Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	RS INVESTMENT TRUST
Prospectus Date	rr_ProspectusDate	May 01, 2013
Retail Class Prospectus | RS Large Cap Alpha Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	RS Large Cap Alpha Fund
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	Long-term capital appreciation.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses of the Fund
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The tables below describe the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for sales charge discounts for the purchase of Class A shares if you and your family invest, or agree to invest in the future, at least $50,000 in RS Funds. More information about these and other discounts is available from your financial professional and in the “Types of Shares Available — Class A Shares” section on page 110 of the Fund’s prospectus and the “Waivers of Certain Sales Loads” section on page 37 of the Fund’s statement of additional information.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	Shareholder Fees (fees paid directly from your investment)
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, 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 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 51% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	51.00%
Expense Breakpoint Discounts [Text]	rr_ExpenseBreakpointDiscounts	You may qualify for sales charge discounts for the purchase of Class A shares if you and your family invest, or agree to invest in the future, at least $50,000 in RS Funds.
Expense Breakpoint, Minimum Investment Required [Amount]	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	50,000
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. 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:
Expense Example by, Year, Caption [Text]	rr_ExpenseExampleByYearCaption	Assuming Redemption at End of  Period
Expense Example, No Redemption, By Year, Caption [Text]	rr_ExpenseExampleNoRedemptionByYearCaption	Assuming No Redemption
Strategy [Heading]	rr_StrategyHeading	Investments, Risks, and Performance Principal Investment Strategies
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund normally invests at least 80% of its net assets in companies considered by the Fund’s investment team (at the time of purchase) to be large-capitalization companies. The Fund’s investment team considers a company to be large-capitalization if its market capitalization is between $5 billion and the market capitalization of the largest company included in the Russell 1000® Index on the last day of the most recent quarter (currently, approximately $415.7 billion, based on the size of the largest company in the Index on March 31, 2013). The Fund’s investment team currently expects that the Fund typically will hold between 35 and 45 securities positions. In evaluating investments for the Fund, the Fund’s investment team conducts fundamental research to identify companies with improving returns on invested capital. The investment team’s research efforts seek to identify the primary economic and value drivers for each company. Research focuses on a company’s capital deployment strategy, including decisions about capital expenditures, acquisitions, cost-saving initiatives, and share repurchase/dividend plans, as the Fund’s investment team seeks to understand how returns on invested capital may improve over time. Valuation is considered an important part of the process. The investment team seeks to invest in companies based on the investment team’s assessment of risk (the possibility of permanent capital impairment) and its assessment of reward (the future value of the enterprise). The Fund may at times, but will not necessarily, hold a substantial portion of its assets in cash and cash equivalents. The Fund will typically invest principally in equity securities. The Fund may at times, but will not necessarily, invest a substantial portion of its assets in securities of companies that the investment team considers to be principally engaged in natural resources industries. Companies in natural resources industries include companies that the Fund’s investment team considers to be principally engaged in the discovery, development, production, or distribution of natural resources; the development of technologies for the production or efficient use of natural resources; or the furnishing of related supplies or services. The Fund typically invests most of its assets in securities of U.S. companies but may also invest any portion of its assets in foreign securities.
