Partners' Capital of the Operating Partnership-EPS (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Stockholders' Equity
Net income basic	$ 235,541	$ 8,276	$ 381,631	$ 27,185
Net income diluted	244,186	8,520	395,005	27,984
Basic weighted average common shares outstanding (in shares)	95,455,000	91,660,000	95,288,000	91,530,000
Common stock shares excluded from the diluted shares outstanding	748,000	894,000	797,000	939,000
SL Green Operating Partnership
Stockholders' Equity
Net income basic	244,186	8,520	395,005	27,984
Net income diluted	$ 244,186	$ 8,520	$ 395,005	$ 27,984
Basic weighted average common shares outstanding (in shares)	98,970,000	94,312,000	98,627,000	94,224,000
Stock-based compensation plans (shares)	514,000	224,000	501,000	228,000
Diluted weighted average common units outstanding (shares)	99,484,000	94,536,000	99,128,000	94,452,000
Common stock shares excluded from the diluted shares outstanding	748,000	894,000	797,000	939,000