Label	Element	Value
DREYFUS NEW YORK MUNICIPAL CASH MANAGEMENT
Risk/Return:	rr_RiskReturnAbstract
Supplement [Text Block]	ck0000878734_SupplementTextBlock	November 30, 2015 DREYFUS NEW YORK MUNICIPAL CASH MANAGEMENT Supplement to Prospectus dated June 1, 2015, As Revised November 30, 2015 Dreyfus New York Municipal Cash Management
Risk/Return [Heading]	rr_RiskReturnHeading	DREYFUS NEW YORK MUNICIPAL CASH MANAGEMENT
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	Until January 1, 2016, notwithstanding any contrary information contained in the prospectus, the fund will normally invest substantially all of its net assets in short-term, high quality municipal obligations that provide income exempt from federal, New York state and New York city income taxes. Thereafter, the fund will normally invest at least 80% of its net assets, plus any borrowings for investment purposes, in such municipal obligations, and may invest a portion of its assets in municipal obligations that do not pay income exempt from New York state and New York city income taxes.

Principal investment strategies of the Fund. Summarize how the Fund intends to achieve its investment objectives by identifying the Fund's principal investment strategies (including the type or types of securities in which the Fund invests or will invest principally) and any policy to concentrate in securities of issuers in a particular industry or group of industries.

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

Name:	rr_StrategyNarrativeTextBlock
Namespace Prefix:	rr_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration