Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly distributions declared, per share/unit (usd per share/unit)	$ 0.775	$ 0.72	$ 0.60
SL Green Operating Partnership
Quarterly distributions declared, per share/unit (usd per share/unit)	$ 0.775	$ 0.72	$ 0.6
388-390 Greenwich Street
Amortization of below market leases	$ 172.4
388-390 Greenwich Street | SL Green Operating Partnership
Amortization of below market leases	$ 172.4