Consolidated Statement of Capital Consolidated Statement of Capital (Parentheticals) (USD $)	9 Months Ended
Sep. 30, 2013
Statement of Partners' Capital [Abstract]
Cash distribution declared, per common unit (usd per share)	$ 0.0099
Return of capital, per common unit (usd per share)	$ 0

Total distributions per unit to each class of partners (i.e., general, limited and preferred partners).

No definition available.

Name:	slg_PartnersCapitalAccountDistributionsPerUnitDeclared
Namespace Prefix:	slg_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration