Segment Information (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Reconciliation of income from continuing operations to net income attributable to SL Green common stockholders
Income from continuing operations before purchase price fair value adjustment and equity in net gain (loss) on sale of interest in unconsolidated joint venture/real estate	$ 58,318	$ 33,298	$ 106,500	$ 57,841
Purchase price fair value adjustment	71,446	(2,305)	71,446	(2,305)
Equity in net gain (loss) on sale of interest in unconsolidated joint venture/real estate	1,444	(3,583)	106,084	(3,583)
Income from continuing operations	131,208	27,410	284,030	51,953
Net income from discontinued operations	4,389	3,838	8,178	8,519
Gain on sale of discontinued operations	114,735	0	114,735	1,113
Net income	$ 250,332	$ 31,248	$ 406,943	$ 61,585