Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Commercial real estate properties, at cost:
Land and land interests	$ 2,684,626	$ 1,750,220
Building and improvements	7,147,527	5,840,701
Building leasehold and improvements	1,302,790	1,286,935
Property under capital lease	12,208	12,208
Total commercial real estate properties, at cost	11,147,151	8,890,064
Less: accumulated depreciation	(1,136,603)	(916,293)
Total commercial real estate properties, net	10,010,548	7,973,771
Assets held for sale	76,562
Cash and cash equivalents	138,192	332,830
Restricted cash	86,584	137,673
Investment in marketable securities	25,323	34,052
Tenant and other receivables, net of allowance of $16,772 and $12,981 in 2011 and 2010, respectively	32,107	27,054
Related party receivables	4,001	6,295
Deferred rents receivable, net of allowance of $29,156 and $30,834 in 2011 and 2010, respectively	281,974	201,317
Debt and preferred equity investments, net of discount of $24,996 and $42,937 and allowance of $50,175 and $61,361 in 2011 and 2010, respectively	985,942	963,772
Investments in unconsolidated joint ventures	893,933	631,570
Deferred costs, net	210,786	172,517
Other assets	737,900	819,443
Total assets	13,483,852	11,300,294
Liabilities
Mortgages and other loans payable	4,314,741	3,400,468
Revolving credit facility	350,000	650,000
Senior unsecured notes	1,270,656	1,100,545
Accrued interest payable and other liabilities	126,135	38,149
Accounts payable and accrued expenses	142,428	133,389
Deferred revenue/gains	357,193	307,678
Capitalized lease obligation	17,112	17,044
Deferred land leases payable	18,495	18,267
Dividend and distributions payable	28,398	14,182
Security deposits	46,367	38,690
Liabilities related to assets held for sale	61,988
Junior subordinate deferrable interest debentures held by trusts that issued trust preferred securities	100,000	100,000
Total liabilities	6,833,513	5,818,412
Commitments and contingencies
Noncontrolling interests in operating partnership	195,030	84,338
SL Green stockholders equity:
Common stock, $0.01 par value, 160,000 shares authorized and 89,210 and 81,675 issued and outstanding at December 31, 2011 and 2010, respectively (including 3,427 and 3,369 shares at December 31, 2011 and 2010 held in Treasury, respectively)	892	817
Additional paid-in-capital	4,236,959	3,660,842
Treasury stock at cost	(308,708)	(303,222)
Accumulated other comprehensive loss	(28,445)	(22,659)
Retained earnings	1,704,506	1,172,963
Total SL Green stockholders' equity	5,975,547	4,879,084
Noncontrolling interests in other partnerships	477,762	518,460
Total equity	6,453,309	5,397,544
Total liabilities and equity	13,483,852	11,300,294
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
6.00% Series H Preferred Units, $0.01 par value, $25.00 liquidation preference, 80 issued and outstanding at December 31, 2011	$ 2,000