInceptionDateSecondary	Apr. 27, 2001
Utilities Fund | Advisor
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.85%
Distribution (12b-1) and/or Shareholder Service Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.77%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.87%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	190
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	588
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	1,011
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	2,190
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Return Before Taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	6.31%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	3.09%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(0.68%)
Utilities 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	3.89%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	1.94%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(1.86%)
Utilities 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	4.07%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	1.99%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(1.29%)
Utilities Fund | Investor
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.85%
Distribution (12b-1) and/or Shareholder Service Fees	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses	rr_OtherExpensesOverAssets	0.52%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.37%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	139
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	434
Expense Example, With Redemption, 5 Years	rr_ExpenseExampleYear05	750
Expense Example, With Redemption, 10 Years	rr_ExpenseExampleYear10	1,646
Annual Return 2001	rr_AnnualReturn2001	(24.33%)
Annual Return 2002	rr_AnnualReturn2002	(32.37%)
Annual Return 2003	rr_AnnualReturn2003	25.41%
Annual Return 2004	rr_AnnualReturn2004	16.64%
Annual Return 2005	rr_AnnualReturn2005	10.17%
Annual Return 2006	rr_AnnualReturn2006	20.38%
Annual Return 2007	rr_AnnualReturn2007	13.20%
Annual Return 2008	rr_AnnualReturn2008	(28.09%)
Annual Return 2009	rr_AnnualReturn2009	14.03%
Annual Return 2010	rr_AnnualReturn2010	6.87%
Average Annual Returns, Label	rr_AverageAnnualReturnLabel	Return Before Taxes
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	6.87%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	3.61%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(0.15%)
Utilities 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	4.59%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	2.52%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(1.30%)
Utilities 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	4.44%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	2.46%
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	(0.84%)