SL Green Realty (SLG) 10-K24 Feb 152014 FY Annual reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Billions, except Share data, unless otherwise specified	Dec. 31, 2014	Feb. 17, 2015	Jun. 30, 2014
Document Information [Line Items]
Entity Registrant Name	SL GREEN REALTY CORP
Entity Central Index Key	1040971
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	FY
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding (shares)		98,625,888
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$9.80
SL Green Operating Partnership
Document Information [Line Items]
Entity Registrant Name	SL GREEN OPERATING PARTNERSHIP, LP.
Entity Central Index Key	1492869
Current Fiscal Year End Date	-19
Entity Filer Category	Non-accelerated Filer
Document Type	10-K
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	FY
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding (shares)		1,005,426
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$0

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Commercial real estate properties, at cost:
Land and land interests	$3,844,518	$3,032,526
Building and improvements	8,778,593	7,884,663
Building leasehold and improvements	1,418,585	1,366,281
Properties under capital lease	27,445	50,310
Total commercial real estate properties, at cost	14,069,141	12,333,780
Less: accumulated depreciation	-1,905,165	-1,646,240
Total commercial real estate properties, net	12,163,976	10,687,540
Assets held for sale	462,430	0
Cash and cash equivalents	281,409	206,692
Restricted cash	149,176	142,051
Investment in marketable securities	39,429	32,049
Tenant and other receivables, net of allowance of $18,068 and $17,325 in 2014 and 2013, respectively	57,369	60,393
Related party receivables	11,735	8,530
Deferred rents receivable, net of allowance of $27,411 and $30,333 in 2014 and 2013, respectively	374,944	386,508
Debt and preferred equity investments, net of discounts and deferred origination fees of $19,172 and $18,593 in 2014 and 2013, respectively, and allowance of $1,000 in 2013	1,408,804	1,304,839
Investments in unconsolidated joint ventures	1,172,020	1,113,218
Deferred costs, net	327,962	267,058
Other assets	647,333	750,123
Total assets	17,096,587	14,959,001
Liabilities
Mortgages and other loans payable	5,586,709	4,860,578
Revolving credit facility	385,000	220,000
Term loan and senior unsecured notes	2,107,078	1,739,330
Accrued interest payable and other liabilities	137,634	114,622
Accounts payable and accrued expenses	173,246	145,889
Deferred revenue	187,148	263,261
Capitalized lease obligations	20,822	47,671
Deferred land leases payable	1,215	22,185
Dividend and distributions payable	64,393	52,255
Security deposits	66,614	61,308
Liabilities related to assets held for sale	266,873	0
Junior subordinate deferrable interest debentures held by trusts that issued trust preferred securities	100,000	100,000
Total liabilities	9,096,732	7,627,099
Commitments and contingencies	0	0
Noncontrolling interests in Operating Partnership	469,524	265,476
Preferred Units	71,115	49,550
Equity
Common stock, $0.01 par value, 160,000 shares authorized and 100,928 and 98,563 issued and outstanding at December 31, 2014 and 2013, respectively (including 3,603 and 3,570 shares held in Treasury at December 31, 2014 and 2013, respectively)	1,010	986
Additional paid-in-capital	5,289,479	5,015,904
Treasury stock at cost	-320,471	-317,356
Accumulated other comprehensive loss	-6,980	-15,211
Retained earnings	1,752,404	1,619,150
Total SL Green stockholders' equity	6,937,374	6,525,405
Noncontrolling interests in other partnerships	521,842	491,471
Total equity	7,459,216	7,016,876
Total liabilities and equity	17,096,587	14,959,001
Series I Preferred Stock
Equity
Series I Preferred Stock, $0.01 par value, $25.00 liquidation preference, 9,200 issued and outstanding at December 31, 2014 and 2013, respectively	221,932	221,932
SL Green Operating Partnership
Commercial real estate properties, at cost:
Land and land interests	3,844,518	3,032,526
Building and improvements	8,778,593	7,884,663
Building leasehold and improvements	1,418,585	1,366,281
Properties under capital lease	27,445	50,310
Total commercial real estate properties, at cost	14,069,141	12,333,780
Less: accumulated depreciation	-1,905,165	-1,646,240
Total commercial real estate properties, net	12,163,976	10,687,540
Assets held for sale	462,430	0
Cash and cash equivalents	281,409	206,692
Restricted cash	149,176	142,051
Investment in marketable securities	39,429	32,049
Tenant and other receivables, net of allowance of $18,068 and $17,325 in 2014 and 2013, respectively	57,369	60,393
Related party receivables	11,735	8,530
Deferred rents receivable, net of allowance of $27,411 and $30,333 in 2014 and 2013, respectively	374,944	386,508
Debt and preferred equity investments, net of discounts and deferred origination fees of $19,172 and $18,593 in 2014 and 2013, respectively, and allowance of $1,000 in 2013	1,408,804	1,304,839
Investments in unconsolidated joint ventures	1,172,020	1,113,218
Deferred costs, net	327,962	267,058
Other assets	647,333	750,123
Total assets	17,096,587	14,959,001
Liabilities
Mortgages and other loans payable	5,586,709	4,860,578
Revolving credit facility	385,000	220,000
Term loan and senior unsecured notes	2,107,078	1,739,330
Accrued interest payable and other liabilities	137,634	114,622
Accounts payable and accrued expenses	173,246	145,889
Deferred revenue	187,148	263,261
Capitalized lease obligations	20,822	47,671
Deferred land leases payable	1,215	22,185
Dividend and distributions payable	64,393	52,255
Security deposits	66,614	61,308
Liabilities related to assets held for sale	266,873	0
Junior subordinate deferrable interest debentures held by trusts that issued trust preferred securities	100,000	100,000
Total liabilities	9,096,732	7,627,099
Commitments and contingencies	0	0
Preferred Units	71,115	49,550
Equity
Accumulated other comprehensive loss	-7,256	-15,662
Total liabilities and equity	17,096,587	14,959,001
SL Green stockholders equity:
SL Green partners' capital (1,013 and 979 general partner common units and 96,312 and 94,014 limited partner common units outstanding at December 31, 2014 and 2013, respectively)	7,078,924	6,506,747
Limited partner interests in SLGOP (3,973 and 2,902 limited partner common units outstanding at December 31, 2014 and 2013, respectively	113,298	77,864
Total SLGOP partners' capital	7,406,898	6,790,881
Noncontrolling interests in other partnerships	521,842	491,471
Total capital	7,928,740	7,282,352
SL Green Operating Partnership \| Series I Preferred Stock
SL Green stockholders equity:
Series I Preferred Units, $25.00 liquidation preference, 9,200 issued and outstanding at both December 31, 2014 and 2013	221,932	221,932
Total capital	$221,932	$221,932

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Tenant and other receivables, allowance (in dollars)	$18,068	$17,325
Deferred rents receivable, allowance (in dollars)	27,411	30,333
Debt and preferred equity investments, discount (in dollars)	19,172	18,593
Debt and preferred equity investments, allowance (in dollars)	0	1,000
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 (shares)	160,000,000	160,000,000
Common stock, shares issued (shares)	100,928,000	98,563,000
Common stock, shares outstanding (shares)	100,928,000	98,563,000
Treasury stock, shares (shares)	3,603,000	3,570,000
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	$25
Preferred stock, shares issued (shares)	9,200,000	9,200,000
Preferred stock, shares outstanding (shares)	9,200,000	9,200,000
SL Green Operating Partnership
Tenant and other receivables, allowance (in dollars)	18,068	17,325
Deferred rents receivable, allowance (in dollars)	27,411	30,333
Debt and preferred equity investments, discount (in dollars)	19,172	18,593
Debt and preferred equity investments, allowance (in dollars)	$0	$1,000
SL Green partner's capital, general partner common units outstanding (shares)	1,013,000	979,000
SL Green partners' capital, limited partner common units outstanding (shares)	96,312,000	94,014,000
Limited partner interests in Operating Partnership, limited partner common units outstanding (shares)	3,973,000	2,902,000
SL Green Operating Partnership \| Series I Preferred Stock
Preferred Units, shares issued (shares)	9,200,000	9,200,000
Preferred Units, shares outstanding (shares)	9,200,000	9,200,000
Preferred Units, liquidation preference (in dollars per share)	$25	$25
Preferred stock, par value (in dollars per share)	$0.01	$0.01

Consolidated_Statements_of_Inc

Consolidated Statements of Income (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues
Rental revenue, net	$1,121,066	$996,782	$984,079
Escalation and reimbursement	164,376	155,965	151,187
Investment income	178,815	193,843	119,155
Other income	55,721	24,475	35,631
Total revenues	1,519,978	1,371,065	1,290,052
Expenses
Operating expenses, including $19,308 (2014), $19,152 (2013) and $17,645 (2012) of related party expenses	282,283	276,589	275,872
Real estate taxes	217,843	203,076	194,371
Ground rent	32,307	31,951	31,504
Interest expense, net of interest income	317,400	310,894	309,681
Amortization of deferred financing costs	22,377	15,855	18,558
Depreciation and amortization	371,610	324,461	311,860
Loan loss and other investment reserves, net of recoveries	0	0	564
Transaction related costs, net of recoveries	8,707	3,985	5,402
Marketing, general and administrative	92,488	86,192	82,840
Total expenses	1,345,015	1,253,003	1,230,652
Income from continuing operations before equity in net income from unconsolidated joint ventures, equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain (loss) on sale of investment in marketable securities and loss on early extinguishment of debt	174,963	118,062	59,400
Equity in net income from unconsolidated joint ventures	26,537	9,921	76,418
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	123,253	3,601	37,053
Purchase price fair value adjustment	67,446	-2,305	0
Gain (loss) on sale of investment in marketable securities	3,895	-65	4,940
Loss on early extinguishment of debt	-32,365	-18,518	-6,978
Income from continuing operations	363,729	110,696	170,833
Net income from discontinued operations	19,075	25,687	32,240
Gain on sale of discontinued operations	163,059	14,900	6,627
Net income	545,863	151,283	209,700
Net income attributable to noncontrolling interests:
Noncontrolling interests in the Operating Partnership	-18,467	-3,023	-5,597
Noncontrolling interests in other partnerships	-6,590	-10,629	-5,591
Preferred units distributions	-2,750	-2,260	-2,107
Net income attributable to SL Green	518,056	135,371	196,405
Preferred stock redemption costs	0	-12,160	-10,010
Perpetual preferred stock dividends	-14,952	-21,881	-30,411
Amounts attributable to SL Green common stockholders:
Income from continuing operations before gains on sale and discontinued operations	143,466	60,654	82,696
Purchase price fair value adjustment	65,059	-2,239	0
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	118,891	3,497	35,769
Net income from discontinued operations	18,400	24,947	31,122
Gain on sale of discontinued operations	157,288	14,471	6,397
Net income attributable to SL Green common stockholders	503,104	101,330	155,984
Basic earnings per share:
Income from continuing operations before discontinued operations (usd per share)	$2.18	$0.64	$0.93
Equity in net gain on sale of interest in unconsolidated joint venture/real estate (usd per share)	$1.24	$0.04	$0.40
Net income from discontinued operations (usd per share)	$0.19	$0.27	$0.35
Gain on sale of discontinued operations (usd per share)	$1.64	$0.15	$0.07
Net income attributable to SL Green common stockholders (usd per share)	$5.25	$1.10	$1.75
Diluted earnings per share:
Income from continuing operations before discontinued operations (usd per share)	$2.17	$0.63	$0.92
Equity in net gain on sale of interest in unconsolidated joint venture/real estate (usd per share)	$1.24	$0.04	$0.40
Net income from discontinued operations (usd per share)	$0.19	$0.27	$0.35
Gain on sale of discontinued operations (usd per share)	$1.63	$0.16	$0.07
Net income attributable to SL Green common stockholders (usd per share)	$5.23	$1.10	$1.74
Basic weighted average common shares outstanding (in shares)	95,774	92,269	89,319
Diluted weighted average common shares and common share equivalents outstanding (in shares)	99,696	95,266	92,873
SL Green Operating Partnership
Revenues
Rental revenue, net	1,121,066	996,782	984,079
Escalation and reimbursement	164,376	155,965	151,187
Investment income	178,815	193,843	119,155
Other income	55,721	24,475	35,631
Total revenues	1,519,978	1,371,065	1,290,052
Expenses
Operating expenses, including $19,308 (2014), $19,152 (2013) and $17,645 (2012) of related party expenses	282,283	276,589	275,872
Real estate taxes	217,843	203,076	194,371
Ground rent	32,307	31,951	31,504
Interest expense, net of interest income	317,400	310,894	309,681
Amortization of deferred financing costs	22,377	15,855	18,558
Depreciation and amortization	371,610	324,461	311,860
Loan loss and other investment reserves, net of recoveries	0	0	564
Transaction related costs, net of recoveries	8,707	3,985	5,402
Marketing, general and administrative	92,488	86,192	82,840
Total expenses	1,345,015	1,253,003	1,230,652
Income from continuing operations before equity in net income from unconsolidated joint ventures, equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, gain (loss) on sale of investment in marketable securities and loss on early extinguishment of debt	174,963	118,062	59,400
Equity in net income from unconsolidated joint ventures	26,537	9,921	76,418
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	123,253	3,601	37,053
Purchase price fair value adjustment	67,446	-2,305	0
Gain (loss) on sale of investment in marketable securities	3,895	-65	4,940
Loss on early extinguishment of debt	-32,365	-18,518	-6,978
Income from continuing operations	363,729	110,696	170,833
Net income from discontinued operations	19,075	25,687	32,240
Gain on sale of discontinued operations	163,059	14,900	6,627
Net income	545,863	151,283	209,700
Net income attributable to noncontrolling interests:
Noncontrolling interests in other partnerships	-6,590	-10,629	-5,591
Net income attributable to SL Green	536,523	138,394	202,002
Amounts attributable to SL Green common stockholders:
Income from continuing operations before gains on sale and discontinued operations	148,738	62,470	85,661
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	123,253	3,601	37,053
Gain on sale of discontinued operations	163,059	14,900	6,627
Basic earnings per share:
Equity in net gain on sale of interest in unconsolidated joint venture/real estate (usd per share)	$1.24	$0.04	$0.40
Gain on sale of discontinued operations (usd per share)	$1.64	$0.15	$0.07
Diluted earnings per share:
Equity in net gain on sale of interest in unconsolidated joint venture/real estate (usd per share)	$1.24	$0.04	$0.40
Gain on sale of discontinued operations (usd per share)	$1.63	$0.16	$0.07
Noncontrolling Interest [Abstract]
Preferred unit distributions	-2,750	-2,260	-2,107
Preferred unit redemption costs	0	-12,160	-10,010
Perpetual preferred unit distributions	-14,952	-21,881	-30,411
Net income attributable to SLGOP common unitholders	521,571	104,353	161,581
Purchase price fair value adjustment	67,446	-2,305	0
Net income from discontinued operations	$19,075	$25,687	$32,240
Net income from continuing operations before gains on sale and discontinued operations (in dollars per share)	$2.18	$0.64	$0.93
Net income from discontinued operations (in dollars per share)	$0.19	$0.27	$0.35
Net income attributable to SL Green common stockholders (in dollars per share)	$5.25	$1.10	$1.75
Net income from continuing operations before gains on sale and discontinued operations (in dollars per share)	$2.17	$0.63	$0.92
Net income from discontinued operations (in dollars per share)	$0.19	$0.27	$0.35
Net income attributable to SL Green common stockholders (in dollars per share)	$5.23	$1.10	$1.74
Basic weighted average common shares outstanding (in shares)	99,288	95,004	92,526
Diluted weighted average common shares and common share equivalents outstanding (in shares)	99,696	95,266	92,873

Consolidated_Statements_of_Inc1

Consolidated Statements of Income (Parenthetical) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating expenses, paid to related parties	$19,308	$19,152	$17,645
SL Green Operating Partnership
Operating expenses, paid to related parties	$19,308	$19,152	$17,645

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net income	$545,863	$151,283	$209,700
Other comprehensive income (loss):
Change in net unrealized gain on derivative instruments, including share of joint venture net unrealized gain on derivative instruments	10,643	13,490	2,127
Change in unrealized (loss) gain on marketable securities	-2,237	1,497	-3,657
Other comprehensive income (loss)	8,406	14,987	-1,530
Comprehensive income	554,269	166,270	208,170
Net income attributable to noncontrolling interests	-27,807	-15,912	-13,295
Other comprehensive (income) loss attributable to noncontrolling interests	-175	-611	388
Comprehensive income attributable to SL Green	526,287	149,747	195,263
SL Green Operating Partnership
Net income	545,863	151,283	209,700
Other comprehensive income (loss):
Change in net unrealized gain on derivative instruments, including share of joint venture net unrealized gain on derivative instruments	10,643	13,490	2,127
Change in unrealized (loss) gain on marketable securities	-2,237	1,497	-3,657
Other comprehensive income (loss)	8,406	14,987	-1,530
Comprehensive income	554,269	166,270	208,170
Net income attributable to noncontrolling interests	-6,590	-10,629	-5,591
Comprehensive income attributable to SL Green	$547,679	$155,641	$202,579

Consolidated_Statements_of_Equ

Consolidated Statements of Equity (USD $)	Total	Preferred Stock	Common Stock	Additional Paid- In-Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Noncontrolling Interests	Series C Preferred Stock	Series D Preferred Stock	Series I Preferred Stock	Common Stock	Common Stock	Common Stock
In Thousands, except Share data, unless otherwise specified	Total	Preferred Stock	Common Stock	Additional Paid- In-Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Noncontrolling Interests	Preferred Stock	Preferred Stock	Preferred Stock	Common Stock	Common Stock	Additional Paid- In-Capital
Balance at Dec. 31, 2011	$6,453,309		$892	$4,236,959	($308,708)	($28,445)	$1,704,506	$477,762	$274,022	$96,321	$0
Increase (Decrease) in Stockholders' Equity
Net income	201,996						196,405	5,591
Other comprehensive income:	-1,142					-1,142
Preferred dividends	-30,411						-30,411
DRIP proceeds	99,570		13	99,557
DRIP proceeds (in shares)			1,305,000
Conversion of units of the Operating Partnership to common stock	87,513		11	87,502
Redemption of units of the Operating Partnership to common stock (in shares)			1,096,000
Redemption of preferred stock	-200,013						-10,010		-93,682	-96,321
Reallocation of noncontrolling interest in the operating partnership	-61,238						-61,238
Deferred compensation plan and stock award, net	-13,428		3	719	-14,150
Deferred compensation plan and stock award, net (in shares)			43,000
Amortization of deferred compensation plan	28,742			28,742
Issuance of stock		221,965									221,965	201,279	27	201,252
Issuance of stock (shares)													2,640,000
Proceeds from stock options exercised	13,173		4	13,169
Proceeds from stock options exercised (in shares)			383,000
Contributions to consolidated joint venture interest	25,894							25,894
Cash distributions to noncontrolling interests	-21,946							-21,946
Cash distribution declared	-98,160						-98,160
Balance at Dec. 31, 2012	6,907,103		950	4,667,900	-322,858	-29,587	1,701,092	487,301	180,340	0	221,965
Balance (in shares) at Dec. 31, 2012			91,250,000
Increase (Decrease) in Stockholders' Equity
Net income	146,000						135,371	10,629
Other comprehensive income:	14,376					14,376
Preferred dividends	-21,881						-21,881
DRIP proceeds	67			67
Conversion of units of the Operating Partnership to common stock	17,287		2	17,285
Redemption of units of the Operating Partnership to common stock (in shares)			239,000
Redemption of preferred stock	-192,500						-12,160		-180,340
Preferred stock issuance costs	-33										-33
Reallocation of noncontrolling interest in the operating partnership	-45,618						-45,618
Deferred compensation plan and stock award, net	166		2	752	-588
Deferred compensation plan and stock award, net (in shares)			135,000
Amortization of deferred compensation plan	26,329			26,329
Issuance of stock	290,699		30	290,669
Issuance of stock (shares)			3,062,000
Proceeds from stock options exercised	12,904		2	12,902
Proceeds from stock options exercised (in shares)			224,000
Contributions-treasury shares	7,120				6,090		1,030
Sale of treasury stock (shares)			83,000
Contributions to consolidated joint venture interest	8,164							8,164
Cash distributions to noncontrolling interests	-14,623							-14,623
Cash distribution declared	-138,684						-138,684
Balance at Dec. 31, 2013	7,016,876		986	5,015,904	-317,356	-15,211	1,619,150	491,471	0	0	221,932
Balance (in shares) at Dec. 31, 2013			94,993,000
Increase (Decrease) in Stockholders' Equity
Net income	524,646						518,056	6,590
Other comprehensive income:	8,231					8,231
Preferred dividends	-14,952						-14,952
DRIP proceeds	64			64
Conversion of units of the Operating Partnership to common stock	31,653		3	31,650
Redemption of units of the Operating Partnership to common stock (in shares)			315,000
Reallocation of noncontrolling interest in the operating partnership	-168,439						-168,439
Deferred compensation plan and stock award, net	-1,514			1,601	-3,115
Deferred compensation plan and stock award, net (in shares)			15,000
Amortization of deferred compensation plan	29,749			29,749
Issuance of stock	185,321		17	185,304
Issuance of stock (shares)			1,654,000
Proceeds from stock options exercised	25,211		4	25,207
Proceeds from stock options exercised (in shares)			348,000
Contributions to consolidated joint venture interest	30,800							30,800
Cash distributions to noncontrolling interests	-7,019							-7,019
Cash distribution declared	-201,411						-201,411
Balance at Dec. 31, 2014	$7,459,216		$1,010	$5,289,479	($320,471)	($6,980)	$1,752,404	$521,842	$0	$0	$221,932
Balance (in shares) at Dec. 31, 2014			97,325,000

Consolidated_Statements_of_Equ1

Consolidated Statements of Equity (Parenthetical) (USD $)	12 Months Ended
Consolidated Statements of Equity (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Stockholders' Equity [Abstract]
Cash distribution declared, per common share (usd per share)	$2.10	$1.49	$1.08

Consolidated_Statements_of_Cap

Consolidated Statements of Capital Statement (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Increase (Decrease) in Partner's Capital
Other comprehensive income	$8,406	$14,987	($1,530)
Issuance of units in the Operating Partnership	56,469	24,750	42,239
DRIP proceeds	64	67	99,570
Redemption of units	31,653	17,287	87,513
Redemption of preferred units		-192,500	-200,013
Preferred units issuance costs		-33
Deferred compensation plan	-1,514	166	-13,428
Amortization of deferred compensation plan	29,749	26,329	28,742
Contributions-treasury shares		7,120
Cash distributions to noncontrolling interests	-7,019	-14,623	-21,946
Common Stock
Increase (Decrease) in Partner's Capital
DRIP proceeds			13
DRIP proceeds (in shares)			1,305
Redemption of units	3	2	11
Redemption of units (in units)	315	239	1,096
Deferred compensation plan		2	3
Contributions-treasury shares (units)		83
Noncontrolling Interests
Increase (Decrease) in Partner's Capital
Cash distributions to noncontrolling interests	-7,019	-14,623	-21,946
SL Green Operating Partnership
Increase (Decrease) in Partner's Capital
Beginning Balance	7,282,352	7,120,010	6,648,339
Net income	543,113	149,023	207,593
Other comprehensive income	8,406	14,987	-1,530
Preferred distributions	-14,952	-21,881	-30,411
Issuance of units in the Operating Partnership	56,469	24,750	42,239
DRIP proceeds	64	67	99,570
Redemption of units	0	0	0
Redemption of preferred units		-192,500	-200,013
Preferred units issuance costs		-33
Deferred compensation plan	-1,514	166	-13,428
Amortization of deferred compensation plan	29,749	26,329	28,742
Contribution to consolidated joint venture interest	30,800	8,164	25,894
Contributionsbnet proceeds from preferred stock offering			221,965
Contributionsbnet proceeds from common stock offering	185,321	290,699	201,279
Contributions-treasury shares		7,120
Contributions - proceeds from stock options exercised	25,211	12,904	13,173
Cash distributions to noncontrolling interests	-7,019	-14,623	-21,946
Cash distribution declared	-209,260	-142,830	-101,456
Ending Balance	7,928,740	7,282,352	7,120,010
SL Green Operating Partnership \| General Partner
Increase (Decrease) in Partner's Capital
Beginning Balance	6,506,747	6,189,529	5,714,856
Balance (units)	94,993	91,250	85,783
Net income	503,104	113,490	165,994
DRIP proceeds	64	67	99,570
DRIP proceeds (in shares)		0	1,305
Redemption of units	31,653	17,287	87,513
Redemption of units (in units)	315	239	1,096
Redemption of preferred units		-12,160	-10,010
Deferred compensation plan (units)	15	135	43
Deferred compensation plan	-1,514	166	-13,428
Amortization of deferred compensation plan	29,749	26,329	28,742
Contributionsbnet proceeds from common stock offering	185,321	290,699	201,279
Contributions - net proceeds from common stock offering (in units)	1,654	3,062	2,640
Contributions-treasury shares		7,120
Contributions-treasury shares (units)		83
Contributions - proceeds from stock options exercised	25,211	12,904	13,173
Contributions - proceeds from stock options exercised (in units)	348	224	383
Cash distribution declared	-201,411	-138,684	-98,160
Ending Balance	7,078,924	6,506,747	6,189,529
Balance (units)	97,325	94,993	91,250
SL Green Operating Partnership \| Limited Partners
Increase (Decrease) in Partner's Capital
Balance (units)	2,902	2,760	2,765
Issuance of units (in units)	1,386	381	801
Redemption of units (in units)	-315	-239	-1,096
Deferred compensation plan (units)			290
Balance (units)	3,973	2,902	2,760
SL Green Operating Partnership \| Series C Preferred Stock
Increase (Decrease) in Partner's Capital
Beginning Balance		180,340	274,022
Net income		6,932	20,290
Preferred distributions		-6,932	-20,290
Redemption of preferred units		-180,340	-93,682
Ending Balance	0	0	180,340
SL Green Operating Partnership \| Series D Preferred Stock
Increase (Decrease) in Partner's Capital
Beginning Balance			96,321
Net income			4,266
Preferred distributions			-4,266
Redemption of preferred units			-96,321
Ending Balance	0	0	0
SL Green Operating Partnership \| Series I Preferred Stock
Increase (Decrease) in Partner's Capital
Beginning Balance	221,932	221,965	0
Net income	14,952	14,949	5,855
Preferred distributions	-14,952	-14,949	-5,855
Preferred units issuance costs		-33
Contributionsbnet proceeds from preferred stock offering			221,965
Ending Balance	221,932	221,932	221,965
SL Green Operating Partnership \| Common Stock \| Limited Partners
Increase (Decrease) in Partner's Capital
Beginning Balance	77,864	71,524	114,497
Net income	18,467	3,023	5,597
Issuance of units in the Operating Partnership	56,469	24,750	42,239
Redemption of units	-31,653	-17,287	-87,513
Cash distribution declared	-7,849	-4,146	-3,296
Ending Balance	113,298	77,864	71,524
SL Green Operating Partnership \| Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Partner's Capital
Beginning Balance	-15,662	-30,649	-29,119
Other comprehensive income	8,406	14,987	-1,530
Ending Balance	-7,256	-15,662	-30,649
SL Green Operating Partnership \| Noncontrolling Interests
Increase (Decrease) in Partner's Capital
Beginning Balance	491,471	487,301	477,762
Net income	6,590	10,629	5,591
Contribution to consolidated joint venture interest	30,800	8,164	25,894
Cash distributions to noncontrolling interests	-7,019	-14,623	-21,946
Ending Balance	$521,842	$491,471	$487,301

Consolidated_Statements_of_Cap1

Consolidated Statements of Capital (Parenthetical) (USD $)	12 Months Ended
Consolidated Statements of Capital (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash distribution declared, per common share (usd per share)	$2.10	$1.49	$1.08
SL Green Operating Partnership
Cash distribution declared, per common share (usd per share)	$2.10	$1.49	$1.08

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
Consolidated Statements of Cash Flows (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Activities
Net income	$545,863,000	$151,283,000	$209,700,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	400,001,000	357,599,000	351,539,000
Equity in net income from unconsolidated joint ventures	-26,537,000	-9,921,000	-76,418,000
Distributions of cumulative earnings from unconsolidated joint ventures	28,859,000	34,997,000	91,145,000
Equity in net gain on sale of interest in unconsolidated joint venture interest/real estate	-123,253,000	-3,601,000	-37,053,000
Purchase price fair value adjustment	-71,446,000	2,305,000	0
Depreciable real estate reserves	0	2,150,000	0
Gain on sale of discontinued operations	-163,059,000	-14,900,000	-6,627,000
Loan loss and other investment reserves, net of recoveries	0	0	564,000
Gain on sale of investment in marketable securities	-3,895,000	0	-4,940,000
Loss on early extinguishment of debt	32,365,000	10,963,000	6,978,000
Deferred rents receivable	-56,362,000	-56,739,000	-66,079,000
Other non-cash adjustments	-28,559,000	-37,843,000	-18,868,000
Changes in operating assets and liabilities:
Restricted cashboperations	861,000	2,037,000	-13,812,000
Tenant and other receivables	1,978,000	-7,570,000	-10,998,000
Related party receivables	-3,673,000	-917,000	-3,529,000
Deferred lease costs	-53,333,000	-52,228,000	-48,368,000
Other assets	9,340,000	2,904,000	-35,932,000
Accounts payable, accrued expenses and other liabilities and security deposits	-7,796,000	-1,473,000	9,389,000
Deferred revenue and land leases payable	9,027,000	7,157,000	62,000
Net cash provided by operating activities	490,381,000	386,203,000	346,753,000
Investing Activities
Acquisitions of real estate property	-1,039,530,000	-594,595,000	-544,568,000
Additions to land, buildings and improvements	-369,887,000	-196,571,000	-148,148,000
Escrowed cashbcapital improvements/acquisition deposits	-8,461,000	-7,672,000	-70,080,000
Investments in unconsolidated joint ventures	-382,010,000	-150,274,000	-215,174,000
Distributions in excess of cumulative earnings from unconsolidated joint ventures	236,181,000	42,720,000	127,876,000
Proceeds from disposition of real estate/joint venture interest	820,599,000	227,615,000	178,485,000
Proceeds from sale of marketable securities	8,248,000	2,370,000	11,070,000
Purchases of marketable securities	-14,364,000	-11,493,000	-6,660,000
Other investments	-7,448,000	-43,163,000	-36,750,000
Origination of debt and preferred equity investments	-617,090,000	-555,137,000	-645,229,000
Repayments or redemption of debt and preferred equity investments	576,927,000	657,765,000	185,775,000
Net cash used in investing activities	-796,835,000	-628,435,000	-1,163,403,000
Financing Activities
Proceeds from mortgages and other loans payable	2,151,603,000	1,257,172,000	1,230,167,000
Repayments of mortgages and other loans payable	-2,201,999,000	-1,085,220,000	-684,954,000
Proceeds from revolving credit facility and senior unsecured notes	1,908,000,000	1,164,000,000	1,751,480,000
Repayments of revolving credit facility and senior unsecured notes	-1,386,588,000	-1,020,215,000	-1,577,756,000
Payments of debt extinguishment costs	-50,150,000	0	-6,909,000
Proceeds from stock options exercised and DRIP issuance	25,275,000	12,971,000	112,743,000
Net proceeds from sale of common stock	185,321,000	290,699,000	201,279,000
Net proceeds from sale of preferred stock	0	0	221,965,000
Redemption of preferred stock	-2,000,000	-192,533,000	-200,013,000
Sale or purchase of treasury stock	0	7,120,000	-14,150,000
Distributions to noncontrolling interests in other partnerships	-7,019,000	-14,623,000	-21,946,000
Contributions from noncontrolling interests in other partnerships	30,675,000	8,164,000	25,894,000
Distributions to noncontrolling interests in the Operating Partnership	-7,849,000	-4,146,000	-3,296,000
Dividends paid on common and preferred stock	-206,974,000	-148,407,000	-121,238,000
Other obligations related to mortgage loan participations	0	0	5,000,000
Deferred loan costs and capitalized lease obligation	-57,124,000	-16,042,000	-49,824,000
Net cash provided by financing activities	381,171,000	258,940,000	868,442,000
Net increase in cash and cash equivalents	74,717,000	16,708,000	51,792,000
Cash and cash equivalents at beginning of year	206,692,000	189,984,000	138,192,000
Cash and cash equivalents at end of year	281,409,000	206,692,000	189,984,000
Supplemental cash flow disclosures:
Interest paid	348,230,000	325,903,000	322,469,000
Income taxes paid	4,056,000	2,666,000	17,000
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of common stock as deferred compensation	1,601,000	164,000	722,000
Issuance of units in the Operating Partnership	56,469,000	24,750,000	42,239,000
Redemption of units in the Operating Partnership	31,653,000	17,287,000	87,513,000
Derivative instruments at fair value	11,230,000	636,000	92,000
Assignment of debt investment to joint venture	0	0	25,362,000
Mortgage assigned to joint venture	150,000,000	0	0
Tenant improvements and capital expenditures payable	9,408,000	502,000	1,738,000
Fair value adjustment to noncontrolling interest in the Operating Partnership	168,439,000	45,618,000	61,238,000
Assumption of mortgage loans	16,000,000	84,642,000	0
Consolidation of real estate investments and other adjustments	1,316,591,000	90,934,000	0
Repayment of mezzanine loans	0	0	13,750,000
Redemption of Series E units	0	0	31,698,000
Repayment of financing receivable	0	0	28,195,000
Investment in joint venture	88,957,000	0	5,135,000
Capital leased asset	0	9,992,000	28,132,000
Deconsolidation of a subsidiary	112,095,000	0	104,107,000
Transfer to net assets held for sale	462,430,000	0	4,901,000
Transfer to liabilities related to net assets held for sale	266,873,000	0	136,000
Transfer of financing receivable to debt investment	19,675,000	0	0
Deferred leasing payable	8,667,000	5,024,000	91,000
Issuance of preferred units	27,565,000	0	47,550,000
SL Green Operating Partnership
Operating Activities
Net income	545,863,000	151,283,000	209,700,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	400,001,000	357,599,000	351,539,000
Equity in net income from unconsolidated joint ventures	-26,537,000	-9,921,000	-76,418,000
Distributions of cumulative earnings from unconsolidated joint ventures	28,859,000	34,997,000	91,145,000
Equity in net gain on sale of interest in unconsolidated joint venture interest/real estate	-123,253,000	-3,601,000	-37,053,000
Purchase price fair value adjustment	-71,446,000	2,305,000	0
Depreciable real estate reserves	0	2,150,000	0
Gain on sale of discontinued operations	-163,059,000	-14,900,000	-6,627,000
Loan loss and other investment reserves, net of recoveries	0	0	564,000
Gain on sale of investment in marketable securities	-3,895,000	0	-4,940,000
Loss on early extinguishment of debt	32,365,000	10,963,000	6,978,000
Deferred rents receivable	-56,362,000	-56,739,000	-66,079,000
Other non-cash adjustments	-28,559,000	-37,843,000	-18,868,000
Changes in operating assets and liabilities:
Restricted cashboperations	861,000	2,037,000	-13,812,000
Tenant and other receivables	1,978,000	-7,570,000	-10,998,000
Related party receivables	-3,673,000	-917,000	-3,529,000
Deferred lease costs	-53,333,000	-52,228,000	-48,368,000
Other assets	9,340,000	2,904,000	-35,932,000
Accounts payable, accrued expenses and other liabilities and security deposits	-7,796,000	-1,473,000	9,389,000
Deferred revenue and land leases payable	9,027,000	7,157,000	62,000
Net cash provided by operating activities	490,381,000	386,203,000	346,753,000
Investing Activities
Acquisitions of real estate property	-1,039,530,000	-594,595,000	-544,568,000
Additions to land, buildings and improvements	-369,887,000	-196,571,000	-148,148,000
Escrowed cashbcapital improvements/acquisition deposits	-8,461,000	-7,672,000	-70,080,000
Investments in unconsolidated joint ventures	-382,010,000	-150,274,000	-215,174,000
Distributions in excess of cumulative earnings from unconsolidated joint ventures	236,181,000	42,720,000	127,876,000
Proceeds from disposition of real estate/joint venture interest	820,599,000	227,615,000	178,485,000
Proceeds from sale of marketable securities	8,248,000	2,370,000	11,070,000
Purchases of marketable securities	-14,364,000	-11,493,000	-6,660,000
Other investments	-7,448,000	-43,163,000	-36,750,000
Origination of debt and preferred equity investments	-617,090,000	-555,137,000	-645,229,000
Repayments or redemption of debt and preferred equity investments	576,927,000	657,765,000	185,775,000
Net cash used in investing activities	-796,835,000	-628,435,000	-1,163,403,000
Financing Activities
Proceeds from mortgages and other loans payable	2,151,603,000	1,257,172,000	1,230,167,000
Repayments of mortgages and other loans payable	-2,201,999,000	-1,085,220,000	-684,954,000
Proceeds from revolving credit facility and senior unsecured notes	1,908,000,000	1,164,000,000	1,751,480,000
Repayments of revolving credit facility and senior unsecured notes	-1,386,588,000	-1,020,215,000	-1,577,756,000
Payments of debt extinguishment costs	-50,150,000	0	-6,909,000
Proceeds from stock options exercised and DRIP issuance	25,275,000	12,971,000	112,743,000
Net proceeds from sale of common stock	185,321,000	290,699,000	201,279,000
Net proceeds from sale of preferred stock	0	0	221,965,000
Redemption of preferred stock	-2,000,000	-192,533,000	-200,013,000
Sale or purchase of treasury stock	0	7,120,000	-14,150,000
Distributions to noncontrolling interests in other partnerships	-7,019,000	-14,623,000	-21,946,000
Contributions from noncontrolling interests in other partnerships	30,675,000	8,164,000	25,894,000
Dividends paid on common and preferred stock	-214,823,000	-152,553,000	-124,534,000
Other obligations related to mortgage loan participations	0	0	5,000,000
Deferred loan costs and capitalized lease obligation	-57,124,000	-16,042,000	-49,824,000
Net cash provided by financing activities	381,171,000	258,940,000	868,442,000
Net increase in cash and cash equivalents	74,717,000	16,708,000	51,792,000
Cash and cash equivalents at beginning of year	206,692,000	189,984,000	138,192,000
Cash and cash equivalents at end of year	281,409,000	206,692,000	189,984,000
Supplemental cash flow disclosures:
Interest paid	348,230,000	325,903,000	322,469,000
Income taxes paid	4,056,000	2,666,000	17,000
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of common stock as deferred compensation	1,601,000	164,000	722,000
Issuance of units in the Operating Partnership	56,469,000	24,750,000	42,239,000
Redemption of units in the Operating Partnership	31,653,000	17,287,000	87,513,000
Derivative instruments at fair value	11,230,000	636,000	92,000
Assignment of debt investment to joint venture	0	0	25,362,000
Mortgage assigned to joint venture	150,000,000	0	0
Tenant improvements and capital expenditures payable	9,408,000	502,000	1,738,000
Assumption of mortgage loans	16,000,000	84,642,000	0
Consolidation of real estate investments and other adjustments	1,316,591,000	90,934,000	0
Repayment of mezzanine loans	0	0	13,750,000
Redemption of Series E units	0	0	31,698,000
Repayment of financing receivable	0	0	28,195,000
Investment in joint venture	88,957,000	0	5,135,000
Capital leased asset	0	9,992,000	28,132,000
Deconsolidation of a subsidiary	112,095,000	0	104,107,000
Transfer to net assets held for sale	462,430,000	0	4,901,000
Transfer to liabilities related to net assets held for sale	266,873,000	0	136,000
Transfer of financing receivable to debt investment	19,675,000	0	0
Deferred leasing payable	8,667,000	5,024,000	91,000
Issuance of preferred units	$27,565,000	$0	$47,550,000

Consolidated_Statements_of_Cas1

Consolidated Statements of Cash Flows (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly distributions declared, per share/unit (usd per share/unit)	$0.60	$0.50	$0.33
SL Green Operating Partnership
Quarterly distributions declared, per share/unit (usd per share/unit)	$0.60	$0.50	$0.33

Organization_and_Basis_of_Pres

Organization and Basis of Presentation	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Basis of Presentation	Organization and Basis of Presentation
	SL Green Realty Corp., which is referred to as the Company or SL Green, a Maryland corporation, and SL Green Operating Partnership, L.P., which is referred to as SLGOP or the Operating Partnership, a Delaware limited partnership, were formed in June 1997 for the purpose of combining the commercial real estate business of S.L. Green Properties, Inc. and its affiliated partnerships and entities. The Operating Partnership received a contribution of interest in the real estate properties, as well as 95% of the economic interest in the management, leasing and construction companies which are referred to as the Service Corporation, a consolidated variable interest entity. All of the management, leasing and construction services with respect to the properties that are wholly-owned by us are conducted through SL Green Management LLC which is 100% owned by the Operating Partnership. The Company has qualified, and expects to qualify in the current fiscal year, as a real estate investment trust, or REIT, under the Internal Revenue Code of 1986, as amended, or the Code, and operates as a self-administered, self-managed REIT. A REIT is a legal entity that holds real estate interests and, through payments of dividends to stockholders, is permitted to minimize the payment of Federal income taxes at the corporate level. Unless the context requires otherwise, all references to "we," "our" and "us" means the Company and all entities owned or controlled by the Company, including the Operating Partnership.
	Substantially all of our assets are held by, and our operations are conducted through, the Operating Partnership. The Company is the sole managing general partner of the Operating Partnership. As of December 31, 2014, noncontrolling investors held, in the aggregate, a 3.92% limited partnership interest in the Operating Partnership. We refer to these interests as the noncontrolling interests in the Operating Partnership. See Note 11, "Noncontrolling Interests on the Company's Consolidated Financial Statements."
	Reckson Associates Realty Corp., or Reckson, and Reckson Operating Partnership, L.P., or ROP, are wholly-owned subsidiaries of the Operating Partnership.
	As of December 31, 2014, we owned the following interests in commercial office buildings in the New York Metropolitan area, primarily in midtown Manhattan. Our investments in the New York Metropolitan area also include investments in Brooklyn, Long Island, Westchester County, Connecticut and New Jersey, which are collectively known as the Suburban properties:


				Consolidated			Unconsolidated		Total
	Location		Type	Number of Properties		Approximate Square Feet (unaudited)	Number of Properties	Approximate Square Feet (unaudited)	Number of Properties	Approximate Square Feet (unaudited)	Weighted Average Occupancy(1)
											(unaudited)
	Commercial:
	Manhattan		Office	23		18,429,045	7	3,476,115	30	21,905,160	95.3	%

			Retail	9	-2	403,735	7	279,628	16	683,363	91	%

			Development/Redevelopment	9	-3	1,973,862	5	1,952,782	14	3,926,644	32.6	%

			Fee Interest	2		783,530	—	—	2	783,530	100	%

				43		21,590,172	19	5,708,525	62	27,298,697	86.3	%

	Suburban		Office	27		4,365,400	4	1,222,100	31	5,587,500	82.4	%

			Retail	1		52,000	—	—	1	52,000	100	%

			Development/Redevelopment	1		85,000	2	65,641	3	150,641	54.2	%

				29		4,502,400	6	1,287,741	35	5,790,141	81.8	%

	Total commercial properties			72		26,092,572	25	6,996,266	97	33,088,838	85.5	%

	Residential:

	Manhattan		Residential	3	-2	735,587	—	—	3	735,587	95.6	%

	Suburban		Residential	1		66,611	—	—	1	66,611	89.6	%

	Total residential properties			4		802,198	—	—	4	802,198	95.2	%

	Total portfolio			76		26,894,770	25	6,996,266	101	33,891,036	85.8	%

	____________________________________________________________________

	-1	The weighted average occupancy for commercial properties represents the total occupied square feet divided by total available rentable square feet. The weighted average occupancy for residential properties represents the total occupied units divided by total available units.

