Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Tenant and other receivables, allowance	$ 18,365	$ 16,592
Deferred rents receivable, allowance	21,257	25,203
Debt and preferred equity investments, discount and deferred origination fees	$ 24,782	$ 16,705
Preferred stock, par value (in dollars per share)	$ 0.01
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	160,000,000	160,000,000
Common stock, shares issued (in shares)	98,501,000	101,617,000
Common stock, shares outstanding (in shares)	98,501,000	101,617,000
Treasury stock, shares (in shares)	1,055,000	1,055,000
Land and land interests	$ 2,917,993	$ 3,309,710
Building and improvements	7,468,436	7,948,852
Building leasehold and improvements	1,444,698	1,437,325
Properties under capital lease	47,445	47,445
Accumulated depreciation	2,457,071	2,264,694
Other assets	395,612	614,067
Mortgages and other loans payable, net	3,804,174	4,073,830
Accrued interest payable	34,367	36,052
Capital lease obligations	42,660	42,132
Other liabilities	$ 95,718	$ 206,238
Series I Preferred Stock
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, liquidation preference (in dollars per share)	$ 25.00	$ 25.00
Preferred stock, shares issued (in shares)	9,200,000	9,200,000
Preferred stock, shares outstanding (in shares)	9,200,000	9,200,000
Consolidated VIEs
Land and land interests	$ 384,300	$ 412,300
Building and improvements	1,400,000	1,500,000
Building leasehold and improvements	2,000	2,000
Properties under capital lease	47,400	47,400
Accumulated depreciation	323,300	327,200
Other assets	235,400	244,200
Mortgages and other loans payable, net	627,800	621,800
Accrued interest payable	2,500	2,200
Capital lease obligations	42,700	42,100
Other liabilities	58,500	73,300
SL Green Operating Partnership
Tenant and other receivables, allowance	18,365	16,592
Deferred rents receivable, allowance	21,257	25,203
Debt and preferred equity investments, discount and deferred origination fees	$ 24,782	$ 16,705
Limited partner interests in Operating Partnership, limited partner common units outstanding (shares)	4,542,000	4,364,000
SL Green partner's capital, general partner common units outstanding (shares)	1,020,000	1,049,000
SL Green partners' capital, limited partner common units outstanding (shares)	96,426,000	99,513,000
Land and land interests	$ 2,917,993	$ 3,309,710
Building and improvements	7,468,436	7,948,852
Building leasehold and improvements	1,444,698	1,437,325
Properties under capital lease	47,445	47,445
Accumulated depreciation	2,457,071	2,264,694
Other assets	395,612	614,067
Mortgages and other loans payable, net	3,804,174	4,073,830
Accrued interest payable	34,367	36,052
Capital lease obligations	42,660	42,132
Other liabilities	$ 95,718	$ 206,238
SL Green Operating Partnership | Series I Preferred Stock
Preferred units, liquidation preference (in dollars per share)	$ 25.00	$ 25.00
Preferred units, shares issued	9,200,000	9,200,000
Preferred units, shares outstanding	9,200,000	9,200,000
SL Green Operating Partnership | Consolidated VIEs
Land and land interests	$ 384,300	$ 412,300
Building and improvements	1,400,000	1,500,000
Building leasehold and improvements	2,000	2,000
Properties under capital lease	47,400	47,400
Accumulated depreciation	323,300	327,200
Other assets	235,400	244,200
Mortgages and other loans payable, net	267,800	621,800
Accrued interest payable	2,500	2,200
Capital lease obligations	42,700	42,100
Other liabilities	$ 58,500	$ 73,300