Label	Element	Value
Risk/Return:	rr_RiskReturnAbstract
ProspectusDate	rr_ProspectusDate	Dec. 20, 2011
Dreyfus Opportunistic U.S. Stock Fund (Prospectus Summary) | Dreyfus Opportunistic U.S. Stock Fund
Risk/Return:	rr_RiskReturnAbstract
Risk/Return, Heading	rr_RiskReturnHeading	FUND SUMMARY
Investment Objective, Heading	rr_ObjectiveHeading	INVESTMENT OBJECTIVE
investment Objective, Primary	rr_ObjectivePrimaryTextBlock	The fund seeks long-term capital appreciation.
Expense, Heading	rr_ExpenseHeading	FEES AND EXPENSES
Expense, Narrative	rr_ExpenseNarrativeTextBlock	This table describes the fees and expenses that you may pay if you buy and hold shares of the fund. You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain funds in the Dreyfus Family of Funds. More information about these and other discounts is available from your financial professional and in the Shareholder Guide section on page 9 of the prospectus and in the How to Buy Shares section on page B-36 of the fund's Statement of Additional Information (SAI). Class A shares bought without an initial sales charge as part of an investment of $1 million or more may be charged a deferred sales charge of 1.00% if redeemed within one year.
Shareholder Fees, Caption	rr_ShareholderFeesCaption	Shareholder fees (fees paid directly from your investment)
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 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 annual fund operating expenses or in the example, affect the fund's performance.
Expense Breakpoint, Discounts	rr_ExpenseBreakpointDiscounts	You may qualify for sales charge discounts if you and your family invest, or agree to invest in the future, at least $50,000 in certain funds in the Dreyfus Family of Funds.
Expense Breakpoint, Minimum Investment Required Amount	rr_ExpenseBreakpointMinimumInvestmentRequiredAmount	50,000
Other Expenses, New Fund, Based on Estimates	rr_OtherExpensesNewFundBasedOnEstimates	Other expenses are based on estimated amounts for the current fiscal year.
Operating Expense, Closing	ck0000914775_ExpenseClosingTextBlock	The Dreyfus Corporation has contractually agreed, until January 1, 2013, to waive receipt of its fees and/or assume the expenses of the fund so that the expenses of none of the classes (excluding Rule 12b-1 fees, shareholder services fees, taxes, interest, brokerage commissions, commitment fees on borrowings and extraordinary expenses) exceed 0.95%.
Expense Example, Heading	rr_ExpenseExampleHeading	EXAMPLE
Expense Example, Narrative	rr_ExpenseExampleNarrativeTextBlock	The 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. The one-year example and the first year of the three-years example are based on net operating expenses, which reflect the expense waiver/reimbursement by The Dreyfus Corporation. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Expense Example, No Redemption, By Year, Caption	rr_ExpenseExampleNoRedemptionByYearCaption	You would pay the following expenses if you did not redeem your shares:
Investment Strategy, Heading	rr_StrategyHeading	PRINCIPAL INVESTMENT STRATEGY
Investment Strategy, Narrative	rr_StrategyNarrativeTextBlock	To pursue its goal, the fund normally invests at least 80% of its net assets, plus any borrowings for investment purposes, in stocks of publicly traded companies located in the United States. The fund may invest in the stocks of companies of any market capitalization and may hold growth or value stocks or a blend of both. The fund's portfolio construction combines a fundamental, bottom-up research process with macro insights and risk management. The fund's portfolio managers, supported by a team of research analysts, use a disciplined opportunistic investment approach to identify stocks of companies that the portfolio managers believe are trading materially below their intrinsic market value, that have strong or improving fundamentals and have a revaluation catalyst. The fund seeks exposure to stocks and sectors that the fund's portfolio managers perceive to be attractive from a valuation and fundamental standpoint. Portfolio position sizes and sector weightings reflect the collaborative investment process among the fund's portfolio managers and research analysts. The portfolio managers also assess and manage the overall risk profile of the fund's portfolio.
Risk, Heading	rr_RiskHeading	PRINCIPAL RISKS
Risk, Narrative	rr_RiskNarrativeTextBlock	An investment in the fund is not a bank deposit. It is not insured or guaranteed by the Federal Deposit Insurance Company (FDIC) or any other government agency. It is not a complete investment program. The fund's share price fluctuates, sometimes dramatically, which means you could lose money. o Risks of stock investing. Stocks generally fluctuate more in value than bonds and may decline significantly over short time periods. There is the chance that stock prices overall will decline because stock markets tend to move in cycles, with periods of rising prices and falling prices. The market value of a stock may decline due to general weakness in the stock market or because of factors that affect the company or its particular industry. o Market sector risk. The fund may significantly overweight or underweight certain companies, industries or market sectors, which may cause the fund's performance to be more or less sensitive to developments affecting those companies, industries or sectors. o Growth and value stock risk. By investing in a mix of growth and value companies, the fund assumes the risk of both. Investors often expect growth companies to increase their earnings at a certain rate. If these expectations are not met, investors can punish the stocks inordinately, even if earnings do increase. In addition, growth stocks may lack the dividend yield that can cushion stock prices in market downturns. Value stocks involve the risk that they may never reach their expected full market value, either because the market fails to recognize the stock's intrinsic worth, or the expected value was misgauged. They also may decline in price even though in theory they are already undervalued. o Small and midsize company risk. To the extent the fund invests in small and midsize companies, it will be subject to additional risks because the operating histories of these companies tend to be more limited, their earnings and revenues less predictable (and some companies may be experiencing significant losses), and their share prices more volatile than those of larger, more established companies. The shares of smaller companies tend to trade less frequently than those of larger, more established companies, which can adversely affect the pricing of these securities and the fund's ability to sell these securities. o Liquidity risk. When there is little or no active trading market for specific types of securities, it can become more difficult to sell the securities at or near their perceived value. In such a market, the value of such securities and the fund's share price may fall dramatically.