	-2	As of December 31, 2014, we owned a building that was comprised of approximately 270,132 square feet (unaudited) of retail space and approximately 222,855 square feet (unaudited) of residential space. For the purpose of this report, we have included the building as part of retail properties and have shown the square footage under its respective classifications.

	-3	Includes one property which was held for sale as of December 31, 2014 and sold in January 2015.
	As of December 31, 2014, we also managed an approximately 336,201 square foot (unaudited) office building owned by a third party and held debt and preferred equity investments with a book value of $1.4 billion.
	Partnership Agreement
	In accordance with the partnership agreement of the Operating Partnership, or the Operating Partnership Agreement, we allocate all distributions and profits and losses in proportion to the percentage of ownership interests of the respective partners. As the managing general partner of the Operating Partnership, we are required to take such reasonable efforts, as determined by us in our sole discretion, to cause the Operating Partnership to distribute sufficient amounts to enable the payment of sufficient dividends by us to minimize any Federal income or excise tax at the Company level. Under the Operating Partnership Agreement, each limited partner has the right to redeem units of limited partnership interests for cash, or if we so elect, shares of SL Green's common stock on a one-for-one basis.

Significant_Accounting_Policie

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies
	Principles of Consolidation
	The consolidated financial statements include our accounts and those of our subsidiaries, which are wholly-owned or controlled by us. Entities which we do not control through our voting interest and entities which are variable interest entities, but where we are not the primary beneficiary, are accounted for under the equity method or as debt and preferred equity investments. See Note 5, "Debt and Preferred Equity Investments" and Note 6, "Investments in Unconsolidated Joint Ventures." All significant intercompany balances and transactions have been eliminated.
	We consolidate a variable interest entity, or VIE, in which we are considered the primary beneficiary. The primary beneficiary is the entity that has (i) the power to direct the activities that most significantly impact the entity's economic performance and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE that could be significant to the VIE. Included in commercial real estate properties on our consolidated balance sheets as of December 31, 2014 and 2013 are $198.4 million and $605.9 million, respectively, related to our consolidated VIEs. Included in mortgages and other loans payable on our consolidated balance sheets as of December 31, 2014 and 2013 are $106.5 million and $370.9 million, respectively, related to our consolidated VIEs. Also, included in assets held for sale and liabilities related to assets held for sale on our consolidated balance sheet as of December 31, 2014 are $445.0 million of commercial real estate and $253.9 million of mortgage related to our consolidated VIEs.
	A noncontrolling interest in a consolidated subsidiary is defined as the portion of the equity (net assets) in a subsidiary not attributable, directly or indirectly, to us. Noncontrolling interests are required to be presented as a separate component of equity in the consolidated balance sheet and the presentation of net income was modified to present earnings and other comprehensive income attributed to controlling and noncontrolling interests.
	We assess the accounting treatment for each joint venture and debt and preferred equity investment. This assessment includes a review of each joint venture or limited liability company agreement to determine which party has what rights and whether those rights are protective or participating. For all VIEs, we review such agreements in order to determine which party has the power to direct the activities that most significantly impact the entity's economic performance. In situations where we and our partner approve, among other things, the annual budget, receive a detailed monthly reporting package from us, meet on a quarterly basis to review the results of the joint venture, review and approve the joint venture's tax return before filing, and approve all leases that cover more than a nominal amount of space relative to the total rentable space at each property, we do not consolidate the joint venture as we consider these to be substantive participation rights that result in shared power of the activities that most significantly impact the performance of the joint venture. Our joint venture agreements typically contain certain protective rights such as the requirement of partner approval to sell, finance or refinance the property and the payment of capital expenditures and operating expenditures outside of the approved budget or operating plan.
	Investment in Commercial Real Estate Properties
	Real estate properties are presented at cost less accumulated depreciation and amortization. Costs directly related to the development or redevelopment of properties are capitalized. Ordinary repairs and maintenance are expensed as incurred; major replacements and betterments, which improve or extend the life of the asset, are capitalized and depreciated over their estimated useful lives.
	A property to be disposed of is reported at the lower of its carrying value or its estimated fair value, less its cost to sell. Once an asset is held for sale, depreciation expense is no longer recorded and the historic results are reclassified as discontinued operations. See Note 4, "Properties Held for Sale and Dispositions."
	Properties are depreciated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives are as follows:


	Category		Term
	Building (fee ownership)		40 years
	Building improvements		shorter of remaining life of the building or useful life
	Building (leasehold interest)		lesser of 40 years or remaining term of the lease
	Property under capital lease		remaining lease term
	Furniture and fixtures		four to seven years
	Tenant improvements		shorter of remaining term of the lease or useful life
	Depreciation expense (including amortization of the capital lease asset) amounted to $338.8 million, $296.5 million and $287.5 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	On a periodic basis, we assess whether there are any indications that the value of our real estate properties may be impaired or that their carrying value may not be recoverable. A property's value is considered impaired if management's estimate of the aggregate future cash flows (undiscounted and without interest charges for consolidated properties) to be generated by the property is less than the carrying value of the property. To the extent impairment has occurred, the loss will be measured as the excess of the carrying amount of the property over the calculated fair value of the property. We do not believe that the values of any of our consolidated properties were impaired at December 31, 2014.
	We also evaluate our real estate properties for potential impairment when a real estate property has been classified as held for sale. Real estate assets held for sale are valued at the lower of their carrying value or fair value less costs to sell. In June 2013, we recorded a $2.2 million impairment charge in connection with the sale of 300 Main Street in Stamford, Connecticut. We do not believe that the value of our real estate property held for sale was impaired at December 31, 2014.
	We incur a variety of costs in the development and leasing of our properties. After determination is made to capitalize a cost, it is allocated to the specific component of a project that is benefited. Determination of when a development project is substantially complete and capitalization must cease involves a degree of judgment. The costs of land and building under development include specifically identifiable costs. The capitalized costs include, but are not limited to, pre-construction costs essential to the development of the property, development costs, construction costs, interest costs, real estate taxes, salaries and related costs and other costs incurred during the period of development. We consider a construction project as substantially completed and held available for occupancy upon the completion of tenant improvements, but no later than one year from cessation of major construction activity. We cease capitalization on the portions substantially completed and occupied or held available for occupancy, and capitalize only those costs associated with the portions under construction.
	Results of operations of properties acquired are included in the consolidated statements of income from the date of acquisition.
	We recognize the assets acquired, liabilities assumed (including contingencies) and any noncontrolling interests in an acquired entity at their fair values on the acquisition date. We expense acquisition-related transaction costs as incurred, which are included in transaction related costs on our consolidated statements of income.
	When we acquire our partner's equity interest in an existing unconsolidated joint venture and gain control over the investment, we record the consolidated investment at fair value. The difference between the book value of our equity investment on the purchase date and our share of the fair value of the investment's purchase price is recorded as a purchase price fair value adjustment in our consolidated statements of income. In May 2014, we recognized a purchase price fair value adjustment of $71.4 million in connection with the consolidation of 388-390 Greenwich Street. In April 2013, we recognized a purchase price fair value adjustment of $(2.3) million in connection with the consolidation of 16 Court Street. These acquisitions were previously accounted for as investments in unconsolidated joint ventures.
	We allocate the purchase price of real estate to land and building (inclusive of tenant improvements) and, if determined to be material, intangibles, such as the value of above- and below-market leases and origination costs associated with the in-place leases. We depreciate the amount allocated to building (inclusive of tenant improvements) over their estimated useful lives, which generally range from three to 40 years. We amortize the amount allocated to the above- and below-market leases over the remaining term of the associated lease, which generally range from one to 14 years, and record it as either an increase (in the case of below-market leases) or a decrease (in the case of above-market leases) to rental income. We amortize the amount allocated to the values associated with in-place leases over the expected term of the associated lease, which generally ranges from one to 14 years. If a tenant vacates its space prior to the contractual termination of the lease and no rental payments are being made on the lease, any unamortized balance of the related intangible will be written off. The tenant improvements and origination costs are amortized as an expense over the remaining life of the lease (or charged against earnings if the lease is terminated prior to its contractual expiration date). We assess fair value of the leases based on estimated cash flow projections that utilize appropriate discount and capitalization rates and available market information. Estimates of future cash flows are based on a number of factors including the historical operating results, known trends, and market/economic conditions that may affect the property. To the extent acquired leases contain fixed rate renewal options that are below-market and determined to be material, we amortize such below-market lease value into rental income over the renewal period. As of December 31, 2014, the weighted average amortization period for above-market leases, below-market leases, and in-place lease costs is 7.03 years, 5.62 years, and 5.96 years, respectively.
	We recognized an increase of $23.3 million, $18.8 million and $16.5 million in rental revenue for the years ended December 31, 2014, 2013 and 2012, respectively, for the amortization of aggregate below-market leases in excess of above-market leases and a reduction in lease origination costs, resulting from the allocation of the purchase price of the applicable properties. The increase in rental revenue for the year ended December 31, 2013 is net of $6.8 million resulting from a write-off of above-market and in-place balances associated with a former tenant. Excluding this non-recurring charge, we recognized an increase of $25.6 million in rental revenue for the year ended December 31, 2013 for the amortization of aggregate below-market leases in excess of above-market leases and reductions in lease origination costs. We recognized a reduction in interest expense for the amortization of the above-market rate mortgages assumed of $5.0 million, $5.0 million and $1.4 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	The following summarizes our identified intangible assets (acquired above-market leases and in-place leases) and intangible liabilities (acquired below-market leases) as of December 31, 2014 and 2013 (in thousands):


		December 31,
		2014				2013
	Identified intangible assets (included in other assets):
	Gross amount	$	664,297			$	746,704

	Accumulated amortization	(383,236		)		(343,339		)
	Net	$	281,061			$	403,365

	Identified intangible liabilities (included in deferred revenue):
	Gross amount	$	655,755			$	671,380

	Accumulated amortization	(483,948		)		(429,138		)
	Net	$	171,807			$	242,242

	The estimated annual amortization of acquired above-market leases, net of acquired (below-market) leases (a component of rental revenue), for each of the five succeeding years is as follows (in thousands):


	2015		$	1,978

	2016		(592		)
	2017		(1,303		)
	2018		(3,135		)
	2019		(3,994		)
	The estimated annual amortization of all other identifiable assets (a component of depreciation and amortization expense) including tenant improvements for each of the five succeeding years is as follows (in thousands):


	2015		$	9,150

	2016		5,919

	2017		4,442

	2018		3,005

2019		2,467

Cash and Cash Equivalents
We consider all highly liquid investments with maturity of three months or less when purchased to be cash equivalents.
Fair Value Measurements
See Note 17, "Fair Value Measurements."
Investment in Marketable Securities
We invest in marketable securities. At the time of purchase, we are required to designate a security as held-to-maturity, available-for-sale, or trading depending on ability and intent. We do not have any securities designated as held-to-maturity or trading at this time. Securities available-for-sale are reported at fair value pursuant to ASC 820-10, with the net unrealized gains or losses reported as a component of accumulated other comprehensive income or loss. Unrealized losses that are determined to be other-than-temporary are recognized in earnings up to their credit component.
The cost of bonds and marketable securities sold is determined using the specific identification method.
At December 31, 2014 and 2013, we held the following marketable securities (in thousands):


	December 31,
	2014				2013
Equity marketable securities	$	4,332			$	4,307

Commercial mortgage-backed securities	35,097				24,419

Rake bonds	—				3,323

Total marketable securities available-for-sale	$	39,429			$	32,049

The cost basis of the commercial mortgage-backed securities was $32.4 million and $23.0 million at December 31, 2014 and 2013, respectively. These securities mature at various times through 2049. The cost basis of the rake bonds was $3.6 million at December 31, 2013.
During the year ended December 31, 2014 and 2012, we disposed of marketable securities for aggregate net proceeds of $4.4 million and $6.8 million, respectively, and realized gains of $3.9 million and $4.9 million, respectively, which are included in gain on sale of investment in marketable securities on the consolidated statements of income. We did not sell any of our marketable securities during the year ended December 31, 2013.
Investments in Unconsolidated Joint Ventures
We account for our investments in unconsolidated joint ventures under the equity method of accounting in cases where we exercise significant influence over, but do not control, these entities and are not considered to be the primary beneficiary. We consolidate those joint ventures that we control or which are VIEs and where we are considered to be the primary beneficiary. In all these joint ventures, the rights of the joint venture partner are both protective as well as participating. Unless we are determined to be the primary beneficiary in a VIE, these participating rights preclude us from consolidating these non-VIE entities. These investments are recorded initially at cost, as investments in unconsolidated joint ventures, and subsequently adjusted for equity in net income (loss) and cash contributions and distributions. Equity income (loss) from unconsolidated joint ventures is allocated based on our ownership or economic interest in each joint venture. When a capital event (as defined in each joint venture agreement) such as a refinancing occurs, if return thresholds are met, future equity income will be allocated at our increased economic interest. We recognize incentive income from unconsolidated real estate joint ventures as income to the extent it is earned and not subject to a clawback feature. Distributions we receive from unconsolidated real estate joint ventures in excess of our basis in the investment are recorded as offsets to our investment balance if we remain liable for future obligations of the joint venture or may otherwise be committed to provide future additional financial support. None of the joint venture debt is recourse to us, except for $18.4 million which we guarantee at one joint ventures and performance guarantees under master leases at two other joint ventures. See Note 6, "Investments in Unconsolidated Joint Ventures."
We assess our investments in unconsolidated joint ventures for recoverability, and if it is determined that a loss in value of the investment is other than temporary, we write down the investment to its fair value. We evaluate our equity investments for impairment based on the joint venture's projected discounted cash flows. We do not believe that the values of any of our equity investments were impaired at December 31, 2014.
We may originate loans for real estate acquisition, development and construction, where we expect to receive some or all of the residual profit from such projects. When the risk and rewards of these arrangements are essentially the same as an investor or joint venture partner, we account for these arrangements as real estate investments under the equity method of accounting for investments. Otherwise, we account for these arrangements consistent with our loan accounting for our debt and preferred equity investments.
Restricted Cash
Restricted cash primarily consists of security deposits held on behalf of our tenants, interest reserves, as well as capital improvement and real estate tax escrows required under certain loan agreements.
Deferred Lease Costs
Deferred lease costs consist of fees and direct costs incurred to initiate and renew operating leases and are amortized on a straight-line basis over the related lease term. Certain of our employees provide leasing services to the wholly-owned properties. For the years ended December 31, 2014, 2013 and 2012, $15.1 million, $12.4 million and $11.0 million of their compensation, respectively, was capitalized and is amortized over an estimated average lease term of seven years.
Deferred Financing Costs
Deferred financing costs represent commitment fees, legal, title and other third party costs associated with obtaining commitments for financing which result in a closing of such financing. These costs are amortized over the terms of the respective agreements. Unamortized deferred financing costs are expensed when the associated debt is refinanced or repaid before maturity. Costs incurred in seeking financing transactions, which do not close, are expensed in the period in which it is determined that the financing will not close.
Revenue Recognition
Rental revenue is recognized on a straight-line basis over the term of the lease. Rental revenue recognition commences when the tenant takes possession or controls the physical use of the leased space. In order for the tenant to take possession, the leased space must be substantially ready for its intended use. To determine whether the leased space is substantially ready for its intended use, management evaluates whether we are or the tenant is the owner of tenant improvements for accounting purposes. When management concludes that we are the owner of tenant improvements, rental revenue recognition begins when the tenant takes possession of the finished space, which is when such tenant improvements are substantially complete. In certain instances, when management concludes that we are not the owner (the tenant is the owner) of tenant improvements, rental revenue recognition begins when the tenant takes possession of or controls the space. When management concludes that we are the owner of tenant improvements for accounting purposes, we record amounts funded to construct the tenant improvements as a capital asset. For these tenant improvements, we record amounts reimbursed by tenants as a reduction of the capital asset. When management concludes that the tenant is the owner of tenant improvements for accounting purposes, we record our contribution towards those improvements as a lease incentive, which is included in deferred costs, net on our consolidated balance sheets and amortized as a reduction to rental revenue on a straight-line basis over the term of the lease. The excess of rents recognized over amounts contractually due pursuant to the underlying leases are included in deferred rents receivable on the consolidated balance sheets. We establish, on a current basis, an allowance for future potential tenant credit losses, which may occur against this account. The balance reflected on the consolidated balance sheets is net of such allowance.
In addition to base rent, our tenants also generally will pay their pro rata share of increases in real estate taxes and operating expenses for the building over a base year. In some leases, in lieu of paying additional rent based upon increases in building operating expenses, the tenant will pay additional rent based upon increases in the wage rate paid to porters over the porters' wage rate in effect during a base year or increases in the consumer price index over the index value in effect during a base year. In addition, many of our leases contain fixed percentage increases over the base rent to cover escalations. Electricity is most often supplied by the landlord either on a sub-metered basis, or rent inclusion basis (i.e., a fixed fee is included in the rent for electricity, which amount may increase based upon increases in electricity rates or increases in electrical usage by the tenant). Base building services other than electricity (such as heat, air conditioning and freight elevator service during business hours, and base building cleaning) are typically provided at no additional cost, with the tenant paying additional rent only for services which exceed base building services or for services which are provided outside normal business hours. These escalations are based on actual expenses incurred in the prior calendar year. If the expenses in the current year are different from those in the prior year, then during the current year, the escalations will be adjusted to reflect the actual expenses for the current year.
We record a gain on sale of real estate when title is conveyed to the buyer, subject to the buyer's financial commitment being sufficient to provide economic substance to the sale and we have no substantial economic involvement with the buyer.
Interest income on debt and preferred equity investments is accrued based on the outstanding principal amount and contractual terms of the instruments and when, in the opinion of management, it is deemed collectible. Several of the debt and preferred equity investments provide for accrual of interest at specified rates, which differ from current payment terms. Interest is recognized on such loans at the accrual rate subject to management's determination that accrued interest is ultimately collectible, based on the underlying collateral and operations of the borrower. If management cannot make this determination, interest income above the current pay rate is recognized only upon actual receipt.
Deferred origination fees, original issue discounts and loan origination costs, if any, are recognized as a reduction to the interest income over the terms of the related investments using the effective interest method. Fees received in connection with loan commitments are also deferred until the loan is funded and are then recognized over the term of the loan as an adjustment to yield. Discounts or premiums associated with the purchase of loans are amortized or accreted into interest income as a yield adjustment on the effective interest method based on expected cashflows through the expected maturity date of the related investment. If we purchase a debt or preferred equity investment at a discount, intend to hold it until maturity and expect to recover the full value of the investment, we accrete the discount into income as an adjustment to yield over the term of the investment. If we purchase a debt or preferred equity investment at a discount with the intention of foreclosing on the collateral, we do not accrete the discount. For debt investments acquired at a discount for credit quality, the difference between contractual cash flows and expected cash flows at acquisition is not accreted. Anticipated exit fees, the collection of which is expected, are also recognized over the term of the loan as an adjustment to yield.
Debt and preferred equity investments are placed on a non-accrual status at the earlier of the date at which payments become 90 days past due or when, in the opinion of management, a full recovery of interest income becomes doubtful. Interest income recognition on any non-accrual debt or preferred equity investment is resumed when such non-accrual debt or preferred equity investment becomes contractually current and performance is demonstrated to be resumed. Interest is recorded as income on impaired loans only to the extent cash is received.
We may syndicate a portion of the loans that we originate or sell these loans individually. When a transaction meets the criteria of sale accounting, we derecognize the loan sold and recognize gain or loss based on the difference between the sales price and the carrying value of the loan sold. Any related unamortized deferred origination fees, loan origination costs, discounts or premiums at the time of sale are recognized as an adjustment to the gain or loss on sale, which is included in investment income on the consolidated statement of income. Any fees received at the time of sale or syndication are recognized as part of investment income.
Asset management fees are recognized on a straight-line basis over the term of the asset management agreement.
Allowance for Doubtful Accounts
We maintain an allowance for doubtful accounts for estimated losses resulting from the inability of our tenants to make required payments. If the financial condition of a specific tenant were to deteriorate, resulting in an impairment of its ability to make payments, additional allowances may be required.
Reserve for Possible Credit Losses
The expense for possible credit losses in connection with debt and preferred equity investments is the charge to earnings to increase the allowance for possible credit losses to the level that we estimate to be adequate, based on Level 3 data, considering delinquencies, loss experience and collateral quality. Other factors considered relate to geographic trends and product diversification, the size of the portfolio and current economic conditions. Based upon these factors, we establish the provision for possible credit losses on each individual investment. When it is probable that we will be unable to collect all amounts contractually due, the investment is considered impaired.
Where impairment is indicated on an investment that is held to maturity, a valuation allowance is measured based upon the excess of the recorded investment amount over the net fair value of the collateral. Any deficiency between the carrying amount of an asset and the calculated value of the collateral is charged to expense. We continue to assess or adjust our estimates based on circumstances of a loan and the underlying collateral. If the additional information obtained reflects increased recovery of our investment, we will adjust our reserves accordingly. There were no loan reserves recorded during the years ended December 31, 2014 and 2013. We recorded loan loss reserves of $3.0 million on investments held to maturity during the year ended December 31, 2012, partially offset by recoveries of $2.4 million.
Debt and preferred equity investments held for sale are carried at the lower of cost or fair market value using available market information obtained through consultation with dealers or other originators of such investments as well as discounted cash flow models based on Level 3 data pursuant to ASC 820-10. As circumstances change, management may conclude not to sell an investment designated as held for sale. In such situations, the investment will be reclassified at its net carrying value to debt and preferred equity investments held to maturity. For these reclassified investments, the difference between the current carrying value and the expected cash to be collected at maturity will be accreted into income over the remaining term of the investment.
Rent Expense
Rent expense is recognized on a straight-line basis over the initial term of the lease. The excess of the rent expense recognized over the amounts contractually due pursuant to the underlying lease is included in the deferred land lease payable on the consolidated balance sheets.
Income Taxes
SL Green is taxed as a REIT under Section 856(c) of the Code. As a REIT, SL Green generally is not subject to Federal income tax. To maintain its qualification as a REIT, SL Green must distribute at least 90% of its REIT taxable income to its stockholders and meet certain other requirements. If SL Green fails to qualify as a REIT in any taxable year, we will be subject to Federal income tax on SL Green's taxable income at regular corporate rates. SL Green may also be subject to certain state, local and franchise taxes. Under certain circumstances, Federal income and excise taxes may be due on SL Green's undistributed taxable income.
The Operating Partnership is a partnership and, as a result, all income and losses of the partnership are allocated to the partners for inclusion in their respective income tax returns. The only provision for income taxes included in the consolidated statements of income relates to the Operating Partnership’s consolidated taxable REIT subsidiaries. The Operating Partnership may also be subject to certain state, local and franchise taxes.
Pursuant to amendments to the Code that became effective January 1, 2001, we have elected, and may elect in the future, to treat certain of our existing or newly created corporate subsidiaries as taxable REIT subsidiaries, or TRSs. In general, TRSs may perform non-customary services for the tenants of the Company, hold assets that we cannot hold directly and generally may engage in any real estate or non-real estate related business. The TRSs generate income, resulting in Federal and state income tax liability for these entities.
During the years ended December 31, 2014 and 2013, we recorded Federal, state and local tax provisions of $7.8 million and $4.4 million, respectively. There were no Federal, state and local tax provisions for the year ended December 31, 2012.
We follow a two-step approach for evaluating uncertain tax positions. Recognition (step one) occurs when an enterprise concludes that a tax position, based solely on its technical merits, is more-likely-than-not to be sustained upon examination. Measurement (step two) determines the amount of benefit that is more-likely-than-not to be realized upon settlement. Derecognition of a tax position that was previously recognized would occur when a company subsequently determines that a tax position no longer meets the more-likely-than-not threshold of being sustained. The use of a valuation allowance as a substitute for derecognition of tax positions is prohibited.
Underwriting Commissions and Costs
Underwriting commissions and costs incurred in connection with our stock offerings are reflected as a reduction of additional paid-in-capital.
Exchangeable Debt Instruments
The initial proceeds from exchangeable debt that may be settled in cash, including partial cash settlements, must be bifurcated between a liability component and an equity component associated with the embedded conversion option. The objective of the accounting guidance is to require the liability and equity components of exchangeable debt to be separately accounted for in a manner such that the interest expense on the exchangeable debt is not recorded at the stated rate of interest but rather at an effective rate that reflects the issuer's conventional debt borrowing rate at the date of issuance. We calculate the liability component of exchangeable debt based on the present value of the contractual cash flows discounted at our comparable market conventional debt borrowing rate at the date of issuance. The difference between the principal amount and the fair value of the liability component is reported as a discount on the exchangeable debt that is accreted as additional interest expense from the issuance date through the contractual maturity date using the effective interest method. A portion of this additional interest expense may be capitalized to the development and redevelopment balances qualifying for interest capitalization each period. The liability component of the exchangeable debt is reported net of discounts on our consolidated balance sheets. We calculate the equity component of exchangeable debt based on the difference between the initial proceeds received from the issuance of the exchangeable debt and the fair value of the liability component at the issuance date. The equity component is included in additional paid-in-capital, net of issuance costs, on our consolidated balance sheets. We allocate issuance costs for exchangeable debt between the liability and the equity components based on their relative values.
Stock-Based Employee Compensation Plans
We have a stock-based employee compensation plan, described more fully in Note 14, "Share-based Compensation."
The Company's stock options are recorded at fair value at the time of issuance. Fair value of the stock options is determined using the Black-Scholes option pricing model. The Black-Scholes model was developed for use in estimating the fair value of traded options, which have no vesting restrictions and are fully transferable. In addition, option valuation models require the input of highly subjective assumptions including the expected stock price volatility. Because our plan has characteristics significantly different from those of traded options and because changes in the subjective input assumptions can materially affect the fair value estimate, in our opinion, the existing models do not necessarily provide a reliable single measure of the fair value of the employee stock options.
Compensation cost for stock options, if any, is recognized ratably over the vesting period of the award. Our policy is to grant options with an exercise price equal to the quoted closing market price of the Company's common stock on the grant date. Awards of stock or restricted stock are expensed as compensation over the benefit period based on the fair value of the stock on the grant date.
For share-based awards with a performance or market measure, we recognize compensation cost over the requisite service period, using the accelerated attribution expense method. The requisite service period begins on the date the compensation committee of SL Green's board of directors authorizes the award, adopts any relevant performance measures and communicates the award to the employees. For programs with awards that vest based on the achievement of a performance condition or market condition, we determine whether it is probable that the performance condition will be met, and estimate compensation cost based on the fair value of the award at the applicable reporting date estimated using a binomial model or market quotes. For share-based awards for which there is no pre-established performance measure, we recognize compensation cost over the service vesting period, which represents the requisite service period, on a straight-line basis. In accordance with the provisions of our share-based incentive compensation plans, we accept the return of shares of the Company's common stock, at the current quoted market price, from certain key employees to satisfy minimum statutory tax-withholding requirements related to shares that vested during the period.
Awards can also be made in the form of a separate series of units of limited partnership interest in the Operating Partnership called long-term incentive plan units, or LTIP units. LTIP units, which can be granted either as free-standing awards or in tandem with other awards under our stock incentive plan, are valued by reference to the value of the Company's common stock at the time of grant, and are subject to such conditions and restrictions as the compensation committee of the Company's board of directors may determine, including continued employment or service, computation of financial metrics and/or achievement of pre-established performance goals and objectives.
Derivative Instruments
In the normal course of business, we use a variety of commonly used derivative instruments, such as interest rate swaps, caps, collar and floors, to manage, or hedge, interest rate risk. Effectiveness is essential for those derivatives that we intend to quality for hedge accounting. Some derivative instruments are associated with an anticipated transaction. In those cases, hedge effectiveness criteria also require that it be probable that the underlying transaction occurs. Instruments that meet these hedging criteria are formally designated as hedges at the inception of the derivative contract.
To determine the fair values of derivative instruments, we use a variety of methods and assumptions that are based on market conditions and risks existing at each balance sheet date. For the majority of financial instruments including most derivatives, long-term investments and long-term debt, standard market conventions and techniques such as discounted cash flow analysis, option pricing models, replacement cost, and termination cost are used to determine fair value. All methods of assessing fair value result in a general approximation of value, and such value may never actually be realized.
In the normal course of business, we are exposed to the effect of interest rate changes and limit these risks by following established risk management policies and procedures including the use of derivatives. To address exposure to interest rates, derivatives are used primarily to fix the rate on debt based on floating-rate indices and manage the cost of borrowing obligations.
We use a variety of commonly used derivative products that are considered plain vanilla derivatives. These derivatives typically include interest rate swaps, caps, collars and floors. We expressly prohibit the use of unconventional derivative instruments and using derivative instruments for trading or speculative purposes. Further, we have a policy of only entering into contracts with major financial institutions based upon their credit ratings and other factors.
We may employ swaps, forwards or purchased options to hedge qualifying forecasted transactions. Gains and losses related to these transactions are deferred and recognized in net income as interest expense in the same period or periods that the underlying transaction occurs, expires or is otherwise terminated.
Hedges that are reported at fair value and presented on the balance sheet could be characterized as cash flow hedges or fair value hedges. Interest rate caps and collars are examples of cash flow hedges. Cash flow hedges address the risk associated with future cash flows of interest payments. For all hedges held by us and which were deemed to be fully effective in meeting the hedging objectives established by our corporate policy governing interest rate risk management, no net gains or losses were reported in earnings. The changes in fair value of hedge instruments are reflected in accumulated other comprehensive income. For derivative instruments not designated as hedging instruments, the gain or loss, resulting from the change in the estimated fair value of the derivative instruments, is recognized in current earnings during the period of change.
Earnings per Share of the Company
The Company presents both basic and diluted earnings per share, or EPS. Basic EPS excludes dilution and is computed by dividing net income attributable to common stockholders by the weighted average number of common shares outstanding during the period. Basic EPS includes participating securities, consisting of unvested restricted stock that receive nonforfeitable dividends similar to shares of common stock. Diluted EPS reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock, where such exercise or conversion would result in a lower EPS amount. Diluted EPS also includes units of limited partnership interest. The dilutive effect of stock options is reflected in the weighted average diluted outstanding shares calculation by application of the treasury stock method. There is no dilutive effect for the exchangeable senior notes as the conversion premium will be paid in cash.
Earnings per Unit of the Operating Partnership
The Operating Partnership presents both basic and diluted earnings per unit, or EPU. Basic EPU excludes dilution and is computed by dividing net income attributable to common unitholders by the weighted average number of common units outstanding during the period. Basic EPU includes participating securities, consisting of unvested restricted units that receive nonforfeitable dividends similar to shares of common units. Diluted EPU reflects the potential dilution that could occur if securities or other contracts to issue common units were exercised or converted into common units, where such exercise or conversion would result in a lower EPU amount. The dilutive effect of unit options is reflected in the weighted average diluted outstanding units calculation by application of the treasury stock method. There is no dilutive effect for the exchangeable senior notes as the conversion premium will be paid in cash.
Use of Estimates
The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.
Concentrations of Credit Risk
Financial instruments that potentially subject us to concentrations of credit risk consist primarily of cash investments, debt and preferred equity investments and accounts receivable. We place our cash investments in excess of insured amounts with high quality financial institutions. The collateral securing our debt and preferred equity investments is primarily located in New York City. See Note 5, "Debt and Preferred Equity Investments." We perform ongoing credit evaluations of our tenants and require most tenants to provide security deposits or letters of credit. Though these security deposits and letters of credit are insufficient to meet the total value of a tenant's lease obligation, they are a measure of good faith and a source of funds to offset the economic costs associated with lost rent and the costs associated with re-tenanting a space. Although the properties in our real estate portfolio are primarily located in Manhattan, we also have properties located in Brooklyn, Long Island, Westchester County, Connecticut and New Jersey. The tenants located in our buildings operate in various industries. Other than three tenants who account for 10.9%, 7.2% and 5.6% of our share of annualized cash rent, respectively, no other tenant in our portfolio accounted for more than 2.0% of our share of annualized cash rent, including our share of joint venture annualized rent, at December 31, 2014. For the year ended December 31, 2014, 9.9%, 9.8%, 7.8% and 7.5% of our annualized cash rent for consolidated properties was attributable to 1515 Broadway, 388-390 Greenwich Street, 1185 Avenue of the Americas and 919 Third Avenue, respectively. For the year ended December 31, 2013, 10.6%, 7.8%, 7.7% and 6.4% of our annualized cash rent for consolidated properties was attributable to 1515 Broadway, 919 Third Avenue, 1185 Avenue of the Americas and One Madison Avenue, respectively. For the year ended December 31, 2012, 10.2%, 8.0%, 7.1%, and 6.2% of our annualized rent for consolidated properties was attributable to 1515 Broadway, 919 Third Avenue, 1185 Avenue of the Americas and One Madison Avenue, respectively. As of December 31, 2014, 73.4% of our work force is covered by six collective bargaining agreements and 77.6% of our work force which services substantially all of our properties is covered by a collective bargaining agreement which expires in December 2015. See Note 20, "Benefits Plans."
Reclassification
Certain prior year balances have been reclassified to conform to our current year presentation primarily in order to eliminate discontinued operations from income from continuing operations.
Accounting Standards Updates
In February 2015, the Financial Accounting Standards Board, or FASB, issued new guidance that amends the current consolidation guidance, including introducing a separate consolidation analysis specific to limited partnerships and other similar entities (Accounting Standards Update, or ASU, No. 2015-02). Under this analysis, limited partnerships and other similar entities will be considered a VIE unless the limited partners hold substantive kick-out rights or participating rights. The guidance is effective for annual and interim periods beginning after December 15, 2015. Early adoption of this guidance is permitted. The Company is currently evaluating the new guidance to determine the impact it may have on our consolidated financial statements.
In June 2014, the FASB, issued final guidance that requires repurchase-to-maturity transactions to be accounted for as secured borrowings as if the transferor retains effective control, even though the transferred financial assets are not returned to the transferor at settlement and also eliminates existing guidance for repurchase financings (ASU, No. 2014-11). New disclosures are required for (1) certain transactions accounted for as secured borrowings and (2) transfers accounted for as sales when the transferor also retains substantially all of the exposure to the economic return on the transferred financial assets throughout the term of the transaction. The guidance is effective for the first interim or annual period beginning after December 15, 2014, except for the disclosures related to transactions accounted for as secured borrowings, which are effective for periods beginning after March 15, 2015. Early adoption of this guidance is prohibited. The Company will adopt this standard beginning in the first quarter of 2015. The adoption of this guidance is not anticipated to have a material impact on our consolidated financial statements.
In May 2014, the FASB issued a new comprehensive revenue recognition guidance which requires us to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those goods and services (ASU No. 2014-09). The guidance also requires enhanced disclosures to help users of financial statements better understand the nature, amount, timing, and uncertainty of revenue that is recognized. The guidance is effective for annual and interim periods beginning after December 15, 2016 and early adoption is not permitted. The new guidance can be applied either retrospectively to each prior reporting period presented, or as a cumulative-effect adjustment as of the date of adoption. The Company is currently evaluating the new guidance to determine the impact it may have on our consolidated financial statements.
In April 2014, the FASB issued new guidance on reporting discontinued operations which raises the threshold for disposals to qualify as discontinued operations (ASU No. 2014-08). The guidance also allows us to have a significant continuing involvement and continuing cash flows with the discontinued operations. Additionally, the guidance requires additional disclosures for discontinued operations and new disclosures for individually material disposal transactions that do not meet the definition of a discontinued operation. The guidance is effective for calendar year public companies beginning in the first quarter of 2015 and is to be applied on a prospective basis for new disposals. Early adoption of this guidance is permitted. The Company will adopt this standard beginning in the first quarter of 2015. The adoption of this guidance will change the presentation of discontinued operations but will not have a material impact on our consolidated financial statements.
In February 2013, the FASB issued guidance on the presentation and disclosure of reclassification adjustments out of accumulated other comprehensive income, or AOCI (ASU No. 2013-02). The standard requires an entity to present information about significant items reclassified out of AOCI by component either on the face of the statement where net income is presented or as a separate disclosure in the notes to financial statements. The guidance was effective for calendar year-end public companies beginning in the first quarter of 2013 and its adoption did not have a material impact on our consolidated financial statements.
In December 2011, the FASB issued guidance that concluded when a parent ceases to have a controlling financial interest in a subsidiary that is in-substance real estate as a result of default on the subsidiary's nonrecourse debt, the reporting entity must apply the accounting guidance for sales of real estate to determine whether it should derecognize the in-substance real estate (ASU No. 2011-10). The reporting entity is precluded from derecognizing the real estate until legal ownership has been transferred to the lender to satisfy the debt. The guidance was effective for calendar year-end public and nonpublic companies in 2013 and is to be applied on a prospective basis. Early adoption of the guidance is permitted. Adoption of this guidance did not have a material impact on our consolidated financial statements.
In May 2011, the FASB issued updated guidance on fair value measurement which amends U.S. GAAP to conform to IFRS measurement and disclosure requirements (ASU No. 2011-04). The amendments change the wording used to describe the requirements in U.S. GAAP for measuring fair value, changes certain fair value measurement principles and enhances disclosure requirements. This guidance was effective as of the first quarter of 2012, and its adoption did not have a material impact on our consolidated financial statements.

