Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Tenant and other receivables, allowance	$ 18,363	$ 18,637
Deferred rents receivable, allowance	16,897	17,207
Debt and preferred equity investments, discount and deferred origination fees	$ 24,998	$ 25,507
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)	90,190,000	93,858,000
Common stock, shares outstanding (in shares)	90,190,000	93,858,000
Treasury stock, shares (in shares)	1,055,000	1,055,000
Land and land interests	$ 2,098,406	$ 2,357,051
Building and improvements	5,206,982	6,351,012
Building leasehold and improvements	1,420,346	1,450,614
Properties under capital lease	47,445	47,445
Accumulated depreciation	1,944,629	2,300,116
Other assets	360,556	310,688
Mortgages and other loans payable, net	2,433,994	2,837,282
Accrued interest payable	36,808	38,142
Capital lease obligations	43,029	42,843
Other liabilities	$ 103,654	$ 188,005
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	$ 174,800	$ 398,000
Building and improvements	300,000	1,400,000
Building leasehold and improvements	2,000	2,000
Properties under capital lease	47,400	47,400
Accumulated depreciation	29,800	330,900
Other assets	706,000	221,000
Mortgages and other loans payable, net	134,400	628,900
Accrued interest payable	400	2,500
Capital lease obligations	43,000	42,800
Other liabilities	17,700	56,800
SL Green Operating Partnership
Tenant and other receivables, allowance	18,363	18,637
Deferred rents receivable, allowance	16,897	17,207
Debt and preferred equity investments, discount and deferred origination fees	$ 24,998	$ 25,507
Limited partner interests in Operating Partnership, limited partner common units outstanding (shares)	4,715,000	4,453,000
SL Green partner's capital, general partner common units outstanding (shares)	939,000	973,000
SL Green partners' capital, limited partner common units outstanding (shares)	88,196,000	91,831,000
Land and land interests	$ 2,098,406	$ 2,357,051
Building and improvements	5,206,982	6,351,012
Building leasehold and improvements	1,420,346	1,450,614
Properties under capital lease	47,445	47,445
Accumulated depreciation	1,944,629	2,300,116
Other assets	360,556	310,688
Mortgages and other loans payable, net	2,433,994	2,837,282
Accrued interest payable	36,808	38,142
Capital lease obligations	43,029	42,843
Other liabilities	$ 103,654	$ 188,005
SL Green Operating Partnership | Series I Preferred Stock
Preferred units, liquidation preference (in dollars per share)	$ 25.00	$ 25.00
Preferred units, shares issued (in shares)	9,200,000	9,200,000
Preferred units, shares outstanding (in shares)	9,200,000	9,200,000
SL Green Operating Partnership | Consolidated VIEs
Land and land interests	$ 174,800	$ 398,000
Building and improvements	300,000	1,400,000
Building leasehold and improvements	2,000	2,000
Properties under capital lease	47,400	47,400
Accumulated depreciation	29,800	330,900
Other assets	706,000	221,000
Mortgages and other loans payable, net	134,400	628,900
Accrued interest payable	400	2,500
Capital lease obligations	43,000	42,800
Other liabilities	$ 17,700	$ 56,800