Partners' Capital of the Operating Partnership (Details)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Common Stock
Stockholders' Equity
Shares outstanding (shares)	94,993,000	91,250,000	85,783,000	78,307,000
SL Green Operating Partnership
Stockholders' Equity
Noncontrolling interest in the operating partnership (as a percent)	2.96%	2.94%
Number of units of operating partnership owned by the noncontrolling interest unit holders (shares)	2,902,317	2,759,758
SL Green Operating Partnership | Common Stock
Stockholders' Equity
Shares outstanding (shares)	94,993,284
SL Green Operating Partnership | Series I Preferred Units
Stockholders' Equity
Shares outstanding (shares)	9,200,000