Label	Element	Value
Investor Shares Prospectus \| Dreyfus Municipal Cash Management Plus
Risk/Return:	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Fund Summary - Dreyfus Municipal Cash Management Plus
Objective [Heading]	rr_ObjectiveHeading	Investment Objective
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The fund seeks as high a level of current income exempt from federal income tax as is consistent with the preservation of capital and the maintenance of liquidity.
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.
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)
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:
Strategy [Heading]	rr_StrategyHeading	Principal Investment Strategy
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	As a money market fund, the fund is subject to the maturity, quality, liquidity and diversification requirements of Rule 2a-7 under the Investment Company Act of 1940, as amended, which are designed to help money market funds maintain a stable share price of $1.00. To pursue its goal, the fund normally invests substantially all of its assets in short-term, high quality municipal obligations that provide income exempt from federal income taxes. The fund also may invest in high quality, short-term structured notes, which are derivative instruments whose value is tied to underlying municipal obligations. The fund seeks to provide income exempt from the federal alternative minimum tax. The fund may invest temporarily in high quality, taxable money market instruments, including when the portfolio manager believes that acceptable municipal obligations are unavailable for investment.
Risk [Heading]	rr_RiskHeading	Principal Risks
Risk Narrative [Text Block]	rr_RiskNarrativeTextBlock	An investment in the fund is not a bank deposit. An investment in the fund is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. You could lose money by investing in the fund. Although the fund seeks to preserve the value of your investment at $1.00 per share, it cannot guarantee it will do so. Neither The Dreyfus Corporation nor its affiliates has a legal obligation to provide financial support to the fund, and you should not expect that The Dreyfus Corporation or its affiliates will provide financial support to the fund at any time. The fund's yield will fluctuate as the short-term securities in its portfolio mature and the proceeds are reinvested in securities with different interest rates. The following are the principal risks that could reduce the fund's income level and/or share price: · Interest rate risk. This risk refers to the decline in the prices of fixed-income securities that may accompany a rise in the overall level of interest rates. A sharp and unexpected rise in interest rates could cause a money market fund's share price to drop below a dollar. A low interest rate environment may prevent the fund from providing a positive yield or paying fund expenses out of fund assets and could impair the fund's ability to maintain a stable net asset value. · 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 in a timely manner at or near their perceived value. In such a market, the value of such securities may fall dramatically, potentially impairing the fund's ability to maintain a stable net asset value, even during periods of declining interest rates. · Credit risk. Failure of an issuer of a security to make timely interest or principal payments when due, or a decline or perception of a decline in the credit quality of a security, can cause the security's price to fall. Although the fund invests only in high quality debt securities, the credit quality and prices of the securities held by the fund can change rapidly in certain market environments, and the default or a significant price decline of a single holding could impair the fund's ability to maintain a stable net asset value. · Regulatory risk. The Securities and Exchange Commission has adopted amendments to the rules governing money market funds that will change the way that the fund, and similar money market funds, operates. The amended rules permit, and in some cases will require, the fund to impose a "liquidity fee" of up to 2% of the amount redeemed or temporarily restrict shareholder redemptions from the fund. The liquidity fee or redemption restrictions could be applied (subject to board determination) when the fund's "weekly liquid assets"—including cash, certain U.S. government securities and securities maturing in five business days—fall below 30% of the fund's total assets. These changes are anticipated to take effect on October 14, 2016. The changes to the rules may affect fund investment strategies and the cost of operating the fund. · Municipal securities risk. The amount of public information available about municipal securities 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 securities. Other factors include the general conditions of the municipal securities market, the size of the particular offering, the maturity of the obligation and the rating of the issue. · Tax risk. To be tax-exempt, municipal obligations generally must meet certain regulatory requirements. If any such municipal obligation fails to meet these regulatory requirements, the interest received by the fund from its investment in such obligations and distributed to fund shareholders will be taxable. · Structured notes risk. Structured notes, a type of derivative instrument, can be volatile, and the possibility of default by the financial institution or counterparty may be greater for these instruments than for other types of money market instruments. Structured notes typically are purchased in privately negotiated transactions from financial institutions and, thus, an active trading market for such instruments may not exist.
Risk Money Market Fund [Text]	rr_RiskMoneyMarketFund	Although the fund seeks to preserve the value of your investment at $1.00 per share, it cannot guarantee it will do so.
Risk Not Insured Depository Institution [Text]	rr_RiskNotInsuredDepositoryInstitution	An investment in the fund is not a bank deposit. An investment in the fund 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 bar chart shows changes in the performance of the fund's Investor shares from year to year. The table shows the average annual total returns of the fund's Investor shares over time. The fund's past performance is not necessarily an indication of how the fund will perform in the future. 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 is not necessarily an indication of how the fund will perform in the future.
Bar Chart [Heading]	rr_BarChartHeading	Year-by-Year Total Returns as of 12/31 each year (%)
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	Best Quarter Q2, 2007: 0.84% Worst Quarter Q3, 2015: 0.00% The year-to-date total return of the fund's Investor shares as of 3/31/16 was 0.02%.
Year to Date Return, Label	rr_YearToDateReturnLabel	year-to-date total return
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Mar. 31, 2016
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	0.02%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	Best Quarter
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2007
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	0.84%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	Worst Quarter
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Sep. 30, 2015
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	none
Performance Table Closing [Text Block]	rr_PerformanceTableClosingTextBlock	For the current yield for Investor shares call toll-free 1-800-346-3621. Individuals or entities for whom institutions may purchase or redeem shares should call the institution directly.
Caption	rr_AverageAnnualReturnCaption	Average Annual Total Returns as of 12/31/15
Money Market Seven Day Yield Phone	rr_MoneyMarketSevenDayYieldPhone	1-800-346-3621
Investor Shares Prospectus \| Dreyfus Municipal Cash Management Plus \| Investor Shares
Risk/Return:	rr_RiskReturnAbstract
Management fees	rr_ManagementFeesOverAssets	0.20%
Distribution and/or service (12b-1) fees	rr_DistributionAndService12b1FeesOverAssets	0.25%
Other expenses	rr_OtherExpensesOverAssets	0.09%
Total annual fund operating expenses	rr_ExpensesOverAssets	0.54%
Expense Example, with Redemption, 1 Year	rr_ExpenseExampleYear01	$ 55
Expense Example, with Redemption, 3 Years	rr_ExpenseExampleYear03	173
Expense Example, with Redemption, 5 Years	rr_ExpenseExampleYear05	302
Expense Example, with Redemption, 10 Years	rr_ExpenseExampleYear10	$ 677
Annual Return 2006	rr_AnnualReturn2006	3.06%
Annual Return 2007	rr_AnnualReturn2007	3.28%
Annual Return 2008	rr_AnnualReturn2008	2.08%
Annual Return 2009	rr_AnnualReturn2009	0.34%
Annual Return 2010	rr_AnnualReturn2010	none
Annual Return 2011	rr_AnnualReturn2011	none
Annual Return 2012	rr_AnnualReturn2012	none
Annual Return 2013	rr_AnnualReturn2013	none
Annual Return 2014	rr_AnnualReturn2014	none
Annual Return 2015	rr_AnnualReturn2015	0.01%
Average Annual Returns, 1 Year	rr_AverageAnnualReturnYear01	0.01%
Average Annual Returns, 5 Years	rr_AverageAnnualReturnYear05	none
Average Annual Returns, 10 Years	rr_AverageAnnualReturnYear10	0.87%

If the Fund has annual returns for at least one calendar year, provide a bar chart showing the Fund's annual total returns for each of the last 10 calendar years (or for the life of the Fund if less than 10 years), but only for periods subsequent to the effective date of the Fund's registration statement. Present the corresponding numerical return adjacent to each bar. If the Fund's fiscal year is other than a calendar year, include the year-to-date return information as of the end of the most recent quarter in a footnote to the bar chart. Following the bar chart, disclose the Fund's highest and lowest return for a quarter during the 10 years or other period of the bar chart. When a Multiple Class Fund offers more than one Class in the prospectus, provide annual total returns in the bar chart for only one of those Classes. The Fund can select which Class to include (e.g., the oldest Class, the Class with the greatest net assets).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form
-Number N-1A
-Chapter A
-Section 4
-Subsection b
-Paragraph 2
-Subparagraph ii