Label	Element	Value
Risk Return [Abstract]	rr_RiskReturnAbstract
ProspectusDate	rr_ProspectusDate	Sep. 01, 2012
Dreyfus Massachusetts Fund (Prospectus Summary) | Dreyfus Massachusetts Fund
Risk Return [Abstract]	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Summary
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The fund seeks to maximize current income exempt from federal income tax and from Massachusetts state income tax, without undue risk.
Expense [Heading]	rr_ExpenseHeading	Fees and Expenses
Expense Narrative [Text Block]	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 29 of the Prospectus and in the How to Buy Shares section and the Additional Information About How to Buy Shares section on page II-1 and page III-1, respectively, of the fund's Statement of Additional Information. 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 [Text]	rr_ShareholderFeesCaption	Shareholder Fees (fees paid directly from your investment)
Operating Expenses Caption [Text]	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 [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 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. During the most recent fiscal year, the fund's portfolio turnover rate was 11.44% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	11.44%
Expense Breakpoint Discounts [Text]	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
Expense Example [Heading]	rr_ExpenseExampleHeading	Example
Expense Example Narrative [Text Block]	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. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Expense Example, No Redemption, By Year, Caption [Text]	rr_ExpenseExampleNoRedemptionByYearCaption	You would pay the following expenses if you did not redeem your shares:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategy
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	To pursue its goal, the fund normally invests substantially all of its assets in municipal bonds that provide income exempt from federal and Massachusetts state income taxes. The fund invests primarily in municipal bonds rated investment grade (Baa/BBB or higher) or the unrated equivalent as determined by The Dreyfus Corporation. For additional yield, the fund may invest up to 30% of its assets in municipal bonds rated below investment grade ("high yield" or "junk" bonds) or the unrated equivalent as determined by The Dreyfus Corporation. The dollar-weighted average maturity of the fund's portfolio normally exceeds ten years, but the fund may invest without regard to maturity. Dollar-weighted average maturity is an average of the stated maturities of the securities held by the fund, based on their dollar-weighted proportions in the fund. The portfolio managers focus on identifying undervalued sectors and securities and select municipal bonds by (i) using fundamental credit analysis to estimate the relative value and attractiveness of various sectors and securities and to exploit pricing inefficiencies in the municipal bond market, and (ii) actively trading among various sectors based on their apparent relative values. The fund may buy securities that pay interest at rates that float inversely with changes in prevailing interest rates (inverse floaters) in an effort to increase returns, to manage interest rate risk or as part of a hedging strategy. Although the fund seeks to provide income exempt from federal and Massachusetts state income taxes, income from some of the fund's holdings may be subject to the federal alternative minimum tax.
Risk [Heading]	rr_RiskHeading	Principal Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	An investment in the fund is not a bank deposit. It is not insured or guaranteed by the Federal Deposit Insurance Corporation (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 Municipal bond market risk. The amount of public information available about   municipal bonds is generally less than that for corporate equities or bonds.   Special factors, such as legislative changes, and state and local economic and   business developments, may adversely affect the yield and/or value of the fund's   investments in municipal bonds. Other factors include the general conditions of   the municipal bond market, the size of the particular offering, the maturity of   the obligation and the rating of the issue. Changes in economic, business or   political conditions relating to a particular municipal project, municipality,   or state in which the fund invests may have an impact on the fund's share price. o Interest rate risk. Prices of municipal bonds tend to move inversely with   changes in interest rates. Typically, a rise in rates will adversely affect   bond prices and, accordingly, the fund's share price. The longer the effective   maturity and duration of the fund's portfolio, the more the fund's share price   is likely to react to interest rates. o Credit risk. Failure of an issuer to make timely interest or principal   payments, or a decline or perception of a decline in the credit quality of a   municipal bond, can cause the bond's price to fall, potentially lowering the   fund's share price. The lower a bond's credit rating, the greater the chance -   in the rating agency's opinion - that the bond issuer will default or fail to   meet its payment obligations. To the extent the fund invests in high yield   ("junk") bonds, its portfolio is subject to heightened credit risk. 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, even during periods of declining   interest rates. The secondary market for  certain municipal bonds tends to be   less well developed or liquid than many other securities markets, which may   adversely affect the fund's ability to sell such municipal bonds at attractive   prices. o State-specific risk. The fund is subject to the risk that Massachusetts's   economy, and the revenues underlying its municipal bonds, may decline. Investing   primarily in a single state makes the fund more sensitive to risks specific to   the state and may magnify other risks. o Inverse floating rate securities risk. The interest payment received on   inverse floating rate securities generally will decrease when short-term   interest rates increase. Inverse floaters are derivatives that involve   leverage and could magnify the fund's gains or losses. o Non-diversification risk. The fund is non-diversified, meaning that a   relatively high percentage of the fund's assets may be invested in a limited   number of issuers. Therefore, the fund's performance may be more vulnerable to   changes in the market value of a single issuer or group of issuers and more   susceptible to risks associated with a single economic, political or regulatory   occurrence than a diversified fund.
