Partners' Capital of the Operating Partnership-EPS (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Stockholders' Equity
Net income attributable to SL Green common stockholders	$ 146,090	$ 18,909
Basic weighted average common shares outstanding (in shares)	95,117,000	91,399,000
Stock-based compensation plans (in shares)	520,000	216,000
Common stock shares excluded from the diluted shares outstanding	860,720	988,887
SL Green Operating Partnership
Stockholders' Equity
Net income attributable to SL Green common stockholders	$ 150,819	$ 19,464
Basic weighted average common shares outstanding (in shares)	98,196,000	94,086,000
Stock-based compensation plans (shares)	520,000	216,000
Diluted weighted average common units outstanding (shares)	98,716,000	94,302,000
Common stock shares excluded from the diluted shares outstanding	860,720	988,887