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. Equity Securities Risk The value of a company’s stock may decline in response to factors affecting that particular company or stock markets generally. Investment Style Risk A mutual fund investing principally in value style stocks may at times underperform other mutual funds that invest more broadly or that have different investment styles. Overweighting Risk Overweighting investments in an industry or group of industries relative to the Fund’s primary benchmark increases the risk that the Fund will underperform its primary benchmark because a general decline in the prices of stocks in that industry or group of industries will affect the Fund to a greater extent than its primary benchmark. Underweighting Risk If the Fund underweights its investment in an industry or group of industries relative to the Fund’s primary benchmark, the Fund will participate in any general increase in the value of companies in that industry or group of industries to a lesser extent than the Fund’s primary benchmark. Foreign Securities Risk Foreign securities are subject to political, regulatory, and economic risks not present in domestic investments. In addition, when the Fund buys securities denominated in a foreign currency, there are special risks such as changes in currency exchange rates and the risk that a foreign government could regulate foreign exchange transactions. In addition, to the extent that investments are made in a limited number of countries, events in those countries will have a more significant impact on the Fund. Cash Position Risk To the extent that the Fund holds assets in cash and cash equivalents and not in the investments previously described, the ability of the Fund to meet its objective may be limited. 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 RS Investments, 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. Natural Resources Investment Risk Investment in companies in natural resources industries can be significantly affected by (often rapid) changes in supply of, or demand for, various natural resources. They may also be affected by changes in energy prices, international political and economic developments, environmental incidents, energy conservation, the success of exploration projects, changes in commodity prices, and tax and other government regulations. Investments in interests in oil, gas or mineral exploration or development programs, including pipelines, may be held through master limited partnerships (“MLPs”), which are generally subject to many of the risks that apply to partnerships and may also be subject to certain tax risks. Limited Portfolio Risk To the extent the Fund invests its assets in a more limited number of issuers than many other mutual funds, a decline in the market value of a particular security may affect the Fund’s value more than if the Fund invested in a larger number of issuers. Mid-sized Companies Risk Mid-sized companies may be subject to a number of risks not associated with larger, more established companies, potentially making their stock prices more volatile and increasing the risk of loss.
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 two broad measures of market performance. The returns in the bar chart do not reflect the impact of sales loads. If they did, the returns would be lower than those shown. The Fund’s investment strategy and investment team changed on March 30, 2009. 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 two broad measures 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 Total Return for Class A Shares (calendar year-end)
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	The returns in the bar chart do not reflect the impact of sales loads. If they did, the returns would be lower than those shown.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Best Quarter  Third Quarter 2009  17.47%            Worst Quarter  Third Quarter 2011  -20.78%
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 One Class of after Tax Shown [Text]	rr_PerformanceTableOneClassOfAfterTaxShown	After-tax returns are shown for Class A shares only; after-tax returns for other classes will vary.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	After-tax returns are shown for Class A shares only; after-tax returns for other classes will vary. 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.
Retail Class Prospectus | RS Large Cap Alpha Fund | Class A
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	4.75%
Maximum Deferred Sales Charge (Load) (as a percentage of the lower of sale proceeds or the original offering price)	rr_MaximumDeferredSalesChargeOverOfferingPrice	none	[1]
Management Fees	rr_ManagementFeesOverAssets	0.50%
Distribution (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other Expenses	rr_OtherExpensesOverAssets	0.23%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	0.98%	[2]
Fee Waiver/Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	none	[2]
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement	rr_NetExpensesOverAssets	0.98%	[2]
Expenses Deferred Charges [Text Block]	rr_ExpensesDeferredChargesTextBlock	Contingent deferred sales load of 1.00% applies to purchases of $1 million or more of Class A shares if these shares are sold within 18 months of purchase.
1 Year	rr_ExpenseExampleYear01	570
3 Years	rr_ExpenseExampleYear03	772
5 Years	rr_ExpenseExampleYear05	991
10 Years	rr_ExpenseExampleYear10	1,619
1 Year	rr_ExpenseExampleNoRedemptionYear01	570
3 Years	rr_ExpenseExampleNoRedemptionYear03	772
5 Years	rr_ExpenseExampleNoRedemptionYear05	991
10 Years	rr_ExpenseExampleNoRedemptionYear10	1,619
2003	rr_AnnualReturn2003	20.95%
2004	rr_AnnualReturn2004	5.64%
2005	rr_AnnualReturn2005	3.90%
2006	rr_AnnualReturn2006	16.87%
2007	rr_AnnualReturn2007	14.78%
2008	rr_AnnualReturn2008	(29.29%)
2009	rr_AnnualReturn2009	24.89%
2010	rr_AnnualReturn2010	16.63%
2011	rr_AnnualReturn2011	(8.92%)
2012	rr_AnnualReturn2012	16.26%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	17.47%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2011
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(20.78%)
1 Year	rr_AverageAnnualReturnYear01	10.74%
5 Years	rr_AverageAnnualReturnYear05	0.76%
10 Years	rr_AverageAnnualReturnYear10	6.34%
Since Inception	rr_AverageAnnualReturnSinceInception	11.36%
Inception Date of Share Class	rr_AverageAnnualReturnInceptionDate	Jun. 01, 1972
Retail Class Prospectus | RS Large Cap Alpha Fund | Class C
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of the lower of sale proceeds or the original offering price)	rr_MaximumDeferredSalesChargeOverOfferingPrice	1.00%	[3]
Management Fees	rr_ManagementFeesOverAssets	0.50%
Distribution (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	1.00%
Other Expenses	rr_OtherExpensesOverAssets	0.25%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.75%	[2]
Fee Waiver/Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	none	[2]
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement	rr_NetExpensesOverAssets	1.75%	[2]
Expenses Deferred Charges [Text Block]	rr_ExpensesDeferredChargesTextBlock	Contingent deferred sales load applies for shares sold within one year of purchase.
