Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net income									$ 151,283	$ 209,700	$ 677,122
Other comprehensive income (loss):
Change in net unrealized gain (loss) on derivative instruments, including SL Green's share of joint venture net unrealized gain (loss) on derivative instruments									13,490	2,127	(3,346)
Change in unrealized gain (loss) on marketable securities									1,497	(3,657)	(2,731)
Other comprehensive income (loss)									14,987	(1,530)	(6,077)
Comprehensive income									166,270	208,170	671,045
Net income attributable to noncontrolling interests									(15,912)	(13,295)	(29,712)
Other comprehensive (income) loss attributable to noncontrolling interests									(611)	388	291
Comprehensive income attributable to SL Green									149,747	195,263	641,624
SL Green Operating Partnership
Net income									151,283	209,700	677,122
Other comprehensive income (loss):
Change in net unrealized gain (loss) on derivative instruments, including SL Green's share of joint venture net unrealized gain (loss) on derivative instruments									13,490	2,127	(3,346)
Change in unrealized gain (loss) on marketable securities									1,497	(3,657)	(2,731)
Other comprehensive income (loss)									14,987	(1,530)	(6,077)
Comprehensive income									166,270	208,170	671,045
Net income attributable to noncontrolling interests	41,971	41,873	27,679	26,871	28,084	26,224	114,005	33,689	(10,629)	(5,591)	(15,083)
Comprehensive income attributable to SL Green									$ 155,641	$ 202,579	$ 655,962