Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	RS INVESTMENT TRUST
Prospectus Date	rr_ProspectusDate	May 01, 2013
Class Y Prospectus | RS Tax-Exempt Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	RS Tax-Exempt Fund
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	To maximize current income exempt from federal income taxes, consistent with the preservation of capital.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses of the Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The table below describes the fees and expenses that you may pay if you buy and hold shares of the Fund. No sales loads are imposed on Class Y shares.
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	Annual Fund Operating Expenses (expenses are deducted from Fund assets as a percentage of average daily net assets)
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	April 30, 2014
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	Portfolio Turnover
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs 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 for you if your 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. During the most recent fiscal year, the Fund’s portfolio turnover rate was 15% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	15.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	rr_ExpenseExampleNarrativeTextBlock	This Example is intended to help you compare the cost of investing in the Fund with the costs of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated, whether or not you redeem at the end of such periods. This Example also assumes that your investment earns a 5% return each year and that the Fund’s operating expenses remain the same as shown above. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:
Strategy [Heading]	rr_StrategyHeading	Investments, Risks, and Performance Principal Investment Strategies
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund invests primarily in investment-grade municipal obligations, the interest on which is, in the opinion of the issuer’s bond counsel, exempt from federal income tax including the federal alternative minimum tax (“AMT”). The Fund’s investment team allocates the Fund’s investments among a diversified portfolio of investment-grade municipal obligations and will invest primarily in municipal securities with remaining maturities of between seven and 25 years. The Fund’s investment team may, however, invest in municipal obligations with remaining maturities outside of that range based on its analysis of the market and the economy. As of March 31, 2013, the Fund’s dollar weighted average maturity was 14.89 years; the Fund’s dollar weighted average maturity may be substantially longer or shorter any time in the future. Under normal circumstances at least 80% of the value of the Fund’s net assets will be invested in tax-exempt municipal obligations. This is a fundamental policy that cannot be changed without shareholder approval. For purposes of the fundamental policy stated above, the Fund will include borrowings for investment purposes when it calculates its net assets. Up to 20% of the value of the Fund’s net assets may be invested in bonds that pay interest subject to federal income tax, including bonds that pay interest subject to the AMT. Municipal obligations are debt securities issued by states, the District of Columbia, and territories and possessions of the United States, their political subdivisions, agencies, authorities, and instrumentalities. Types of municipal obligations in which the Fund may invest include: general obligation bonds, guaranteed by the issuer’s full faith, credit, and taxing power; specific obligation bonds, payable by a special tax or revenue source; revenue bonds, supported by a revenue source related to the project being financed; notes or short-term obligations issued in anticipation of a bond sale, guaranteed by the collection of taxes or receipt of revenues; and private activity bonds, including industrial development bonds, issued by or on behalf of public authorities. The Fund will normally invest in municipal securities that, at the time of purchase, are of investment grade. An investment-grade security is one that is rated by Moody’s Investors Service, Inc. or Standard & Poor’s Ratings Group Baa3 or BBB-, respectively, or higher, or, if unrated, has been determined by the Fund’s investment team to be of comparable quality. The Fund may invest up to 10% of its assets in below investment grade or unrated municipal obligations that the Fund’s investment team determines to be of comparable quality. The Fund is not required to sell a bond that has been downgraded to below investment grade after the Fund acquires it, but the Fund’s overall holdings in below investment grade bonds, including those that have been downgraded since the time of investment, generally will not exceed 20% of the Fund’s assets. The Fund may invest in other tax-exempt securities that are not municipal obligations. The Fund’s investments may include any type of debt instrument, including, for example, zero-coupon securities as well as floating and variable-rate demand notes and bonds. The Fund may invest without limit in municipal obligations that pay interest from similar revenue sources, in municipal securities of issuers within a single state, or in municipal securities issued by entities having similar characteristics. The issuers may be located in the same geographic areas or may pay their interest obligations from revenue of similar projects, such as hospitals, airports, utility systems and housing finance agencies. This may make the Fund’s investments more susceptible to economic, political, regulatory, or other factors affecting issuers in those geographic areas or issuers whose revenues are derived from such projects, and may increase the volatility of the Fund’s net asset value. The Fund may invest more than 25% of its total assets in a segment of the municipal securities market with similar characteristics if the Fund’s investment team determines that the potential return from such investment justifies the additional risk. The Fund may enter into exchange-traded or over-the-counter derivatives transactions of any kind, such as futures contracts, options on futures, and swap contracts, including, for example, interest rate swaps and credit default swaps. The Fund may enter into any of these transactions for a variety of purposes, including, but not limited to, hedging various risks such as credit risk, interest rate risk, and liquidity risk; taking a net long or short position in certain investments or markets; providing liquidity in the Fund; equitizing cash; minimizing transaction costs; generating income; adjusting the Fund’s sensitivity to interest rate risk or other risk; replicating certain direct investments; and asset and sector allocation.
Risk [Heading]	rr_RiskHeading	Principal Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	You may lose money by investing in the Fund. The Fund may not achieve its investment objective. The principal risks of investing in the Fund, which could adversely affect its net asset value and total return, are as follows. Debt Securities Risk The value of a debt security or other income-producing security changes in response to various factors, including, by way of example, market-related factors (such as changes in interest rates or changes in the risk appetite of investors generally) and changes in the actual or perceived ability of the issuer (or of issuers generally) to meet its (or their) obligations. Municipal Obligations Risk Issuers, including governmental issuers, may be unable to pay their obligations as they come due. The values of municipal obligations that depend on a specific revenue source to fund their payment obligations may fluctuate as a result of changes in the cash flows generated by the revenue source or changes in the priority of the municipal obligation to receive the cash flows generated by the revenue source. In addition, changes in federal tax laws or the activity of an issuer may adversely affect the tax-exempt status of municipal obligations. Loss of tax-exempt status may cause interest received and distributed to shareholders by the Fund to be taxable and may result in a significant decline in the values of such municipal obligations. High-yield/Junk Bond Risk Lower-quality debt securities can involve a substantially greater risk of default than higher quality debt securities, and their values can decline significantly over short periods of time. Lower-quality debt securities tend to be more sensitive to adverse news about the issuer, or the market or economy in general. Liquidity Risk Lack of a ready market or restrictions on resale may limit the ability of the Fund to sell a security at an advantageous time or price. In addition, the Fund, by itself or together with other accounts managed by Guardian Investor Services LLC, may hold a position in a security that is large relative to the typical trading volume for that security, which can make it difficult for the Fund to dispose of the position at an advantageous time or price. Derivatives Risk Derivative transactions can create investment leverage and may be highly volatile. It is possible that a derivative transaction will result in a loss greater than the principal amount invested, and the Fund may not be able to close out a derivative transaction at a favorable time or price. The counterparty to a derivatives contract may be unable or unwilling to make timely settlement payments, return the Fund’s margin, or otherwise honor its obligations. Credit Derivatives Risk The Fund may enter into credit derivatives, including credit default swaps and credit default index investments. The Fund may use these investments (i) as alternatives to direct long or short investment in a particular security, (ii) to adjust the Fund’s asset allocation or risk exposure, or (iii) for hedging purposes. The use by the Fund of credit default swaps may have the effect of creating a short position in a security. These investments can create investment leverage and may create additional investment risks that may subject the Fund to greater volatility than investments in more traditional securities.
Risk Lose Money [Text]	rr_RiskLoseMoney	You may lose money by investing in the Fund.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Fund Performance
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual returns for 1, 5, and 10 years and since inception compare with those of a broad measure of market performance. The Fund’s past performance (before and after taxes) is not an indication of future performance. Updated performance information for the Fund is available at www.rsinvestments.com or by calling 800-766-3863.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The bar chart and table provide some indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year to year and by showing how the Fund’s average annual returns for 1, 5, and 10 years and since inception compare with those of a broad measure of market performance.
Performance Availability Phone [Text]	rr_PerformanceAvailabilityPhone	800-766-3863
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.rsinvestments.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The Fund’s past performance (before and after taxes) is not an indication of future performance.
Bar Chart [Heading]	rr_BarChartHeading	Annual Return for Class Y Shares (calendar year-end)
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Best Quarter  Third Quarter 2009  7.67%            Worst Quarter  Fourth Quarter 2010  -5.25%
Performance Table Heading	rr_PerformanceTableHeading	Average Annual Total Returns (periods ended 12/31/12)
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns are calculated using the historical highest 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	Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	After-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns shown are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. The Fund commenced investment operations February 16, 1993, with the offering of Class A shares. Performance shown for Class Y shares reflects the performance of the Fund’s Class A shares for periods through the Class Y shares’ inception on May 12, 2009. Blended class performance has been adjusted to take into account differences in sales load applicable to these share classes (Class A shares charge a sales load and Class Y shares do not charge a sales load), but has not been adjusted to take into account differences in class-specific operating expenses (such as Rule 12b-1 fees; Class A shares pay a 12b-1 fee of 0.25% and Class Y shares do not pay a 12b-1 fee). Because Class Y shares’ operating expenses are lower than Class A shares’ historical operating expenses, historical performance of Class A shares is likely lower than what the performance of Class Y shares would have been during that period.