1 Year	rr_ExpenseExampleYear01	278
3 Years	rr_ExpenseExampleYear03	551
5 Years	rr_ExpenseExampleYear05	949
10 Years	rr_ExpenseExampleYear10	2,062
1 Year	rr_ExpenseExampleNoRedemptionYear01	178
3 Years	rr_ExpenseExampleNoRedemptionYear03	551
5 Years	rr_ExpenseExampleNoRedemptionYear05	949
10 Years	rr_ExpenseExampleNoRedemptionYear10	2,062
1 Year	rr_AverageAnnualReturnYear01	14.37%
5 Years	rr_AverageAnnualReturnYear05	0.97%
10 Years	rr_AverageAnnualReturnYear10	5.88%
Since Inception	rr_AverageAnnualReturnSinceInception	(1.49%)
Inception Date of Share Class	rr_AverageAnnualReturnInceptionDate	Aug. 07, 2000
Retail Class Prospectus | RS Large Cap Alpha Fund | Class K
Risk/Return:	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Maximum Deferred Sales Charge (Load) (as a percentage of the lower of sale proceeds or the original offering price)	rr_MaximumDeferredSalesChargeOverOfferingPrice	none
Management Fees	rr_ManagementFeesOverAssets	0.50%
Distribution (12b-1) Fees	rr_DistributionAndService12b1FeesOverAssets	0.65%
Other Expenses	rr_OtherExpensesOverAssets	0.18%
Total Annual Fund Operating Expenses	rr_ExpensesOverAssets	1.33%	[2]
Fee Waiver/Expense Reimbursement	rr_FeeWaiverOrReimbursementOverAssets	none	[2]
Total Annual Fund Operating Expenses After Fee Waiver/Expense Reimbursement	rr_NetExpensesOverAssets	1.33%	[2]
1 Year	rr_ExpenseExampleYear01	135
3 Years	rr_ExpenseExampleYear03	421
5 Years	rr_ExpenseExampleYear05	729
10 Years	rr_ExpenseExampleYear10	1,601
1 Year	rr_ExpenseExampleNoRedemptionYear01	135
3 Years	rr_ExpenseExampleNoRedemptionYear03	421
5 Years	rr_ExpenseExampleNoRedemptionYear05	729
10 Years	rr_ExpenseExampleNoRedemptionYear10	1,601
1 Year	rr_AverageAnnualReturnYear01	15.84%
5 Years	rr_AverageAnnualReturnYear05	1.37%
10 Years	rr_AverageAnnualReturnYear10	6.48%
Since Inception	rr_AverageAnnualReturnSinceInception	2.21%
Inception Date of Share Class	rr_AverageAnnualReturnInceptionDate	May 15, 2001
Retail Class Prospectus | RS Large Cap Alpha Fund | Return After Taxes on Distributions | Class A
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	10.06%
5 Years	rr_AverageAnnualReturnYear05	0.40%
10 Years	rr_AverageAnnualReturnYear10	5.97%
Since Inception	rr_AverageAnnualReturnSinceInception
Inception Date of Share Class	rr_AverageAnnualReturnInceptionDate	Jun. 01, 1972
Retail Class Prospectus | RS Large Cap Alpha Fund | Return After Taxes on Distributions and Sale of Fund Shares | Class A
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	6.98%
5 Years	rr_AverageAnnualReturnYear05	0.43%
10 Years	rr_AverageAnnualReturnYear10	5.34%
Since Inception	rr_AverageAnnualReturnSinceInception
Inception Date of Share Class	rr_AverageAnnualReturnInceptionDate	Jun. 01, 1972
Retail Class Prospectus | RS Large Cap Alpha Fund | Russell 1000® Value Index (reflects no deduction for fees, expenses or taxes) | Class A
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	17.51%
5 Years	rr_AverageAnnualReturnYear05	0.59%
10 Years	rr_AverageAnnualReturnYear10	7.38%
Since Inception	rr_AverageAnnualReturnSinceInception		[4]
Inception Date of Share Class	rr_AverageAnnualReturnInceptionDate	Jun. 01, 1972
