Consolidated Statements of Capital Statement (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2014
Increase (Decrease) in Stockholders' Equity
Other comprehensive income	$ 8,952	$ 9,249
DRIP proceeds		26
Redemption of units		23,066
Deferred compensation plan and stock award, net		(1,390)
Amortization of deferred compensation plan		17,069
Contributions to consolidated joint venture interest		1,673
Cash distributions to noncontrolling interests		(4,352)
Common Stock
Increase (Decrease) in Stockholders' Equity
Redemption of units		2
Redemption of units (in units)		233
Deferred compensation plan and stock award, net		0
Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity
Contributions to consolidated joint venture interest		1,673
Cash distributions to noncontrolling interests		(4,352)
SL Green Operating Partnership
Increase (Decrease) in Stockholders' Equity
Beginning Balance		7,282,352
Net income		405,813
Other comprehensive income	8,952	9,249
Preferred distributions		(7,475)
Issuance of common units		19,460
DRIP proceeds		26
Redemption of units		0
Deferred compensation plan and stock award, net		(1,390)
Amortization of deferred compensation plan		17,069
Contributions to consolidated joint venture interest		1,673
Contributions—net proceeds from common stock offering		8,750
Contributions—proceeds from stock options exercised		19,751
Cash distributions to noncontrolling interests		(4,352)
Cash distribution declared ($1.00 per common unit, none of which represented a return of capital for federal income tax purposes)		(98,874)
Ending Balance	7,652,052	7,652,052
SL Green Operating Partnership | General Partner
Increase (Decrease) in Stockholders' Equity
Beginning Balance		6,506,747
Balance (shares)		94,993
Net income		381,631
DRIP proceeds		26
DRIP proceeds (in units)		0
Redemption of units		23,066
Redemption of units (in units)		233
Deferred compensation plan and stock award, net		(1,390)
Deferred compensation plan and stock award, net (in units)		2
Amortization of deferred compensation plan		17,069
Contributions—net proceeds from common stock offering		8,750
Contributions—net proceeds from common stock offering (in units)		82
Contributions—proceeds from stock options exercised		19,751
Contributions—proceeds from stock options exercised (in units)		277
Cash distribution declared ($1.00 per common unit, none of which represented a return of capital for federal income tax purposes)		(95,276)
Ending Balance	6,860,374	6,860,374
Balance (shares)	95,587	95,587
SL Green Operating Partnership | Limited Partners
Increase (Decrease) in Stockholders' Equity
Balance (shares)		2,902
Issuance of common units (in units)		833
Redemption of units (in units)		(235)
Deferred compensation plan and stock award, net (in units)
Balance (shares)	3,500	3,500
SL Green Operating Partnership | Series I Preferred Stock
Increase (Decrease) in Stockholders' Equity
Beginning Balance		221,932
Net income		7,475
Preferred distributions		(7,475)
Ending Balance	221,932	221,932
SL Green Operating Partnership | Common Stock | Limited Partners
Increase (Decrease) in Stockholders' Equity
Beginning Balance		77,864
Net income		13,374
Issuance of common units		19,460
Redemption of units		(23,066)
Cash distribution declared ($1.00 per common unit, none of which represented a return of capital for federal income tax purposes)		(3,598)
Ending Balance	84,034	84,034
SL Green Operating Partnership | Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity
Beginning Balance		(15,662)
Other comprehensive income		9,249
Ending Balance	(6,413)	(6,413)
SL Green Operating Partnership | Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity
Beginning Balance		491,471
Net income		3,333
Contributions to consolidated joint venture interest		1,673
Cash distributions to noncontrolling interests		(4,352)
Ending Balance	$ 492,125	$ 492,125