Class Y Prospectus | RS Tax-Exempt Fund | Class Y
Risk/Return:	rr_RiskReturnAbstract
Management Fees	rr_ManagementFeesOverAssets	0.50%
Distribution (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets
Other Expenses	rr_OtherExpensesOverAssets	0.17%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.67%	[1]
Fee Waiver/Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement	rr_NetExpensesOverAssets	0.67%	[1]
1 Year	rr_ExpenseExampleYear01	68
3 Years	rr_ExpenseExampleYear03	214
5 Years	rr_ExpenseExampleYear05	373
10 Years	rr_ExpenseExampleYear10	835
1 Year	rr_ExpenseExampleNoRedemptionYear01	68
3 Years	rr_ExpenseExampleNoRedemptionYear03	214
5 Years	rr_ExpenseExampleNoRedemptionYear05	373
10 Years	rr_ExpenseExampleNoRedemptionYear10	835
2003	rr_AnnualReturn2003	5.34%	[2]
2004	rr_AnnualReturn2004	4.37%	[2]
2005	rr_AnnualReturn2005	4.01%	[2]
2006	rr_AnnualReturn2006	5.03%	[2]
2007	rr_AnnualReturn2007	1.47%	[2]
2008	rr_AnnualReturn2008	(0.23%)	[2]
2009	rr_AnnualReturn2009	11.52%	[2]
2010	rr_AnnualReturn2010	1.47%
2011	rr_AnnualReturn2011	11.14%
2012	rr_AnnualReturn2012	7.34%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	7.67%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2010
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(5.25%)
1 Year	rr_AverageAnnualReturnYear01	7.34%
5 Years	rr_AverageAnnualReturnYear05	6.13%	[2]
10 Years	rr_AverageAnnualReturnYear10	5.08%	[2]
Since Inception	rr_AverageAnnualReturnSinceInception	5.24%	[2]
Inception Date	rr_AverageAnnualReturnInceptionDate	Feb. 16, 1993
Class Y Prospectus | RS Tax-Exempt Fund | Return After Taxes on Distributions | Class Y
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	7.34%
5 Years	rr_AverageAnnualReturnYear05	6.13%	[2]
10 Years	rr_AverageAnnualReturnYear10	4.89%	[2]
Since Inception	rr_AverageAnnualReturnSinceInception	5.06%	[2]
Inception Date	rr_AverageAnnualReturnInceptionDate	Feb. 16, 1993
Class Y Prospectus | RS Tax-Exempt Fund | Return After Taxes on Distributions and Sale of Fund Shares | Class Y
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	5.89%
5 Years	rr_AverageAnnualReturnYear05	5.78%	[2]
10 Years	rr_AverageAnnualReturnYear10	4.79%	[2]
Since Inception	rr_AverageAnnualReturnSinceInception	4.98%	[2]
Inception Date	rr_AverageAnnualReturnInceptionDate	Feb. 16, 1993
Class Y Prospectus | RS Tax-Exempt Fund | Barclays Municipal Bond Index (reflects no deduction for fees, expenses or taxes)
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	6.78%
5 Years	rr_AverageAnnualReturnYear05	5.91%	[2]
10 Years	rr_AverageAnnualReturnYear10	5.10%	[2]
Since Inception	rr_AverageAnnualReturnSinceInception	5.81%	[2]
Inception Date	rr_AverageAnnualReturnInceptionDate	Feb. 16, 1993

[1] RS Investments has contractually agreed to limit the Total Annual Fund Operating Expenses (excluding expenses indirectly incurred by the Fund through investments in pooled investment vehicles, interest, taxes, investment-related expenses (e.g., brokerage commissions), and extraordinary expenses) to 0.69% for Class Y shares. This expense limitation will continue through April 30, 2014 and cannot be terminated by RS Investments prior to that date without the action or consent of the Fund's Board of Trustees.

[2] Returns for the periods through May 12, 2009 reflect performance for the Fund's Class A shares. Class A shares represent an investment in the same portfolio of securities as Class Y shares. Annual returns for Class A and Class Y shares differ to the extent Class Y shares do not have the same expenses as Class A shares.