Retail Class Prospectus | RS Large Cap Alpha Fund | Russell 1000® Value Index (reflects no deduction for fees, expenses or taxes) | Class C
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	17.51%
5 Years	rr_AverageAnnualReturnYear05	0.59%
10 Years	rr_AverageAnnualReturnYear10	7.38%
Since Inception	rr_AverageAnnualReturnSinceInception	4.47%
Inception Date of Share Class	rr_AverageAnnualReturnInceptionDate	Aug. 07, 2000
Retail Class Prospectus | RS Large Cap Alpha Fund | Russell 1000® Value Index (reflects no deduction for fees, expenses or taxes) | Class K
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	17.51%
5 Years	rr_AverageAnnualReturnYear05	0.59%
10 Years	rr_AverageAnnualReturnYear10	7.38%
Since Inception	rr_AverageAnnualReturnSinceInception	4.29%
Inception Date of Share Class	rr_AverageAnnualReturnInceptionDate	May 15, 2001
Retail Class Prospectus | RS Large Cap Alpha Fund | S&P 500® Index (reflects no deduction for fees, expenses or taxes) | Class A
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	16.00%
5 Years	rr_AverageAnnualReturnYear05	1.66%
10 Years	rr_AverageAnnualReturnYear10	7.10%
Since Inception	rr_AverageAnnualReturnSinceInception	9.86%	[5]
Inception Date of Share Class	rr_AverageAnnualReturnInceptionDate	May 31, 1972
Retail Class Prospectus | RS Large Cap Alpha Fund | S&P 500® Index (reflects no deduction for fees, expenses or taxes) | Class C
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	16.00%
5 Years	rr_AverageAnnualReturnYear05	1.66%
10 Years	rr_AverageAnnualReturnYear10	7.10%
Since Inception	rr_AverageAnnualReturnSinceInception	1.63%
Inception Date of Share Class	rr_AverageAnnualReturnInceptionDate	Aug. 07, 2000
Retail Class Prospectus | RS Large Cap Alpha Fund | S&P 500® Index (reflects no deduction for fees, expenses or taxes) | Class K
Risk/Return:	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	16.00%
5 Years	rr_AverageAnnualReturnYear05	1.66%
10 Years	rr_AverageAnnualReturnYear10	7.10%
Since Inception	rr_AverageAnnualReturnSinceInception	3.14%
Inception Date of Share Class	rr_AverageAnnualReturnInceptionDate	May 15, 2001

[1] Contingent deferred sales load of 1.00% applies to purchases of $1 million or more of Class A shares if these shares are sold within 18 months of purchase.

[2] 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) for Class A shares to 0.99% and to limit the Total Annual Fund Operating Expenses of each of the other classes of the Fund so that each of those classes benefits from a level of reimbursement (as expressed in basis points) that is the same as the level of reimbursement for Class A shares during the period. 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.

[3] Contingent deferred sales load applies for shares sold within one year of purchase.

[4] No since inception performance return is shown for Class A shares because the inception date for Class A shares was prior to the inception date of the Russell 1000® Value Index.

[5] Since inception returns for the S&P 500® Index shown in the table are since May 31, 1972, the month end prior to the inception of Class A shares.