Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Commercial real estate properties, at cost:
Land and land interests	$ 2,872,822	$ 2,684,626
Building and improvements	7,310,651	7,147,527
Building leasehold and improvements	1,316,523	1,302,790
Property under capital lease	12,208	12,208
Total commercial real estate properties, at cost	11,512,204	11,147,151
Less: accumulated depreciation	(1,269,979)	(1,136,603)
Total commercial real estate properties, net	10,242,225	10,010,548
Assets held for sale	91,574	76,562
Cash and cash equivalents	256,799	138,192
Restricted cash	138,493	86,584
Investment in marketable securities	23,502	25,323
Tenant and other receivables, net of allowance of $20,826 and $16,772 in 2012 and 2011, respectively	32,728	32,107
Related party receivables	7,793	4,001
Deferred rents receivable, net of allowance of $31,343 and $29,156 in 2012 and 2011, respectively	315,700	281,974
Debt and preferred equity investments, net of discount of $22,601 and $24,996 and allowance of $41,050 and $50,175 in 2012 and 2011, respectively	982,209	985,942
Investments in unconsolidated joint ventures	1,014,042	893,933
Deferred costs, net	249,147	210,786
Other assets	784,901	737,900
Total assets	14,139,113	13,483,852
Liabilities
Mortgages and other loans payable	4,861,463	4,314,741
Revolving credit facility	80,000	350,000
Senior unsecured notes	1,173,769	1,270,656
Accrued interest payable and other liabilities	114,003	126,135
Accounts payable and accrued expenses	140,910	142,428
Deferred revenue/gains	352,151	357,193
Capitalized lease obligation	17,148	17,112
Deferred land leases payable	18,721	18,495
Dividend and distributions payable	30,126	28,398
Security deposits	47,463	46,367
Liabilities related to assets held for sale	62,792	61,988
Junior subordinate deferrable interest debentures held by trusts that issued trust preferred securities	100,000	100,000
Total liabilities	6,998,546	6,833,513
Commitments and contingencies
Noncontrolling interest in operating partnership	279,685	195,030
SL Green stockholders' equity:
Common stock, $0.01 par value 160,000 shares authorized and 93,543 and 89,210 issued and outstanding at June 30, 2012 and December 31, 2011, respectively (including 3,605 and 3,427 shares at June 30, 2012 and December 31, 2011, held in Treasury, respectively)	936	892
Additional paid-in-capital	4,557,652	4,236,959
Treasury stock at cost	(319,866)	(308,708)
Accumulated other comprehensive loss	(28,413)	(28,445)
Retained earnings	1,741,160	1,704,506
Total SL Green stockholders' equity	6,321,812	5,975,547
Noncontrolling interests in other partnerships	489,520	477,762
Total equity	6,811,332	6,453,309
Total liabilities and equity	14,139,113	13,483,852
Series C Preferred Stock
SL Green stockholders' equity:
Preferred stock	274,022	274,022
Total equity	274,022	274,022
Series D Preferred Stock
SL Green stockholders' equity:
Preferred stock	96,321	96,321
Total equity	96,321	96,321
Series H Preferred Units
Liabilities
Preferred Units	2,000	2,000
Series G Preferred Units
Liabilities
Preferred Units	$ 47,550