Property_Acquisitions

Property Acquisitions	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Property Acquisitions	Property Acquisitions
	2014 Acquisitions
	During the year ended December 31, 2014, the properties listed below were acquired from third parties. The following summarizes our allocation of the purchase price of the assets acquired and liabilities assumed upon the closing of these acquisitions (in thousands):


		102 Greene Street(1)			635 Madison Avenue(1)(4)			752 Madison Avenue(1)(2)			719 Seventh Avenue(1)(5)			115 Spring Street(1)		388-390 Greenwich Street (1)(3)
	Acquisition Date	Oct-14			Sep-14			Aug-14			Jul-14			Jul-14		May-14
	Ownership Type	Fee Interest			Fee Interest			Leasehold Interest			Fee Interest			Fee Interest		Fee Interest
	Property Type	Retail			Land			Retail			Development			Retail		Office

	Purchase Price Allocation:
	Land	$	11,288		$	153,745		$	282,415		$	14,402		$	15,938	$	558,777

	Building and building leasehold	20,962			—			—			26,747			37,187		1,037,729

	Above market lease value	—			—			—			—			—		—

	Acquired in-place leases	—			—			—			—			—		—

	Other assets, net of other liabilities	—			—			—			—			—		6,495

	Assets acquired	32,250			153,745			282,415			41,149			53,125		1,603,001

	Mark-to-market assumed debt	—			—			—			—			—		—

	Below market lease value	—			—			—			—			—		—

	Derivatives	—			—			—			—			—		18,001

	Liabilities assumed	—			—			—			—			—		18,001

	Purchase price	$	32,250		$	153,745		$	282,415		$	41,149		$	53,125	$	1,585,000

	Net consideration funded by us at closing, excluding consideration financed by debt	$	32,250		$	153,745		$	282,415		$	41,149		$	53,125	$	208,614

	Equity and/or debt investment held	$	—		$	—		$	—		$	—		$	—	$	148,025

	Debt assumed	$	—		$	—		$	—		$	—		$	—	$	1,162,379

	____________________________________________________________________

	-1	We are currently in the process of analyzing the purchase price allocation and, as such, we have not allocated any value to intangible assets such as above- and below-market lease or in-place leases.

	-2	In January 2012, a separate joint venture in which an SL Green entity holds an 80% interest acquired the ground tenancy position.

	-3	In May 2014, we acquired Ivanhoe Cambridge, Inc.'s 49.65% economic interest in this property, thereby consolidating full ownership of the property. The transaction valued the consolidated interests at $1.585 billion. Simultaneous with the closing, we refinanced the previous mortgage with a $1.45 billion mortgage. We also assumed the existing derivative instruments, which swapped $504.0 million of the mortgage to fixed rate. We recognized a purchase price fair value adjustment of $71.4 million upon closing of this transaction. This property, which we initially acquired in December 2007, was previously accounted for as an investment in unconsolidated joint ventures.

	-4	This property was acquired inclusive of the issuance of $4.0 million aggregate liquidation preference of Series J Preferred Units of limited partnership interest of the Operating Partnership.

	-5	We, along with our joint venture partner, acquired this property inclusive of the issuance of $14.1 million aggregate liquidation preference of Series L Preferred Units of limited partnership interest of the Operating Partnership and $9.5 million aggregate liquidation preference of Series K Preferred Units of limited partnership interest of the Operating Partnership. We hold a 75.0% controlling interest in this joint venture.
	2013 Acquisitions
	During the year ended December 31, 2013, the properties listed below were acquired from unrelated third parties. The following summarizes our allocation of the purchase price of the assets acquired and liabilities assumed upon the closing of these acquisitions (in thousands):


			315 West 33rd Street(1)			Assemblage of Retail Development Properties on Fifth Avenue(1)			16 Court(2)			248-252
												Bedford
												Avenue(3)
	Acquisition Date		Nov-13			Nov-13			Apr-13			Mar-13
	Ownership Type		Fee Interest			Fee Interest			Fee Interest			Fee Interest
	Property Type		Residential			Development			Office			Residential

	Purchase Price Allocation:
	Land		$	195,834		$	135,513		$	19,217		$	10,865

Building and building leasehold		164,429			10,487			63,210			44,035

Above market lease value		7,084			—			5,122			—

Acquired in-place leases		26,125			—			9,422			—

Other assets, net of other liabilities		1,142			—			3,380			—

Assets acquired		394,614			146,000			100,351			54,900

Mark-to-market assumed debt		—			—			294			—

Below market lease value		7,839			—			3,885			—

Liabilities assumed		7,839			—			4,179			—

Purchase price		$	386,775		$	146,000		$	96,172		$	54,900

Net consideration funded by us at closing, excluding consideration financed by debt		$	386,775		$	146,000		$	4,000		$	21,782

Equity and/or debt investment held		$	—		$	—		$	13,835		$	—

Debt assumed		$	—		$	—		$	84,642		$	—

____________________________________________________________________

-1	During the year ended December 31, 2014, we finalized the purchase price allocation based on a third party appraisal and additional facts and circumstances that existed at the acquisition dates. These adjustments did not have a material impact to our consolidated statement of income for the year ended December 31, 2014.

-2	In April 2013, we acquired interests from our joint venture partner, City Investment Fund, or CIF, in 16 Court Street in Brooklyn for $4.0 million. We have consolidated the ownership of the building. The transaction valued the consolidated interest at $96.2 million, inclusive of the $84.6 million mortgage encumbering the property. In April 2014, we repaid the mortgage. We recognized a purchase price fair value adjustment of $(2.3) million upon the closing of this transaction. This property, which we initially acquired in July 2007, was previously accounted for as an investment in unconsolidated joint ventures.

-3	In March 2013, we, along with Magnum Real Estate Group, acquired 84 residential units, consisting of 72 apartment units and 12 townhouses, located at 248-252 Bedford Avenue, Williamsburg, Brooklyn for $54.9 million. Simultaneous with the closing on this property, the joint venture closed on a $22.0 million mortgage loan which was later refinanced in June 2014. The property is above a commercial property already owned by us. We hold a 90.0% controlling interest in this joint venture.
2012 Acquisitions
During the year ended December 31, 2012, the properties listed below were acquired from unrelated third parties. The following summarizes our allocation of the purchase price of the assets acquired and liabilities assumed upon the closing of these acquisitions (in thousands):


		985-987 Third Avenue(1)			131-137 Spring Street			635-641			304 Park			Stonehenge
								Sixth			Avenue			Properties(3)
								Avenue			South(2)
Acquisition Date		Dec-12			Dec-12			Sep-12			Jun-12			Jan-12
Ownership Type		Fee Interest			Fee Interest			Fee Interest			Fee Interest			Fee Interest/Leasehold Interest
Property Type		Development			Retail			Development			Office			Residential/Retail

Purchase Price Allocation:
Land		$	5,400		$	27,021		$	69,848		$	54,189		$	65,533

Building and building leasehold		12,600			105,342			104,474			75,619			128,457

Above market lease value		—			179			—			2,824			594

Acquired in-place leases		—			7,046			7,727			8,265			9,573

Other assets, net of other liabilities		—			—			—			—			2,190

Assets acquired		18,000			139,588			182,049			140,897			206,347

Fair value adjustment to mortgage note payable		—			—			—			—			—

Below market lease value		—			17,288			9,049			5,897			13,239

Liabilities assumed		—			17,288			9,049			5,897			13,239

Purchase price		$	18,000		$	122,300		$	173,000		$	135,000		$	193,108

Net consideration funded by us at closing, excluding consideration financed by debt		$	18,000		$	122,300		$	173,000		$	135,000		$	78,121

Equity and/or debt investment held		$	—		$	—		$	—		$	—		$	—

Debt assumed		$	—		$	—		$	—		$	—		$	—

____________________________________________________________________

-1	This property was subsequently sold in July 2014. See Note 4, "Properties Held for Sale and Dispositions."

-2	This property was acquired with $102.0 million in cash and $33.0 million in units of limited partnership interest of the Operating Partnership.

-3	In January 2012, we acquired five retail and two multifamily properties in Manhattan for $193.1 million. This property was acquired inclusive of the issuance of $47.6 million aggregate liquidation preference of Series G Preferred Units of limited partnership interest of the Operating Partnership. Simultaneous with the closing, we financed the multifamily component, which encompasses 385 units and approximately 488,000 square feet (unaudited), with an aggregate $100.0 million fixed rate mortgage which bears interest at 4.1% and one of the retail properties financed with an $8.5 million fixed rate mortgage. We hold an 80.0% interest in this joint venture which we consolidate as it is a VIE and we have been designated as the primary beneficiary. In February 2013, we sold one of the retail properties, which is further described in Note 4, "Properties Held for Sale and Dispositions."
Pro Forma
The following table summarizes, on an unaudited pro forma basis, the results of operations of 388-390 Greenwich Street, which are included in the consolidated statements of income for the years ended December 31, 2014 and 2013 as though the acquisition of our joint venture partner's interest in 388-390 Greenwich Street was completed on January 1, 2013. The supplemental pro forma data is not necessarily indicative of what the actual results of operations would have been assuming the transaction had been completed as set forth above, nor do they purport to represent our results of operations for future periods.


		Year Ended December 31,
(in thousands, except per share amounts)		2014			2013
Actual revenues since acquisition		$	1,519,978

Actual net income since acquisition		545,863

Pro forma revenues		1,562,206			1,481,021

Pro forma income from continuing operations(1)		298,679			205,437

Pro forma basic earnings per share		4.6			2.1

Pro forma diluted earnings per share		4.58			2.09

Pro forma basic earnings per unit		4.6			2.1

Pro forma diluted earnings per unit		4.58			2.09

____________________________________________________________________

-1	The pro forma income from continuing operations for the years ended December 31, 2014 and 2013 includes the effect of the new financing necessary to complete the acquisition and the preliminary allocation of purchase price in connection with the changes in depreciation and amortization. In addition, the pro forma income from continuing operations for the year ended December 31, 2013 was adjusted to include the purchase price fair value adjustment, as though the acquisition was completed on January 1, 2013. The pro forma income from continuing operations for the year ended December 31, 2014 excludes this purchase price fair value adjustment.

Properties_Held_for_Sale_and_D

Properties Held for Sale and Dispositions	12 Months Ended
	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Properties Held for Sale and Dispositions	Properties Held for Sale and Dispositions
	As of December 31, 2014, we classified 180 Maiden Lane, with approximately 1,090,000 usable square feet (unaudited), as held for sale. Subsequent to year end, we sold the property for a gross sale price of $470.0 million.
	Dispositions
	The following table summarizes the properties sold during the years ended December 31, 2014, 2013, and 2012:


	Property		Disposition Date	Property Type		Approximate Usable Square Feet	Sales Price		Gain (Loss) on Sale(1)
						(unaudited)	(in millions)		(in millions)
	2 Herald Square		Nov-14	Land		354,400	$	365	$	18.8

	985-987 Third Avenue		Jul-14	Development		13,678	68.7		29.8

	673 First Avenue		May-14	Office		422,000	145		117.6

	300 Main Street		Sep-13	Office		130,000	13.5		(2.2		)

	333 West 34th Street		Aug-13	Office		345,400	220.3		13.8

	44 West 55th Street		Feb-13	Retail		8,557	6.3		1.1

	292 Madison Avenue		Feb-12	Land		203,800	85		6.6

	____________________________________________________________________

	-1	The gain on sale for 2 Herald Square, 985-987 Third Avenue, 673 First Avenue, 333 West 34th Street, and 292 Madison Avenue are net of a $2.5 million, $1.3 million, $3.4 million, $3.0 million and $1.5 million employee compensation award, respectively, accrued in connection with the realization of this investment gain as a bonus to certain employees that were instrumental in realizing the gain on sale. Additionally, amounts do not include adjustments for expense recorded in subsequent periods.
	Discontinued Operations
	Discontinued operations included the results of operations of real estate assets under contract or sold prior to December 31, 2014. This included 180 Maiden Lane, which was held for sale at December 31, 2014, 2 Herald Square, 985-987 Third Avenue and 673 First Avenue, which were sold during 2014, 44 West 55th Street, 333 West 34th Street and 300 Main Street, which were sold in 2013, and 292 Madison Avenue, which was sold in 2012.
	The following table summarizes net income from discontinued operations for the years ended December 31, 2014, 2013 and 2012, respectively (in thousands).


		Year Ended December 31,
		2014			2013		2012
	Revenues
	Rental revenue	$	51,090		$	94,558	$	97,254

	Escalation and reimbursement revenues	4,646			14,856		16,232

	Other income	23			554		8,295

	Total revenues	55,759			109,968		121,781

	Operating expenses	7,772			20,568		23,166

	Real estate taxes	7,156			16,521		16,190

	Ground rent	3,001			7,975		6,362

	Interest expense, net of interest income	12,652			19,782		22,298

	Depreciable real estate reserves	—			2,150		—

	Transaction related costs, net of recoveries	89			2		383

	Depreciation and amortization	5,581			16,443		20,250

	Amortization of deferred financing costs	433			840		892

	Total expenses	36,684			84,281		89,541

	Net income from discontinued operations	$	19,075		$	25,687	$	32,240

Debt_and_Preferred_Equity_Inve

Debt and Preferred Equity Investments	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Debt and Preferred Equity Investments	Debt and Preferred Equity Investments
	During the years ended December 31, 2014 and 2013, our debt and preferred equity investments (net of discounts and deferred origination fees) increased $680.1 million and $601.3 million, respectively, due to originations, purchases, advances under future funding obligations, protective advances, accretion of reserves, discounts, premiums and paid-in-kind interest. We recorded repayments, participations and sales of $576.1 million and $644.9 million during the years ended December 31, 2014 and 2013, respectively, which offset the increases in debt and preferred equity investments.
	Debt Investments
	As of December 31, 2014 and 2013, we held the following debt investments with an aggregate weighted average current yield of 10.33% at December 31, 2014 (in thousands):


	Loan Type		December 31, 2014				December 31, 2014				December 31, 2014			December 31, 2013			Initial
			Future Funding				Senior				Carrying Value,			Carrying Value,			Maturity
			Obligations				Financing				Net of Discounts and Deferred Origination Fees(1)			Net of Discounts and Deferred Origination Fees(1)			Date
	Fixed Rate Investments:
	Jr. Mortgage Participation		$	—			$	398,500			$	11,934		$	11,856		Mar-15

	Jr. Mortgage Participation		—				205,000				70,688			68,319			Feb-16
	/Mezzanine Loan
	Other(2)		—				—				45,611			44,742			Various(2)

	Mezzanine Loan(3)		—				177,000				14,068			15,012			May-16

	Jr. Mortgage Participation		—				133,000				49,000			49,000			Jun-16

	Mezzanine Loan		—				165,000				71,656			71,312			Nov-16

	Jr. Mortgage Participation/Mezzanine Loan(4)		—				1,109,000				98,934			26,884			Mar-17

	Other(4)		—				—				65,770			54,099			Mar-17

	Mezzanine Loan(5)		16,424				521,750				24,608			20,954			Jun-17

	Mezzanine Loan		—				539,000				49,629			—			Jul-18

	Mortgage Loan(6)		—				—				26,209			—			Feb-19



	Mortgage Loan		—				—				637			—			Aug-19

	Mezzanine Loan		—				15,000				3,500			3,500			Sep-21

	Mezzanine Loan(7)		—				90,000				19,930			19,926			Nov-23

	Mezzanine Loan		—				95,000				30,000			—			Jan-25

	Total fixed rate		$	16,424			$	3,448,250			$	582,174		$	385,604

	Floating Rate Investments:
	Mezzanine Loan		7,785				50,000				37,322			—			Apr-15

	Mortgage/Mezzanine Loan		—				—				109,527			—			Jun-15

	Mezzanine Loan		—				110,000				49,614			49,110			Sep-15

	Mezzanine Loan		7,249				113,633				42,750			27,662			Dec-15

	Mezzanine Loan		—				775,000				73,402			72,823			Mar-16

	Mezzanine Loan(8)		—				160,000				22,573			22,526			Jun-16

	Mezzanine Loan		—				115,000				24,910			25,590			Jul-16

	Mezzanine Loan		3,641				172,105				33,726			25,725			Nov-16

	Mezzanine Loan		—				360,000				99,023			—			Nov-16

	Mezzanine Loan		333				33,833				11,835			11,798			Dec-16

Mezzanine Loan		9,053				91,727				20,651			—			Jan-17

Mortgage/Mezzanine Loan		2,847				110,767				38,524			—			Jul-17

Mortgage/Mezzanine Loan		—				—				22,803			—			Jul-17

Mortgage/Mezzanine Loan		—				—				16,848			—			Sep-17

Mezzanine Loan		—				60,000				14,859			—			Nov-17

Mortgage/Mezzanine Loan(9)		795				—				14,845			—			Dec-17

Jr. Mortgage Participation/Mezzanine Loan		—				55,000				20,533			20,553			Jul-18

Mortgage/Mezzanine Loan		—				—				18,083			—			Feb-19

Mezzanine Loan		—				38,000				21,807			—			Mar-19

Mortgage Loan(10)		—				—				—			30,000

Jr. Mortgage Participation(11)		—				—				—			24,046

Jr. Mortgage Participation/Mezzanine Loan(11)		—				—				—			131,724

Mezzanine Loan(12)		—				—				—			59,892

Jr. Mortgage Participation(12)		—				—				—			10,873

Mezzanine Loan(12)		—				—				—			38,549

Total floating rate		$	31,703			$	2,245,065			$	693,635		$	550,871

Total		$	48,127			$	5,693,315			$	1,275,809		$	936,475

Loan loss reserve										—			(1,000		)

										$	1,275,809		$	935,475

____________________________________________________________________

-1	Carrying value is net of discounts, premiums, original issue discounts and deferred origination fees.

-2	During the fourth quarter of 2014, both our $22.6 million junior participation and our $23.0 mezzanine loan were defeased and are now collateralized by defeasance securities. In connection with the defeasance, the maturity date of the mortgage in which we are a junior participant was accelerated from the May 2016 to February 2016, per the terms of the loan agreement. The maturity date of the mezzanine loan was not changed in connection with the defeasance and will mature in May 2016.

-3	This loan was repaid in February 2015.

-4	During the first quarter of 2014, we recognized $10.1 million of previously unaccrued interest income which was deemed collectible as a result of the sale of the underlying property, which closed in June 2014. In connection with the sale of the underlying property, our existing $66.7 million mezzanine loan was defeased and is now shown separately, as it is collateralized by defeasance securities. The buyer assumed our $30.0 million participating interest in the mortgage and we acquired a $67.3 million participating interest in the new mezzanine loan.

-5	Carrying value is net of $41.3 million that was participated out, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfer not meeting the conditions for sale accounting.

-6	In September 2014, we acquired a $26.4 million mortgage loan at a $0.2 million discount and a $5.7 million junior mortgage participation at a $5.7 million discount. The junior mortgage participation was a nonperforming loan at acquisition and is currently on non-accrual status.

-7	Carrying value is net of $5.0 million that was participated out, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfer not meeting the conditions for sale accounting.

-8	Carrying value is net of $7.4 million that was participated out, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfer not meeting the conditions for sale accounting.

-9	Carrying value is net of $5.1 million that was participated out, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfer not meeting the conditions for sale accounting.

-10	This loan was repaid in May 2014.

-11	This loan was repaid in July 2014.

-12	This loan was repaid in August 2014.
Preferred Equity Investments
As of December 31, 2014 and 2013, we held the following preferred equity investments with an aggregate weighted average current yield of 10.89% at December 31, 2014 (in thousands):


Type		December 31, 2014				December 31, 2014				December 31, 2013			Initial
		Senior				Carrying Value,				Carrying Value,			Mandatory
		Financing				Net of Discounts and Deferred Origination Fees(1)				Net of Discounts and Deferred Origination Fees(1)			Redemption
Preferred equity(2)		$	550,000			$	123,041			$	115,198		Jul-15

Preferred equity		70,000				9,954				9,940			Nov-17

Preferred equity(3)		—				—				25,896

Preferred equity(2)(4)		—				—				218,330

		$	620,000			$	132,995			$	369,364

____________________________________________________________________

-1	Carrying value is net of discounts and deferred origination fees.

-2	The difference between the pay and accrual rates is included as an addition to the principal balance outstanding.

-3	This preferred equity investment was redeemed in April 2014.

-4	This preferred equity investment was redeemed in November 2014.
The following table is a rollforward of our total loan loss reserves at December 31, 2014, 2013 and 2012 (in thousands):


	December 31,
	2014				2013				2012
Balance at beginning of year	$	1,000			$	7,000			$	50,175

Expensed	—				—				3,000

Recoveries	—				—				(2,436		)

Charge-offs and reclassifications	(1,000		)		(6,000		)		(43,739		)
Balance at end of period	$	—			$	1,000			$	7,000

At December 31, 2014, 2013 and 2012, all debt and preferred equity investments were performing in accordance with the terms of the relevant investments, with the exception of a junior mortgage participation acquired in September 2014, which has a carrying value of zero.
We have determined that we have one portfolio segment of financing receivables at December 31, 2014 and 2013 comprising commercial real estate which is primarily recorded in debt and preferred equity investments. Included in other assets is an additional amount of financing receivables totaling $133.5 million and $172.8 million at December 31, 2014 and 2013, respectively. No financing receivables were 90 days past due at December 31, 2014.
The following table presents impaired loans, which may include non-accrual loans, as of December 31, 2013 (in thousands):


							31-Dec-13
							Unpaid				Recorded			Allowance
							Principal				Investment			Allocated
							Balance
With no related allowance recorded:
Commercial real estate							$	—			$	—		$	—

With an allowance recorded:
Commercial real estate(1)							10,750				10,750			1,000

Total							$	10,750			$	10,750		$	1,000

____________________________________________________________________

-1	This loan was repaid during the year ended December 31, 2014.
During the year ended December 31, 2013, the average recorded investment in impaired loans, which may include non-accrual loans, and the related investment and preferred equity income recognized were $10.9 million and $7.1 million, respectively. On an ongoing basis, we monitor the credit quality of our financing receivables based on payment activity. We assess credit quality indicators based on the underlying collateral.

Investments_in_Unconsolidated_

Investments in Unconsolidated Joint Ventures	12 Months Ended
	Dec. 31, 2014
Equity Method Investments and Joint Ventures [Abstract]
Investments in Unconsolidated Joint Ventures	Investments in Unconsolidated Joint Ventures
	We have investments in several real estate joint ventures with various partners, including Ivanhoe Cambridge, Inc., formerly
	SITQ Immobilier, a subsidiary of Caisse de depot et placement du Quebec, SITQ, Canada Pension Plan Investment Board, or CPPIB, Prudential Real Estate Investors, or Prudential, Onyx Equities, or Onyx, or Credit Suisse, Jeff Sutton, or Sutton, Harel Insurance and Finance, or Harel, TNG 33 LLC, or Naftali, Louis Cappelli, or Cappelli, The Moinian Group, or Moinian, Vornado Realty Trust (NYSE:VNO), or Vornado, Plaza Global Real Estate Partners LP, or Plaza, KCLW 3rd Street LLC, or Kushner Companies, LIVWRK LLC, or LIVWRK, as well as private investors. All the investments below are voting interest entities, except for 650 Fifth Avenue, 33 Beekman, and 3 Columbus Circle, which are VIEs in which we are not the primary beneficiary as of December 31, 2014 and 2013. Prior to the acquisition of our joint venture partner's interest in May 2014, 388-390 Greenwich Street was also a VIE. Prior to the sale of the property in September 2014, 180-182 Broadway was a VIE. Our net equity investment in these VIEs was $146.2 million and $310.7 million at December 31, 2014 and 2013, respectively. As we do not control the joint ventures listed below, we account for them under the equity method of accounting.
	The table below provides general information on each of our joint ventures as of December 31, 2014:


	Property	Partner	Ownership	Economic	Approximate Square		Acquisition Date	Acquisition
			Interest	Interest	Feet			Price(1)
					(unaudited)			(in thousands)
	100 Park Avenue	Prudential	49.90%	49.90%	834,000		Jan-00	$	95,800

	717 Fifth Avenue(2)	Sutton/Private Investor	10.92%	10.92%	119,500		Sep-06	251,900

	800 Third Avenue	Private Investors	42.95%	42.95%	526,000		Dec-06	285,000

	1745 Broadway(3)	Ivanhoe Cambridge	56.88%	56.88%	674,000		Apr-07	520,000

	Jericho Plaza	Onyx/Credit Suisse	20.26%	20.26%	640,000		Apr-07	210,000

	The Meadows	Onyx	50.00%	50.00%	582,100		Sep-07	111,500

	600 Lexington Avenue	CPPIB	55.00%	55.00%	303,515		May-10	193,000

	11 West 34th Street	Private Investor\Sutton	30.00%	30.00%	17,150		Dec-10	10,800

	7 Renaissance	Cappelli	50.00%	50.00%	65,641		Dec-10	4,000

	3 Columbus Circle(4)	Moinian	48.90%	48.90%	741,500		Jan-11	500,000

	280 Park Avenue(5)	Vornado	50.00%	50.00%	1,219,158		Mar-11	400,000

	1552-1560 Broadway(6)	Sutton	50.00%	50.00%	35,897		Aug-11	136,550

	724 Fifth Avenue	Sutton	50.00%	50.00%	65,040		Jan-12	223,000

	10 East 53rd Street	CPPIB	55.00%	55.00%	354,300		Feb-12	252,500

	33 Beekman(7)	Harel/Naftali	45.90%	45.90%	—		Aug-12	31,000

	521 Fifth Avenue(8)	Plaza	50.50%	50.50%	460,000		Nov-12	315,000



	21 East 66th Street(9)	Private Investors	32.28%	32.28%	16,736		Dec-12	75,000

	315 West 36th Street	Private Investors	35.50%	35.50%	147,619		Dec-12	45,000

	650 Fifth Avenue(10)	Sutton	50.00%	50.00%	32,324		Nov-13	—

	121 Greene Street	Sutton	50.00%	50.00%	7,131		Sep-14	27,400

	175-225 Third Street(11)	Kushner Companies/LIVWRK	95.00%	95.00%	—		Oct-14	74,600

	55 West 46th Street(12)	Prudential	25.00%	25.00%	347,000		Nov-14	295,000

	____________________________________________________________________

	-1	Acquisition price represents the actual or implied gross purchase price for the joint venture.

	-2	In June 2012, we recognized $67.9 million of additional cash income, equivalent to profit, due to the distribution of refinancing proceeds and a gain on sale of $3.0 million, on the sale of 50.0% of our remaining interest.

	-3	In November 2014, we acquired Lehman Bros.' 7.37% interest in 1745 Broadway. In December 2014, we additionally acquired Witkoff's 14.79% interest and Wells Fargo's 2.46% interest in the property. In connection with the acquisition of Witkoff's interest, we assumed a partner loan of $16.0 million, which is included in mortgages and other loans payable in the consolidated balance sheet, and $7.0 million of accrued interest.

	-4	As a result of the sale of a condominium interest in September 2012, Young & Rubicam, Inc., or Y&R, owns a portion of the property, generally floors three through eight referred to as Y&R units. Because the joint venture has an option to repurchase the Y&R units, the gain associated with this sale was deferred.

-5	In October 2014, we, along with Vornado, acquired equally the interest of minority shareholders for $11.0 million.

-6	The purchase price represents only the purchase of the 1552 Broadway interest which comprised approximately 13,045 square feet (unaudited). The joint venture also owns a long-term leasehold interest in the retail space and certain other spaces at 1560 Broadway, which is adjacent to 1552 Broadway.

-7	The property is currently being developed into a 30 story dormitory building, which will be conveyed to Pace University upon its completion under a long-term ground lease arrangement.

-8	In November 2012, we refinanced the previous mortgage and sold 49.5% of our partnership interest. We recognized a gain of $19.4 million on the sale. Due to lack of control, we deconsolidated the entity effective November 30, 2012 and adopted the equity method of accounting thereafter. During the year ended December 31, 2013, we recognized additional post closing costs of $2.8 million as an adjustment to the gain.

-9	In October 2014, the joint venture sold one of the residential units at the property. We recognized a gain of $0.7 million on the sale. As of December 31, 2014, we hold a 32.28% interest in three retail and two residential units at the property and a 16.14% interest in three residential units at the property.

-10	The joint venture owns a long-term leasehold interest in the retail space at 650 Fifth Avenue. In connection with the ground lease obligation, SLG provided a performance guaranty and Sutton executed a contribution agreement to reflect its pro rata obligation. In the event the property is converted into a condominium unit and the landlord elects the purchase option, the joint venture shall be obligated to acquire the unit at the then fair value.

-11	In October 2014, we, along with our joint venture partners, acquired a development site at 175-225 Third Street in Brooklyn, New York. The property is being managed by our joint venture partners. We did not consolidate the property as a result of multiple partners having substantive participating rights.

-12	In October 2014, we acquired the vacant commercial condominium units on floors 2 and 22-34 in the building located at 55 West 46th Street for $295.0 million. We also acquired a retail space on 46th Street and the building’s parking garage and fitness center. We consolidated the property from acquisition through October 31, 2014. In November 2014, we, together with Prudential, formed a joint venture for the ownership of the condominium units. We sold 75.00% of our interest to Prudential and retained 25.00% interest in the joint venture. As a result of Prudential having substantive participating rights, we deconsolidated the property and adopted the equity method of accounting subsequently thereafter.
Acquisition, Development, and Construction Arrangements
In March 2014, we closed on the origination of a $100.0 million acquisition and equity participating financing consisting of a $60.0 million mezzanine loan and a $40.0 million preferred equity, which are both due to mature in March 2016, subject to three one-year extension options and a two-year option for the last extension. As of December 31, 2014, the carrying value of this investment was $99.6 million.
In October 2014, we closed on the origination of a $45.8 million acquisition and equity financing, which is due to mature in February 2022. We have an option to convert our loan into equity interest subject to certain conditions. As of December 31, 2014, the carrying value of this investment was $46.2 million.
Based on the characteristics of these arrangements which are similar to those of an investment, combined with the expected residual profit of not greater than 50%, we have accounted for our investment under the equity method. In addition, we determined that the option to purchase is not a derivative financial instrument pursuant to GAAP. As such, the embedded feature is not required to be bifurcated and the fair value accounting for the embedded feature at each reporting date is not applicable.
Sale of Joint Venture Interest or Property
The following table summarizes the investments in unconsolidated joint ventures sold during the years ended December 31, 2014, 2013, and 2012:


Property		Ownership Percentage			Disposition Date		Type of Sale		Implied Sales Price (1)				Gain on Sale(2)
									(in millions)				(in millions)
180 Broadway(3)		25.5	%		Sep-14		Property		$	222.5			$	16.5

747 Madison Avenue(4)		33.33	%		May-14		Ownership Interest		160				—

West Coast Office portfolio(5)		42.02	%		Mar-14		Ownership Interest		756				85.6

21-25 West 34th Street(6)		49.9	%		Jan-14		Ownership Interest		114.9				20.9

27-29 West 34th Street(7)		50	%		Dec-13		Ownership Interest		70.1				7.6

West Coast Office Portfolio(5)		42.04	%		Various dates in 2013		Property		224.3				2.1

One Court Square(8)		30	%		Jul-12		Property		481.1				1

379 West Broadway(9)		45	%		Apr-12		Property		48.5				6.5

141 Fifth Avenue(10)		50	%		Mar-12		Property		46				7.3

____________________________________________________________________

-1	Represents implied gross valuation for the joint venture or sales price of the property.

-2	Represents the Company's share of the gain.

-3	In connection with the sale of the property, we also recognized a promote of $3.3 million.

-4	We sold our ownership interest in the joint venture, which owns 100% interest as tenant-in-common in 30 East 65th Street Corporation and the related proprietary lease of five cooperative apartment units in the property. We also recognized a promote of $10.3 million and originated a $30.0 million preferred equity investment. Given our continuing involvement as a preferred equity holder, we deferred the gain on sale of $13.1 million as we did not meet the requirements of a sale under the full accrual method. We, along with our joint venture partners, retained one apartment unit at this property.

-5	Prior to the recapitalization, we consolidated the investment for the months of August and September 2012 as a result of our 63.18% ownership interest and control over its activities. Immediately following the recapitalization in September 2012, our investment was 27.63%. The change in ownership resulted in a change in accounting from consolidating the investment to accounting for the joint venture under the equity method of accounting. During the year ended December 31, 2013, the joint venture sold three properties, the proceeds of which were used primarily to repay a portion of the debt. Also during the year ended December 31, 2013, we acquired in aggregate 14.39% ownership interest of two of our joint venture partners. As a result, we had a 42.04% effective ownership interest (43.74% effective economic interest) in the West Coast portfolio as of December 31, 2013. During the year ended December 31, 2014, we sold our ownership interest in the joint venture.

-6	We sold our ownership interest in the joint venture. We, along with our joint venture partner, retained approximately 91,300 square feet (unaudited) of development rights at the property.

-7	We sold our ownership interest in the joint venture. The gain on the sale of this investment is net of a $1.5 million employee compensation award, accrued in connection with the realization of this investment gain as a bonus to certain employees that were instrumental in realizing the gain on this sale. Simultaneously, we, along with Sutton, also formed a new joint venture and retained the air rights at this property.

-8	We, along with our joint venture partner, sold the property, which included the assumption by the purchaser of $315.0 million of existing debt.

-9	We, along with our joint venture partner, sold the property, inclusive of the fee position, which was acquired for $13.5 million.

-10	We, along with our joint venture partner, sold the property. The gain on the sale of this investment is net of a $1.5 million employee compensation award, accrued in connection with the realization of this investment gain as a bonus to certain employees that were instrumental in realizing the gain on this sale.
In December 2013, the preferred equity interest held by the joint venture which holds Herald Center was redeemed. This preferred equity interest bore interest at a rate of 8.75% per annum through the redemption date.
Mortgages and Other Loans Payable
We generally finance our joint ventures with non-recourse debt. However, in certain cases we have provided guarantees or master leases for tenant space. These guarantees and master leases terminate upon the satisfaction of specified circumstances or repayment of the underlying loans. The first mortgage notes and other loans payable collateralized by the respective joint venture properties and assignment of leases at December 31, 2014 and 2013, respectively, are as follows (amounts in thousands):


Property		Maturity Date			Interest			31-Dec-14				31-Dec-13
					Rate(1)
Fixed Rate Debt:
7 Renaissance		Dec-15			10	%		$	2,147			$	1,276

11 West 34th Street		Jan-16			4.82	%		16,905				17,205

280 Park Avenue		Jun-16			6.57	%		700,171				706,886

1745 Broadway		Jan-17			5.68	%		340,000				340,000

Jericho Plaza		May-17			5.65	%		163,750				163,750

800 Third Avenue		Aug-17			6	%		20,910				20,910

315 West 36th Street		Dec-17			3.16	%		25,000				25,000

521 Fifth Avenue(2)		Nov-19			2.48	%		170,000				—

717 Fifth Avenue(3)		Jul-22			4.45	%		300,000				300,000

21 East 66th Street		Apr-23			3.6	%		12,000				12,000

717 Fifth Avenue(3)		Jul-24			9	%		314,381				304,000

388-390 Greenwich Street(4)		—			—			—				996,082

100 Park Avenue(5)		—			—			—				209,786

21 West 34th Street(6)		—			—			—				100,000

1604-1610 Broadway(7)		—			—			—				27,000

Total fixed rate debt								$	2,065,264			$	3,223,895

Floating Rate Debt:
The Meadows		Sep-15			7.75	%		67,350				67,350

3 Columbus Circle(8)		Apr-16			2.33	%		230,974				239,233

1552 Broadway(9)		Apr-16			4.25	%		184,210				158,690

Other loan payable		Jun-16			1.05	%		30,000				30,000

650 Fifth Avenue(10)		Oct-16			3.66	%		65,000				—

175-225 Third Street		Dec-16			4.25	%		40,000				—

10 East 53rd Street		Feb-17			2.65	%		125,000				125,000

724 Fifth Avenue(11)		Apr-17			2.57	%		275,000				120,000

33 Beekman(12)		Aug-17			2.9	%		52,283				18,362

600 Lexington Avenue		Oct-17			2.23	%		116,740				120,616

55 West 46th Street(13)		Oct-17			2.45	%		150,000				—

121 Greene Street		Nov-19			1.67	%		15,000				—

100 Park Avenue(5)		Feb-21			2.36	%		360,000				—

21 East 66th Street		Jun-33			2.88	%		1,883				1,959

521 Fifth Avenue(2)		—			—			—				170,000

388-390 Greenwich Street(4)		—			—			—				142,297

747 Madison Avenue		—			—			—				33,125

West Coast Office portfolio(14)		—			—			—				526,290

180/182 Broadway(15)		—			—			—				89,893

Total floating rate debt								$	1,713,440			$	1,842,815

Total joint venture mortgages and other loans payable								$	3,778,704			$	5,066,710

____________________________________________________________________

-1	Effective weighted average interest rate for the year ended December 31, 2014, taking into account interest rate hedges in effect during the period.

-2	This loan became a 3.73% fixed rate mortgage upon the effectivity of the interest rate swap in November 2014.

-3	These loans are comprised of a $300.0 million fixed rate mortgage loan and $290.0 million mezzanine loan. The mezzanine loan is subject to accretion based on the difference between contractual interest rate and contractual pay rate.

-4	In May 2014, we acquired the interest of our joint venture partner, thereby consolidating the entity. Simultaneous with the acquisition, we refinanced the mortgage and incurred a net loss on early extinguishment of debt of $2.4 million.

-5	In February 2014, the joint venture refinanced the previous mortgage and incurred a net loss on early extinguishment of debt of $3.2 million.

-6	In January 2014, we sold our interest in the joint venture, inclusive of our share of the joint venture debt.

-7	This loan was in default since November 2009 due to the non-payment of debt service. In January 2014, the joint venture surrendered its ground lease position to the lender. During the year ended December 31, 2014, we recognized $7.7 million of incentive income, which is included in other income on the consolidated statements of income.

-8	The joint venture has the ability to increase the mortgage by $40.0 million based on meeting certain performance hurdles. In connection with this obligation, we executed a master lease agreement and our joint venture partner executed a contribution agreement to reflect its pro rata obligation under the master lease. The lien on the mortgage and the master lease excludes the condominium interest owned by Y&R. See Note 4 of the first table.

-9	These loans are comprised of a $150.0 million mortgage loan and a $41.5 million mezzanine loan. As of December 31, 2014, $3.9 million of the mortgage loan and $3.4 million of the mezzanine loan remained unfunded.

-10	In October 2014, the joint venture closed on a $97.0 million leasehold mortgage, of which $32.0 million remained unfunded as of December 31, 2014.

-11	In April 2014, the joint venture refinanced the previous mortgage and incurred a net loss on early extinguishment of debt of $1.2 million.

-12	This loan has a committed amount of $75.0 million, of which $18.4 million is recourse to us. Our partner has indemnified us for its pro rata share of the recourse guarantee. A portion of the guarantee terminates upon the joint venture reaching certain milestones. We believe it is unlikely that we will be required to perform under this guarantee.

-13	This loan has a committed amount of $190.0 million, of which $40.0 million remained unfunded as of December 31, 2014.

-14	In March 2014, we sold our interest in the joint venture, inclusive of our share in the joint venture debt.

-15	In September 2014, the joint venture sold the property and repaid the debt.
We act as the operating partner and day-to-day manager for all our joint ventures, except for 800 Third Avenue, Jericho Plaza, 280 Park Avenue, 3 Columbus Circle, The Meadows, 315 West 36th Street, 21 East 66th Street, and 175-225 Third Street. We are entitled to receive fees for providing management, leasing, construction supervision and asset management services to our joint ventures. We earned $16.9 million, $4.7 million and $7.9 million from these services for the years ended December 31, 2014, 2013 and 2012, respectively. In addition, we have the ability to earn incentive fees based on the ultimate financial performance of certain of the joint venture properties.
The combined balance sheets for the unconsolidated joint ventures, at December 31, 2014 and 2013, are as follows (in thousands):


	December 31,
	2014				2013
Assets
Commercial real estate property, net	$	5,275,632			$	6,846,021

Other assets	810,567				827,282

Total assets	$	6,086,199			$	7,673,303

Liabilities and members' equity
Mortgages and other loans payable	$	3,778,704			$	5,066,710

Other liabilities	485,572				596,960

Members' equity	1,821,923				2,009,633

Total liabilities and members' equity	$	6,086,199			$	7,673,303

Company's investments in unconsolidated joint ventures	$	1,172,020			$	1,113,218

The combined statements of income for the unconsolidated joint ventures, from acquisition date through the years ended December 31, 2014, 2013 and 2012 are as follows (in thousands):


	Years Ended December 31,
	2014				2013				2012
Total revenues	$	522,132			$	628,649			$	511,157

Operating expenses	82,436				114,633				80,722

Ground rent	9,898				2,863				2,975

Real estate taxes	64,217				71,755				53,613

Interest expense, net of interest income	178,743				225,765				221,476

Amortization of deferred financing costs	12,395				17,092				9,739

Transaction related costs	535				808				2,044

Depreciation and amortization	137,793				192,504				166,336

Total expenses	486,017				625,420				536,905

(Loss) gain on early extinguishment of debt	(6,743		)		—				21,421

Net income (loss) before gain on sale	$	29,372			$	3,229			$	(4,327	)

Company's equity in net income from unconsolidated joint ventures	$	26,537			$	9,921			$	76,418

Equity in net income from unconsolidated joint ventures for the year ended December 31, 2012 includes additional income of $67.9 million as a result of the distribution of the recapitalization of 717 Fifth Avenue and $10.8 million as a result of the repayment of the Meadows' previous mortgage at a discount.

Deferred_Costs

Deferred Costs	12 Months Ended
	Dec. 31, 2014
Deferred Costs [Abstract]
Deferred Costs	Deferred Costs
	Deferred costs at December 31, 2014 and 2013 consisted of the following (in thousands):


		December 31,
		2014			2013
	Deferred leasing	$	385,555		$	326,379

	Deferred financing	193,776			157,088

		579,331			483,467

	Less accumulated amortization	(251,369		)	(216,409		)
	Deferred costs, net	$	327,962		$	267,058

Mortgages_and_Other_Loans_Paya

Mortgages and Other Loans Payable	12 Months Ended
	Dec. 31, 2014
Mortgages and Other Loans Payable
Mortgages and Other Loans Payable	Mortgages and Other Loans Payable
	The first mortgages and other loans payable collateralized by the respective properties and assignment of leases at December 31, 2014 and 2013, respectively, were as follows (amounts in thousands):


	Property		Maturity		Interest			31-Dec-14			31-Dec-13
			Date		Rate(1)
	Fixed Rate Debt:
	711 Third Avenue		Jun-15		4.99	%		$	120,000		$	120,000

	500 West Putnam Avenue		Jan-16		5.52	%		22,968			23,529

	Landmark Square		Dec-16		4	%		81,269			82,909

	485 Lexington Avenue		Feb-17		5.61	%		450,000			450,000

	120 West 45th Street		Feb-17		6.12	%		170,000			170,000

	762 Madison Avenue		Feb-17		3.75	%		8,045			8,211

	885 Third Avenue		Jul-17		6.26	%		267,650			267,650

	1745 Broadway(2)		Jun-18		4.81	%		16,000			—

	388-390 Greenwich Street(3)		Jun-18		2.99	%		1,004,000			—

	One Madison Avenue		May-20		5.91	%		565,742			587,336



	100 Church		Jul-22		4.68	%		228,612			230,000

	919 Third Avenue(4)		Jun-23		5.12	%		500,000			500,000

	400 East 57th Street		Feb-24		4.13	%		68,896			70,000

	400 East 58th Street		Feb-24		4.13	%		29,527			30,000

	420 Lexington Avenue(5)		Oct-24		5.95	%		300,000			182,641

	1515 Broadway(6)		Mar-25		3.93	%		900,000			900,000

	Series J Preferred Units(7)		Apr-51		3.75	%		4,000			—

	Other loan payable(8)							—			50,000

	609 Partners, LLC(9)							—			23

	125 Park Avenue(10)							—			146,250

	2 Herald Square(11)							—			191,250

	625 Madison Avenue(12)							—			120,830

	Total fixed rate debt							$	4,736,709		$	4,130,629

	Floating Rate Debt:
	Master repurchase agreement(13)		Dec-15		3.38	%		100,000			91,000

	180 Maiden Lane(14)		Nov-16		2.35	%		253,942			262,706

	388-390 Greenwich Street(3)		Jun-18		1.91	%		446,000			—

	248-252 Bedford Avenue(15)		Jun-19		1.93	%		29,000			22,000

220 East 42nd Street		Oct-20		1.75	%		275,000			275,000

16 Court Street(16)							—			79,243

Total floating rate debt							$	1,103,942		$	729,949

Total mortgages and other loans payable							$	5,840,651		$	4,860,578

____________________________________________________________________

-1	Effective weighted average interest rate for the year ended December 31, 2014, taking into account interest rate hedges in effect during the period.

-2	In connection with our acquisition of Witkoff's interest in the unconsolidated joint venture which holds 1745 Broadway, we have assumed this partner loan.

-3	Simultaneous with the acquisition of our joint venture partner's interest, we refinanced the $1.1 billion floating rate mortgage with a $1.45 billion seven-year floating rate mortgage (including the as-of right extension option), and have consolidated the property. We assumed the existing derivative instruments, which swapped $504.0 million of the floating rate mortgage to a fixed rate mortgage which bears interest at 3.80% per annum. In October 2014, we entered into multiple swap agreements to hedge our interest rate exposure on the additional $500.0 million portion of this mortgage, which was swapped to a fixed rate of 2.69% per annum.

-4	We own a 51.0% controlling interest in the joint venture that is the borrower on this loan.

-5	In September 2014, we refinanced the previous mortgage and incurred a loss on early extinguishment of debt of $24.5 million. The new loan bears a fixed interest rate of 3.99% per annum.

-6	In February 2013, we refinanced the mortgage and incurred a loss on early extinguishment of debt of $18.5 million.

-7	In connection with the acquisition of a commercial real estate property, the Operating Partnership issued $4.0 million or 4,000 3.75% Series J Preferred Units of limited partnership interest, or the Series J Preferred Units, with a mandatory liquidation preference of $1,000.00 per unit. The Series J Preferred Units can be redeemed in cash by the Operating Partnership on the earlier of (i) the date of the sale of the property or (ii) April 30, 2051 or at the option of the unitholders as further prescribed in the related agreement.

-8	In November 2014, we repaid the loan.

-9	In April 2014, the remaining 22,658 Series E Preferred Units of the Operating Partnership were canceled.

-10	In October 2014, we repaid the loan at maturity.

-11	In November 2014, we sold the property and defeased the debt.

-12	In December 2014, we prepaid the loan and incurred a loss on early extinguishment of debt of $6.9 million.

-13	The Master Repurchase Agreement, or MRA, has a maximum facility capacity of $300.0 million. In December 2014, we extended the maturity date of the MRA to December 5, 2015.

-14	In connection with this consolidated joint venture obligation, we executed a master lease agreement. Our partner has executed a contribution agreement to reflect its pro rata share of the obligation under the master lease. This property was held for sale at December 31, 2014 and the related mortgage is included in liabilities related to assets held for sale. In January 2015, the property was sold and the debt was repaid.

-15	In June 2014, we refinanced the mortgage and incurred a loss on early extinguishment of debt of $0.5 million. In April 2014, we repaid the mortgage and incurred a loss on early extinguishment of debt of $0.5 million.
At December 31, 2014 and 2013, the gross book value of the properties and debt and preferred equity investments collateralizing the mortgages and other loans payable was approximately $8.2 billion and $8.0 billion, respectively.

Corporate_Indebtedness

Corporate Indebtedness	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Corporate Indebtedness	Corporate Indebtedness
	2012 Credit Facility
	In March 2014, we entered into an amendment to the $1.6 billion credit facility entered into by the Company in November 2012, or the 2012 credit facility, which among other things, increased the term loan portion of the facility by $383.0 million to $783.0 million, decreased the interest-rate margin applicable to the term loan portion of the facility by 25 basis points and extended the maturity of the term loan portion of the facility from March 30, 2018 to June 30, 2019. In November 2014, we increased the term loan portion of the facility by $50.0 million to $833.0 million. As of December 31, 2014, the 2012 credit facility, as amended, consists of a $1.2 billion revolving credit facility, or the revolving credit facility, and an $833.0 million term loan, or the term loan facility. In January 2015, we entered into a second amended and restated credit agreement, which decreased the interest-rate margin and facility fee applicable to the revolving credit facility by 20 basis points and five basis points, respectively, and extended the maturity date of the revolving credit facility to March 29, 2019 with an as-of-right extension through March 29, 2020. We also have an option, subject to customary conditions, without the consent of existing lenders, to increase the capacity under the revolving credit facility to $1.5 billion at any time prior to the maturity date for the revolving credit facility, by obtaining additional commitments from our existing lenders and other financial institutions.
	As of December 31, 2014, the 2012 credit facility bore interest at a spread over LIBOR ranging from (i) 100 basis points to 175 basis points for loans under the revolving credit facility and (ii) 95 basis points to 190 basis points for loans under the term loan facility, in each case based on the credit rating assigned to the senior unsecured long term indebtedness of ROP. At December 31, 2014, the applicable spread was 145 basis points for revolving credit facility and 140 basis points for the term loan facility. At December 31, 2014, the effective interest rate was 1.61% for the revolving credit facility and 1.67% for the term loan facility. We are required to pay quarterly in arrears a 15 to 35 basis point facility fee on the total commitments under the revolving credit facility based on the credit rating assigned to the senior unsecured long term indebtedness of ROP. As of December 31, 2014, the facility fee was 30 basis points. As of December 31, 2014, we had $113.2 million of outstanding letters of credit, $385.0 million drawn under the revolving credit facility and $833.0 million outstanding under the term loan facility, with total undrawn capacity of $701.8 million under the 2012 credit facility.
	In connection with the amendment of the 2012 credit facility, we incurred debt origination and other loan costs of $3.0 million. We evaluated the modification pursuant to ASC 470 and determined that the terms of the amendment were not substantially different from the terms of the previous 2012 credit facility. As a result, these deferred costs and the unamortized balance of the costs previously incurred are amortized through the extended maturity date of the term loan facility.
	The Company, the Operating Partnership and ROP are all borrowers jointly and severally obligated under the 2012 credit facility. None of our other subsidiaries are obligors under the 2012 credit facility.
	The 2012 credit facility includes certain restrictions and covenants (see Restrictive Covenants below).
	2011 Revolving Credit Facility
	The 2012 credit facility replaced our $1.5 billion revolving credit facility, or the 2011 revolving credit facility, which was terminated concurrently with the entering into the 2012 credit facility. The 2011 revolving credit facility bore interest at a spread over LIBOR ranging from 100 basis points to 185 basis points, based on the credit rating assigned to the senior unsecured long-term indebtedness of ROP, and required to pay quarterly in arrears a 17.5 to 45 basis point facility fee on the total commitments under the 2011 revolving credit facility. The 2011 revolving credit facility included certain restrictions and covenants and, as of the time of the termination of the 2011 revolving credit facility and as of November 2012, we were in compliance with all such restrictions and covenants.
	Senior Unsecured Notes
	The following table sets forth our senior unsecured notes and other related disclosures as of December 31, 2014 and 2013, respectively, by scheduled maturity date (dollars in thousands):


	Issuance		December 31,				December 31,				31-Dec-13				Coupon			Effective		Term		Maturity Date
			2014				2014				Accreted				Rate(1)			Rate		(in Years)
			Unpaid				Accreted				Balance
			Principal				Balance
			Balance
	March 31, 2006(2)		$	255,308			$	255,250			$	255,206			6	%		6	%	10		March 31, 2016

	October 12, 2010(3)		345,000				309,069				297,837				3	%		3	%	7		October 15, 2017

	August 5, 2011(4)		250,000				249,744				249,681				5	%		5	%	7		August 15, 2018

	March 16, 2010(4)		250,000				250,000				250,000				7.75	%		7.75	%	10		March 15, 2020

	November 15, 2012(4)		200,000				200,000				200,000				4.5	%		4.5	%	10		December 1, 2022

	June 27, 2005(2)(5)		7				7				7				4	%		4	%	20		June 15, 2025

	March 26, 2007(6)		10,008				10,008				10,701				3	%		3	%	20		March 30, 2027

	August 13, 2004(2)(7)		—				—				75,898

			$	1,310,323			$	1,274,078			$	1,339,330

	____________________________________________________________________

	-1	Interest on the senior unsecured notes is payable semi-annually with principal and unpaid interest due on the scheduled maturity dates.

	-2	Issued by ROP.

	-3	Issued by the Operating Partnership. Interest on these exchangeable notes is payable semi-annually on April 15 and October 15. The notes had an initial exchange rate representing an exchange price that was set at a 30.0% premium to the last reported sale price of SL Green's common stock on October 6, 2010, or $85.81. The initial exchange rate is subject to adjustment under certain circumstances. The current exchange rate is 12.1163 shares of SL Green's common stock per $1,000 principal amount of these notes. The notes are senior unsecured obligations of the Operating Partnership and are exchangeable upon the occurrence of specified events and during the period beginning on the twenty-second scheduled trading day prior to the maturity date and ending on the second business day prior to the maturity date, into cash or a combination of cash and shares of SL Green's common stock, if any, at our option. As a result of meeting specified events (as defined in the Indenture Agreement), these notes are exchangeable commencing January 1, 2015 and will remain exchangeable through March 31, 2015. The notes are guaranteed by ROP. On the issuance date, $78.3 million of the debt balance was recorded in equity. As of December 31, 2014, $35.9 million remained to be amortized into the debt balance.

	-4	Issued by the Company, the Operating Partnership and ROP, as co-obligors.

	-5	Exchangeable senior debentures which are currently callable at par. In addition, the debentures can be put to ROP, at the option of the holder at par plus accrued and unpaid interest, on June 15, 2015 and 2020 and upon the occurrence of certain change of control transactions. As a result of the acquisition of all outstanding shares of common stock of Reckson, or the Reckson Merger, the adjusted exchange rate for the debentures is 7.7461 shares of SL Green's common stock per $1,000 of principal amount of debentures and the adjusted reference dividend for the debentures is $1.3491.

	-6	Issued by the Operating Partnership. Interest on these remaining exchangeable notes is payable semi-annually on March 30 and September 30. The notes have an initial exchange rate representing an exchange price that was set at a 25.0% premium to the last reported sale price of the Company's common stock on March 20, 2007, or $173.30. The initial exchange rate is subject to adjustment under certain circumstances. The current exchange rate is 5.7952 shares of SL Green's common stock per $1,000 principal amount of these notes. The notes are senior unsecured obligations of the Operating Partnership and are exchangeable upon the occurrence of specified events and during the period beginning on the twenty-second scheduled trading day prior to the maturity date and ending on the second business day prior to the maturity date, into cash or a combination of cash and shares of SL Green's common stock, if any, at our option. The notes are currently redeemable at the Operating Partnership’s option. The Operating Partnership may be required to repurchase the notes on March 30, 2017 and 2022, and upon the occurrence of certain designated events.

	-7	In August 2014, these notes were repaid at maturity.
	Restrictive Covenants
	The terms of the 2012 credit facility, as amended, and certain of our senior unsecured notes include certain restrictions and covenants which may limit, among other things, our ability to pay dividends, make certain types of investments, incur additional indebtedness, incur liens and enter into negative pledge agreements and dispose of assets, and which require compliance with financial ratios relating to the minimum amount of tangible net worth, a maximum ratio of total indebtedness to total asset value, a minimum ratio of EBITDA to fixed charges, a maximum ratio of secured indebtedness to total asset value and a maximum ratio of unsecured indebtedness to unencumbered asset value. The dividend restriction referred to above provides that, we will not during any time when a default is continuing, make distributions with respect to common stock or other equity interests, except to enable the Company to continue to qualify as a REIT for Federal income tax purposes. As of December 31, 2014 and 2013, we were in compliance with all such covenants.
	Junior Subordinate Deferrable Interest Debentures
	In June 2005, the Company and the Operating Partnership issued $100.0 million in unsecured trust preferred securities through a newly formed trust, SL Green Capital Trust I, or the Trust, which is a wholly-owned subsidiary of the Operating Partnership. The securities mature in 2035 and bear interest at a fixed rate of 5.61% for the first ten years ending July 2015. Thereafter, the interest rate will float at 125 basis points over the three-month LIBOR. Interest payments may be deferred for a period of up to eight consecutive quarters if the Operating Partnership exercises its right to defer such payments. The Trust preferred securities are redeemable at the option of the Operating Partnership, in whole or in part, with no prepayment premium. We do not consolidate the Trust even though it is a variable interest entity as we are not the primary beneficiary. Because the Trust is not consolidated, we have recorded the debt on our consolidated balance sheets and the related payments are classified as interest expense.
	Principal Maturities
	Combined aggregate principal maturities of mortgages and other loans payable, 2012 credit facility, trust preferred securities, senior unsecured notes and our share of joint venture debt as of December 31, 2014, including as-of-right extension options and put options, were as follows (in thousands):


		Scheduled				Principal				Revolving				Unsecured Term Loan				Trust			Senior			Total			Joint
		Amortization				Repayments				Credit								Preferred			Unsecured						Venture
										Facility								Securities			Notes						Debt
	2015	$	39,353		-1	$	220,000			$	—			$	—			$	—		$	7		$	259,360		$	44,700

2016	54,344			-1	338,465			-1	—				—				—			255,308			648,117			640,176

2017	61,063				895,329				—				—				—			355,008			1,311,400			572,003

2018	64,462				16,000				385,000				—				—			250,000			715,462			28

2019	71,133				28,317				—				833,000				—			—			932,450			94,890

Thereafter	203,098				3,849,087				—				—				100,000			450,000			4,602,185			266,191

	$	493,453		-1	$	5,347,198		-1	$	385,000			$	833,000			$	100,000		$	1,310,323		$	8,468,974		$	1,617,988

____________________________________________________________________

-1	Scheduled amortization and principal repayments include the mortgage at 180 Maiden Lane, which is included in liabilities related to assets held for sale. In January 2015, the property was sold and the debt was repaid.
Consolidated interest expense, excluding capitalized interest, was comprised of the following (in thousands):


	Year Ended December 31,
	2014				2013				2012
Interest expense	$	319,898			$	312,897			$	311,235

Interest income	(2,498		)		(2,003		)		(1,554		)
Interest expense, net	$	317,400			$	310,894			$	309,681

Interest capitalized	$	22,750			$	11,475			$	12,218

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions
	Cleaning/ Security/ Messenger and Restoration Services
	Through Alliance Building Services, or Alliance, First Quality Maintenance, L.P., or First Quality, provides cleaning, extermination and related services, Classic Security LLC provides security services, Bright Star Couriers LLC provides messenger services, and Onyx Restoration Works provides restoration services with respect to certain properties owned by us. Alliance is partially owned by Gary Green, a son of Stephen L. Green, the chairman of SL Green's board of directors. In addition, First Quality has the non-exclusive opportunity to provide cleaning and related services to individual tenants at our properties on a basis separately negotiated with any tenant seeking such additional services. The Service Corporation has entered into an arrangement with Alliance whereby it will receive a profit participation above a certain threshold for services provided by Alliance to certain tenants at certain buildings above the base services specified in their lease agreements. Income earned from profit participation, which is included in other income on the consolidated statements of income, was $3.8 million, $3.5 million and $4.0 million for the years ended December 31, 2014, 2013 and 2012, respectively. We also recorded expenses of $21.5 million, $23.4 million and $20.5 million for the years ended December 31, 2014, 2013 and 2012, respectively, for these services (excluding services provided directly to tenants).
	Management Fees
	S.L. Green Management Corp., a consolidated entity, receives property management fees from an entity in which Stephen L. Green owns an interest. We received management fees from such entity of $444,300, $441,100 and $384,900 for the years ended December 31, 2014, 2013 and 2012, respectively.
	Other
	Amounts due from related parties at December 31, 2014 and 2013 consisted of the following (in thousands):


		December 31,
		2014		2013
	Due from joint ventures	$	1,254	$	2,376

	Other	10,481		6,154

	Related party receivables	$	11,735	$	8,530

Noncontrolling_Interests_on_th

Noncontrolling Interests on the Company's Consolidated Financial Statements	12 Months Ended
	Dec. 31, 2014
Noncontrolling Interest [Abstract]
Noncontrolling Interests on the Company's Consolidated Financial Statements	Noncontrolling Interests on the Company's Consolidated Financial Statements
	Noncontrolling interests represent the common and preferred units of limited partnership interest in the Operating Partnership not held by the Company as well as third party equity interests in our other consolidated subsidiaries. Noncontrolling interests in the Operating Partnership are shown in the mezzanine equity while the noncontrolling interests in our other consolidated subsidiaries are shown in the equity section of the Company’s consolidated financial statements.
	Common Units of Limited Partnership Interest in the Operating Partnership
	As of December 31, 2014 and 2013, the noncontrolling interest unit holders owned 3.92%, or 3,973,016 units, and 2.96%, or 2,902,317 units, of the Operating Partnership, respectively. At December 31, 2014, 3,973,016 shares of SL Green's common stock were reserved for issuance upon redemption of units of limited partnership interest of the Operating Partnership.
	Noncontrolling interests in the Operating Partnership is recorded at the greater of its cost basis or fair market value based on the closing stock price of SL Green's common stock at the end of the reporting period.
	Below is the rollforward analysis of the activity relating to the noncontrolling interests in the Operating Partnership (in thousands) as of December 31, 2014 and 2013:


		December 31,
		2014			2013
	Balance at beginning of period	$	265,476		$	212,907

	Distributions	(7,849		)	(4,146		)
	Issuance of common units	56,469			24,750

	Redemption of common units	(31,653		)	(17,287		)
	Net income	18,467			3,023

	Accumulated other comprehensive income allocation	175			611

	Fair value adjustment	168,439			45,618

	Balance at end of period	$	469,524		$	265,476

	Preferred Units of Limited Partnership Interest in the Operating Partnership
	The Operating Partnership has 1,902,000 4.5% Series G Preferred Units of limited partnership interest, or the Series G Preferred Units outstanding, with a liquidation preference of $25.00 per unit, which were issued in January 2012 in conjunction with an acquisition. The Series G Preferred unitholders receive annual dividends of $1.125 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Series G Preferred Units are convertible into a number of common units of limited partnership interest in the Operating Partnership equal to (i) the liquidation preference plus accumulated and unpaid distributions on the conversion date divided by (ii) $88.50. The common units of limited partnership interest in the Operating Partnership may be redeemed in exchange for SL Green's common stock on a 1-to-1 basis. The Series G Preferred Units also provide the holder with the right to require the Operating Partnership to repurchase the Series G Preferred Units for cash before January 31, 2022.
	The Operating Partnership has 60 Series F Preferred Units outstanding with a mandatory liquidation preference of $1,000.00 per unit.
	The Operating Partnership has authorized up to 700,000 3.5% Series K Preferred Units of limited partnership interest, or the Series K Preferred Units, with a liquidation preference of $25.00 per unit. In August 2014, the Company issued 563,954 Series K Preferred Units in conjunction with an acquisition. The Series K Preferred unitholders receive annual dividends of $0.875 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Series K Preferred Units can be redeemed at anytime, at the option of the unitholder, either for cash or are convertible into a number of common units of limited partnership interest in the Operating Partnership equal to (i) the liquidation preference plus accumulated and unpaid distributions on the conversion date divided by (ii) $134.67.
	The Operating Partnership has authorized up to 500,000 4.00% Series L Preferred Units of limited partnership interest, or the Series L Preferred Units, with a liquidation preference of $25.00 per unit. In August 2014, the Company issued 378,634 Series L Preferred Units in conjunction with an acquisition. The Series L Preferred unitholders receive annual dividends of $1.00 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Series L Preferred Units can be redeemed at any time at par for cash at the option of the unitholder.
	In October 2014, the Operating Partnership redeemed the 80,000 6.0% Series H Preferred Units of limited partnership interest, or the Series H Preferred Units, at a redemption price of $25.00 per unit plus $0.05833 in accumulated and unpaid dividends on such Preferred Units from October 15 through October 28, 2014.

Stockholders_Equity_of_the_Com

Stockholders' Equity of the Company	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Stockholders' Equity of the Company	Stockholders’ Equity of the Company
	Common Stock
	Our authorized capital stock consists of 260,000,000 shares, $0.01 par value per share, consisting of 160,000,000 shares of common stock, $0.01 par value per share, 75,000,000 shares of excess stock, at $0.01 par value per share, and 25,000,000 shares of preferred stock, par value $0.01 per share. As of December 31, 2014, 97,325,200 shares of common stock and no shares of excess stock were issued and outstanding.
	In November 2013, the Company completed an offering of 2,600,000 shares of its common stock, par value $0.01 per share, at a price of $95.94 per share. The Company received net proceeds of $248.9 million, after deducting offering expenses. The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 2,600,000 common units of limited partnership interest and were used to repay debt, fund new investments and for other corporate purposes.
	At-The-Market Equity Offering Program
	In July 2011, the Company, along with the Operating Partnership, entered into an "at-the-market" equity offering program, or ATM Program, to sell an aggregate of $250.0 million of SL Green's common stock. During the year ended December 31, 2014, we sold 25,659 shares of our common stock out of the remaining balance of the ATM Program for aggregate net proceeds of $2.8 million. The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 25,659 units of limited partnership interest of the Operating Partnership.
	In June 2014, the Company, along with the Operating Partnership, entered into a new ATM Program to sell an aggregate of $300.0 million of SL Green's common stock. During the year ended December 31, 2014, we sold 1,626,999 shares of our common stock for aggregate net proceeds of $182.9 million. The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 1,626,999 units of limited partnership interest of the Operating Partnership. In January 2015, the Company sold the remaining common stock available for issuance under the new ATM program. See Note 25, "Subsequent Events" for further details.
	Perpetual Preferred Stock
	We have 9,200,000 shares of our 6.50% Series I Cumulative Redeemable Preferred Stock, or the Series I Preferred Stock, outstanding with a mandatory liquidation preference of $25.00 per share. The Series I Preferred stockholders receive annual dividends of $1.625 per share paid on a quarterly basis and dividends are cumulative, subject to certain provisions. We are entitled to redeem the Series I Preferred Stock at par for cash at our option on or after August 10, 2017. In August 2012, we received $221.9 million in net proceeds from the issuance of the Series I Preferred Stock, which were recorded net of underwriters' discount and issuance costs, and contributed the net proceeds to the Operating Partnership in exchange for 9,200,000 units of 6.50% Series I Cumulative Redeemable Preferred Units of limited partnership interest, or the Series I Preferred Units.
	In June 2013, we redeemed the remaining 7,700,000 outstanding shares of our 7.625% Series C Cumulative Redeemable Preferred stock, or the Series C Preferred Stock at a redemption price of $25.00 per share plus $0.3495 in accumulated and unpaid dividends on such Preferred Stock through June 21, 2013. We recognized $12.2 million of costs to redeem the remaining Series C Preferred Stock. In September 2012, we had redeemed 4,000,000 shares of our 11,700,000 shares of Series C Preferred Stock, at a redemption price of $25.00 per share plus $0.3707 in accumulated and unpaid dividends on such Preferred Stock through September 24, 2012. We recognized $6.3 million of costs to redeem partially the Series C Preferred Stock. Simultaneously with each redemption, an equal number of 7.625% Series C Cumulative Redeemable Preferred Units of limited partnership interest of the Operating Partnership, or the Series C Preferred Units, were redeemed at the redemption price paid by us to the Series C Preferred stockholders. The Series C Preferred stockholders received annual dividends of $1.90625 per share paid on a quarterly basis and dividends were cumulative, subject to certain provisions.
	Dividend Reinvestment and Stock Purchase Plan
	In March 2012, the Company filed a registration statement with the SEC for our dividend reinvestment and stock purchase plan, or DRSPP, which automatically became effective upon filing. The Company registered 3,500,000 shares of SL Green's common stock under the DRSPP. The DRSPP commenced on September 24, 2001.
	During the years ended December 31, 2014, 2013, and 2012, the Company issued 608, 761, and 1,300,000 shares, respectively, of SL Green's common stock and received $63,720, $66,600, and $99.6 million of proceeds, respectively, from dividend reinvestments and/or stock purchases under the DRSPP. DRSPP shares may be issued at a discount to the market price.
	Earnings per Share
	SL Green's earnings per share for the years ended December 31, 2014, 2013 and 2012 are computed as follows (in thousands):


		Year Ended December 31,
	Numerator	2014				2013			2012
	Basic Earnings:
	Income attributable to SL Green common stockholders	$	503,104			$	101,330		$	155,984

	Effect of Dilutive Securities:
	Redemption of units to common shares	18,467				3,023			5,597

	Diluted Earnings:
	Income attributable to SL Green common stockholders	$	521,571			$	104,353		$	161,581



		Year Ended December 31,
	Denominator	2014			2013			2012
	Basic Shares:
	Weighted average common stock outstanding	95,774			92,269			89,319

	Effect of Dilutive Securities:
	Redemption of units to common shares	3,514			2,735			3,207

	Stock-based compensation plans	408			262			347

	Diluted weighted average common stock outstanding	99,696			95,266			92,873

	SL Green has excluded 737,361, 964,789 and 627,000 common stock equivalents from the diluted shares outstanding for the years ended December 31, 2014, 2013 and 2012, respectively, as they were anti-dilutive.
	Partners' Capital of the Operating Partnership
	The Company is the sole general partner of the Operating Partnership and at December 31, 2014 owned 97,325,200 general and limited partnership interests in the Operating Partnership and 9,200,000 Series I Preferred Units. Partnership interests in the Operating Partnership are denominated as “common units of limited partnership interest” (also referred to as “OP Units”) or “preferred units of limited partnership interest” (also referred to as “Preferred Units”). All references to OP Units and Preferred Units outstanding exclude such units held by the Company. A holder of an OP Unit may present such OP Unit to the Operating Partnership for redemption at any time (subject to restrictions agreed upon at the issuance of OP Units to particular holders that may restrict such right for a period of time, generally one year from issuance). Upon presentation of an OP Unit for redemption, the Operating Partnership must redeem such OP Unit in exchange for the cash equal to the then value of a share of common stock of the Company, except that the Company may, at its election, in lieu of cash redemption, acquire such OP Unit for one share of common stock. Because the number of shares of common stock outstanding at all times equals the number of OP Units that the Company owns, one share of common stock is generally the economic equivalent of one OP Unit, and the quarterly distribution that may be paid to the holder of an OP Unit equals the quarterly dividend that may be paid to the holder of a share of common stock. Each series of Preferred Units makes a distribution that is set in accordance with an amendment to the partnership agreement of the Operating Partnership. Preferred Units may also be convertible into OP Units at the election of the holder thereof or the Company, subject to the terms of such Preferred Units.
	Net income (loss) allocated to the preferred unitholders and common unitholders reflects their pro rata share of net income (loss) and distributions.
	Limited Partner Units
	As of December 31, 2014, limited partners other than SL Green owned 3.92%, or 3,973,016 common units, of the Operating Partnership.
	Preferred Units
	Preferred units not owned by SL Green are further described in Note 11, “Noncontrolling Interests on the Company’s Consolidated Financial Statements - Preferred Units of Limited Partnership Interest in the Operating Partnership.”
	Earnings per Unit
	The Operating Partnership's earnings per unit for the years ended December 31, 2014, 2013 and 2012 are computed as follows (in thousands):


		Year Ended December 31,
	Numerator	2014				2013			2012
	Basic and Diluted Earnings:
	Income attributable to SLGOP common unitholders	$	521,571			$	104,353		$	161,581



		Year Ended December 31,
	Denominator	2014			2013			2012
	Basic units:
Weighted average common units outstanding	99,288			95,004			92,526

Effect of Dilutive Securities:
Stock-based compensation plans	408			262			347

Diluted weighted average common units outstanding	99,696			95,266			92,873

The Operating Partnership has excluded 737,361 ,964,789 and 627,000 common unit equivalents from the diluted units outstanding for the years ended December 31, 2014, 2013 and 2012, respectively, as they were anti-dilutive.

Partners_Capital_of_the_Operat

Partners' Capital of the Operating Partnership	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Partners' Capital of the Operating Partnership	Stockholders’ Equity of the Company
	Common Stock
	Our authorized capital stock consists of 260,000,000 shares, $0.01 par value per share, consisting of 160,000,000 shares of common stock, $0.01 par value per share, 75,000,000 shares of excess stock, at $0.01 par value per share, and 25,000,000 shares of preferred stock, par value $0.01 per share. As of December 31, 2014, 97,325,200 shares of common stock and no shares of excess stock were issued and outstanding.
	In November 2013, the Company completed an offering of 2,600,000 shares of its common stock, par value $0.01 per share, at a price of $95.94 per share. The Company received net proceeds of $248.9 million, after deducting offering expenses. The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 2,600,000 common units of limited partnership interest and were used to repay debt, fund new investments and for other corporate purposes.
	At-The-Market Equity Offering Program
	In July 2011, the Company, along with the Operating Partnership, entered into an "at-the-market" equity offering program, or ATM Program, to sell an aggregate of $250.0 million of SL Green's common stock. During the year ended December 31, 2014, we sold 25,659 shares of our common stock out of the remaining balance of the ATM Program for aggregate net proceeds of $2.8 million. The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 25,659 units of limited partnership interest of the Operating Partnership.
	In June 2014, the Company, along with the Operating Partnership, entered into a new ATM Program to sell an aggregate of $300.0 million of SL Green's common stock. During the year ended December 31, 2014, we sold 1,626,999 shares of our common stock for aggregate net proceeds of $182.9 million. The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 1,626,999 units of limited partnership interest of the Operating Partnership. In January 2015, the Company sold the remaining common stock available for issuance under the new ATM program. See Note 25, "Subsequent Events" for further details.
	Perpetual Preferred Stock
	We have 9,200,000 shares of our 6.50% Series I Cumulative Redeemable Preferred Stock, or the Series I Preferred Stock, outstanding with a mandatory liquidation preference of $25.00 per share. The Series I Preferred stockholders receive annual dividends of $1.625 per share paid on a quarterly basis and dividends are cumulative, subject to certain provisions. We are entitled to redeem the Series I Preferred Stock at par for cash at our option on or after August 10, 2017. In August 2012, we received $221.9 million in net proceeds from the issuance of the Series I Preferred Stock, which were recorded net of underwriters' discount and issuance costs, and contributed the net proceeds to the Operating Partnership in exchange for 9,200,000 units of 6.50% Series I Cumulative Redeemable Preferred Units of limited partnership interest, or the Series I Preferred Units.
	In June 2013, we redeemed the remaining 7,700,000 outstanding shares of our 7.625% Series C Cumulative Redeemable Preferred stock, or the Series C Preferred Stock at a redemption price of $25.00 per share plus $0.3495 in accumulated and unpaid dividends on such Preferred Stock through June 21, 2013. We recognized $12.2 million of costs to redeem the remaining Series C Preferred Stock. In September 2012, we had redeemed 4,000,000 shares of our 11,700,000 shares of Series C Preferred Stock, at a redemption price of $25.00 per share plus $0.3707 in accumulated and unpaid dividends on such Preferred Stock through September 24, 2012. We recognized $6.3 million of costs to redeem partially the Series C Preferred Stock. Simultaneously with each redemption, an equal number of 7.625% Series C Cumulative Redeemable Preferred Units of limited partnership interest of the Operating Partnership, or the Series C Preferred Units, were redeemed at the redemption price paid by us to the Series C Preferred stockholders. The Series C Preferred stockholders received annual dividends of $1.90625 per share paid on a quarterly basis and dividends were cumulative, subject to certain provisions.
	Dividend Reinvestment and Stock Purchase Plan
	In March 2012, the Company filed a registration statement with the SEC for our dividend reinvestment and stock purchase plan, or DRSPP, which automatically became effective upon filing. The Company registered 3,500,000 shares of SL Green's common stock under the DRSPP. The DRSPP commenced on September 24, 2001.
	During the years ended December 31, 2014, 2013, and 2012, the Company issued 608, 761, and 1,300,000 shares, respectively, of SL Green's common stock and received $63,720, $66,600, and $99.6 million of proceeds, respectively, from dividend reinvestments and/or stock purchases under the DRSPP. DRSPP shares may be issued at a discount to the market price.
	Earnings per Share
	SL Green's earnings per share for the years ended December 31, 2014, 2013 and 2012 are computed as follows (in thousands):


		Year Ended December 31,
	Numerator	2014				2013			2012
	Basic Earnings:
	Income attributable to SL Green common stockholders	$	503,104			$	101,330		$	155,984

	Effect of Dilutive Securities:
	Redemption of units to common shares	18,467				3,023			5,597

	Diluted Earnings:
	Income attributable to SL Green common stockholders	$	521,571			$	104,353		$	161,581



		Year Ended December 31,
	Denominator	2014			2013			2012
	Basic Shares:
	Weighted average common stock outstanding	95,774			92,269			89,319

	Effect of Dilutive Securities:
	Redemption of units to common shares	3,514			2,735			3,207

	Stock-based compensation plans	408			262			347

	Diluted weighted average common stock outstanding	99,696			95,266			92,873

	SL Green has excluded 737,361, 964,789 and 627,000 common stock equivalents from the diluted shares outstanding for the years ended December 31, 2014, 2013 and 2012, respectively, as they were anti-dilutive.
	Partners' Capital of the Operating Partnership
	The Company is the sole general partner of the Operating Partnership and at December 31, 2014 owned 97,325,200 general and limited partnership interests in the Operating Partnership and 9,200,000 Series I Preferred Units. Partnership interests in the Operating Partnership are denominated as “common units of limited partnership interest” (also referred to as “OP Units”) or “preferred units of limited partnership interest” (also referred to as “Preferred Units”). All references to OP Units and Preferred Units outstanding exclude such units held by the Company. A holder of an OP Unit may present such OP Unit to the Operating Partnership for redemption at any time (subject to restrictions agreed upon at the issuance of OP Units to particular holders that may restrict such right for a period of time, generally one year from issuance). Upon presentation of an OP Unit for redemption, the Operating Partnership must redeem such OP Unit in exchange for the cash equal to the then value of a share of common stock of the Company, except that the Company may, at its election, in lieu of cash redemption, acquire such OP Unit for one share of common stock. Because the number of shares of common stock outstanding at all times equals the number of OP Units that the Company owns, one share of common stock is generally the economic equivalent of one OP Unit, and the quarterly distribution that may be paid to the holder of an OP Unit equals the quarterly dividend that may be paid to the holder of a share of common stock. Each series of Preferred Units makes a distribution that is set in accordance with an amendment to the partnership agreement of the Operating Partnership. Preferred Units may also be convertible into OP Units at the election of the holder thereof or the Company, subject to the terms of such Preferred Units.
	Net income (loss) allocated to the preferred unitholders and common unitholders reflects their pro rata share of net income (loss) and distributions.
	Limited Partner Units
	As of December 31, 2014, limited partners other than SL Green owned 3.92%, or 3,973,016 common units, of the Operating Partnership.
	Preferred Units
	Preferred units not owned by SL Green are further described in Note 11, “Noncontrolling Interests on the Company’s Consolidated Financial Statements - Preferred Units of Limited Partnership Interest in the Operating Partnership.”
	Earnings per Unit
	The Operating Partnership's earnings per unit for the years ended December 31, 2014, 2013 and 2012 are computed as follows (in thousands):


		Year Ended December 31,
	Numerator	2014				2013			2012
	Basic and Diluted Earnings:
	Income attributable to SLGOP common unitholders	$	521,571			$	104,353		$	161,581



		Year Ended December 31,
	Denominator	2014			2013			2012
	Basic units:
Weighted average common units outstanding	99,288			95,004			92,526

Effect of Dilutive Securities:
Stock-based compensation plans	408			262			347

Diluted weighted average common units outstanding	99,696			95,266			92,873

The Operating Partnership has excluded 737,361 ,964,789 and 627,000 common unit equivalents from the diluted units outstanding for the years ended December 31, 2014, 2013 and 2012, respectively, as they were anti-dilutive.