Risk, Lose Money	rr_RiskLoseMoney	The fund's share price fluctuates, sometimes dramatically, which means you could lose money.
Risk, Not Insured Depository Institution	rr_RiskNotInsuredDepositoryInstitution	An investment in the fund is not a bank deposit. It is not insured or guaranteed by the Federal Deposit Insurance Company (FDIC) or any other government agency.
Bar Chart and Performance Table, Heading	rr_BarChartAndPerformanceTableHeading	PERFORMANCE
Performance, Narrative	rr_PerformanceNarrativeTextBlock	As a new fund, past performance information is not available for the fund as of the date of this prospectus. Annual performance returns provide some indication of the risks of investing in the fund by showing changes in performance from year to year. Comparison of fund performance to an appropriate index indicates how the fund's average annual returns compare with those of a broad measure of market performance. The fund's past performance (before and after taxes) is no guarantee of future results.
Performance, One Year or Less	rr_PerformanceOneYearOrLess	As a new fund, past performance information is not available for the fund as of the date of this prospectus.
Performance, Past Does Not Indicate Future	rr_PerformancePastDoesNotIndicateFuture	The fund's past performance (before and after taxes) is no guarantee of future results.
Dreyfus Opportunistic U.S. Stock Fund (Prospectus Summary) | Dreyfus Opportunistic U.S. Stock Fund | Class A
Risk/Return:	rr_RiskReturnAbstract
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	2013-01-01
Dreyfus Opportunistic U.S. Stock Fund (Prospectus Summary) | Dreyfus Opportunistic U.S. Stock Fund | Class C
Risk/Return:	rr_RiskReturnAbstract
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	2013-01-01
Dreyfus Opportunistic U.S. Stock Fund (Prospectus Summary) | Dreyfus Opportunistic U.S. Stock Fund | Class I
Risk/Return:	rr_RiskReturnAbstract
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	2013-01-01
Dreyfus Opportunistic U.S. Stock Fund | Class A
Risk/Return:	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	5.75%
Maximum deferred sales charge (load) (as a percentage of lower of purchase or sale price)	rr_MaximumDeferredSalesChargeOverOfferingPrice	none
Management fees	rr_ManagementFeesOverAssets	0.75%
Distribution (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses (including shareholder services fees)	rr_OtherExpensesOverAssets	0.65%	[1]
Total annual fund operating expenses	rr_ExpensesOverAssets	1.40%
Fee waiver and/or expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.20%)
Total annual fund operating expenses (after fee waiver and/or expense reimbursement)	rr_NetExpensesOverAssets	1.20%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	690
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	974
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	690
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	974
Dreyfus Opportunistic U.S. Stock 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 lower of purchase or sale price)	rr_MaximumDeferredSalesChargeOverOfferingPrice	1.00%
Management fees	rr_ManagementFeesOverAssets	0.75%
Distribution (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.75%
Other expenses (including shareholder services fees)	rr_OtherExpensesOverAssets	0.65%	[1]
Total annual fund operating expenses	rr_ExpensesOverAssets	2.15%
Fee waiver and/or expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.20%)
Total annual fund operating expenses (after fee waiver and/or expense reimbursement)	rr_NetExpensesOverAssets	1.95%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	298
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	654
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	198
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	654
Dreyfus Opportunistic U.S. Stock Fund | Class I
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 lower of purchase or sale price)	rr_MaximumDeferredSalesChargeOverOfferingPrice	none
Management fees	rr_ManagementFeesOverAssets	0.75%
Distribution (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses (including shareholder services fees)	rr_OtherExpensesOverAssets	0.40%	[1]
Total annual fund operating expenses	rr_ExpensesOverAssets	1.15%
Fee waiver and/or expense reimbursement	rr_FeeWaiverOrReimbursementOverAssets	(0.20%)
Total annual fund operating expenses (after fee waiver and/or expense reimbursement)	rr_NetExpensesOverAssets	0.95%
Expense Example, With Redemption, 1 Year	rr_ExpenseExampleYear01	97
Expense Example, With Redemption, 3 Years	rr_ExpenseExampleYear03	346
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	97
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	346

[1] Other expenses are based on estimated amounts for the current fiscal year.