Risk Lose Money [Text]	rr_RiskLoseMoney	The fund's share price fluctuates, sometimes dramatically, which means you could lose money.
Risk Nondiversified Status [Text]	rr_RiskNondiversifiedStatus	The fund is non-diversified, meaning that a relatively high percentage of the fund's assets may be invested in a limited number of issuers. Therefore, the fund's performance may be more vulnerable to changes in the market value of a single issuer or group of issuers and more susceptible to risks associated with a single economic, political or regulatory occurrence than a diversified fund.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the fund is not a bank deposit. It is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency.
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	Performance
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The following bar chart and table provide some indication of the risks of investing in the fund. The table compares the average annual total returns of the fund's shares to those of a broad measure of market performance. The fund's past performance (before and after taxes) is no guarantee of future results. More recent performance information may be available at www.dreyfus.com.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	The following bar chart and table provide some indication of the risks of investing in the fund.
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	www.dreyfus.com
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	The fund's past performance (before and after taxes) is no guarantee of future results.
Bar Chart [Heading]	rr_BarChartHeading	Year-by-Year Total Returns as of 12/31 each year (%) -- Class A
Bar Chart Narrative [Text Block]	rr_BarChartNarrativeTextBlock	The bar chart shows changes in the performance of the fund's Class A shares from year to year. Sales charges, if any, are not reflected in the bar chart, and if those charges were included, returns would have been less than those shown.
Bar Chart Does Not Reflect Sales Loads [Text]	rr_BarChartDoesNotReflectSalesLoads	Sales charges, if any, are not reflected in the bar chart, and if those charges were included, returns would have been less than those shown.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Best Quarter               Q3, 2009: 7.31%            Worst Quarter              Q4, 2010: -4.94%           The year to date total return of the fund's Class A shares as of 6/30/12 was 4.11%.
Index No Deduction for Fees, Expenses, Taxes [Text]	rr_IndexNoDeductionForFeesExpensesTaxes	reflects no deduction for fees, expenses or taxes
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	After-tax returns are calculated using the historical highest individual federal marginal 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 the investor's tax situation and may differ from those shown, and the after tax returns shown are not relevant to investors who hold their 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 performance is shown only for Class A shares. After tax performance of the fund's other share classes will vary.
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	After-tax performance is shown only for Class A shares. After tax performance of the fund's other share classes will vary. After-tax returns are calculated using the historical highest individual federal marginal tax rates, and do not reflect the impact of state and local taxes. Actual after-tax returns depend on the investor's tax situation and may differ from those shown, and the after tax returns shown are not relevant to investors who hold their shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts.
