Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Tenant and other receivables, allowance (in dollars)	$ 20,947	$ 21,652
Deferred rents receivable, allowance (in dollars)	28,475	29,580
Debt and preferred equity investments, discount (in dollars)	11,251	13,572
Debt and preferred equity investments, allowance (in dollars)	$ 7,000	$ 7,000
SL Green partners' capital, general partner common units outstanding	941	940
SL Green partners' capital, limited partner common units outstanding	90,614	90,310
Limited partner interests in Operating Partnership, limited partner common units outstanding	2,586	2,760
Series H Preferred Units
Preferred Units, liquidation preference (in dollars per unit)	$ 25.00	$ 25.00
Preferred units, issued	80	80
Preferred units, outstanding	80	80
Series C preferred units
Preferred units, outstanding	7,700	7,700
Series I Preferred Units
Preferred units, outstanding	9,200	9,200
Series G Preferred Units
Preferred Units, liquidation preference (in dollars per unit)	$ 25.00	$ 25.00
Preferred units, issued	1,902	1,902
Preferred units, outstanding	1,902	1,902