Caption	rr_AverageAnnualReturnCaption	Average Annual Total Returns as of 12/31/11
Dreyfus Massachusetts Fund (Prospectus Summary) | Dreyfus Massachusetts Fund | Barclays Municipal Bond Index
Risk Return [Abstract]	rr_RiskReturnAbstract
Label	rr_AverageAnnualReturnLabel	Barclays Municipal Bond Index reflects no deduction for fees, expenses or taxes
1 Year	rr_AverageAnnualReturnYear01	10.70%
5 Years	rr_AverageAnnualReturnYear05	5.22%
10 Years	rr_AverageAnnualReturnYear10	5.38%
Since Inception	rr_AverageAnnualReturnSinceInception	4.86%
Dreyfus Massachusetts Fund (Prospectus Summary) | Dreyfus Massachusetts Fund | Class A
Risk Return [Abstract]	rr_RiskReturnAbstract
Maximum sales charge (load) imposed on purchases (as a percentage of offering price)	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	4.50%
Maximum deferred sales charge (load) (as a percentage of lower of purchase or sale price)	rr_MaximumDeferredSalesChargeOverOfferingPrice	none
Management fees	rr_ManagementFeesOverAssets	0.55%
Distribution (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses (including shareholder services fees)	rr_OtherExpensesOverAssets	0.40%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.95%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	543
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	739
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	952
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	1,564
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	543
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	739
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	952
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	1,564
Annual Return 2002	rr_AnnualReturn2002	9.42%
Annual Return 2003	rr_AnnualReturn2003	4.85%
Annual Return 2004	rr_AnnualReturn2004	4.81%
Annual Return 2005	rr_AnnualReturn2005	3.36%
Annual Return 2006	rr_AnnualReturn2006	4.06%
Annual Return 2007	rr_AnnualReturn2007	2.04%
Annual Return 2008	rr_AnnualReturn2008	(5.76%)
Annual Return 2009	rr_AnnualReturn2009	14.42%
Annual Return 2010	rr_AnnualReturn2010	1.16%
Annual Return 2011	rr_AnnualReturn2011	10.85%
Year to Date Return, Label	rr_YearToDateReturnLabel	The year to date total return of the fund's Class A shares
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Jun. 30, 2012
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	4.11%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Sep. 30, 2009
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	7.31%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2010
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(4.94%)
Label	rr_AverageAnnualReturnLabel	Class A returns before taxes
1 Year	rr_AverageAnnualReturnYear01	5.84%
5 Years	rr_AverageAnnualReturnYear05	3.34%
10 Years	rr_AverageAnnualReturnYear10	4.30%
Since Inception	rr_AverageAnnualReturnSinceInception
Dreyfus Massachusetts Fund (Prospectus Summary) | Dreyfus Massachusetts Fund | Class A | After Taxes on Distributions
Risk Return [Abstract]	rr_RiskReturnAbstract
Label	rr_AverageAnnualReturnLabel	Class A returns after taxes on distributions
1 Year	rr_AverageAnnualReturnYear01	5.77%
5 Years	rr_AverageAnnualReturnYear05	3.29%
10 Years	rr_AverageAnnualReturnYear10	4.25%
Since Inception	rr_AverageAnnualReturnSinceInception
Dreyfus Massachusetts Fund (Prospectus Summary) | Dreyfus Massachusetts Fund | Class A | After Taxes on Distributions and Sales
Risk Return [Abstract]	rr_RiskReturnAbstract
Label	rr_AverageAnnualReturnLabel	Class A returns after taxes on distributions and sale of fund shares
1 Year	rr_AverageAnnualReturnYear01	5.18%
5 Years	rr_AverageAnnualReturnYear05	3.39%
10 Years	rr_AverageAnnualReturnYear10	4.24%
Since Inception	rr_AverageAnnualReturnSinceInception
Dreyfus Massachusetts Fund (Prospectus Summary) | Dreyfus Massachusetts Fund | Class C
Risk Return [Abstract]	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	0.55%
Distribution (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.75%
Other expenses (including shareholder services fees)	rr_OtherExpensesOverAssets	0.41%
Total annual fund operating expenses	rr_ExpensesOverAssets	1.71%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	274
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	539
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	928
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	2,019
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	174
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	539
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	928
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	2,019
Label	rr_AverageAnnualReturnLabel	Class C returns before taxes
1 Year	rr_AverageAnnualReturnYear01	9.13%
5 Years	rr_AverageAnnualReturnYear05	3.51%
10 Years	rr_AverageAnnualReturnYear10	4.00%
Since Inception	rr_AverageAnnualReturnSinceInception
Dreyfus Massachusetts Fund (Prospectus Summary) | Dreyfus Massachusetts Fund | Class Z
Risk Return [Abstract]	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	0.55%
Distribution (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	none
Other expenses (including shareholder services fees)	rr_OtherExpensesOverAssets	0.19%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.74%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	76
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	237
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	411
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	918
Expense Example, No Redemption, 1 Year	rr_ExpenseExampleNoRedemptionYear01	76
Expense Example, No Redemption, 3 Years	rr_ExpenseExampleNoRedemptionYear03	237
Expense Example, No Redemption, 5 Years	rr_ExpenseExampleNoRedemptionYear05	411
Expense Example, No Redemption, 10 Years	rr_ExpenseExampleNoRedemptionYear10	918
Label	rr_AverageAnnualReturnLabel	Class Z returns before taxes
1 Year	rr_AverageAnnualReturnYear01	11.19%
5 Years	rr_AverageAnnualReturnYear05	4.51%
10 Years	rr_AverageAnnualReturnYear10
Since Inception	rr_AverageAnnualReturnSinceInception	4.28%
Inception Date	rr_AverageAnnualReturnInceptionDate	Oct. 20, 2004