Sharebased_Compensation

Share-based Compensation	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based Compensation	Share-based Compensation
	We have stock-based employee and director compensation plans. Our employees are compensated through the Operating Partnership. Under each plan, whenever the Company issues common or preferred stock, the Operating Partnership issues an equivalent number of units of limited partnership interest of a corresponding class to the Company.
	Third Amended and Restated 2005 Stock Option and Incentive Plan
	The Third Amended and Restated 2005 Stock Option and Incentive Plan, or the 2005 Plan, was approved by the Company's board of directors in April 2013 and its stockholders in June 2013 at the Company's annual meeting of stockholders. The 2005 Plan authorizes the issuance of stock options, stock appreciation rights, unrestricted and restricted stock, phantom shares, dividend equivalent rights and other equity-based awards. Subject to adjustments upon certain corporate transactions or events, awards with respect to up to a maximum of 17,130,000 fungible units may be granted under the 2005 Plan. Currently, different types of awards count against the limit on the number of fungible units differently, with (1) full-value awards (i.e., those that deliver the full value of the award upon vesting, such as restricted stock) counting as 2.76 fungible units per share subject to such award (2) stock options, stock appreciation rights and other awards that do not deliver full value and expire five years from the date of grant counting as 0.77 fungible units per share subject to such award and (3) all other awards (e.g., ten-year stock options) counting as 1.0 fungible units per share subject to such award. Awards granted under the 2005 Plan prior to the approval of the second amendment and restatement in June 2010 and third amendment and restatement in June 2013 continue to count against the fungible unit limit based on the ratios that were in effect at the time such awards were granted, which may be different than the current ratios. As a result, depending on the types of awards issued, the 2005 Plan may result in the issuance of more or less than 17,130,000 shares. If a stock option or other award granted under the 2005 Plan expires or terminates, the common stock subject to any portion of the award that expires or terminates without having been exercised or paid, as the case may be, will again become available for the issuance of additional awards. Shares of SL Green's common stock distributed under the 2005 Plan may be treasury shares or authorized but unissued shares. Currently, unless the 2005 Plan has been previously terminated by the Company's board of directors, new awards may be granted under the 2005 Plan until June 13, 2023, which is the tenth anniversary of the date that the 2005 Plan was most recently approved by the Company's stockholders. As of December 31, 2014, 2.6 million fungible units were available for issuance under the 2005 Plan after reserving for shares underlying outstanding restricted stock units, phantom stock units granted pursuant to our Non-Employee Directors' Deferral Program and LTIP Units, including, among others, outstanding LTIP Units issued under our 2011 Long-Term Outperformance Plan.
	Options are granted under the plan at the fair market value on the date of grant and, subject to employment, generally expire five or ten years from the date of grant, are not transferable other than on death, and generally vest in one to five years commencing one year from the date of grant.
	The fair value of each stock option granted is estimated on the date of grant using the Black-Scholes option pricing model based on historical information with the following weighted average assumptions for grants during the years ended December 31, 2014, 2013 and 2012.


		2014			2013			2012
	Dividend yield	1.6	%		1.92	%		2	%
	Expected life of option	3.6 years			4.1 years			3.7 years

	Risk-free interest rate	1.29	%		0.96	%		0.46	%
	Expected stock price volatility	33.97	%		36.12	%		37.4	%
	A summary of the status of the Company's stock options as of December 31, 2014, 2013 and 2012 and changes during the years ended December 31, 2014, 2013 and 2012 are as follows:


		2014								2013					2012
		Options				Weighted				Options			Weighted		Options			Weighted
		Outstanding				Average				Outstanding			Average		Outstanding			Average
						Exercise							Exercise					Exercise
						Price							Price					Price
	Balance at beginning of year	1,765,034				$	83.24			1,201,000			$	75.05	1,277,200			$	63.37

	Granted	102,050				119.12				828,100			87.23		361,331			75.36

	Exercised	(348,156		)		72.76				(223,531		)	53.93		(382,612		)	36.65

	Lapsed or cancelled	(56,202		)		90.03				(40,535		)	83.94		(54,919		)	72.99

	Balance at end of year	1,462,726				$	87.98			1,765,034			$	83.24	1,201,000			$	75.05

	Options exercisable at end of year	428,951				$	90.32			461,458			$	89.38	479,913			$	86.85

	Weighted average fair value of options granted during the year	$	2,841,678							$	18,041,576				$	6,602,967

	All options were granted with strike prices ranging from $20.67 to $137.18. The remaining weighted average contractual life of the options outstanding was 4.06 years and the remaining average contractual life of the options exercisable was 3.83 years.
	During the years ended December 31, 2014, 2013, and 2012, we recognized $8.1 million, $6.5 million and $5.1 million of compensation expense, respectively, for these options. As of December 31, 2014, there was $14.1 million of total unrecognized compensation cost related to unvested stock options, which is expected to be recognized over a weighted average period of three years.
	Stock-based Compensation
	Effective January 1, 1999, the Company implemented a deferred compensation plan, or the Deferred Plan, where shares issued under the Deferred Plan were granted to certain employees, including our executives and vesting will occur annually upon the completion of a service period or our meeting established financial performance criteria. Annual vesting occurs at rates ranging from 15% to 35% once performance criteria are reached.
	A summary of the Company's restricted stock as of December 31, 2014, 2013 and 2012 and charges during the years ended December 31, 2014, 2013 and 2012 are as follows:


		2014				2013				2012
	Balance at beginning of year	2,994,197				2,804,901				2,912,456

	Granted	9,550				192,563				92,729

	Cancelled	(2,768		)		(3,267		)		(200,284		)
	Balance at end of year	3,000,979				2,994,197				2,804,901

	Vested during the year	75,043				21,074				408,800

	Compensation expense recorded	$	9,658,019			$	6,713,155			$	6,930,381

	Weighted average fair value of restricted stock granted during the year	$	1,141,675			$	17,386,949			$	7,023,942

	The fair value of restricted stock that vested during the years ended December 31, 2014, 2013 and 2012 was $5.5 million, $1.6 million and $22.4 million, respectively. As of December 31, 2014, there was $11.7 million of total unrecognized compensation cost related to unvested restricted stock, which is expected to be recognized over a weighted average period of 2.1 years.
	For the years ended December 31, 2014, 2013 and 2012, $6.8 million, $4.5 million and $4.1 million, respectively, was capitalized to assets associated with compensation expense related to our long-term compensation plans, restricted stock and stock options.
	We granted LTIP units, which include bonus, time-based and performance based awards, with a fair value of $33.2 million and $27.1 million as of December 31, 2014 and 2013, respectively. We did not grant any LTIP units in 2012. The grant date fair value of the LTIP unit awards was calculated in accordance with ASC 718. A third party consultant determined the fair value of the LTIP units to have a discount from SL Green's common stock price. The discount was calculated by considering the inherent uncertainty that the LTIP units will reach parity with other common partnership units and the illiquidity due to transfer restrictions. As of December 31, 2014, there was $7.1 million of total unrecognized compensation expense related to the time-based and performance based awards, which is expected to be recognized over a weighted average period of 1.5 years. During the years ended December 31, 2014, 2013 and 2012, we recorded compensation expense related to bonus, time-based and performance based awards of $31.4 million, $27.3 million and $12.6 million, respectively.
	2010 Notional Unit Long-Term Compensation Plan
	In December 2009, the compensation committee of the Company's board of directors approved the general terms of the SL Green Realty Corp. 2010 Notional Unit Long-Term Compensation Program, or the 2010 Long-Term Compensation Plan. The 2010 Long-Term Compensation Plan is a long-term incentive compensation plan pursuant to which award recipients could earn, in the aggregate, from $15.0 million up to $75.0 million of LTIP Units in the Operating Partnership based on the Company's stock price appreciation over three years beginning on December 1, 2009; provided that, if maximum performance had been achieved, $25.0 million of awards could be earned at any time after the beginning of the second year and an additional $25.0 million of awards could be earned at any time after the beginning of the third year. In order to achieve maximum performance under the 2010 Long-Term Compensation Plan, the Company's aggregate stock price appreciation during the performance period had to equal or exceed 50%. The compensation committee determined that maximum performance had been achieved at or shortly after the beginning of each of the second and third years of the performance period and for the full performance period and, accordingly, 366,815 LTIP Units, 385,583 LTIP Units and 327,416 LTIP Units were earned under the 2010 Long-Term Compensation Plan in December 2010, 2011 and 2012, respectively. Substantially in accordance with the original terms of the program, 50% of these LTIP Units vested on December 17, 2012 (accelerated from the original January 1, 2013 vesting date), 25% of these LTIP Units vested on December 11, 2013 (accelerated from the original January 1, 2014 vesting date) and the remainder vested on January 1, 2015 based on continued employment. In accordance with the terms of the 2010 Long-Term Compensation Plan, distributions were not paid on any LTIP Units until they were earned, at which time we paid all distributions that would have been paid on the earned LTIP Units since the beginning of the performance period.
	The cost of the 2010 Long-Term Compensation Plan ($31.7 million, subject to forfeitures) was amortized into earnings through the final vesting period. We recorded compensation expense of $2.7 million, $4.5 million and $10.7 million during the years ended December 31, 2014, 2013 and 2012, respectively, related to the 2010 Long-Term Compensation Plan.
	2011 Outperformance Plan
In August 2011, the compensation committee of the Company's board of directors approved the general terms of the SL Green Realty Corp. 2011 Outperformance Plan, or the 2011 Outperformance Plan. Participants in the 2011 Outperformance Plan could earn, in the aggregate, up to $85.0 million of LTIP Units in the Operating Partnership based on our total return to stockholders for the three-year period beginning September 1, 2011. Under the 2011 Outperformance Plan, participants were entitled to share in a "performance pool" comprised of LTIP Units with a value equal to 10% of the amount by which our total return to stockholders during the three-year period exceeded a cumulative total return to stockholders of 25%, subject to the maximum of $85.0 million of LTIP Units; provided that if maximum performance was achieved, one-third of each award could be earned at any time after the beginning of the second year and an additional one-third of each award could be earned at any time after the beginning of the third year. LTIP Units earned under the 2011 Outperformance Plan are subject to continued vesting requirements, with 50% of any awards earned vested on August 31, 2014 and the remaining 50% vesting on August 31, 2015, subject to continued employment with us through such dates. Participants were not entitled to distributions with respect to LTIP Units granted under the 2011 Outperformance Plan unless and until they were earned. For LTIP Units that were earned, each participant was also be entitled to the distributions that would have been paid had the number of earned LTIP Units been issued at the beginning of the performance period, with such distributions being paid in the form of additional LTIP Units. Thereafter, distributions are to be paid currently with respect to all earned LTIP Units, whether vested or unvested. In June 2014, the compensation committee determined that maximum performance had been achieved during the third year of the performance period and, accordingly, 560,908 LTIP Units, representing two-thirds of each award, were earned, subject to vesting, under the 2011 Outperformance Plan. In September 2014, the compensation committee determined that maximum performance had been achieved for the full three-year performance period and, accordingly, 280,454 LTIP units, representing the final third of each award, were earned, subject to vesting, under the 2011 Outperformance Plan.
The cost of the 2011 Outperformance Plan ($27.0 million, subject to forfeitures) will be amortized into earnings through the final vesting period. We recorded compensation expense of $8.6 million, $8.0 million and $5.5 million during the years ended December 31, 2014, 2013 and 2012, respectively, related to the 2011 Outperformance Plan.
2014 Outperformance Plan
In August 2014, the compensation committee of the Company's board of directors approved the general terms of the SL Green Realty Corp. 2014 Outperformance Plan, or the 2014 Outperformance Plan. Participants in the 2014 Outperformance Plan may earn, in the aggregate, up to 610,000 LTIP Units in our Operating Partnership based on our total return to stockholders for the three-year period beginning September 1, 2014. For each individual award, two-thirds of the LTIP Units may be earned based on the Company’s absolute total return to stockholders and one-third of the LTIP Units may be earned based on relative total return to stockholders compared to the constituents of the MSCI REIT Index. Awards earned based on absolute total return to stockholders will be determined independently of awards earned based on relative total return to stockholders. In the event the Company’s performance reaches either threshold before the end of the three-year performance period, a pro-rata portion of the maximum award may be earned. For each component, if the Company’s performance reaches the maximum threshold beginning with the 19th month of the performance period, participants will earn one-third of the maximum award that may be earned for that component. If the Company’s performance reaches the maximum threshold during the third year of the performance period for a component, participants will earn two-thirds (or an additional one-third) of the maximum award that may be earned for that component. LTIP Units earned under the 2014 Outperformance Plan will be subject to continued vesting requirements, with 50% of any awards earned vesting on August 31, 2017 and the remaining 50% vesting on August 31, 2018, subject to continued employment with us through such dates. Participants will not be entitled to distributions with respect to LTIP Units granted under the 2014 Outperformance Plan unless and until they are earned. If LTIP Units are earned, each participant will also be entitled to the distributions that would have been paid had the number of earned LTIP Units been issued at the beginning of the performance period, with such distributions being paid in the form of cash or additional LTIP Units. Thereafter, distributions will be paid currently with respect to all earned LTIP Units, whether vested or unvested.
The cost of the 2014 Outperformance Plan ($17.1 million, subject to forfeitures), based on the portion of the 2014 Outperformance Plan granted as of December 31, 2014, will be amortized into earnings through the final vesting period. We recorded compensation expense of $0.2 million during the year ended December 31, 2014 related to the 2014 Outperformance Plan.
Deferred Compensation Plan for Directors
Under our Non-Employee Director's Deferral Program, which commenced July 2004, the Company's non-employee directors may elect to defer up to 100% of their annual retainer fee, chairman fees, meeting fees and annual stock grant. Unless otherwise elected by a participant, fees deferred under the program shall be credited in the form of phantom stock units. The program provides that a director's phantom stock units generally will be settled in an equal number of shares of common stock upon the earlier of (i) the January 1 coincident with or next following such director's termination of service from the Board of Directors or (ii) a change in control by us, as defined by the program. Phantom stock units are credited to each non-employee director quarterly using the closing price of SL Green's common stock on the first business day of the respective quarter. Each participating non-employee director is also credited with dividend equivalents or phantom stock units based on the dividend rate for each quarter, which are either paid in cash currently or credited to the director’s account as additional phantom stock units.
During the year ended December 31, 2014, 9,305 phantom stock units were earned and 7,701 shares of common stock were issued to our board of directors. We recorded compensation expense of $1.6 million during the year ended December 31, 2014 related to the Deferred Compensation Plan. As of December 31, 2014, there were 75,649 phantom stock units outstanding pursuant to our Non-Employee Director's Deferral Program.
Employee Stock Purchase Plan
In 2007, the Company's board of directors adopted the 2008 Employee Stock Purchase Plan, or ESPP, to encourage our employees to increase their efforts to make our business more successful by providing equity-based incentives to eligible employees. The ESPP is intended to qualify as an "employee stock purchase plan" under Section 423 of the Code, and has been adopted by the board to enable our eligible employees to purchase the Company's shares of common stock through payroll deductions. The ESPP became effective on January 1, 2008 with a maximum of 500,000 shares of the common stock available for issuance, subject to adjustment upon a merger, reorganization, stock split or other similar corporate change. The Company filed a registration statement on Form S-8 with the SEC with respect to the ESPP. The common stock is offered for purchase through a series of successive offering periods. Each offering period will be three months in duration and will begin on the first day of each calendar quarter, with the first offering period having commenced on January 1, 2008. The ESPP provides for eligible employees to purchase the common stock at a purchase price equal to 85% of the lesser of (1) the market value of the common stock on the first day of the offering period or (2) the market value of the common stock on the last day of the offering period. The ESPP was approved by our stockholders at our 2008 annual meeting of stockholders. As of December 31, 2014, 80,437 shares of SL Green's common stock had been issued under the ESPP.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Loss of the Company	12 Months Ended
	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Loss of the Company	Stockholders’ Equity of the Company
	Common Stock
	Our authorized capital stock consists of 260,000,000 shares, $0.01 par value per share, consisting of 160,000,000 shares of common stock, $0.01 par value per share, 75,000,000 shares of excess stock, at $0.01 par value per share, and 25,000,000 shares of preferred stock, par value $0.01 per share. As of December 31, 2014, 97,325,200 shares of common stock and no shares of excess stock were issued and outstanding.
	In November 2013, the Company completed an offering of 2,600,000 shares of its common stock, par value $0.01 per share, at a price of $95.94 per share. The Company received net proceeds of $248.9 million, after deducting offering expenses. The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 2,600,000 common units of limited partnership interest and were used to repay debt, fund new investments and for other corporate purposes.
	At-The-Market Equity Offering Program
	In July 2011, the Company, along with the Operating Partnership, entered into an "at-the-market" equity offering program, or ATM Program, to sell an aggregate of $250.0 million of SL Green's common stock. During the year ended December 31, 2014, we sold 25,659 shares of our common stock out of the remaining balance of the ATM Program for aggregate net proceeds of $2.8 million. The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 25,659 units of limited partnership interest of the Operating Partnership.
	In June 2014, the Company, along with the Operating Partnership, entered into a new ATM Program to sell an aggregate of $300.0 million of SL Green's common stock. During the year ended December 31, 2014, we sold 1,626,999 shares of our common stock for aggregate net proceeds of $182.9 million. The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 1,626,999 units of limited partnership interest of the Operating Partnership. In January 2015, the Company sold the remaining common stock available for issuance under the new ATM program. See Note 25, "Subsequent Events" for further details.
	Perpetual Preferred Stock
	We have 9,200,000 shares of our 6.50% Series I Cumulative Redeemable Preferred Stock, or the Series I Preferred Stock, outstanding with a mandatory liquidation preference of $25.00 per share. The Series I Preferred stockholders receive annual dividends of $1.625 per share paid on a quarterly basis and dividends are cumulative, subject to certain provisions. We are entitled to redeem the Series I Preferred Stock at par for cash at our option on or after August 10, 2017. In August 2012, we received $221.9 million in net proceeds from the issuance of the Series I Preferred Stock, which were recorded net of underwriters' discount and issuance costs, and contributed the net proceeds to the Operating Partnership in exchange for 9,200,000 units of 6.50% Series I Cumulative Redeemable Preferred Units of limited partnership interest, or the Series I Preferred Units.
	In June 2013, we redeemed the remaining 7,700,000 outstanding shares of our 7.625% Series C Cumulative Redeemable Preferred stock, or the Series C Preferred Stock at a redemption price of $25.00 per share plus $0.3495 in accumulated and unpaid dividends on such Preferred Stock through June 21, 2013. We recognized $12.2 million of costs to redeem the remaining Series C Preferred Stock. In September 2012, we had redeemed 4,000,000 shares of our 11,700,000 shares of Series C Preferred Stock, at a redemption price of $25.00 per share plus $0.3707 in accumulated and unpaid dividends on such Preferred Stock through September 24, 2012. We recognized $6.3 million of costs to redeem partially the Series C Preferred Stock. Simultaneously with each redemption, an equal number of 7.625% Series C Cumulative Redeemable Preferred Units of limited partnership interest of the Operating Partnership, or the Series C Preferred Units, were redeemed at the redemption price paid by us to the Series C Preferred stockholders. The Series C Preferred stockholders received annual dividends of $1.90625 per share paid on a quarterly basis and dividends were cumulative, subject to certain provisions.
	Dividend Reinvestment and Stock Purchase Plan
	In March 2012, the Company filed a registration statement with the SEC for our dividend reinvestment and stock purchase plan, or DRSPP, which automatically became effective upon filing. The Company registered 3,500,000 shares of SL Green's common stock under the DRSPP. The DRSPP commenced on September 24, 2001.
	During the years ended December 31, 2014, 2013, and 2012, the Company issued 608, 761, and 1,300,000 shares, respectively, of SL Green's common stock and received $63,720, $66,600, and $99.6 million of proceeds, respectively, from dividend reinvestments and/or stock purchases under the DRSPP. DRSPP shares may be issued at a discount to the market price.
	Earnings per Share
	SL Green's earnings per share for the years ended December 31, 2014, 2013 and 2012 are computed as follows (in thousands):


		Year Ended December 31,
	Numerator	2014				2013			2012
	Basic Earnings:
	Income attributable to SL Green common stockholders	$	503,104			$	101,330		$	155,984

	Effect of Dilutive Securities:
	Redemption of units to common shares	18,467				3,023			5,597

	Diluted Earnings:
	Income attributable to SL Green common stockholders	$	521,571			$	104,353		$	161,581



		Year Ended December 31,
	Denominator	2014			2013			2012
	Basic Shares:
	Weighted average common stock outstanding	95,774			92,269			89,319

	Effect of Dilutive Securities:
	Redemption of units to common shares	3,514			2,735			3,207

	Stock-based compensation plans	408			262			347

	Diluted weighted average common stock outstanding	99,696			95,266			92,873

	SL Green has excluded 737,361, 964,789 and 627,000 common stock equivalents from the diluted shares outstanding for the years ended December 31, 2014, 2013 and 2012, respectively, as they were anti-dilutive.
	Partners' Capital of the Operating Partnership
	The Company is the sole general partner of the Operating Partnership and at December 31, 2014 owned 97,325,200 general and limited partnership interests in the Operating Partnership and 9,200,000 Series I Preferred Units. Partnership interests in the Operating Partnership are denominated as “common units of limited partnership interest” (also referred to as “OP Units”) or “preferred units of limited partnership interest” (also referred to as “Preferred Units”). All references to OP Units and Preferred Units outstanding exclude such units held by the Company. A holder of an OP Unit may present such OP Unit to the Operating Partnership for redemption at any time (subject to restrictions agreed upon at the issuance of OP Units to particular holders that may restrict such right for a period of time, generally one year from issuance). Upon presentation of an OP Unit for redemption, the Operating Partnership must redeem such OP Unit in exchange for the cash equal to the then value of a share of common stock of the Company, except that the Company may, at its election, in lieu of cash redemption, acquire such OP Unit for one share of common stock. Because the number of shares of common stock outstanding at all times equals the number of OP Units that the Company owns, one share of common stock is generally the economic equivalent of one OP Unit, and the quarterly distribution that may be paid to the holder of an OP Unit equals the quarterly dividend that may be paid to the holder of a share of common stock. Each series of Preferred Units makes a distribution that is set in accordance with an amendment to the partnership agreement of the Operating Partnership. Preferred Units may also be convertible into OP Units at the election of the holder thereof or the Company, subject to the terms of such Preferred Units.
	Net income (loss) allocated to the preferred unitholders and common unitholders reflects their pro rata share of net income (loss) and distributions.
	Limited Partner Units
	As of December 31, 2014, limited partners other than SL Green owned 3.92%, or 3,973,016 common units, of the Operating Partnership.
	Preferred Units
	Preferred units not owned by SL Green are further described in Note 11, “Noncontrolling Interests on the Company’s Consolidated Financial Statements - Preferred Units of Limited Partnership Interest in the Operating Partnership.”
	Earnings per Unit
	The Operating Partnership's earnings per unit for the years ended December 31, 2014, 2013 and 2012 are computed as follows (in thousands):


		Year Ended December 31,
	Numerator	2014				2013			2012
	Basic and Diluted Earnings:
	Income attributable to SLGOP common unitholders	$	521,571			$	104,353		$	161,581



		Year Ended December 31,
	Denominator	2014			2013			2012
	Basic units:
Weighted average common units outstanding	99,288			95,004			92,526

Effect of Dilutive Securities:
Stock-based compensation plans	408			262			347

Diluted weighted average common units outstanding	99,696			95,266			92,873

The Operating Partnership has excluded 737,361 ,964,789 and 627,000 common unit equivalents from the diluted units outstanding for the years ended December 31, 2014, 2013 and 2012, respectively, as they were anti-dilutive.
SL Green Realty Corp
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Loss of the Company	Accumulated Other Comprehensive Loss of the Company
	The following tables set forth the changes in accumulated other comprehensive income (loss) by component as of December 31, 2014, 2013 and 2012 (in thousands):


		Net unrealized loss on derivative instruments(1)				SL Green’s share of joint venture net unrealized loss on derivative instruments(2)			Unrealized gain and (loss) on marketable securities			Total
	Balance at December 31, 2011	$	(17,510	)		$	(17,401	)	$	6,466		$	(28,445	)

	Other comprehensive loss before reclassifications	(1,124		)		(9,098		)	(4,879		)	(15,101		)
	Amounts reclassified from accumulated other comprehensive income	1,800				10,436			1,723			13,959

	Balance at December 31, 2012	(16,834		)		(16,063		)	3,310			(29,587		)

	Other comprehensive (loss) income before reclassifications	(168		)		6,267			1,474			7,573

	Amounts reclassified from accumulated other comprehensive income	1,877				4,926			—			6,803

	Balance at December 31, 2013	(15,125		)		(4,870		)	4,784			(15,211		)

	Other comprehensive (loss) income before reclassifications	(576		)		2,847			(2,692		)	(421		)

	Amounts reclassified from accumulated other comprehensive income	6,203				1,928			521			8,652

	Balance at December 31, 2014	$	(9,498	)		$	(95	)	$	2,613		$	(6,980	)

	____________________________________________________________________

	-1	Amount reclassified from accumulated other comprehensive income (loss) is included in interest expense in the respective consolidated statements of income. As of December 31, 2014, 2013 and 2012, the deferred net losses from these terminated hedges, which is included in accumulated other comprehensive loss relating to net unrealized loss on derivative instrument, was $11.8 million , $13.8 million and $15.0 million, respectively.

	-2	Amount reclassified from accumulated other comprehensive income (loss) is included in equity in net income from unconsolidated joint ventures in the respective consolidated statements of income.

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Loss of the Operating Partnership	12 Months Ended
	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Loss of the Company	Stockholders’ Equity of the Company
	Common Stock
	Our authorized capital stock consists of 260,000,000 shares, $0.01 par value per share, consisting of 160,000,000 shares of common stock, $0.01 par value per share, 75,000,000 shares of excess stock, at $0.01 par value per share, and 25,000,000 shares of preferred stock, par value $0.01 per share. As of December 31, 2014, 97,325,200 shares of common stock and no shares of excess stock were issued and outstanding.
	In November 2013, the Company completed an offering of 2,600,000 shares of its common stock, par value $0.01 per share, at a price of $95.94 per share. The Company received net proceeds of $248.9 million, after deducting offering expenses. The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 2,600,000 common units of limited partnership interest and were used to repay debt, fund new investments and for other corporate purposes.
	At-The-Market Equity Offering Program
	In July 2011, the Company, along with the Operating Partnership, entered into an "at-the-market" equity offering program, or ATM Program, to sell an aggregate of $250.0 million of SL Green's common stock. During the year ended December 31, 2014, we sold 25,659 shares of our common stock out of the remaining balance of the ATM Program for aggregate net proceeds of $2.8 million. The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 25,659 units of limited partnership interest of the Operating Partnership.
	In June 2014, the Company, along with the Operating Partnership, entered into a new ATM Program to sell an aggregate of $300.0 million of SL Green's common stock. During the year ended December 31, 2014, we sold 1,626,999 shares of our common stock for aggregate net proceeds of $182.9 million. The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 1,626,999 units of limited partnership interest of the Operating Partnership. In January 2015, the Company sold the remaining common stock available for issuance under the new ATM program. See Note 25, "Subsequent Events" for further details.
	Perpetual Preferred Stock
	We have 9,200,000 shares of our 6.50% Series I Cumulative Redeemable Preferred Stock, or the Series I Preferred Stock, outstanding with a mandatory liquidation preference of $25.00 per share. The Series I Preferred stockholders receive annual dividends of $1.625 per share paid on a quarterly basis and dividends are cumulative, subject to certain provisions. We are entitled to redeem the Series I Preferred Stock at par for cash at our option on or after August 10, 2017. In August 2012, we received $221.9 million in net proceeds from the issuance of the Series I Preferred Stock, which were recorded net of underwriters' discount and issuance costs, and contributed the net proceeds to the Operating Partnership in exchange for 9,200,000 units of 6.50% Series I Cumulative Redeemable Preferred Units of limited partnership interest, or the Series I Preferred Units.
	In June 2013, we redeemed the remaining 7,700,000 outstanding shares of our 7.625% Series C Cumulative Redeemable Preferred stock, or the Series C Preferred Stock at a redemption price of $25.00 per share plus $0.3495 in accumulated and unpaid dividends on such Preferred Stock through June 21, 2013. We recognized $12.2 million of costs to redeem the remaining Series C Preferred Stock. In September 2012, we had redeemed 4,000,000 shares of our 11,700,000 shares of Series C Preferred Stock, at a redemption price of $25.00 per share plus $0.3707 in accumulated and unpaid dividends on such Preferred Stock through September 24, 2012. We recognized $6.3 million of costs to redeem partially the Series C Preferred Stock. Simultaneously with each redemption, an equal number of 7.625% Series C Cumulative Redeemable Preferred Units of limited partnership interest of the Operating Partnership, or the Series C Preferred Units, were redeemed at the redemption price paid by us to the Series C Preferred stockholders. The Series C Preferred stockholders received annual dividends of $1.90625 per share paid on a quarterly basis and dividends were cumulative, subject to certain provisions.
	Dividend Reinvestment and Stock Purchase Plan
	In March 2012, the Company filed a registration statement with the SEC for our dividend reinvestment and stock purchase plan, or DRSPP, which automatically became effective upon filing. The Company registered 3,500,000 shares of SL Green's common stock under the DRSPP. The DRSPP commenced on September 24, 2001.
	During the years ended December 31, 2014, 2013, and 2012, the Company issued 608, 761, and 1,300,000 shares, respectively, of SL Green's common stock and received $63,720, $66,600, and $99.6 million of proceeds, respectively, from dividend reinvestments and/or stock purchases under the DRSPP. DRSPP shares may be issued at a discount to the market price.
	Earnings per Share
	SL Green's earnings per share for the years ended December 31, 2014, 2013 and 2012 are computed as follows (in thousands):


		Year Ended December 31,
	Numerator	2014				2013			2012
	Basic Earnings:
	Income attributable to SL Green common stockholders	$	503,104			$	101,330		$	155,984

	Effect of Dilutive Securities:
	Redemption of units to common shares	18,467				3,023			5,597

	Diluted Earnings:
	Income attributable to SL Green common stockholders	$	521,571			$	104,353		$	161,581



		Year Ended December 31,
	Denominator	2014			2013			2012
	Basic Shares:
	Weighted average common stock outstanding	95,774			92,269			89,319

	Effect of Dilutive Securities:
	Redemption of units to common shares	3,514			2,735			3,207

	Stock-based compensation plans	408			262			347

	Diluted weighted average common stock outstanding	99,696			95,266			92,873

	SL Green has excluded 737,361, 964,789 and 627,000 common stock equivalents from the diluted shares outstanding for the years ended December 31, 2014, 2013 and 2012, respectively, as they were anti-dilutive.
	Partners' Capital of the Operating Partnership
	The Company is the sole general partner of the Operating Partnership and at December 31, 2014 owned 97,325,200 general and limited partnership interests in the Operating Partnership and 9,200,000 Series I Preferred Units. Partnership interests in the Operating Partnership are denominated as “common units of limited partnership interest” (also referred to as “OP Units”) or “preferred units of limited partnership interest” (also referred to as “Preferred Units”). All references to OP Units and Preferred Units outstanding exclude such units held by the Company. A holder of an OP Unit may present such OP Unit to the Operating Partnership for redemption at any time (subject to restrictions agreed upon at the issuance of OP Units to particular holders that may restrict such right for a period of time, generally one year from issuance). Upon presentation of an OP Unit for redemption, the Operating Partnership must redeem such OP Unit in exchange for the cash equal to the then value of a share of common stock of the Company, except that the Company may, at its election, in lieu of cash redemption, acquire such OP Unit for one share of common stock. Because the number of shares of common stock outstanding at all times equals the number of OP Units that the Company owns, one share of common stock is generally the economic equivalent of one OP Unit, and the quarterly distribution that may be paid to the holder of an OP Unit equals the quarterly dividend that may be paid to the holder of a share of common stock. Each series of Preferred Units makes a distribution that is set in accordance with an amendment to the partnership agreement of the Operating Partnership. Preferred Units may also be convertible into OP Units at the election of the holder thereof or the Company, subject to the terms of such Preferred Units.
	Net income (loss) allocated to the preferred unitholders and common unitholders reflects their pro rata share of net income (loss) and distributions.
	Limited Partner Units
	As of December 31, 2014, limited partners other than SL Green owned 3.92%, or 3,973,016 common units, of the Operating Partnership.
	Preferred Units
	Preferred units not owned by SL Green are further described in Note 11, “Noncontrolling Interests on the Company’s Consolidated Financial Statements - Preferred Units of Limited Partnership Interest in the Operating Partnership.”
	Earnings per Unit
	The Operating Partnership's earnings per unit for the years ended December 31, 2014, 2013 and 2012 are computed as follows (in thousands):


		Year Ended December 31,
	Numerator	2014				2013			2012
	Basic and Diluted Earnings:
	Income attributable to SLGOP common unitholders	$	521,571			$	104,353		$	161,581



		Year Ended December 31,
	Denominator	2014			2013			2012
	Basic units:
Weighted average common units outstanding	99,288			95,004			92,526

Effect of Dilutive Securities:
Stock-based compensation plans	408			262			347

Diluted weighted average common units outstanding	99,696			95,266			92,873

The Operating Partnership has excluded 737,361 ,964,789 and 627,000 common unit equivalents from the diluted units outstanding for the years ended December 31, 2014, 2013 and 2012, respectively, as they were anti-dilutive.
SL Green Operating Partnership
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Loss of the Company	Accumulated Other Comprehensive Loss of the Operating Partnership
	The following tables set forth the changes in accumulated other comprehensive income (loss) by component as of December 31, 2014, 2013 and 2012 (in thousands):


		Net unrealized loss on derivative instruments(1)				SLGOP’s share of joint venture net unrealized loss on derivative instruments(2)			Unrealized gain and (loss) on marketable securities			Total
	Balance at December 31, 2011	$	(18,391	)		$	(17,814	)	$	7,086		$	(29,119	)

	Other comprehensive loss before reclassifications	(912		)		(9,637		)	(5,442		)	(15,991		)
	Amounts reclassified from accumulated other comprehensive income (loss)	1,865				10,811			1,785			$	14,461

	Balance at December 31, 2012	(17,438		)		(16,640		)	3,429			(30,649		)

	Other comprehensive (loss) income before reclassifications	(68		)		6,553			1,497			7,982

	Amounts reclassified from accumulated other comprehensive income	1,933				5,072			—			7,005

	Balance at December 31, 2013	(15,573		)		(5,015		)	4,926			(15,662		)

	Other comprehensive (loss) income before reclassifications	(703		)		2,916			(2,777		)	(564		)

	Amounts reclassified from accumulated other comprehensive income	6,431				1,999			540			8,970

	Balance at December 31, 2014	$	(9,845	)		$	(100	)	$	2,689		$	(7,256	)

	____________________________________________________________________

	-1	Amount reclassified from accumulated other comprehensive income (loss) is included in interest expense in the respective consolidated statements of income. As of December 31, 2014, 2013 and 2012, the deferred net losses from these terminated hedges, which is included in accumulated other comprehensive loss relating to net unrealized loss on derivative instrument, was $12.2 million, $14.2 million and $15.5 million, respectively.

	-2	Amount reclassified from accumulated other comprehensive income (loss) is included in equity in net income from unconsolidated joint ventures in the respective consolidated statements of income.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements
	We are required to disclose fair value information with regard to our financial instruments, whether or not recognized in the consolidated balance sheets, for which it is practical to estimate fair value. The FASB guidance defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants on the measurement date. We measure and/or disclose the estimated fair value of financial assets and liabilities based on a hierarchy that distinguishes between market participant assumptions based on market data obtained from sources independent of the reporting entity and the reporting entity’s own assumptions about market participant assumptions. This hierarchy consist of three broad levels: Level 1 - quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity can access at the measurement date; Level 2 - inputs other than quoted prices included within Level 1, that are observable for the asset or liability, either directly or indirectly; and Level 3 - unobservable inputs for the asset or liability that are used when little or no market data is available. We follow this hierarchy for our assets and liabilities measured at fair value on a recurring and nonrecurring basis. In instances in which the determination of the fair value measurement is based on inputs from different levels of the fair value hierarchy, the level in the fair value hierarchy within which the entire fair value measurement falls is based on the lowest level of input that is significant to the fair value measurement in its entirety. Our assessment of the significance of the particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset or liability.
	The following tables set forth the assets and liabilities that we measure at fair value on a recurring and non-recurring basis by their levels in the fair value hierarchy at December 31, 2014 and 2013 (in thousands):


		December 31, 2014
		Total		Level 1		Level 2		Level 3
	Assets:
	Marketable securities	$	39,429	$	4,332	$	35,097	$	—

	Interest rate swap agreements (included in other assets)	$	2,174	$	—	$	2,174	$	—

	Liabilities:
	Interest rate swap agreements (included in accrued interest payable and other liabilities)	$	14,728	$	—	$	14,728	$	—



		December 31, 2013
		Total		Level 1		Level 2		Level 3
	Assets:
	Marketable securities	$	32,049	$	4,307	$	24,419	$	3,323

	Liabilities:
	Interest rate swap agreements (included in accrued interest payable and other liabilities)	$	1,329	—		$	1,329	—

	We determine impairment in real estate investments and debt and preferred equity investments, including intangibles utilizing cash flow projections that apply, among other things, estimated revenue and expense growth rates, discount rates and capitalization rates, which are classified as Level 3 inputs.
	The marketable securities classified as Level 1 were derived from quoted prices in active markets. The valuation technique used to measure the fair value of the marketable securities classified as Level 2 were valued based on quoted market prices or model driven valuations using the significant inputs derived from or corroborated by observable market data. The marketable securities classified as Level 3 are classified as such because the fair values are derived from discounted cashflow models using inputs that we are unable to corroborate with observable market data. Marketable securities in an unrealized loss position are not considered to be other than temporarily impaired. We do not intend to sell these securities and it is not more likely than not that we will be required to sell the investments before recovery of their amortized cost bases.
	The fair value of derivative instruments is based on current market data received from financial sources that trade such instruments and are based on prevailing market data and derived from third party proprietary models based on well-recognized financial principles and reasonable estimates about relevant future market conditions, which are classified as Level 2 inputs.
	The financial assets and liabilities that are not measured at fair value on our consolidated balance sheets include cash and cash equivalents, restricted cash, accounts receivable, accounts payable and accrued expenses, debt and preferred equity investments, and mortgages and other loans payable and other secured and unsecured debt. The carrying amount of cash and cash equivalents, restricted cash, accounts receivable, and accounts payable and accrued expenses reported in our consolidated balance sheets approximates fair value due to the short term nature of these instruments. The fair value of debt and preferred equity investments, which is classified as Level 3, is estimated by discounting the future cash flows using current interest rates at which similar loans with the same maturities would be made to borrowers with similar credit ratings. The fair value of borrowings, which is classified as Level 3, is estimated by discounting the contractual cash flows of each debt to their present value using adjusted market interest rates, which is provided by a third-party specialist.
	The following table provides the carrying value and fair value of these financial instruments as of December 31, 2014 and 2013 (in thousands):


		December 31, 2014				December 31, 2013
		Carrying Value		Fair Value		Carrying Value		Fair Value

	Debt and preferred equity investments	$	1,408,804	-1		$	1,304,839	-1



	Fixed rate debt	$	6,140,786	$	6,565,236	$	5,599,960	$	5,886,980

	Variable rate debt	2,291,943		2,315,952		1,319,948		1,327,422

		$	8,432,729	$	8,881,188	$	6,919,908	$	7,214,402

	____________________________________________________________________

	-1	At December 31, 2014, debt and preferred equity investments had an estimated fair value ranging between $1.5 billion and $1.8 billion. At December 31, 2013, debt and preferred equity investments had an estimated fair value ranging between $1.3 billion and $1.4 billion.
	Disclosure about fair value of financial instruments was based on pertinent information available to us as of December 31, 2014 and 2013. Although we are not aware of any factors that would significantly affect the reasonable fair value amounts, such amounts have not been comprehensively revalued for purposes of these financial statements since that date and current estimates of fair value may differ significantly from the amounts presented herein.

Financial_Instruments_Derivati

Financial Instruments: Derivatives and Hedging	12 Months Ended
Financial Instruments: Derivatives and Hedging	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments: Derivatives and Hedging	Financial Instruments: Derivatives and Hedging
	In the normal course of business, we use a variety of commonly used derivative instruments, such as interest rate swaps, caps, collar and floors, to manage, or hedge interest rate risk. We hedge our exposure to variability in future cash flows for forecasted transactions in addition to anticipated future interest payments on existing debt. We recognize all derivatives on the balance sheets at fair value. Derivatives that are not hedges are adjusted to fair value through earnings. If a derivative is a hedge, depending on the nature of the hedge, changes in the fair value of the derivative will either be offset against the change in fair value of the hedge asset, liability, or firm commitment through earnings, or recognized in other comprehensive income until the hedged item is recognized in earnings. The ineffective portion of a derivative's change in fair value will be immediately recognized in earnings. Reported net income and equity may increase or decrease prospectively, depending on future levels of interest rates and other variables affecting the fair values of derivative instruments and hedged items, but will have no effect on cash flows. Currently, all of our designated derivative instruments are effective hedging instruments.
	The following table summarizes the notional and fair value of our consolidated derivative financial instruments at December 31, 2014 based on Level 2 information. The notional value is an indication of the extent of our involvement in these instruments at that time, but does not represent exposure to credit, interest rate or market risks (amounts in thousands).


		Notional				Strike			Effective	Expiration		Balance Sheet Location	Fair
		Value				Rate			Date	Date		Balance Sheet Location	Value
	Interest Rate Cap - Sold	$	504,000			4.75	%		May-14	May-16		Other Assets	$	4
	Interest Rate Cap - Sold	$	504,000			4.75	%		May-14	May-16		Other Assets	$	4
	Interest Rate Cap	504,000				4.75	%		May-14	May-16		Other Liabilities	(4		)
	Interest Rate Cap	504,000				4.75	%		May-14	May-16		Other Liabilities	(4		)
	Interest Rate Cap	500,000				4.75	%		Oct-14	May-16		Other Assets	4
	Interest Rate Cap	500,000				4.75	%		Oct-14	May-16		Other Assets	4
	Interest Rate Cap - Sold	500,000				4.75	%		Nov-14	May-16		Other Liabilities	(4		)
	Interest Rate Cap - Sold	500,000				4.75	%		Nov-14	May-16		Other Liabilities	(4		)
	Interest Rate Cap	446,000				4.75	%		Oct-14	May-16		Other Assets	3
	Interest Rate Cap	446,000				4.75	%		Oct-14	May-16		Other Assets	3
	Interest Rate Cap	263,426				6	%		Nov-13	Nov-15		Other Assets	—
	Interest Rate Cap	263,426				6	%		Nov-13	Nov-15		Other Assets	—
	Interest Rate Cap	137,500				4	%		Oct-13	Sep-15		Other Assets	—
	Interest Rate Cap	137,500				4	%		Oct-13	Sep-15		Other Assets	—
	Interest Rate Swap	200,000				0.938	%		Oct-14	Dec-17		Other Assets	871
	Interest Rate Swap	200,000				0.938	%		Oct-14	Dec-17		Other Assets	871
	Interest Rate Swap	150,000				0.94	%		Oct-14	Dec-17		Other Assets	647
	Interest Rate Swap	150,000				0.94	%		Oct-14	Dec-17		Other Assets	647
	Interest Rate Swap	150,000				0.94	%		Oct-14	Dec-17		Other Assets	645
	Interest Rate Swap	150,000				0.94	%		Oct-14	Dec-17		Other Assets	645
	Interest Rate Swap	144,000				2.236	%		Dec-12	Dec-17		Other Liabilities	(4,757		)
	Interest Rate Swap	144,000				2.236	%		Dec-12	Dec-17		Other Liabilities	(4,757		)
	Interest Rate Swap	86,400				1.948	%		Dec-12	Dec-17		Other Liabilities	(2,124		)
	Interest Rate Swap	86,400				1.948	%		Dec-12	Dec-17		Other Liabilities	(2,124		)
	Interest Rate Swap	72,000				2.31	%		Dec-12	Dec-17		Other Liabilities	(2,533		)
	Interest Rate Swap	72,000				2.31	%		Dec-12	Dec-17		Other Liabilities	(2,533		)
	Interest Rate Swap	72,000				1.345	%		Dec-12	Dec-17		Other Liabilities	(506		)
	Interest Rate Swap	72,000				1.345	%		Dec-12	Dec-17		Other Liabilities	(506		)
	Interest Rate Swap	72,000				2.31	%		Dec-12	Dec-17		Other Liabilities	(2,534		)
	Interest Rate Swap	72,000				2.31	%		Dec-12	Dec-17		Other Liabilities	(2,534		)
	Interest Rate Swap	57,600				1.99	%		Dec-12	Dec-17		Other Liabilities	(1,487		)
	Interest Rate Swap	57,600				1.99	%		Dec-12	Dec-17		Other Liabilities	(1,487		)
	Interest Rate Swap	30,000				2.295	%		Jul-10	Jun-16		Other Liabilities	(774		)
	Interest Rate Swap	30,000				2.295	%		Jul-10	Jun-16		Other Liabilities	(774		)
	Interest Rate Swap	8,500				0.74	%		Feb-12	Feb-15		Other Liabilities	(5		)
	Interest Rate Swap	8,500				0.74	%		Feb-12	Feb-15		Other Liabilities	(5		)
													$	(12,554	)
	During the year ended December 31, 2014, 2013 and 2012, we recorded a loss on the changes in the fair value of $61,000, $16,000 and $770,000, respectively, which is included in interest expense on the consolidated statements of income. Included in 2012 was $0.7 million of change in fair value of a terminated currency hedge which was marked to market.
	The Company has agreements with each of its derivative counterparties that contain a provision where if the Company either defaults or is capable of being declared in default on any of its indebtedness, then the Company could also be declared in default on its derivative obligations. As of December 31, 2014, the fair value of derivatives in a net liability position including accrued interest but excluding any adjustment for nonperformance risk related to these agreements was $13.4 million. As of December 31, 2014, the Company has not posted any collateral related to these agreements and was not in breach of any agreement provisions. If the Company had breached any of these provisions, it could have been required to settle its obligations under the agreements at their aggregate termination value of $13.4 million at December 31, 2014.
	Gains and losses on terminated hedges are included in the accumulated other comprehensive loss, and are recognized into earnings over the term of the related mortgage obligation. Over time, the realized and unrealized gains and losses held in accumulated other comprehensive loss will be reclassified into earnings as an adjustment to interest expense in the same periods in which the hedged interest payments affect earnings. We estimate that $9.4 million of the current balance held in accumulated other comprehensive loss will be reclassified into interest expense and $1.2 million of the portion related to our share of joint venture accumulated other comprehensive loss will be reclassified into equity in net income from unconsolidated joint ventures within the next 12 months.
	The following table presents the effect of our derivative financial instruments and our share of our joint ventures' derivative financial instruments that are designated and qualify as hedging instruments on the consolidated statements of income for the years ended December 31, 2014, 2013 and 2012, respectively (in thousands):


			Amount of (Loss) or Gain										Location of Gain or (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income		Amount of Loss						Location of Gain Recognized in Income on Derivative	Amount of Gain
			Recognized in												Reclassified from							Recognized into Income
			Other Comprehensive												Accumulated Other							(Ineffective Portion)
			Loss												Comprehensive Loss into Income
			(Effective Portion)												(Effective Portion)
			Year Ended												Year Ended							Year Ended
			December 31,												December 31,							December 31,
	Derivative		2014				2013			2012					2014		2013		2012			2014		2013		2012
	Interest Rate Swaps/Caps		$	(703	)		$	(68	)	$	(912	)	Interest expense		$	6,431	$	1,933	$	1,865	Interest expense	$	4	$	3	$	3
	Interest Rate Swaps/Caps		$	(703	)		$	(68	)	$	(912	)	Interest expense		$	6,431	$	1,933	$	1,865	Interest expense	$	4	$	3	$	3
	Share of unconsolidated joint ventures' derivative instruments		2,916				6,553			(9,637		)	Equity in net income from unconsolidated joint ventures		1,999		5,072		10,811		Equity in net income from unconsolidated joint ventures	—		—		—
			2,916				6,553			(9,637		)	Equity in net income from unconsolidated joint ventures		1,999		5,072		10,811		Equity in net income from unconsolidated joint ventures	—		—		—
			$	2,213			$	6,485		$	(10,549	)			$	8,430	$	7,005	$	12,676		$	4	$	3	$	3
			$	2,213			$	6,485		$	(10,549	)			$	8,430	$	7,005	$	12,676		$	4	$	3	$	3

Rental_Income

Rental Income	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Rental Income	Rental Income
	The Operating Partnership is the lessor and the sublessor to tenants under operating leases with expiration dates ranging from January 1, 2015 to 2044. The minimum rental amounts due under the leases are generally either subject to scheduled fixed increases or adjustments. The leases generally also require that the tenants reimburse us for increases in certain operating costs and real estate taxes above their base year costs. Approximate future minimum rents to be received over the next five years and thereafter for non-cancelable operating leases in effect at December 31, 2014 for the consolidated properties, including consolidated joint venture properties, and our share of unconsolidated joint venture properties are as follows (in thousands):


		Consolidated		Unconsolidated
		Properties		Properties
	2015	$	975,025	$	157,438

	2016	964,428		157,514

	2017	941,014		152,226

	2018	879,727		146,605

	2019	799,744		134,451

	Thereafter	5,774,406		699,568

		$	10,334,344	$	1,447,802

Benefit_Plans

Benefit Plans	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Benefit Plans	Benefit Plans
	The building employees are covered by multi-employer defined benefit pension plans and post-retirement health and welfare plans. We participate in the Building Service 32BJ, or Union, Pension Plan and Health Plan. The Pension Plan is a multi-employer, non-contributory defined benefit pension plan that was established under the terms of collective bargaining agreements between the Service Employees International Union, Local 32BJ, the Realty Advisory Board on Labor Relations, Inc. and certain other employees. This Pension Plan is administered by a joint board of trustees consisting of union trustees and employer trustees and operates under employer identification number 13-1879376. The Pension Plan year runs from July 1 to June 30. Employers contribute to the Pension Plan at a fixed rate on behalf of each covered employee. Separate actuarial information regarding such pension plans is not made available to the contributing employers by the union administrators or trustees, since the plans do not maintain separate records for each reporting unit. However, on September 28, 2012, September 28, 2013, and September 30, 2014, the actuary certified that for the plan years beginning July 1, 2012, July 1, 2013, and July 1, 2014, respectively, the Pension Plan was in critical status under the Pension Protection Act of 2006. The Pension Plan trustees adopted a rehabilitation plan consistent with this requirement. No surcharges have been paid to the Pension Plan as of December 31, 2014. For the years ended December 31, 2014, 2013 and 2012, the Pension Plan received contributions from employers totaling $224.5 million, $221.9 million and $212.7 million, respectively.
	The Health Plan was established under the terms of collective bargaining agreements between the Union, the Realty Advisory Board on Labor Relations, Inc. and certain other employers. The Health Plan provides health and other benefits to eligible participants employed in the building service industry who are covered under collective bargaining agreements, or other written agreements, with the Union. The Health Plan is administered by a Board of Trustees with equal representation by the employers and the Union and operates under employer identification number 13-2928869. The Health Plan receives contributions in accordance with collective bargaining agreements or participation agreements. Generally, these agreements provide that the employers contribute to the Health Plan at a fixed rate on behalf of each covered employee. For the years ended, December 31, 2013 and 2012, the Health Plan received contributions from employers totaling $923.5 million and $893.3 million, respectively. For the year ended December 31, 2014, information related to total contributions received by the Health Plan was not available at the time of filing. Our contributions to the Health Plan represent less than 5.0% of total contributions to the plan.
	Contributions we made to the multi-employer plans for the years ended December 31, 2014, 2013 and 2012 are included in the table below (in thousands):


	Benefit Plan	2014		2013		2012
	Pension Plan	$	2,807	$	2,765	$	2,506

	Health Plan	8,470		8,522		8,020

	Other plans	5,838		6,006		6,025

	Total plan contributions	$	17,115	$	17,293	$	16,551

	401(K) Plan
	In August 1997, we implemented a 401(K) Savings/Retirement Plan, or the 401(K) Plan, to cover eligible employees of ours, and any designated affiliate. The 401(K) Plan permits eligible employees to defer up to 15% of their annual compensation, subject to certain limitations imposed by the Code. The employees' elective deferrals are immediately vested and non-forfeitable upon contribution to the 401(K) Plan. During 2000, we amended our 401(K) Plan to include a matching contribution, subject to ERISA limitations, equal to 50% of the first 4% of annual compensation deferred by an employee. During 2003, we amended our 401(K) Plan to provide for discretionary matching contributions only. For 2014, 2013 and 2012, a matching contribution equal to 50% of the first 6% of annual compensation was made. For the years ended December 31, 2014, 2013 and 2012, we made matching contributions of $550,000, $550,000 and $561,000, respectively.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	Legal Proceedings
	As of December 31, 2014, the Company and the Operating Partnership were not involved in any material litigation nor, to management's knowledge, was any material litigation threatened against us or our portfolio other than routine litigation arising in the ordinary course of business or litigation that is adequately covered by insurance.
	Environmental Matters
	Our management believes that the properties are in compliance in all material respects with applicable Federal, state and local ordinances and regulations regarding environmental issues. Management is not aware of any environmental liability that it believes would have a materially adverse impact on our financial position, results of operations or cash flows. Management is unaware of any instances in which it would incur significant environmental cost if any of our properties were sold.
	Employment Agreements
	We have entered into employment agreements with certain executives, which expire between January 2016 and January 2018. The minimum cash-based compensation, including base salary and guaranteed bonus payments, associated with these employment agreements total $4.6 million for 2015. In addition these employment agreements provide for deferred compensation awards based on our stock price and which were valued at $1.3 million on the grant date. The value of these awards may change based on fluctuations in our stock price.
	Insurance
	We maintain “all-risk” property and rental value coverage (including coverage regarding the perils of flood, earthquake and terrorism) within three property insurance portfolios and liability insurance. The first property portfolio maintains a blanket limit of $950.0 million per occurrence, including terrorism, for the majority of the New York City properties in our portfolio and expires December 31, 2015. The second portfolio maintains a limit of $700.0 million per occurrence, including terrorism, for several New York City properties and the majority of the Suburban properties and expires December 31, 2015. Each of these policies includes $100.0 million of flood coverage, with a lower sublimit for locations in high hazard flood zones. A third blanket property policy covers most of our residential assets and maintains a limit of $380 million per occurrence, including terrorism, for our residential properties and expires January 31, 2016. We maintain two liability policies which cover all our properties and provide limits of $201.0 million per occurrence and in the aggregate per location. The liability policies expire on October 31, 2015 and January 31, 2016 and cover our commercial and residential properties, respectively. Additional coverage may be purchased on a stand-alone basis for certain assets.
	In October 2006, we formed a wholly-owned taxable REIT subsidiary, Belmont Insurance Company, or Belmont, to act as a captive insurance company and as one of the elements of our overall insurance program. Belmont is a subsidiary of ours. Belmont was formed in an effort to, among other reasons, stabilize to some extent the fluctuations of insurance market conditions. Belmont is licensed in New York to write Terrorism, NBCR (nuclear, biological, chemical, and radiological), General Liability, Environmental Liability and D&O coverage.
	The Terrorism Risk Insurance Act, or TRIA, which was enacted in November 2002, was renewed December 31, 2005 and again on December 31, 2007. Congress extended TRIA, now called TRIPRA (Terrorism Risk Insurance Program Reauthorization and Extension Act of 2007) until December 31, 2014. TRIPRA was not renewed by Congress and expired on December 31, 2014. However, on January 12, 2015, TRIPRA was reauthorized until December 31, 2020 (Terrorism Insurance Program Reauthorization and Extension Act of 2015).The law extends the federal Terrorism Insurance Program that requires insurance companies to offer terrorism coverage and provides for compensation for insured losses resulting from acts of certified terrorism, subject to the current program trigger of $100.0 million, which will increase by $20 million per annum, commencing December 31, 2015. Our debt instruments, consisting of mortgage loans secured by our properties (which are generally non-recourse to us), mezzanine loans, ground leases, our 2012 credit facility, senior unsecured notes and other corporate obligations, contain customary covenants requiring us to maintain insurance. Although we believe that we currently maintain sufficient insurance coverage to satisfy these obligations, there is no assurance that in the future we will be able to procure coverage at a reasonable cost. In such instances, there can be no assurance that the lenders or ground lessors under these instruments will not take the position that a total or partial exclusion from “all-risk” insurance coverage for losses due to terrorist acts is a breach of these debt and ground lease instruments allowing the lenders or ground lessors to declare an event of default and accelerate repayment of debt or recapture of ground lease positions. In addition, if lenders prevail in asserting that we are required to maintain full coverage for these risks, it could result in substantially higher insurance premiums.
	We own Belmont and the accounts of Belmont are part of our consolidated financial statements. If Belmont experiences a loss and is required to pay under its insurance policy, we would ultimately record the loss to the extent of Belmont’s required payment. Therefore, insurance coverage provided by Belmont should not be considered as the equivalent of third-party insurance, but rather as a modified form of self-insurance.
	We monitor all properties that are subject to triple net leases to ensure that tenants are providing adequate coverage. Certain joint ventures may be covered under policies separate from our policies, at coverage limits which we deem to be adequate. We continually monitor these policies. Although we consider our insurance coverage to be appropriate, in the event of a major catastrophe, we may not have sufficient coverage to replace certain properties.
	Belmont had loss reserves of $6.1 million and $7.0 million as of December 31, 2014 and 2013, respectively.
	Capital and Ground Leases Arrangements
	In November 2013, we renewed and extended the maturity date of the ground lease at 420 Lexington Avenue from December 31, 2029 through December 31, 2050, with two options for further extension through December 2085. Ground lease rent payments will be $10.9 million annually through December 2019, $11.2 million annually through December 2029 and then beginning in January 2030 through the remaining lease term, a minimum annual rent of $12.3 million, subject to a one-time adjustment based on 6% of the fair value of the land.
	In October 2012, we, together with Stonehenge Partners, acquired a leasehold position at 1080 Amsterdam Avenue. The joint venture prepaid $13.0 million of ground lease rent, which will be applied against rental payments over the term of the lease. The lease will expire on July 31, 2111 or earlier in accordance with the terms of the lease agreement. Land was estimated to be 40% of the fair market value of the property. The portion of the lease attributed to land was classified as an operating lease and the remainder as a capital lease which had a cost basis of $27.4 million and accumulated amortization of $0.4 million as of December 31, 2014.
	The property located at 711 Third Avenue operates under an operating sub-lease, which expires in 2083. The ground rent was reset in July 2011. Following the reset, we are responsible for ground rent payments of $5.25 million annually through July 2016 and then $5.5 million annually thereafter on the 50% portion of the fee that we do not own.
	The property located at 461 Fifth Avenue operates under a ground lease ($2.1 million of ground rent annually) with a term expiration date of 2027 and with two options to renew for an additional 21 years each, followed by a third option for 15 years. We also have an option to purchase the ground lease for a fixed price on a specific date.
	The property located at 625 Madison Avenue operates under a ground lease ($4.6 million of ground rent annually) with a term expiration date of 2022 and with two options to renew for an additional 23 years.
	The property located at 1185 Avenue of the Americas operates under a ground lease ($6.9 million of ground rent annually) with a term expiration of 2043 and with an option to renew for an additional 23 years.
	The following is a schedule of future minimum lease payments under capital leases and noncancellable operating leases with initial terms in excess of one year as of December 31, 2014 (in thousands):


		Capital lease			Non-cancellable
					operating leases
	2015	$	145		$	30,491

	2016	170			30,612

	2017	291			30,845

	2018	291			30,845

	2019	315			30,862

	Thereafter	56,569			720,698

	Total minimum lease payments	57,781			$	874,353

	Less amount representing interest	(36,959		)
	Capital lease obligations	$	20,822

Segment_Information

Segment Information	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Segment Information	Segment Information
	The Company is a REIT engaged in all aspects of property ownership and management including investment, leasing operations, capital improvements, development and redevelopment, financing, construction and maintenance in the New York City and have two reportable segments, real estate and debt and preferred equity. We evaluate real estate performance and allocate resources based on earnings contribution to income from continuing operations.
	The primary sources of revenue are generated from tenant rents and escalations and reimbursement revenue. Real estate property operating expenses consist primarily of security, maintenance, utility costs, real estate taxes and ground rent expense (at certain applicable properties). See Note 5, "Debt and Preferred Equity Investments," for additional details on our debt and preferred equity investments.
	Selected results of operations for the years ended December 31, 2014, 2013 and 2012, and selected asset information as of December 31, 2014 and 2013, regarding our operating segments are as follows (in thousands):


		Real			Debt and Preferred			Total
		Estate			Equity			Company
		Segment			Segment
	Total revenues
	Years ended:
	31-Dec-14	$	1,341,163		$	178,815		$	1,519,978

	31-Dec-13	1,177,222			193,843			1,371,065

	31-Dec-12	1,170,897			119,155			1,290,052

	Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate and purchase price fair value adjustment
	Years ended:
	31-Dec-14	$	22,178		$	150,852		$	173,030

	31-Dec-13	(49,793		)	159,193			109,400

	31-Dec-12	41,366			92,414			133,780

	Total assets
	As of:
	31-Dec-14	$	15,671,662		$	1,424,925		$	17,096,587

	31-Dec-13	13,641,727			1,317,274			14,959,001

	Income from continuing operations represents total revenues less total expenses for the real estate segment and total investment income less allocated interest expense for the debt and preferred equity segment. Interest costs for the debt and preferred equity segment are imputed assuming the portfolio is 100% leveraged by our MRA facility and 2012 revolving credit facility borrowing cost. We also allocate loan loss reserves, net of recoveries, and transaction related costs to the debt and preferred equity segment. We do not allocate marketing, general and administrative expenses (totaling $92.5 million, $86.2 million and $82.8 million for the years ended December 31, 2014, 2013 and 2012, respectively) to the debt and preferred equity segment since we base performance on the individual segments prior to allocating marketing, general and administrative expenses. All other expenses, except interest, relate entirely to the real estate assets.
	There were no transactions between the above two segments.
	The table below reconciles income from continuing operations to net income for the years ended December 31, 2014, 2013 and 2012 (in thousands):


		Year ended December 31,
		2014			2013			2012
	Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate and purchase price fair value adjustment	$	173,030		$	109,400		$	133,780

	Equity in net gain on sale of interest in unconsolidated joint venture/real estate	123,253			3,601			37,053

	Purchase price fair value adjustment	67,446			(2,305		)	—

	Income from continuing operations	363,729			110,696			170,833

	Net income from discontinued operations	19,075			25,687			32,240

	Gain on sale of discontinued operations	163,059			14,900			6,627

	Net income	$	545,863		$	151,283		$	209,700

Quarterly_Financial_Data_unaud

Quarterly Financial Data (unaudited)	12 Months Ended
	Dec. 31, 2014
SL Green Realty Corp
Condensed Income Statements, Captions [Line Items]
Quarterly Financial Data (unaudited)	Quarterly Financial Data of the Company (unaudited)
	Summarized quarterly financial data for the years ended December 31, 2014 and 2013, which is reflective of the reclassification of the properties sold or held for sale during 2014 and 2013 as discontinued operations (see Note 4, "Properties Held for Sale and Dispositions"), was as follows (in thousands, except for per share amounts):


	2014 Quarter Ended	December 31			September 30			June 30			March 31
	Total revenues	$	386,627		$	390,274		$	380,631		$	362,446

	Income from continuing before equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, (loss) gain on early extinguishment of debt, loss on sale of investment in marketable securities, net of noncontrolling interests	$	40,379		$	46,863		$	47,035		$	39,416

	Equity in net gain on sale of interest in unconsolidated joint venture/real estate	673			16,496			1,444			104,640

	Purchase price fair value adjustment	—			(4,000		)	71,446			—

	(Loss) gain on early extinguishment of debt	(6,865		)	(24,475		)	(1,028		)	3

	Loss on sale of investment in marketable securities	3,895			—			—			—

	Net income from discontinued operations	3,626			4,035			5,645			5,769

	Gain on sale of discontinued operations	18,817			29,507			114,735			—

	Net income attributable to SL Green	60,525			68,426			239,277			149,828

	Preferred stock redemption costs	—			—			—			—

	Perpetual preferred stock dividends	(3,738		)	(3,738		)	(3,738		)	(3,738		)
	Net income attributable to SL Green common stockholders	$	56,787		$	64,688		$	235,539		$	146,090

	Net income attributable to common stockholders per common share—basic	$	0.59		$	0.68		$	2.47		$	1.54

	Net income attributable to common stockholders per common share—diluted	$	0.59		$	0.68		$	2.46		$	1.53



	2013 Quarter Ended	December 31			September 30			June 30			March 31
	Total revenues	$	350,451		$	338,782		$	340,888		$	340,944

	Income from continuing before equity in net gain (loss) on sale of interest in unconsolidated joint venture/real estate, gain (loss) on early extinguishment of debt, gain on sale of investment in marketable securities, net of noncontrolling interests	$	27,478		$	19,895		$	27,398		$	37,300

	Equity in net gain (loss) on sale of interest in unconsolidated joint venture/ real estate	7,538			(354		)	(3,583		)	—

	Purchase price fair value adjustment	—			—			(2,305		)	—

	Gain (loss) on early extinguishment of debt	5			—			(10		)	(18,513		)

	Gain on sale of investment in marketable securities	—			—			(8		)	(57		)

	Net income from discontinued operations	5,836			7,435			5,943			6,473

	Gain on sale of discontinued operations	—			13,787			—			1,113

	Net income attributable to SL Green	40,857			40,763			27,435			26,316

	Preferred stock redemption costs	—			—			(12,160		)	—

	Perpetual preferred stock dividends	(3,737		)	(3,738		)	(6,999		)	(7,407		)
	Net income attributable to SL Green common stockholders	$	37,120		$	37,025		$	8,276		$	18,909

	Net income attributable to common stockholders per common share—basic	$	0.39		$	0.4		$	0.09		$	0.21

	Net income attributable to common stockholders per common share—diluted	$	0.39		$	0.4		$	0.09		$	0.21

SL Green Operating Partnership
Condensed Income Statements, Captions [Line Items]
Quarterly Financial Data (unaudited)	Quarterly Financial Data of the Operating Partnership (unaudited)
	Summarized quarterly financial data for the years ended December 31, 2014 and 2013, which is reflective of the reclassification of the properties sold or held for sale during 2014 and 2013 as discontinued operations (see Note 4, "Properties Held for Sale and Dispositions"), was as follows (in thousands, except for per share amounts):


	2014 Quarter Ended	December 31			September 30			June 30			March 31
	Total revenues	$	386,627		$	390,274		$	380,631		$	362,446

	Income from continuing before equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, (loss) gain on early extinguishment of debt, loss on sale of investment in marketable securities, net of noncontrolling interests	$	42,837		$	49,499		$	55,680		$	44,144

	Equity in net gain on sale of interest in unconsolidated joint venture/real estate	673			16,496			1,444			104,640

	Purchase price fair value adjustment	—			(4,000		)	71,446			—

	(Loss) gain on early extinguishment of debt	(6,865		)	(24,475		)	(1,028		)	3

	Loss on sale of investment in marketable securities	3,895			—			—			—

	Net income from discontinued operations	3,626			4,035			5,645			5,769

	Gain on sale of discontinued operations	18,817			29,507			114,735			—

	Net income attributable to SLGOP	62,983			71,062			247,922			154,556

	Preferred unit redemption costs	—			—			—			—

	Perpetual preferred units distributions	(3,738		)	(3,738		)	(3,738		)	(3,738		)
	Net income attributable to SLGOP common unitholders	$	59,245		$	67,324		$	244,184		$	150,818

	Net income attributable to common unitholders per common unit—basic	$	0.59		$	0.68		$	2.47		$	1.54

	Net income attributable to common unitholders per common unit—diluted	$	0.59		$	0.68		$	2.46		$	1.53



	2013 Quarter Ended	December 31			September 30			June 30			March 31
	Total revenues	$	350,451		$	338,782		$	340,888		$	340,944

	Income from continuing before equity in net gain (loss) on sale of interest in unconsolidated joint venture/real estate, gain (loss) on early extinguishment of debt, gain on sale of investment in marketable securities, net of noncontrolling interests	$	28,592		$	21,005		$	27,642		$	37,855

	Equity in net gain (loss) on sale of interest in unconsolidated joint venture/ real estate	7,538			(354		)	(3,583		)	—

	Purchase price fair value adjustment	—			—			(2,305		)	—

	Gain (loss) on early extinguishment of debt	5			—			(10		)	(18,513		)

	Gain on sale of investment in marketable securities	—			—			(8		)	(57		)

	Net income from discontinued operations	5,836			7,435			5,943			6,473

	Gain on sale of discontinued operations	—			13,787			—			1,113

	Net income attributable to SLGOP	41,971			41,873			27,679			26,871

	Preferred unit redemption costs	—			—			(12,160		)	—

	Perpetual preferred distributions	(3,737		)	(3,738		)	(6,999		)	(7,407		)
	Net income attributable to SLGOP common unitholders	$	38,234		$	38,135		$	8,520		$	19,464

	Net income attributable to common unitholders per common unit—basic	$	0.39		$	0.4		$	0.09		$	0.21

	Net income attributable to common unitholders per common unit—diluted	$	0.39		$	0.4		$	0.09		$	0.21

Subsequent_Events

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2014
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events
	In January 2015, we closed on the modification and extension of the $1.2 billion revolving credit facility portion of our 2012 credit facility, which decreased the interest-rate margin and facility fee applicable to the revolving credit facility portion of the facility by 20 basis points and 5 basis points, respectively, and extend the maturity date of the revolving credit facility portion of the facility to March 29, 2019 with an as-of-right extension through March 29, 2020.
	In January 2015, we sold the remaining 895,956 shares of our common stock under our ATM Program for aggregate net proceeds of $113.4 million. The net proceeds from this offering were contributed to the Operating Partnership in exchange for 895,956 units of limited partnership interest of the Operating Partnership.

Schedule_IIValuation_and_Quali

Schedule II-Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2014
Valuation and Qualifying Accounts [Abstract]
Schedule II-Valuation and Qualifying Accounts	Schedule II—Valuation and Qualifying Accounts
	December 31, 2014
	(in thousands)




	Column A	Column B		Column C		Column D			Column E
	Description	Balance at		Additions		Uncollectible			Balance at
		Beginning of		Charged Against		Accounts			End of Year
		Year		Operations		Written-off/Recovery
	Year Ended December 31, 2014
	Tenant and other receivables—allowance	$	17,325	$	13,533	$	(12,790	)	$	18,068

	Deferred rent receivable—allowance	$	30,333	$	4,140	$	(7,062	)	$	27,411

	Year Ended December 31, 2013
	Tenant and other receivables—allowance	$	14,341	$	13,425	$	(10,441	)	$	17,325

	Deferred rent receivable—allowance	$	29,580	$	7,563	$	(6,810	)	$	30,333

	Year Ended December 31, 2012
	Tenant receivables—allowance	$	11,326	$	17,232	$	(14,217	)	$	14,341

	Deferred rent receivable—allowance	$	29,156	$	7,153	$	(6,729	)	$	29,580

Schedule_IIIReal_Estate_And_Ac

Schedule III-Real Estate And Accumulated Depreciation	12 Months Ended
	Dec. 31, 2014
SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Abstract]
Schedule III-Real Estate And Accumulated Depreciation	SL Green Realty Corp. and SL Green Operating Partnership, L.P.
	Schedule III—Real Estate And Accumulated Depreciation
	December 31, 2014
	(dollars in thousands)



	Column A		Column B			Column C					Column D Cost								Column E Gross Amount at Which						Column F		Column G		Column H		Column I
						Initial Cost					Capitalized								Carried at Close of Period
											Subsequent To
											Acquisition
	Description		Encumbrances			Land			Building &		Land				Building &				Land		Building &		Total		Accumulated Depreciation		Date of		Date		Life on
									Improvements						Improvements						Improvements						Construction		Acquired		Which
																															Depreciation is
																															Computed
	420 Lexington Ave(1)		300,000			—			107,832		—				221,171				—		329,003		329,003		107,652		1927		Mar-98		Various

	711 Third Avenue(1)(7)		120,000			19,844			42,499		—				40,907				19,844		83,406		103,250		30,035		1955		May-98		Various

	555 W. 57th Street(1)		—			18,846			78,704		—				47,933				18,846		126,637		145,483		48,659		1971		Jan-99		Various

	317 Madison Ave(1)		—			21,205			85,559		—				35,572				21,205		121,131		142,336		53,779		1920		Jun-01		Various

	220 East 42nd Street(1)		275,000			50,373			203,727		635				57,876				51,008		261,603		312,611		81,045		1929		Feb-03		Various

	461 Fifth Avenue(1)		—			—			62,695		—				9,626				—		72,321		72,321		21,838		1988		Oct-03		Various

	750 Third Avenue(1)		—			51,093			205,972		—				35,951				51,093		241,923		293,016		70,362		1958		Jul-04		Various

	625 Madison Ave(1)		—			—			246,673		—				35,576				—		282,249		282,249		77,982		1956		Oct-04		Various

	485 Lexington Avenue(1)		450,000			77,517			326,825		765				89,417				78,282		416,242		494,524		127,566		1956		Dec-04		Various

	609 Fifth Avenue(1)		—			36,677			145,954		—				7,814				36,677		153,768		190,445		32,939		1925		Jun-06		Various

	120 West 45th Street(1)		170,000			60,766			250,922		—				22,227				60,766		273,149		333,915		58,601		1998		Jan-07		Various

	810 Seventh Avenue(1)		—			114,077			476,386		—				54,441				114,077		530,827		644,904		114,957		1970		Jan-07		Various

	919 Third Avenue(1)(2)		500,000			223,529			1,033,198		35,410				22,564				258,939		1,055,762		1,314,701		216,685		1970		Jan-07		Various

	1185 Avenue of the Americas(1)		—			—			728,213		—				35,260				—		763,473		763,473		175,368		1969		Jan-07		Various

	1350 Avenue of the Americas(1)		—			91,038			380,744		—				29,132				91,038		409,876		500,914		90,325		1966		Jan-07		Various

	1100 King Street—		—			49,392			104,376		2,473				19,385				51,865		123,761		175,626		31,003		1983/1986		Jan-07		Various
	1-7 International Drive(3)
	520 White Plains Road(3)		—			6,324			26,096		—				4,785				6,324		30,881		37,205		7,755		1979		Jan-07		Various

	115-117 Stevens Avenue(3)		—			5,933			23,826		—				6,334				5,933		30,160		36,093		7,967		1984		Jan-07		Various

	100 Summit Lake Drive(3)		—			10,526			43,109		—				7,213				10,526		50,322		60,848		11,863		1988		Jan-07		Various

	200 Summit Lake Drive(3)		—			11,183			47,906		—				7,217				11,183		55,123		66,306		12,600		1990		Jan-07		Various

	500 Summit Lake Drive(3)		—			9,777			39,048		—				5,643				9,777		44,691		54,468		9,495		1986		Jan-07		Various

	140 Grand Street(3)		—			6,865			28,264		—				4,606				6,865		32,870		39,735		7,734		1991		Jan-07		Various

	360 Hamilton Avenue(3)		—			29,497			118,250		—				12,851				29,497		131,101		160,598		29,031		2000		Jan-07		Various

	1-6 Landmark Square(4)		81,269			50,947			195,167		—				30,206				50,947		225,373		276,320		48,469		1973-1984		Jan-07		Various

	7 Landmark Square(4)		—			2,088			7,748		(367		)		(133		)		1,721		7,615		9,336		600		2007		Jan-07		Various

680 Washington Boulevard(2)(4)		—			11,696			45,364		—				4,561				11,696		49,925		61,621		11,118		1989		Jan-07		Various

750 Washington Boulevard(2)(4)		—			16,916			68,849		—				7,433				16,916		76,282		93,198		16,313		1989		Jan-07		Various

1010 Washington Boulevard(4)		—			7,747			30,423		—				5,058				7,747		35,481		43,228		7,695		1988		Jan-07		Various

500 West Putnam Avenue(4)		22,968			11,210			44,782		—				4,734				11,210		49,516		60,726		10,272		1973		Jan-07		Various

150 Grand Street(3)		—			1,371			5,446		—				11,225				1,371		16,671		18,042		1,770		1962		Jan-07		Various

400 Summit Lake Drive(3)		—			38,889			—		285				1				39,174		1		39,175		1		---		Jan-07		N/A

331 Madison Avenue(1)		—			14,763			65,241		—				2,681				14,763		67,922		82,685		13,923		1923		Apr-07		Various

1055 Washington Boulevard(4)		—			13,516			53,228		—				3,492				13,516		56,720		70,236		12,515		1987		Jun-07		Various



1 Madison Avenue(1)		565,742			172,641			654,394		905				15,297				173,546		669,691		843,237		124,795		1960		Aug-07		Various

125 Chubb Way(5)		—			5,884			25,958		—				23,832				5,884		49,790		55,674		5,263		2008		Jan-08		Various

100 Church Street(1)		228,612			32,494			79,996		2,500				84,235				34,994		164,231		199,225		27,245		1959		Jan-10		Various

125 Park Avenue(1)		—			120,900			189,714		—				42,165				120,900		231,879		352,779		34,869		1923		Oct-10		Various

885 Third Avenue(1)		267,650			131,766			—		110,771				—				242,537		—		242,537		—		---		Dec-10		N/A

Williamsburg(6)		—			3,677			14,708		2,523				(4,550		)		6,200		10,158		16,358		1,082		2010		Dec-10		Various

1515 Broadway(1)		900,000			462,700			707,938		1,145				68,978				463,845		776,916		1,240,761		88,018		1972		Apr-11		Various

110 East 42nd Street(1)		—			34,000			46,411		2,354				17,179				36,354		63,590		99,944		9,194		1921		May-11		Various

51 East 42nd Street(1)		—			44,095			33,470		5				5,607				44,100		39,077		83,177		3,278		1913		Nov-11		Various

400 East 57th Street(1)(8)		68,896			39,780			69,895		—				10,786				39,780		80,681		120,461		5,536		1931		Jan-12		Various

400 East 58th Street(1)(8)		29,527			17,549			30,916		—				4,673				17,549		35,589		53,138		2,402		1929		Jan-12		Various

752 Madison Avenue(1)(8)		—			282,415			7,131		—				10				282,415		7,141		289,556		644		1996/2012		Jan-12		Various

762 Madison Avenue(1)(8)		8,045			6,153			10,461		—				90				6,153		10,551		16,704		805		1910		Jan-12		Various

19-21 East 65th Street(1)(8)		—			—			7,389		—				159				—		7,548		7,548		559		1928-1940		Jan-12		Various

304 Park Avenue(1)		—			54,189			75,619		300				6,336				54,489		81,955		136,444		7,465		1930		Jun-12		Various

635 Sixth Avenue(1)		—			24,180			37,158		163				38,104				24,343		75,262		99,605		—		1902		Sep-12		Various

641 Sixth Avenue(1)		—			45,668			67,316		308				793				45,976		68,109		114,085		5,076		1902		Sep-12		Various

1080 Amsterdam(1)(9)		—			—			27,445		—				20,182				—		47,627		47,627		590		1932		Oct-12		Various

131-137 Spring Street(1)		—			27,021			105,342		154				3,384				27,175		108,726		135,901		5,606		1891		Dec-12		Various

248-252 Bedford Avenue(6)(10)		29,000			10,865			44,035		(2,194		)		(6,784		)		8,671		37,251		45,922		1,490		2012		Mar-13		Various

16 Court Street(6)		—			19,217			63,210		—				4,954				19,217		68,164		87,381		4,604		1927-1928		Apr-13		Various

315 West 33rd Street (1)		—			195,834			164,429		—				3,180				195,834		167,609		363,443		5,396		2000-2001		Nov-13		Various

Fifth Avenue Retail Assemblage(1)		—			135,513			10,487		—				3,356				135,513		13,843		149,356		1,364		1909/1920/1921		Nov-13		Various

388-390 Greenwich Street(1)		1,450,000			558,731			1,037,729		—				68,780				558,731		1,106,509		1,665,240		18,308		1986/1990		May-14		Various

719 Seventh Avenue(1)(11)		—			14,402			26,866		—				—				14,402		26,866		41,268		334		1927		Jul-14		Various

115 Spring Street(1)		—			15,938			37,309		—				—				15,938		37,309		53,247		—		1900		Jul-14		Various

635 Madison(1)		—			153,745			—		—				—				153,745		—		153,745		—		---		Sep-14		N/A

102 Greene Street(1)					11,288			20,963		—				—				11,288		20,963		32,251		131		1910		Nov-14		Various

Other(12)		—			1,130			—		1,003				11,803				2,133		11,803		13,936		3,194

Total		$	5,466,709		$	3,685,380		$	8,919,315	$	159,138			$	1,305,308			$	3,844,518	$	10,224,623	$	14,069,141	$	1,905,165

______________________________________________________________________

-1	Property located in New York, New York.

-2	We own a 51.0% interest in this property.

-3	Property located in Westchester County, New York.

-4	Property located in Connecticut.

-5	Property located in New Jersey.

-6	Property located in Brooklyn, New York.

-7	We own a 50.0% interest in this property.

-8	We own an 80.0% interest in this property.

-9	We own an 87.5% interest in this property.

-10	We own a 90.0% interest in this property.

-11	We own a 75.0% interest in this property.

-12	Other includes tenant improvements at eEmerge, capitalized interest and corporate improvements.
Schedule III—Real Estate And Accumulated Depreciation
December 31, 2014

The changes in real estate for the years ended December 31, 2014, 2013 and 2012 are as follows (in thousands):


	2014			2013			2012
Balance at beginning of year	$	12,333,780		$	11,662,953		$	11,147,151

Property acquisitions	2,428,259			702,717			649,445

Improvements	379,295			199,141			146,410

Retirements/disposals/deconsolidation	(1,072,193		)	(231,031		)	(280,053		)
Balance at end of year	$	14,069,141		$	12,333,780		$	11,662,953

The aggregate cost of land, buildings and improvements, before depreciation, for Federal income tax purposes at December 31, 2014 was $10.4 billion (unaudited).
The changes in accumulated depreciation, exclusive of amounts relating to equipment, autos, and furniture and fixtures, for the years ended December 31, 2014, 2013 and 2012 are as follows (in thousands):


	2014			2013			2012
Balance at beginning of year	$	1,646,240		$	1,393,323		$	1,136,603

Depreciation for year	307,823			286,776			288,560

Retirements/disposals/deconsolidation	(48,898		)	(33,859		)	(31,840		)
Balance at end of year	$	1,905,165		$	1,646,240		$	1,393,323

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation
	The consolidated financial statements include our accounts and those of our subsidiaries, which are wholly-owned or controlled by us. Entities which we do not control through our voting interest and entities which are variable interest entities, but where we are not the primary beneficiary, are accounted for under the equity method or as debt and preferred equity investments. See Note 5, "Debt and Preferred Equity Investments" and Note 6, "Investments in Unconsolidated Joint Ventures." All significant intercompany balances and transactions have been eliminated.
	We consolidate a variable interest entity, or VIE, in which we are considered the primary beneficiary. The primary beneficiary is the entity that has (i) the power to direct the activities that most significantly impact the entity's economic performance and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE that could be significant to the VIE. Included in commercial real estate properties on our consolidated balance sheets as of December 31, 2014 and 2013 are $198.4 million and $605.9 million, respectively, related to our consolidated VIEs. Included in mortgages and other loans payable on our consolidated balance sheets as of December 31, 2014 and 2013 are $106.5 million and $370.9 million, respectively, related to our consolidated VIEs. Also, included in assets held for sale and liabilities related to assets held for sale on our consolidated balance sheet as of December 31, 2014 are $445.0 million of commercial real estate and $253.9 million of mortgage related to our consolidated VIEs.
	A noncontrolling interest in a consolidated subsidiary is defined as the portion of the equity (net assets) in a subsidiary not attributable, directly or indirectly, to us. Noncontrolling interests are required to be presented as a separate component of equity in the consolidated balance sheet and the presentation of net income was modified to present earnings and other comprehensive income attributed to controlling and noncontrolling interests.
	We assess the accounting treatment for each joint venture and debt and preferred equity investment. This assessment includes a review of each joint venture or limited liability company agreement to determine which party has what rights and whether those rights are protective or participating. For all VIEs, we review such agreements in order to determine which party has the power to direct the activities that most significantly impact the entity's economic performance. In situations where we and our partner approve, among other things, the annual budget, receive a detailed monthly reporting package from us, meet on a quarterly basis to review the results of the joint venture, review and approve the joint venture's tax return before filing, and approve all leases that cover more than a nominal amount of space relative to the total rentable space at each property, we do not consolidate the joint venture as we consider these to be substantive participation rights that result in shared power of the activities that most significantly impact the performance of the joint venture. Our joint venture agreements typically contain certain protective rights such as the requirement of partner approval to sell, finance or refinance the property and the payment of capital expenditures and operating expenditures outside of the approved budget or operating plan.
Investment in Commercial Real Estate Properties	Investment in Commercial Real Estate Properties
	Real estate properties are presented at cost less accumulated depreciation and amortization. Costs directly related to the development or redevelopment of properties are capitalized. Ordinary repairs and maintenance are expensed as incurred; major replacements and betterments, which improve or extend the life of the asset, are capitalized and depreciated over their estimated useful lives.
	A property to be disposed of is reported at the lower of its carrying value or its estimated fair value, less its cost to sell. Once an asset is held for sale, depreciation expense is no longer recorded and the historic results are reclassified as discontinued operations. See Note 4, "Properties Held for Sale and Dispositions."
	Properties are depreciated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives are as follows:


	Category	Term
	Building (fee ownership)	40 years
	Building improvements	shorter of remaining life of the building or useful life
	Building (leasehold interest)	lesser of 40 years or remaining term of the lease
	Property under capital lease	remaining lease term
	Furniture and fixtures	four to seven years
	Tenant improvements	shorter of remaining term of the lease or useful life
	Depreciation expense (including amortization of the capital lease asset) amounted to $338.8 million, $296.5 million and $287.5 million for the years ended December 31, 2014, 2013 and 2012, respectively.
	On a periodic basis, we assess whether there are any indications that the value of our real estate properties may be impaired or that their carrying value may not be recoverable. A property's value is considered impaired if management's estimate of the aggregate future cash flows (undiscounted and without interest charges for consolidated properties) to be generated by the property is less than the carrying value of the property. To the extent impairment has occurred, the loss will be measured as the excess of the carrying amount of the property over the calculated fair value of the property. We do not believe that the values of any of our consolidated properties were impaired at December 31, 2014.
	We also evaluate our real estate properties for potential impairment when a real estate property has been classified as held for sale. Real estate assets held for sale are valued at the lower of their carrying value or fair value less costs to sell. In June 2013, we recorded a $2.2 million impairment charge in connection with the sale of 300 Main Street in Stamford, Connecticut. We do not believe that the value of our real estate property held for sale was impaired at December 31, 2014.
	We incur a variety of costs in the development and leasing of our properties. After determination is made to capitalize a cost, it is allocated to the specific component of a project that is benefited. Determination of when a development project is substantially complete and capitalization must cease involves a degree of judgment. The costs of land and building under development include specifically identifiable costs. The capitalized costs include, but are not limited to, pre-construction costs essential to the development of the property, development costs, construction costs, interest costs, real estate taxes, salaries and related costs and other costs incurred during the period of development. We consider a construction project as substantially completed and held available for occupancy upon the completion of tenant improvements, but no later than one year from cessation of major construction activity. We cease capitalization on the portions substantially completed and occupied or held available for occupancy, and capitalize only those costs associated with the portions under construction.
	Results of operations of properties acquired are included in the consolidated statements of income from the date of acquisition.
	We recognize the assets acquired, liabilities assumed (including contingencies) and any noncontrolling interests in an acquired entity at their fair values on the acquisition date. We expense acquisition-related transaction costs as incurred, which are included in transaction related costs on our consolidated statements of income.
	When we acquire our partner's equity interest in an existing unconsolidated joint venture and gain control over the investment, we record the consolidated investment at fair value. The difference between the book value of our equity investment on the purchase date and our share of the fair value of the investment's purchase price is recorded as a purchase price fair value adjustment in our consolidated statements of income. In May 2014, we recognized a purchase price fair value adjustment of $71.4 million in connection with the consolidation of 388-390 Greenwich Street. In April 2013, we recognized a purchase price fair value adjustment of $(2.3) million in connection with the consolidation of 16 Court Street. These acquisitions were previously accounted for as investments in unconsolidated joint ventures.
	We allocate the purchase price of real estate to land and building (inclusive of tenant improvements) and, if determined to be material, intangibles, such as the value of above- and below-market leases and origination costs associated with the in-place leases. We depreciate the amount allocated to building (inclusive of tenant improvements) over their estimated useful lives, which generally range from three to 40 years. We amortize the amount allocated to the above- and below-market leases over the remaining term of the associated lease, which generally range from one to 14 years, and record it as either an increase (in the case of below-market leases) or a decrease (in the case of above-market leases) to rental income. We amortize the amount allocated to the values associated with in-place leases over the expected term of the associated lease, which generally ranges from one to 14 years. If a tenant vacates its space prior to the contractual termination of the lease and no rental payments are being made on the lease, any unamortized balance of the related intangible will be written off. The tenant improvements and origination costs are amortized as an expense over the remaining life of the lease (or charged against earnings if the lease is terminated prior to its contractual expiration date). We assess fair value of the leases based on estimated cash flow projections that utilize appropriate discount and capitalization rates and available market information. Estimates of future cash flows are based on a number of factors including the historical operating results, known trends, and market/economic conditions that may affect the property. To the extent acquired leases contain fixed rate renewal options that are below-market and determined to be material, we amortize such below-market lease value into rental income over the renewal period.
Cash and Cash Equivalents	Cash and Cash Equivalents
	We consider all highly liquid investments with maturity of three months or less when purchased to be cash equivalents.
Fair Value Measurements	Fair Value Measurements
	See Note 17, "Fair Value Measurements."
Investment in Marketable Securities	Investment in Marketable Securities
	We invest in marketable securities. At the time of purchase, we are required to designate a security as held-to-maturity, available-for-sale, or trading depending on ability and intent. We do not have any securities designated as held-to-maturity or trading at this time. Securities available-for-sale are reported at fair value pursuant to ASC 820-10, with the net unrealized gains or losses reported as a component of accumulated other comprehensive income or loss. Unrealized losses that are determined to be other-than-temporary are recognized in earnings up to their credit component.
	The cost of bonds and marketable securities sold is determined using the specific identification method.
Investment in Unconsolidated Joint Ventures	Investments in Unconsolidated Joint Ventures
	We account for our investments in unconsolidated joint ventures under the equity method of accounting in cases where we exercise significant influence over, but do not control, these entities and are not considered to be the primary beneficiary. We consolidate those joint ventures that we control or which are VIEs and where we are considered to be the primary beneficiary. In all these joint ventures, the rights of the joint venture partner are both protective as well as participating. Unless we are determined to be the primary beneficiary in a VIE, these participating rights preclude us from consolidating these non-VIE entities. These investments are recorded initially at cost, as investments in unconsolidated joint ventures, and subsequently adjusted for equity in net income (loss) and cash contributions and distributions. Equity income (loss) from unconsolidated joint ventures is allocated based on our ownership or economic interest in each joint venture. When a capital event (as defined in each joint venture agreement) such as a refinancing occurs, if return thresholds are met, future equity income will be allocated at our increased economic interest. We recognize incentive income from unconsolidated real estate joint ventures as income to the extent it is earned and not subject to a clawback feature. Distributions we receive from unconsolidated real estate joint ventures in excess of our basis in the investment are recorded as offsets to our investment balance if we remain liable for future obligations of the joint venture or may otherwise be committed to provide future additional financial support. None of the joint venture debt is recourse to us, except for $18.4 million which we guarantee at one joint ventures and performance guarantees under master leases at two other joint ventures. See Note 6, "Investments in Unconsolidated Joint Ventures."
	We assess our investments in unconsolidated joint ventures for recoverability, and if it is determined that a loss in value of the investment is other than temporary, we write down the investment to its fair value. We evaluate our equity investments for impairment based on the joint venture's projected discounted cash flows.
Restricted Cash	Restricted Cash
	Restricted cash primarily consists of security deposits held on behalf of our tenants, interest reserves, as well as capital improvement and real estate tax escrows required under certain loan agreements.
Deferred Lease Costs	Deferred Lease Costs
	Deferred lease costs consist of fees and direct costs incurred to initiate and renew operating leases and are amortized on a straight-line basis over the related lease term. Certain of our employees provide leasing services to the wholly-owned properties. For the years ended December 31, 2014, 2013 and 2012, $15.1 million, $12.4 million and $11.0 million of their compensation, respectively, was capitalized and is amortized over an estimated average lease term of seven years.
Deferred Financing Costs	Deferred Financing Costs
	Deferred financing costs represent commitment fees, legal, title and other third party costs associated with obtaining commitments for financing which result in a closing of such financing. These costs are amortized over the terms of the respective agreements. Unamortized deferred financing costs are expensed when the associated debt is refinanced or repaid before maturity. Costs incurred in seeking financing transactions, which do not close, are expensed in the period in which it is determined that the financing will not close.
Revenue Recognition	Revenue Recognition
	Rental revenue is recognized on a straight-line basis over the term of the lease. Rental revenue recognition commences when the tenant takes possession or controls the physical use of the leased space. In order for the tenant to take possession, the leased space must be substantially ready for its intended use. To determine whether the leased space is substantially ready for its intended use, management evaluates whether we are or the tenant is the owner of tenant improvements for accounting purposes. When management concludes that we are the owner of tenant improvements, rental revenue recognition begins when the tenant takes possession of the finished space, which is when such tenant improvements are substantially complete. In certain instances, when management concludes that we are not the owner (the tenant is the owner) of tenant improvements, rental revenue recognition begins when the tenant takes possession of or controls the space. When management concludes that we are the owner of tenant improvements for accounting purposes, we record amounts funded to construct the tenant improvements as a capital asset. For these tenant improvements, we record amounts reimbursed by tenants as a reduction of the capital asset. When management concludes that the tenant is the owner of tenant improvements for accounting purposes, we record our contribution towards those improvements as a lease incentive, which is included in deferred costs, net on our consolidated balance sheets and amortized as a reduction to rental revenue on a straight-line basis over the term of the lease. The excess of rents recognized over amounts contractually due pursuant to the underlying leases are included in deferred rents receivable on the consolidated balance sheets. We establish, on a current basis, an allowance for future potential tenant credit losses, which may occur against this account. The balance reflected on the consolidated balance sheets is net of such allowance.
	In addition to base rent, our tenants also generally will pay their pro rata share of increases in real estate taxes and operating expenses for the building over a base year. In some leases, in lieu of paying additional rent based upon increases in building operating expenses, the tenant will pay additional rent based upon increases in the wage rate paid to porters over the porters' wage rate in effect during a base year or increases in the consumer price index over the index value in effect during a base year. In addition, many of our leases contain fixed percentage increases over the base rent to cover escalations. Electricity is most often supplied by the landlord either on a sub-metered basis, or rent inclusion basis (i.e., a fixed fee is included in the rent for electricity, which amount may increase based upon increases in electricity rates or increases in electrical usage by the tenant). Base building services other than electricity (such as heat, air conditioning and freight elevator service during business hours, and base building cleaning) are typically provided at no additional cost, with the tenant paying additional rent only for services which exceed base building services or for services which are provided outside normal business hours. These escalations are based on actual expenses incurred in the prior calendar year. If the expenses in the current year are different from those in the prior year, then during the current year, the escalations will be adjusted to reflect the actual expenses for the current year.
	We record a gain on sale of real estate when title is conveyed to the buyer, subject to the buyer's financial commitment being sufficient to provide economic substance to the sale and we have no substantial economic involvement with the buyer.
	Interest income on debt and preferred equity investments is accrued based on the outstanding principal amount and contractual terms of the instruments and when, in the opinion of management, it is deemed collectible. Several of the debt and preferred equity investments provide for accrual of interest at specified rates, which differ from current payment terms. Interest is recognized on such loans at the accrual rate subject to management's determination that accrued interest is ultimately collectible, based on the underlying collateral and operations of the borrower. If management cannot make this determination, interest income above the current pay rate is recognized only upon actual receipt.
	Deferred origination fees, original issue discounts and loan origination costs, if any, are recognized as a reduction to the interest income over the terms of the related investments using the effective interest method. Fees received in connection with loan commitments are also deferred until the loan is funded and are then recognized over the term of the loan as an adjustment to yield. Discounts or premiums associated with the purchase of loans are amortized or accreted into interest income as a yield adjustment on the effective interest method based on expected cashflows through the expected maturity date of the related investment. If we purchase a debt or preferred equity investment at a discount, intend to hold it until maturity and expect to recover the full value of the investment, we accrete the discount into income as an adjustment to yield over the term of the investment. If we purchase a debt or preferred equity investment at a discount with the intention of foreclosing on the collateral, we do not accrete the discount. For debt investments acquired at a discount for credit quality, the difference between contractual cash flows and expected cash flows at acquisition is not accreted. Anticipated exit fees, the collection of which is expected, are also recognized over the term of the loan as an adjustment to yield.
	Debt and preferred equity investments are placed on a non-accrual status at the earlier of the date at which payments become 90 days past due or when, in the opinion of management, a full recovery of interest income becomes doubtful. Interest income recognition on any non-accrual debt or preferred equity investment is resumed when such non-accrual debt or preferred equity investment becomes contractually current and performance is demonstrated to be resumed. Interest is recorded as income on impaired loans only to the extent cash is received.
	We may syndicate a portion of the loans that we originate or sell these loans individually. When a transaction meets the criteria of sale accounting, we derecognize the loan sold and recognize gain or loss based on the difference between the sales price and the carrying value of the loan sold. Any related unamortized deferred origination fees, loan origination costs, discounts or premiums at the time of sale are recognized as an adjustment to the gain or loss on sale, which is included in investment income on the consolidated statement of income. Any fees received at the time of sale or syndication are recognized as part of investment income.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts
	We maintain an allowance for doubtful accounts for estimated losses resulting from the inability of our tenants to make required payments. If the financial condition of a specific tenant were to deteriorate, resulting in an impairment of its ability to make payments, additional allowances may be required.
Reserve for Possible Credit Losses	Reserve for Possible Credit Losses
	The expense for possible credit losses in connection with debt and preferred equity investments is the charge to earnings to increase the allowance for possible credit losses to the level that we estimate to be adequate, based on Level 3 data, considering delinquencies, loss experience and collateral quality. Other factors considered relate to geographic trends and product diversification, the size of the portfolio and current economic conditions. Based upon these factors, we establish the provision for possible credit losses on each individual investment. When it is probable that we will be unable to collect all amounts contractually due, the investment is considered impaired.
	Where impairment is indicated on an investment that is held to maturity, a valuation allowance is measured based upon the excess of the recorded investment amount over the net fair value of the collateral. Any deficiency between the carrying amount of an asset and the calculated value of the collateral is charged to expense. We continue to assess or adjust our estimates based on circumstances of a loan and the underlying collateral. If the additional information obtained reflects increased recovery of our investment, we will adjust our reserves accordingly. There were no loan reserves recorded during the years ended December 31, 2014 and 2013. We recorded loan loss reserves of $3.0 million on investments held to maturity during the year ended December 31, 2012, partially offset by recoveries of $2.4 million.
	Debt and preferred equity investments held for sale are carried at the lower of cost or fair market value using available market information obtained through consultation with dealers or other originators of such investments as well as discounted cash flow models based on Level 3 data pursuant to ASC 820-10. As circumstances change, management may conclude not to sell an investment designated as held for sale. In such situations, the investment will be reclassified at its net carrying value to debt and preferred equity investments held to maturity. For these reclassified investments, the difference between the current carrying value and the expected cash to be collected at maturity will be accreted into income over the remaining term of the investment.
Rent Expense	Rent Expense
	Rent expense is recognized on a straight-line basis over the initial term of the lease. The excess of the rent expense recognized over the amounts contractually due pursuant to the underlying lease is included in the deferred land lease payable on the consolidated balance sheets.
Income Taxes	Income Taxes
	SL Green is taxed as a REIT under Section 856(c) of the Code. As a REIT, SL Green generally is not subject to Federal income tax. To maintain its qualification as a REIT, SL Green must distribute at least 90% of its REIT taxable income to its stockholders and meet certain other requirements. If SL Green fails to qualify as a REIT in any taxable year, we will be subject to Federal income tax on SL Green's taxable income at regular corporate rates. SL Green may also be subject to certain state, local and franchise taxes. Under certain circumstances, Federal income and excise taxes may be due on SL Green's undistributed taxable income.
	The Operating Partnership is a partnership and, as a result, all income and losses of the partnership are allocated to the partners for inclusion in their respective income tax returns. The only provision for income taxes included in the consolidated statements of income relates to the Operating Partnership’s consolidated taxable REIT subsidiaries. The Operating Partnership may also be subject to certain state, local and franchise taxes.
	Pursuant to amendments to the Code that became effective January 1, 2001, we have elected, and may elect in the future, to treat certain of our existing or newly created corporate subsidiaries as taxable REIT subsidiaries, or TRSs. In general, TRSs may perform non-customary services for the tenants of the Company, hold assets that we cannot hold directly and generally may engage in any real estate or non-real estate related business. The TRSs generate income, resulting in Federal and state income tax liability for these entities.
	During the years ended December 31, 2014 and 2013, we recorded Federal, state and local tax provisions of $7.8 million and $4.4 million, respectively. There were no Federal, state and local tax provisions for the year ended December 31, 2012.
	We follow a two-step approach for evaluating uncertain tax positions. Recognition (step one) occurs when an enterprise concludes that a tax position, based solely on its technical merits, is more-likely-than-not to be sustained upon examination. Measurement (step two) determines the amount of benefit that is more-likely-than-not to be realized upon settlement. Derecognition of a tax position that was previously recognized would occur when a company subsequently determines that a tax position no longer meets the more-likely-than-not threshold of being sustained. The use of a valuation allowance as a substitute for derecognition of tax positions is prohibited.
Underwriting Commissions and Costs	Underwriting Commissions and Costs
	Underwriting commissions and costs incurred in connection with our stock offerings are reflected as a reduction of additional paid-in-capital.
Exchangeable Debt Instruments	Exchangeable Debt Instruments
	The initial proceeds from exchangeable debt that may be settled in cash, including partial cash settlements, must be bifurcated between a liability component and an equity component associated with the embedded conversion option. The objective of the accounting guidance is to require the liability and equity components of exchangeable debt to be separately accounted for in a manner such that the interest expense on the exchangeable debt is not recorded at the stated rate of interest but rather at an effective rate that reflects the issuer's conventional debt borrowing rate at the date of issuance. We calculate the liability component of exchangeable debt based on the present value of the contractual cash flows discounted at our comparable market conventional debt borrowing rate at the date of issuance. The difference between the principal amount and the fair value of the liability component is reported as a discount on the exchangeable debt that is accreted as additional interest expense from the issuance date through the contractual maturity date using the effective interest method. A portion of this additional interest expense may be capitalized to the development and redevelopment balances qualifying for interest capitalization each period. The liability component of the exchangeable debt is reported net of discounts on our consolidated balance sheets. We calculate the equity component of exchangeable debt based on the difference between the initial proceeds received from the issuance of the exchangeable debt and the fair value of the liability component at the issuance date. The equity component is included in additional paid-in-capital, net of issuance costs, on our consolidated balance sheets. We allocate issuance costs for exchangeable debt between the liability and the equity components based on their relative values.
Stock-Based Employee Compensation Plans	Stock-Based Employee Compensation Plans
	We have a stock-based employee compensation plan, described more fully in Note 14, "Share-based Compensation."
	The Company's stock options are recorded at fair value at the time of issuance. Fair value of the stock options is determined using the Black-Scholes option pricing model. The Black-Scholes model was developed for use in estimating the fair value of traded options, which have no vesting restrictions and are fully transferable. In addition, option valuation models require the input of highly subjective assumptions including the expected stock price volatility. Because our plan has characteristics significantly different from those of traded options and because changes in the subjective input assumptions can materially affect the fair value estimate, in our opinion, the existing models do not necessarily provide a reliable single measure of the fair value of the employee stock options.
	Compensation cost for stock options, if any, is recognized ratably over the vesting period of the award. Our policy is to grant options with an exercise price equal to the quoted closing market price of the Company's common stock on the grant date. Awards of stock or restricted stock are expensed as compensation over the benefit period based on the fair value of the stock on the grant date.
	For share-based awards with a performance or market measure, we recognize compensation cost over the requisite service period, using the accelerated attribution expense method. The requisite service period begins on the date the compensation committee of SL Green's board of directors authorizes the award, adopts any relevant performance measures and communicates the award to the employees. For programs with awards that vest based on the achievement of a performance condition or market condition, we determine whether it is probable that the performance condition will be met, and estimate compensation cost based on the fair value of the award at the applicable reporting date estimated using a binomial model or market quotes. For share-based awards for which there is no pre-established performance measure, we recognize compensation cost over the service vesting period, which represents the requisite service period, on a straight-line basis. In accordance with the provisions of our share-based incentive compensation plans, we accept the return of shares of the Company's common stock, at the current quoted market price, from certain key employees to satisfy minimum statutory tax-withholding requirements related to shares that vested during the period.
	Awards can also be made in the form of a separate series of units of limited partnership interest in the Operating Partnership called long-term incentive plan units, or LTIP units. LTIP units, which can be granted either as free-standing awards or in tandem with other awards under our stock incentive plan, are valued by reference to the value of the Company's common stock at the time of grant, and are subject to such conditions and restrictions as the compensation committee of the Company's board of directors may determine, including continued employment or service, computation of financial metrics and/or achievement of pre-established performance goals and objectives.
Derivative Instruments	Derivative Instruments
	In the normal course of business, we use a variety of commonly used derivative instruments, such as interest rate swaps, caps, collar and floors, to manage, or hedge, interest rate risk. Effectiveness is essential for those derivatives that we intend to quality for hedge accounting. Some derivative instruments are associated with an anticipated transaction. In those cases, hedge effectiveness criteria also require that it be probable that the underlying transaction occurs. Instruments that meet these hedging criteria are formally designated as hedges at the inception of the derivative contract.
	To determine the fair values of derivative instruments, we use a variety of methods and assumptions that are based on market conditions and risks existing at each balance sheet date. For the majority of financial instruments including most derivatives, long-term investments and long-term debt, standard market conventions and techniques such as discounted cash flow analysis, option pricing models, replacement cost, and termination cost are used to determine fair value. All methods of assessing fair value result in a general approximation of value, and such value may never actually be realized.
	In the normal course of business, we are exposed to the effect of interest rate changes and limit these risks by following established risk management policies and procedures including the use of derivatives. To address exposure to interest rates, derivatives are used primarily to fix the rate on debt based on floating-rate indices and manage the cost of borrowing obligations.
	We use a variety of commonly used derivative products that are considered plain vanilla derivatives. These derivatives typically include interest rate swaps, caps, collars and floors. We expressly prohibit the use of unconventional derivative instruments and using derivative instruments for trading or speculative purposes. Further, we have a policy of only entering into contracts with major financial institutions based upon their credit ratings and other factors.
	We may employ swaps, forwards or purchased options to hedge qualifying forecasted transactions. Gains and losses related to these transactions are deferred and recognized in net income as interest expense in the same period or periods that the underlying transaction occurs, expires or is otherwise terminated.
	Hedges that are reported at fair value and presented on the balance sheet could be characterized as cash flow hedges or fair value hedges. Interest rate caps and collars are examples of cash flow hedges. Cash flow hedges address the risk associated with future cash flows of interest payments. For all hedges held by us and which were deemed to be fully effective in meeting the hedging objectives established by our corporate policy governing interest rate risk management, no net gains or losses were reported in earnings. The changes in fair value of hedge instruments are reflected in accumulated other comprehensive income. For derivative instruments not designated as hedging instruments, the gain or loss, resulting from the change in the estimated fair value of the derivative instruments, is recognized in current earnings during the period of change.
Earnings per Share of the Company	Earnings per Share of the Company
	The Company presents both basic and diluted earnings per share, or EPS. Basic EPS excludes dilution and is computed by dividing net income attributable to common stockholders by the weighted average number of common shares outstanding during the period. Basic EPS includes participating securities, consisting of unvested restricted stock that receive nonforfeitable dividends similar to shares of common stock. Diluted EPS reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock, where such exercise or conversion would result in a lower EPS amount. Diluted EPS also includes units of limited partnership interest. The dilutive effect of stock options is reflected in the weighted average diluted outstanding shares calculation by application of the treasury stock method. There is no dilutive effect for the exchangeable senior notes as the conversion premium will be paid in cash.
Earnings per Unit of the Operating Partnership	Earnings per Unit of the Operating Partnership
	The Operating Partnership presents both basic and diluted earnings per unit, or EPU. Basic EPU excludes dilution and is computed by dividing net income attributable to common unitholders by the weighted average number of common units outstanding during the period. Basic EPU includes participating securities, consisting of unvested restricted units that receive nonforfeitable dividends similar to shares of common units. Diluted EPU reflects the potential dilution that could occur if securities or other contracts to issue common units were exercised or converted into common units, where such exercise or conversion would result in a lower EPU amount. The dilutive effect of unit options is reflected in the weighted average diluted outstanding units calculation by application of the treasury stock method. There is no dilutive effect for the exchangeable senior notes as the conversion premium will be paid in cash.
Use of Estimates	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.
Concentration of Credit Risk	Concentrations of Credit Risk
	Financial instruments that potentially subject us to concentrations of credit risk consist primarily of cash investments, debt and preferred equity investments and accounts receivable. We place our cash investments in excess of insured amounts with high quality financial institutions. The collateral securing our debt and preferred equity investments is primarily located in New York City. See Note 5, "Debt and Preferred Equity Investments." We perform ongoing credit evaluations of our tenants and require most tenants to provide security deposits or letters of credit. Though these security deposits and letters of credit are insufficient to meet the total value of a tenant's lease obligation, they are a measure of good faith and a source of funds to offset the economic costs associated with lost rent and the costs associated with re-tenanting a space. Although the properties in our real estate portfolio are primarily located in Manhattan, we also have properties located in Brooklyn, Long Island, Westchester County, Connecticut and New Jersey.
Reclassification	Reclassification
	Certain prior year balances have been reclassified to conform to our current year presentation primarily in order to eliminate discontinued operations from income from continuing operations.
Accounting Standards Updates	Accounting Standards Updates
	In February 2015, the Financial Accounting Standards Board, or FASB, issued new guidance that amends the current consolidation guidance, including introducing a separate consolidation analysis specific to limited partnerships and other similar entities (Accounting Standards Update, or ASU, No. 2015-02). Under this analysis, limited partnerships and other similar entities will be considered a VIE unless the limited partners hold substantive kick-out rights or participating rights. The guidance is effective for annual and interim periods beginning after December 15, 2015. Early adoption of this guidance is permitted. The Company is currently evaluating the new guidance to determine the impact it may have on our consolidated financial statements.
	In June 2014, the FASB, issued final guidance that requires repurchase-to-maturity transactions to be accounted for as secured borrowings as if the transferor retains effective control, even though the transferred financial assets are not returned to the transferor at settlement and also eliminates existing guidance for repurchase financings (ASU, No. 2014-11). New disclosures are required for (1) certain transactions accounted for as secured borrowings and (2) transfers accounted for as sales when the transferor also retains substantially all of the exposure to the economic return on the transferred financial assets throughout the term of the transaction. The guidance is effective for the first interim or annual period beginning after December 15, 2014, except for the disclosures related to transactions accounted for as secured borrowings, which are effective for periods beginning after March 15, 2015. Early adoption of this guidance is prohibited. The Company will adopt this standard beginning in the first quarter of 2015. The adoption of this guidance is not anticipated to have a material impact on our consolidated financial statements.
	In May 2014, the FASB issued a new comprehensive revenue recognition guidance which requires us to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those goods and services (ASU No. 2014-09). The guidance also requires enhanced disclosures to help users of financial statements better understand the nature, amount, timing, and uncertainty of revenue that is recognized. The guidance is effective for annual and interim periods beginning after December 15, 2016 and early adoption is not permitted. The new guidance can be applied either retrospectively to each prior reporting period presented, or as a cumulative-effect adjustment as of the date of adoption. The Company is currently evaluating the new guidance to determine the impact it may have on our consolidated financial statements.
	In April 2014, the FASB issued new guidance on reporting discontinued operations which raises the threshold for disposals to qualify as discontinued operations (ASU No. 2014-08). The guidance also allows us to have a significant continuing involvement and continuing cash flows with the discontinued operations. Additionally, the guidance requires additional disclosures for discontinued operations and new disclosures for individually material disposal transactions that do not meet the definition of a discontinued operation. The guidance is effective for calendar year public companies beginning in the first quarter of 2015 and is to be applied on a prospective basis for new disposals. Early adoption of this guidance is permitted. The Company will adopt this standard beginning in the first quarter of 2015. The adoption of this guidance will change the presentation of discontinued operations but will not have a material impact on our consolidated financial statements.
	In February 2013, the FASB issued guidance on the presentation and disclosure of reclassification adjustments out of accumulated other comprehensive income, or AOCI (ASU No. 2013-02). The standard requires an entity to present information about significant items reclassified out of AOCI by component either on the face of the statement where net income is presented or as a separate disclosure in the notes to financial statements. The guidance was effective for calendar year-end public companies beginning in the first quarter of 2013 and its adoption did not have a material impact on our consolidated financial statements.
	In December 2011, the FASB issued guidance that concluded when a parent ceases to have a controlling financial interest in a subsidiary that is in-substance real estate as a result of default on the subsidiary's nonrecourse debt, the reporting entity must apply the accounting guidance for sales of real estate to determine whether it should derecognize the in-substance real estate (ASU No. 2011-10). The reporting entity is precluded from derecognizing the real estate until legal ownership has been transferred to the lender to satisfy the debt. The guidance was effective for calendar year-end public and nonpublic companies in 2013 and is to be applied on a prospective basis. Early adoption of the guidance is permitted. Adoption of this guidance did not have a material impact on our consolidated financial statements.
	In May 2011, the FASB issued updated guidance on fair value measurement which amends U.S. GAAP to conform to IFRS measurement and disclosure requirements (ASU No. 2011-04). The amendments change the wording used to describe the requirements in U.S. GAAP for measuring fair value, changes certain fair value measurement principles and enhances disclosure requirements. This guidance was effective as of the first quarter of 2012, and its adoption did not have a material impact on our consolidated financial statements.

Organization_and_Basis_of_Pres1

Organization and Basis of Presentation (Tables)	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of commercial office properties	As of December 31, 2014, we owned the following interests in commercial office buildings in the New York Metropolitan area, primarily in midtown Manhattan. Our investments in the New York Metropolitan area also include investments in Brooklyn, Long Island, Westchester County, Connecticut and New Jersey, which are collectively known as the Suburban properties:


				Consolidated			Unconsolidated		Total
	Location		Type	Number of Properties		Approximate Square Feet (unaudited)	Number of Properties	Approximate Square Feet (unaudited)	Number of Properties	Approximate Square Feet (unaudited)	Weighted Average Occupancy(1)
											(unaudited)
	Commercial:
	Manhattan		Office	23		18,429,045	7	3,476,115	30	21,905,160	95.3	%

			Retail	9	-2	403,735	7	279,628	16	683,363	91	%

			Development/Redevelopment	9	-3	1,973,862	5	1,952,782	14	3,926,644	32.6	%

			Fee Interest	2		783,530	—	—	2	783,530	100	%

				43		21,590,172	19	5,708,525	62	27,298,697	86.3	%

	Suburban		Office	27		4,365,400	4	1,222,100	31	5,587,500	82.4	%

			Retail	1		52,000	—	—	1	52,000	100	%

			Development/Redevelopment	1		85,000	2	65,641	3	150,641	54.2	%

				29		4,502,400	6	1,287,741	35	5,790,141	81.8	%

	Total commercial properties			72		26,092,572	25	6,996,266	97	33,088,838	85.5	%

	Residential:

	Manhattan		Residential	3	-2	735,587	—	—	3	735,587	95.6	%

	Suburban		Residential	1		66,611	—	—	1	66,611	89.6	%

	Total residential properties			4		802,198	—	—	4	802,198	95.2	%

	Total portfolio			76		26,894,770	25	6,996,266	101	33,891,036	85.8	%

	____________________________________________________________________

	-1	The weighted average occupancy for commercial properties represents the total occupied square feet divided by total available rentable square feet. The weighted average occupancy for residential properties represents the total occupied units divided by total available units.

	-2	As of December 31, 2014, we owned a building that was comprised of approximately 270,132 square feet (unaudited) of retail space and approximately 222,855 square feet (unaudited) of residential space. For the purpose of this report, we have included the building as part of retail properties and have shown the square footage under its respective classifications.

	-3	Includes one property which was held for sale as of December 31, 2014 and sold in January 2015.

Significant_Accounting_Policie2

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Schedule of estimated useful lives	Properties are depreciated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives are as follows:


	Category		Term
	Building (fee ownership)		40 years
	Building improvements		shorter of remaining life of the building or useful life
	Building (leasehold interest)		lesser of 40 years or remaining term of the lease
	Property under capital lease		remaining lease term
	Furniture and fixtures		four to seven years
	Tenant improvements		shorter of remaining term of the lease or useful life
Summary of identified intangible assets (acquired above-market leases and in-place leases) and intangible liabilities (acquired below-market leases)	The following summarizes our identified intangible assets (acquired above-market leases and in-place leases) and intangible liabilities (acquired below-market leases) as of December 31, 2014 and 2013 (in thousands):


		December 31,
		2014				2013
	Identified intangible assets (included in other assets):
	Gross amount	$	664,297			$	746,704

	Accumulated amortization	(383,236		)		(343,339		)
	Net	$	281,061			$	403,365

	Identified intangible liabilities (included in deferred revenue):
	Gross amount	$	655,755			$	671,380

	Accumulated amortization	(483,948		)		(429,138		)
	Net	$	171,807			$	242,242

Schedule of estimated annual amortization of acquired below-market leases, net of acquired above-market leases	The estimated annual amortization of acquired above-market leases, net of acquired (below-market) leases (a component of rental revenue), for each of the five succeeding years is as follows (in thousands):


	2015		$	1,978

	2016		(592		)
	2017		(1,303		)
	2018		(3,135		)
	2019		(3,994		)
Schedule of estimated annual amortization of all other identifiable assets	The estimated annual amortization of all other identifiable assets (a component of depreciation and amortization expense) including tenant improvements for each of the five succeeding years is as follows (in thousands):


	2015		$	9,150

	2016		5,919

	2017		4,442

	2018		3,005

	2019		2,467

Schedule of marketable securities	At December 31, 2014 and 2013, we held the following marketable securities (in thousands):


		December 31,
		2014				2013
	Equity marketable securities	$	4,332			$	4,307

	Commercial mortgage-backed securities	35,097				24,419

	Rake bonds	—				3,323

	Total marketable securities available-for-sale	$	39,429			$	32,049

Property_Acquisitions_Tables

Property Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2014
Property Acquisitions
Schedule of Pro Forma Information	The following table summarizes, on an unaudited pro forma basis, the results of operations of 388-390 Greenwich Street, which are included in the consolidated statements of income for the years ended December 31, 2014 and 2013 as though the acquisition of our joint venture partner's interest in 388-390 Greenwich Street was completed on January 1, 2013. The supplemental pro forma data is not necessarily indicative of what the actual results of operations would have been assuming the transaction had been completed as set forth above, nor do they purport to represent our results of operations for future periods.


			Year Ended December 31,
	(in thousands, except per share amounts)		2014			2013
	Actual revenues since acquisition		$	1,519,978

	Actual net income since acquisition		545,863

	Pro forma revenues		1,562,206			1,481,021

	Pro forma income from continuing operations(1)		298,679			205,437

	Pro forma basic earnings per share		4.6			2.1

	Pro forma diluted earnings per share		4.58			2.09

	Pro forma basic earnings per unit		4.6			2.1

	Pro forma diluted earnings per unit		4.58			2.09

	____________________________________________________________________

	-1	The pro forma income from continuing operations for the years ended December 31, 2014 and 2013 includes the effect of the new financing necessary to complete the acquisition and the preliminary allocation of purchase price in connection with the changes in depreciation and amortization. In addition, the pro forma income from continuing operations for the year ended December 31, 2013 was adjusted to include the purchase price fair value adjustment, as though the acquisition was completed on January 1, 2013. The pro forma income from continuing operations for the year ended December 31, 2014 excludes this purchase price fair value adjustment.
2014 Acquisitions
Property Acquisitions
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following summarizes our allocation of the purchase price of the assets acquired and liabilities assumed upon the closing of these acquisitions (in thousands):


		102 Greene Street(1)			635 Madison Avenue(1)(4)			752 Madison Avenue(1)(2)			719 Seventh Avenue(1)(5)			115 Spring Street(1)			388-390 Greenwich Street (1)(3)
	Acquisition Date	Oct-14			Sep-14			Aug-14			Jul-14			Jul-14			May-14
	Ownership Type	Fee Interest			Fee Interest			Leasehold Interest			Fee Interest			Fee Interest			Fee Interest
	Property Type	Retail			Land			Retail			Development			Retail			Office

	Purchase Price Allocation:
	Land	$	11,288		$	153,745		$	282,415		$	14,402		$	15,938		$	558,777

	Building and building leasehold	20,962			—			—			26,747			37,187			1,037,729

	Above market lease value	—			—			—			—			—			—

	Acquired in-place leases	—			—			—			—			—			—

	Other assets, net of other liabilities	—			—			—			—			—			6,495

	Assets acquired	32,250			153,745			282,415			41,149			53,125			1,603,001

	Mark-to-market assumed debt	—			—			—			—			—			—

	Below market lease value	—			—			—			—			—			—

	Derivatives	—			—			—			—			—			18,001

	Liabilities assumed	—			—			—			—			—			18,001

	Purchase price	$	32,250		$	153,745		$	282,415		$	41,149		$	53,125		$	1,585,000

	Net consideration funded by us at closing, excluding consideration financed by debt	$	32,250		$	153,745		$	282,415		$	41,149		$	53,125		$	208,614

	Equity and/or debt investment held	$	—		$	—		$	—		$	—		$	—		$	148,025

	Debt assumed	$	—		$	—		$	—		$	—		$	—		$	1,162,379

	____________________________________________________________________

	-1	We are currently in the process of analyzing the purchase price allocation and, as such, we have not allocated any value to intangible assets such as above- and below-market lease or in-place leases.

	-2	In January 2012, a separate joint venture in which an SL Green entity holds an 80% interest acquired the ground tenancy position.

	-3	In May 2014, we acquired Ivanhoe Cambridge, Inc.'s 49.65% economic interest in this property, thereby consolidating full ownership of the property. The transaction valued the consolidated interests at $1.585 billion. Simultaneous with the closing, we refinanced the previous mortgage with a $1.45 billion mortgage. We also assumed the existing derivative instruments, which swapped $504.0 million of the mortgage to fixed rate. We recognized a purchase price fair value adjustment of $71.4 million upon closing of this transaction. This property, which we initially acquired in December 2007, was previously accounted for as an investment in unconsolidated joint ventures.

	-4	This property was acquired inclusive of the issuance of $4.0 million aggregate liquidation preference of Series J Preferred Units of limited partnership interest of the Operating Partnership.

	-5	We, along with our joint venture partner, acquired this property inclusive of the issuance of $14.1 million aggregate liquidation preference of Series L Preferred Units of limited partnership interest of the Operating Partnership and $9.5 million aggregate liquidation preference of Series K Preferred Units of limited partnership interest of the Operating Partnership. We hold a 75.0% controlling interest in this joint venture.
2013 Acquisitions
Property Acquisitions
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following summarizes our allocation of the purchase price of the assets acquired and liabilities assumed upon the closing of these acquisitions (in thousands):


			315 West 33rd Street(1)			Assemblage of Retail Development Properties on Fifth Avenue(1)			16 Court(2)			248-252
												Bedford
												Avenue(3)
	Acquisition Date		Nov-13			Nov-13			Apr-13			Mar-13
	Ownership Type		Fee Interest			Fee Interest			Fee Interest			Fee Interest
	Property Type		Residential			Development			Office			Residential

	Purchase Price Allocation:
	Land		$	195,834		$	135,513		$	19,217		$	10,865

	Building and building leasehold		164,429			10,487			63,210			44,035

	Above market lease value		7,084			—			5,122			—

	Acquired in-place leases		26,125			—			9,422			—

	Other assets, net of other liabilities		1,142			—			3,380			—

	Assets acquired		394,614			146,000			100,351			54,900

	Mark-to-market assumed debt		—			—			294			—

	Below market lease value		7,839			—			3,885			—

	Liabilities assumed		7,839			—			4,179			—

	Purchase price		$	386,775		$	146,000		$	96,172		$	54,900

	Net consideration funded by us at closing, excluding consideration financed by debt		$	386,775		$	146,000		$	4,000		$	21,782

	Equity and/or debt investment held		$	—		$	—		$	13,835		$	—

	Debt assumed		$	—		$	—		$	84,642		$	—

	____________________________________________________________________

	-1	During the year ended December 31, 2014, we finalized the purchase price allocation based on a third party appraisal and additional facts and circumstances that existed at the acquisition dates. These adjustments did not have a material impact to our consolidated statement of income for the year ended December 31, 2014.

	-2	In April 2013, we acquired interests from our joint venture partner, City Investment Fund, or CIF, in 16 Court Street in Brooklyn for $4.0 million. We have consolidated the ownership of the building. The transaction valued the consolidated interest at $96.2 million, inclusive of the $84.6 million mortgage encumbering the property. In April 2014, we repaid the mortgage. We recognized a purchase price fair value adjustment of $(2.3) million upon the closing of this transaction. This property, which we initially acquired in July 2007, was previously accounted for as an investment in unconsolidated joint ventures.

	-3	In March 2013, we, along with Magnum Real Estate Group, acquired 84 residential units, consisting of 72 apartment units and 12 townhouses, located at 248-252 Bedford Avenue, Williamsburg, Brooklyn for $54.9 million. Simultaneous with the closing on this property, the joint venture closed on a $22.0 million mortgage loan which was later refinanced in June 2014. The property is above a commercial property already owned by us. We hold a 90.0% controlling interest in this joint venture.
2012 Acquisitions
Property Acquisitions
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following summarizes our allocation of the purchase price of the assets acquired and liabilities assumed upon the closing of these acquisitions (in thousands):


			985-987 Third Avenue(1)			131-137 Spring Street			635-641			304 Park			Stonehenge
									Sixth			Avenue			Properties(3)
									Avenue			South(2)
	Acquisition Date		Dec-12			Dec-12			Sep-12			Jun-12			Jan-12
	Ownership Type		Fee Interest			Fee Interest			Fee Interest			Fee Interest			Fee Interest/Leasehold Interest
	Property Type		Development			Retail			Development			Office			Residential/Retail

	Purchase Price Allocation:
	Land		$	5,400		$	27,021		$	69,848		$	54,189		$	65,533

	Building and building leasehold		12,600			105,342			104,474			75,619			128,457

	Above market lease value		—			179			—			2,824			594

	Acquired in-place leases		—			7,046			7,727			8,265			9,573

	Other assets, net of other liabilities		—			—			—			—			2,190

	Assets acquired		18,000			139,588			182,049			140,897			206,347

	Fair value adjustment to mortgage note payable		—			—			—			—			—

	Below market lease value		—			17,288			9,049			5,897			13,239

	Liabilities assumed		—			17,288			9,049			5,897			13,239

	Purchase price		$	18,000		$	122,300		$	173,000		$	135,000		$	193,108

	Net consideration funded by us at closing, excluding consideration financed by debt		$	18,000		$	122,300		$	173,000		$	135,000		$	78,121

	Equity and/or debt investment held		$	—		$	—		$	—		$	—		$	—

	Debt assumed		$	—		$	—		$	—		$	—		$	—

	____________________________________________________________________

	-1	This property was subsequently sold in July 2014. See Note 4, "Properties Held for Sale and Dispositions."

	-2	This property was acquired with $102.0 million in cash and $33.0 million in units of limited partnership interest of the Operating Partnership.

	-3	In January 2012, we acquired five retail and two multifamily properties in Manhattan for $193.1 million. This property was acquired inclusive of the issuance of $47.6 million aggregate liquidation preference of Series G Preferred Units of limited partnership interest of the Operating Partnership. Simultaneous with the closing, we financed the multifamily component, which encompasses 385 units and approximately 488,000 square feet (unaudited), with an aggregate $100.0 million fixed rate mortgage which bears interest at 4.1% and one of the retail properties financed with an $8.5 million fixed rate mortgage. We hold an 80.0% interest in this joint venture which we consolidate as it is a VIE and we have been designated as the primary beneficiary. In February 2013, we sold one of the retail properties, which is further described in Note 4, "Properties Held for Sale and Dispositions."

Properties_Held_for_Sale_and_D1

Properties Held for Sale and Dispositions (Tables)	12 Months Ended
	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Summary of properties sold	The following table summarizes the properties sold during the years ended December 31, 2014, 2013, and 2012:


	Property		Disposition Date	Property Type		Approximate Usable Square Feet	Sales Price		Gain (Loss) on Sale(1)
						(unaudited)	(in millions)		(in millions)
	2 Herald Square		Nov-14	Land		354,400	$	365	$	18.8

	985-987 Third Avenue		Jul-14	Development		13,678	68.7		29.8

	673 First Avenue		May-14	Office		422,000	145		117.6

	300 Main Street		Sep-13	Office		130,000	13.5		(2.2		)

	333 West 34th Street		Aug-13	Office		345,400	220.3		13.8

	44 West 55th Street		Feb-13	Retail		8,557	6.3		1.1

	292 Madison Avenue		Feb-12	Land		203,800	85		6.6

	____________________________________________________________________

	-1	The gain on sale for 2 Herald Square, 985-987 Third Avenue, 673 First Avenue, 333 West 34th Street, and 292 Madison Avenue are net of a $2.5 million, $1.3 million, $3.4 million, $3.0 million and $1.5 million employee compensation award, respectively, accrued in connection with the realization of this investment gain as a bonus to certain employees that were instrumental in realizing the gain on sale. Additionally, amounts do not include adjustments for expense recorded in subsequent periods.
Summary of income from discontinued operations	The following table summarizes net income from discontinued operations for the years ended December 31, 2014, 2013 and 2012, respectively (in thousands).


		Year Ended December 31,
		2014			2013		2012
	Revenues
	Rental revenue	$	51,090		$	94,558	$	97,254

	Escalation and reimbursement revenues	4,646			14,856		16,232

	Other income	23			554		8,295

	Total revenues	55,759			109,968		121,781

	Operating expenses	7,772			20,568		23,166

	Real estate taxes	7,156			16,521		16,190

	Ground rent	3,001			7,975		6,362

	Interest expense, net of interest income	12,652			19,782		22,298

	Depreciable real estate reserves	—			2,150		—

	Transaction related costs, net of recoveries	89			2		383

	Depreciation and amortization	5,581			16,443		20,250

	Amortization of deferred financing costs	433			840		892

	Total expenses	36,684			84,281		89,541

	Net income from discontinued operations	$	19,075		$	25,687	$	32,240

Debt_and_Preferred_Equity_Inve1

Debt and Preferred Equity Investments (Tables)	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Summary of debt investments	As of December 31, 2014 and 2013, we held the following debt investments with an aggregate weighted average current yield of 10.33% at December 31, 2014 (in thousands):


	Loan Type		December 31, 2014			December 31, 2014				December 31, 2014				December 31, 2013				Initial
			Future Funding			Senior				Carrying Value,				Carrying Value,				Maturity
			Obligations			Financing				Net of Discounts and Deferred Origination Fees(1)				Net of Discounts and Deferred Origination Fees(1)				Date
	Fixed Rate Investments:
	Jr. Mortgage Participation		$	—		$	398,500			$	11,934			$	11,856			Mar-15

	Jr. Mortgage Participation		—			205,000				70,688				68,319				Feb-16
	/Mezzanine Loan
	Other(2)		—			—				45,611				44,742				Various(2)

	Mezzanine Loan(3)		—			177,000				14,068				15,012				May-16

	Jr. Mortgage Participation		—			133,000				49,000				49,000				Jun-16

	Mezzanine Loan		—			165,000				71,656				71,312				Nov-16

	Jr. Mortgage Participation/Mezzanine Loan(4)		—			1,109,000				98,934				26,884				Mar-17

	Other(4)		—			—				65,770				54,099				Mar-17

	Mezzanine Loan(5)		16,424			521,750				24,608				20,954				Jun-17

	Mezzanine Loan		—			539,000				49,629				—				Jul-18

	Mortgage Loan(6)		—			—				26,209				—				Feb-19



	Mortgage Loan		—			—				637				—				Aug-19

	Mezzanine Loan		—			15,000				3,500				3,500				Sep-21

	Mezzanine Loan(7)		—			90,000				19,930				19,926				Nov-23

	Mezzanine Loan		—			95,000				30,000				—				Jan-25

	Total fixed rate		$	16,424		$	3,448,250			$	582,174			$	385,604

	Floating Rate Investments:
	Mezzanine Loan		7,785			50,000				37,322				—				Apr-15

	Mortgage/Mezzanine Loan		—			—				109,527				—				Jun-15

	Mezzanine Loan		—			110,000				49,614				49,110				Sep-15

	Mezzanine Loan		7,249			113,633				42,750				27,662				Dec-15

	Mezzanine Loan		—			775,000				73,402				72,823				Mar-16

	Mezzanine Loan(8)		—			160,000				22,573				22,526				Jun-16

	Mezzanine Loan		—			115,000				24,910				25,590				Jul-16

	Mezzanine Loan		3,641			172,105				33,726				25,725				Nov-16

	Mezzanine Loan		—			360,000				99,023				—				Nov-16

	Mezzanine Loan		333			33,833				11,835				11,798				Dec-16

	Mezzanine Loan		9,053			91,727				20,651				—				Jan-17

Mortgage/Mezzanine Loan		2,847			110,767				38,524				—				Jul-17

Mortgage/Mezzanine Loan		—			—				22,803				—				Jul-17

Mortgage/Mezzanine Loan		—			—				16,848				—				Sep-17

Mezzanine Loan		—			60,000				14,859				—				Nov-17

Mortgage/Mezzanine Loan(9)		795			—				14,845				—				Dec-17

Jr. Mortgage Participation/Mezzanine Loan		—			55,000				20,533				20,553				Jul-18

Mortgage/Mezzanine Loan		—			—				18,083				—				Feb-19

Mezzanine Loan		—			38,000				21,807				—				Mar-19

Mortgage Loan(10)		—			—				—				30,000

Jr. Mortgage Participation(11)		—			—				—				24,046

Jr. Mortgage Participation/Mezzanine Loan(11)		—			—				—				131,724

Mezzanine Loan(12)		—			—				—				59,892

Jr. Mortgage Participation(12)		—			—				—				10,873

Mezzanine Loan(12)		—			—				—				38,549

Total floating rate		$	31,703		$	2,245,065			$	693,635			$	550,871

Total		$	48,127		$	5,693,315			$	1,275,809			$	936,475

Loan loss reserve									—				(1,000		)

									$	1,275,809			$	935,475

____________________________________________________________________

-1	Carrying value is net of discounts, premiums, original issue discounts and deferred origination fees.

-2	During the fourth quarter of 2014, both our $22.6 million junior participation and our $23.0 mezzanine loan were defeased and are now collateralized by defeasance securities. In connection with the defeasance, the maturity date of the mortgage in which we are a junior participant was accelerated from the May 2016 to February 2016, per the terms of the loan agreement. The maturity date of the mezzanine loan was not changed in connection with the defeasance and will mature in May 2016.

-3	This loan was repaid in February 2015.

-4	During the first quarter of 2014, we recognized $10.1 million of previously unaccrued interest income which was deemed collectible as a result of the sale of the underlying property, which closed in June 2014. In connection with the sale of the underlying property, our existing $66.7 million mezzanine loan was defeased and is now shown separately, as it is collateralized by defeasance securities. The buyer assumed our $30.0 million participating interest in the mortgage and we acquired a $67.3 million participating interest in the new mezzanine loan.

-5	Carrying value is net of $41.3 million that was participated out, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfer not meeting the conditions for sale accounting.

-6	In September 2014, we acquired a $26.4 million mortgage loan at a $0.2 million discount and a $5.7 million junior mortgage participation at a $5.7 million discount. The junior mortgage participation was a nonperforming loan at acquisition and is currently on non-accrual status.

-7	Carrying value is net of $5.0 million that was participated out, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfer not meeting the conditions for sale accounting.

-8	Carrying value is net of $7.4 million that was participated out, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfer not meeting the conditions for sale accounting.

-9	Carrying value is net of $5.1 million that was participated out, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfer not meeting the conditions for sale accounting.

-10	This loan was repaid in May 2014.

-11	This loan was repaid in July 2014.

-12	This loan was repaid in August 2014.
Summary of preferred equity investments	As of December 31, 2014 and 2013, we held the following preferred equity investments with an aggregate weighted average current yield of 10.89% at December 31, 2014 (in thousands):


	Type		December 31, 2014			December 31, 2014				December 31, 2013				Initial
			Senior			Carrying Value,				Carrying Value,				Mandatory
			Financing			Net of Discounts and Deferred Origination Fees(1)				Net of Discounts and Deferred Origination Fees(1)				Redemption
	Preferred equity(2)		$	550,000		$	123,041			$	115,198			Jul-15

	Preferred equity		70,000			9,954				9,940				Nov-17

	Preferred equity(3)		—			—				25,896

	Preferred equity(2)(4)		—			—				218,330

			$	620,000		$	132,995			$	369,364

	____________________________________________________________________

	-1	Carrying value is net of discounts and deferred origination fees.

	-2	The difference between the pay and accrual rates is included as an addition to the principal balance outstanding.

	-3	This preferred equity investment was redeemed in April 2014.

	-4	This preferred equity investment was redeemed in November 2014.
Rollforward of total allowance for loan loss reserves	The following table is a rollforward of our total loan loss reserves at December 31, 2014, 2013 and 2012 (in thousands):


		December 31,
		2014			2013				2012
	Balance at beginning of year	$	1,000		$	7,000			$	50,175

	Expensed	—			—				3,000

	Recoveries	—			—				(2,436		)

	Charge-offs and reclassifications	(1,000		)	(6,000		)		(43,739		)
	Balance at end of period	$	—		$	1,000			$	7,000

Summary of impaired loans, which may include non-accrual loans	The following table presents impaired loans, which may include non-accrual loans, as of December 31, 2013 (in thousands):


							31-Dec-13
							Unpaid				Recorded				Allowance
							Principal				Investment				Allocated
							Balance
	With no related allowance recorded:
	Commercial real estate						$	—			$	—			$	—

	With an allowance recorded:
	Commercial real estate(1)						10,750				10,750				1,000

	Total						$	10,750			$	10,750			$	1,000

	____________________________________________________________________

	-1	This loan was repaid during the year ended December 31, 2014.

Investment_in_Unconsolidated_J

Investment in Unconsolidated Joint Ventures (Tables)	12 Months Ended
	Dec. 31, 2014
Equity Method Investments and Joint Ventures [Abstract]
Schedule of general information on joint ventures	The table below provides general information on each of our joint ventures as of December 31, 2014:


	Property	Partner	Ownership	Economic	Approximate Square		Acquisition Date	Acquisition
			Interest	Interest	Feet			Price(1)
					(unaudited)			(in thousands)
	100 Park Avenue	Prudential	49.90%	49.90%	834,000		Jan-00	$	95,800

	717 Fifth Avenue(2)	Sutton/Private Investor	10.92%	10.92%	119,500		Sep-06	251,900

	800 Third Avenue	Private Investors	42.95%	42.95%	526,000		Dec-06	285,000

	1745 Broadway(3)	Ivanhoe Cambridge	56.88%	56.88%	674,000		Apr-07	520,000

	Jericho Plaza	Onyx/Credit Suisse	20.26%	20.26%	640,000		Apr-07	210,000

	The Meadows	Onyx	50.00%	50.00%	582,100		Sep-07	111,500

	600 Lexington Avenue	CPPIB	55.00%	55.00%	303,515		May-10	193,000

	11 West 34th Street	Private Investor\Sutton	30.00%	30.00%	17,150		Dec-10	10,800

	7 Renaissance	Cappelli	50.00%	50.00%	65,641		Dec-10	4,000

	3 Columbus Circle(4)	Moinian	48.90%	48.90%	741,500		Jan-11	500,000

	280 Park Avenue(5)	Vornado	50.00%	50.00%	1,219,158		Mar-11	400,000

	1552-1560 Broadway(6)	Sutton	50.00%	50.00%	35,897		Aug-11	136,550

	724 Fifth Avenue	Sutton	50.00%	50.00%	65,040		Jan-12	223,000

	10 East 53rd Street	CPPIB	55.00%	55.00%	354,300		Feb-12	252,500

	33 Beekman(7)	Harel/Naftali	45.90%	45.90%	—		Aug-12	31,000

	521 Fifth Avenue(8)	Plaza	50.50%	50.50%	460,000		Nov-12	315,000



	21 East 66th Street(9)	Private Investors	32.28%	32.28%	16,736		Dec-12	75,000

	315 West 36th Street	Private Investors	35.50%	35.50%	147,619		Dec-12	45,000

	650 Fifth Avenue(10)	Sutton	50.00%	50.00%	32,324		Nov-13	—

	121 Greene Street	Sutton	50.00%	50.00%	7,131		Sep-14	27,400

	175-225 Third Street(11)	Kushner Companies/LIVWRK	95.00%	95.00%	—		Oct-14	74,600

	55 West 46th Street(12)	Prudential	25.00%	25.00%	347,000		Nov-14	295,000

	____________________________________________________________________

	-1	Acquisition price represents the actual or implied gross purchase price for the joint venture.

	-2	In June 2012, we recognized $67.9 million of additional cash income, equivalent to profit, due to the distribution of refinancing proceeds and a gain on sale of $3.0 million, on the sale of 50.0% of our remaining interest.

	-3	In November 2014, we acquired Lehman Bros.' 7.37% interest in 1745 Broadway. In December 2014, we additionally acquired Witkoff's 14.79% interest and Wells Fargo's 2.46% interest in the property. In connection with the acquisition of Witkoff's interest, we assumed a partner loan of $16.0 million, which is included in mortgages and other loans payable in the consolidated balance sheet, and $7.0 million of accrued interest.

	-4	As a result of the sale of a condominium interest in September 2012, Young & Rubicam, Inc., or Y&R, owns a portion of the property, generally floors three through eight referred to as Y&R units. Because the joint venture has an option to repurchase the Y&R units, the gain associated with this sale was deferred.

	-5	In October 2014, we, along with Vornado, acquired equally the interest of minority shareholders for $11.0 million.

-6	The purchase price represents only the purchase of the 1552 Broadway interest which comprised approximately 13,045 square feet (unaudited). The joint venture also owns a long-term leasehold interest in the retail space and certain other spaces at 1560 Broadway, which is adjacent to 1552 Broadway.

-7	The property is currently being developed into a 30 story dormitory building, which will be conveyed to Pace University upon its completion under a long-term ground lease arrangement.

-8	In November 2012, we refinanced the previous mortgage and sold 49.5% of our partnership interest. We recognized a gain of $19.4 million on the sale. Due to lack of control, we deconsolidated the entity effective November 30, 2012 and adopted the equity method of accounting thereafter. During the year ended December 31, 2013, we recognized additional post closing costs of $2.8 million as an adjustment to the gain.

-9	In October 2014, the joint venture sold one of the residential units at the property. We recognized a gain of $0.7 million on the sale. As of December 31, 2014, we hold a 32.28% interest in three retail and two residential units at the property and a 16.14% interest in three residential units at the property.

-10	The joint venture owns a long-term leasehold interest in the retail space at 650 Fifth Avenue. In connection with the ground lease obligation, SLG provided a performance guaranty and Sutton executed a contribution agreement to reflect its pro rata obligation. In the event the property is converted into a condominium unit and the landlord elects the purchase option, the joint venture shall be obligated to acquire the unit at the then fair value.

-11	In October 2014, we, along with our joint venture partners, acquired a development site at 175-225 Third Street in Brooklyn, New York. The property is being managed by our joint venture partners. We did not consolidate the property as a result of multiple partners having substantive participating rights.

-12	In October 2014, we acquired the vacant commercial condominium units on floors 2 and 22-34 in the building located at 55 West 46th Street for $295.0 million. We also acquired a retail space on 46th Street and the building’s parking garage and fitness center. We consolidated the property from acquisition through October 31, 2014. In November 2014, we, together with Prudential, formed a joint venture for the ownership of the condominium units. We sold 75.00% of our interest to Prudential and retained 25.00% interest in the joint venture. As a result of Prudential having substantive participating rights, we deconsolidated the property and adopted the equity method of accounting subsequently thereafter.
Schedule of joint ventures and property sold	The following table summarizes the investments in unconsolidated joint ventures sold during the years ended December 31, 2014, 2013, and 2012:


	Property		Ownership Percentage			Disposition Date		Type of Sale		Implied Sales Price (1)				Gain on Sale(2)
										(in millions)				(in millions)
	180 Broadway(3)		25.5	%		Sep-14		Property		$	222.5			$	16.5

	747 Madison Avenue(4)		33.33	%		May-14		Ownership Interest		160				—

	West Coast Office portfolio(5)		42.02	%		Mar-14		Ownership Interest		756				85.6

	21-25 West 34th Street(6)		49.9	%		Jan-14		Ownership Interest		114.9				20.9

	27-29 West 34th Street(7)		50	%		Dec-13		Ownership Interest		70.1				7.6

	West Coast Office Portfolio(5)		42.04	%		Various dates in 2013		Property		224.3				2.1

	One Court Square(8)		30	%		Jul-12		Property		481.1				1

	379 West Broadway(9)		45	%		Apr-12		Property		48.5				6.5

	141 Fifth Avenue(10)		50	%		Mar-12		Property		46				7.3

	____________________________________________________________________

	-1	Represents implied gross valuation for the joint venture or sales price of the property.

	-2	Represents the Company's share of the gain.

	-3	In connection with the sale of the property, we also recognized a promote of $3.3 million.

	-4	We sold our ownership interest in the joint venture, which owns 100% interest as tenant-in-common in 30 East 65th Street Corporation and the related proprietary lease of five cooperative apartment units in the property. We also recognized a promote of $10.3 million and originated a $30.0 million preferred equity investment. Given our continuing involvement as a preferred equity holder, we deferred the gain on sale of $13.1 million as we did not meet the requirements of a sale under the full accrual method. We, along with our joint venture partners, retained one apartment unit at this property.

	-5	Prior to the recapitalization, we consolidated the investment for the months of August and September 2012 as a result of our 63.18% ownership interest and control over its activities. Immediately following the recapitalization in September 2012, our investment was 27.63%. The change in ownership resulted in a change in accounting from consolidating the investment to accounting for the joint venture under the equity method of accounting. During the year ended December 31, 2013, the joint venture sold three properties, the proceeds of which were used primarily to repay a portion of the debt. Also during the year ended December 31, 2013, we acquired in aggregate 14.39% ownership interest of two of our joint venture partners. As a result, we had a 42.04% effective ownership interest (43.74% effective economic interest) in the West Coast portfolio as of December 31, 2013. During the year ended December 31, 2014, we sold our ownership interest in the joint venture.

	-6	We sold our ownership interest in the joint venture. We, along with our joint venture partner, retained approximately 91,300 square feet (unaudited) of development rights at the property.

	-7	We sold our ownership interest in the joint venture. The gain on the sale of this investment is net of a $1.5 million employee compensation award, accrued in connection with the realization of this investment gain as a bonus to certain employees that were instrumental in realizing the gain on this sale. Simultaneously, we, along with Sutton, also formed a new joint venture and retained the air rights at this property.

	-8	We, along with our joint venture partner, sold the property, which included the assumption by the purchaser of $315.0 million of existing debt.

	-9	We, along with our joint venture partner, sold the property, inclusive of the fee position, which was acquired for $13.5 million.

	-10	We, along with our joint venture partner, sold the property. The gain on the sale of this investment is net of a $1.5 million employee compensation award, accrued in connection with the realization of this investment gain as a bonus to certain employees that were instrumental in realizing the gain on this sale.
Schedule of first mortgage notes payable collateralized by the respective joint venture properties and assignment of leases	The first mortgage notes and other loans payable collateralized by the respective joint venture properties and assignment of leases at December 31, 2014 and 2013, respectively, are as follows (amounts in thousands):


	Property		Maturity Date			Interest			31-Dec-14				31-Dec-13
						Rate(1)
	Fixed Rate Debt:
	7 Renaissance		Dec-15			10	%		$	2,147			$	1,276

	11 West 34th Street		Jan-16			4.82	%		16,905				17,205

	280 Park Avenue		Jun-16			6.57	%		700,171				706,886

	1745 Broadway		Jan-17			5.68	%		340,000				340,000

	Jericho Plaza		May-17			5.65	%		163,750				163,750

	800 Third Avenue		Aug-17			6	%		20,910				20,910

	315 West 36th Street		Dec-17			3.16	%		25,000				25,000

	521 Fifth Avenue(2)		Nov-19			2.48	%		170,000				—

	717 Fifth Avenue(3)		Jul-22			4.45	%		300,000				300,000

	21 East 66th Street		Apr-23			3.6	%		12,000				12,000

	717 Fifth Avenue(3)		Jul-24			9	%		314,381				304,000

	388-390 Greenwich Street(4)		—			—			—				996,082

	100 Park Avenue(5)		—			—			—				209,786

	21 West 34th Street(6)		—			—			—				100,000

	1604-1610 Broadway(7)		—			—			—				27,000

	Total fixed rate debt								$	2,065,264			$	3,223,895

	Floating Rate Debt:
	The Meadows		Sep-15			7.75	%		67,350				67,350

	3 Columbus Circle(8)		Apr-16			2.33	%		230,974				239,233

	1552 Broadway(9)		Apr-16			4.25	%		184,210				158,690

	Other loan payable		Jun-16			1.05	%		30,000				30,000

	650 Fifth Avenue(10)		Oct-16			3.66	%		65,000				—

	175-225 Third Street		Dec-16			4.25	%		40,000				—

	10 East 53rd Street		Feb-17			2.65	%		125,000				125,000

	724 Fifth Avenue(11)		Apr-17			2.57	%		275,000				120,000

	33 Beekman(12)		Aug-17			2.9	%		52,283				18,362

	600 Lexington Avenue		Oct-17			2.23	%		116,740				120,616

	55 West 46th Street(13)		Oct-17			2.45	%		150,000				—

	121 Greene Street		Nov-19			1.67	%		15,000				—

	100 Park Avenue(5)		Feb-21			2.36	%		360,000				—

21 East 66th Street		Jun-33			2.88	%		1,883				1,959

521 Fifth Avenue(2)		—			—			—				170,000

388-390 Greenwich Street(4)		—			—			—				142,297

747 Madison Avenue		—			—			—				33,125

West Coast Office portfolio(14)		—			—			—				526,290

180/182 Broadway(15)		—			—			—				89,893

Total floating rate debt								$	1,713,440			$	1,842,815

Total joint venture mortgages and other loans payable								$	3,778,704			$	5,066,710

____________________________________________________________________

-1	Effective weighted average interest rate for the year ended December 31, 2014, taking into account interest rate hedges in effect during the period.

-2	This loan became a 3.73% fixed rate mortgage upon the effectivity of the interest rate swap in November 2014.

-3	These loans are comprised of a $300.0 million fixed rate mortgage loan and $290.0 million mezzanine loan. The mezzanine loan is subject to accretion based on the difference between contractual interest rate and contractual pay rate.

-4	In May 2014, we acquired the interest of our joint venture partner, thereby consolidating the entity. Simultaneous with the acquisition, we refinanced the mortgage and incurred a net loss on early extinguishment of debt of $2.4 million.

-5	In February 2014, the joint venture refinanced the previous mortgage and incurred a net loss on early extinguishment of debt of $3.2 million.

-6	In January 2014, we sold our interest in the joint venture, inclusive of our share of the joint venture debt.

-7	This loan was in default since November 2009 due to the non-payment of debt service. In January 2014, the joint venture surrendered its ground lease position to the lender. During the year ended December 31, 2014, we recognized $7.7 million of incentive income, which is included in other income on the consolidated statements of income.

-8	The joint venture has the ability to increase the mortgage by $40.0 million based on meeting certain performance hurdles. In connection with this obligation, we executed a master lease agreement and our joint venture partner executed a contribution agreement to reflect its pro rata obligation under the master lease. The lien on the mortgage and the master lease excludes the condominium interest owned by Y&R. See Note 4 of the first table.

-9	These loans are comprised of a $150.0 million mortgage loan and a $41.5 million mezzanine loan. As of December 31, 2014, $3.9 million of the mortgage loan and $3.4 million of the mezzanine loan remained unfunded.

-10	In October 2014, the joint venture closed on a $97.0 million leasehold mortgage, of which $32.0 million remained unfunded as of December 31, 2014.

-11	In April 2014, the joint venture refinanced the previous mortgage and incurred a net loss on early extinguishment of debt of $1.2 million.

-12	This loan has a committed amount of $75.0 million, of which $18.4 million is recourse to us. Our partner has indemnified us for its pro rata share of the recourse guarantee. A portion of the guarantee terminates upon the joint venture reaching certain milestones. We believe it is unlikely that we will be required to perform under this guarantee.

-13	This loan has a committed amount of $190.0 million, of which $40.0 million remained unfunded as of December 31, 2014.

-14	In March 2014, we sold our interest in the joint venture, inclusive of our share in the joint venture debt.

-15	In September 2014, the joint venture sold the property and repaid the debt.
Schedule of combined balance sheets for the unconsolidated joint ventures	The combined balance sheets for the unconsolidated joint ventures, at December 31, 2014 and 2013, are as follows (in thousands):


		December 31,
		2014				2013
	Assets
	Commercial real estate property, net	$	5,275,632			$	6,846,021

	Other assets	810,567				827,282

	Total assets	$	6,086,199			$	7,673,303

	Liabilities and members' equity
	Mortgages and other loans payable	$	3,778,704			$	5,066,710

	Other liabilities	485,572				596,960

	Members' equity	1,821,923				2,009,633

	Total liabilities and members' equity	$	6,086,199			$	7,673,303

	Company's investments in unconsolidated joint ventures	$	1,172,020			$	1,113,218

Schedule of combined statements of income for the unconsolidated joint ventures

		December 31,
		2014				2013
	Assets
	Commercial real estate property, net	$	5,275,632			$	6,846,021

	Other assets	810,567				827,282

	Total assets	$	6,086,199			$	7,673,303

	Liabilities and members' equity
	Mortgages and other loans payable	$	3,778,704			$	5,066,710

	Other liabilities	485,572				596,960

	Members' equity	1,821,923				2,009,633

	Total liabilities and members' equity	$	6,086,199			$	7,673,303

	Company's investments in unconsolidated joint ventures	$	1,172,020			$	1,113,218

	The combined statements of income for the unconsolidated joint ventures, from acquisition date through the years ended December 31, 2014, 2013 and 2012 are as follows (in thousands):

Deferred_Costs_Tables

Deferred Costs (Tables)	12 Months Ended
	Dec. 31, 2014
Deferred Costs [Abstract]
Schedule of components of deferred costs	Deferred costs at December 31, 2014 and 2013 consisted of the following (in thousands):


		December 31,
		2014			2013
	Deferred leasing	$	385,555		$	326,379

	Deferred financing	193,776			157,088

		579,331			483,467

	Less accumulated amortization	(251,369		)	(216,409		)
	Deferred costs, net	$	327,962		$	267,058

Mortgages_and_Other_Loans_Paya1

Mortgages and Other Loans Payable (Tables)	12 Months Ended
	Dec. 31, 2014
Mortgages and Other Loans Payable
Schedule of first mortgages and other loans payable collateralized by the respective properties and assignment of leases	The first mortgages and other loans payable collateralized by the respective properties and assignment of leases at December 31, 2014 and 2013, respectively, were as follows (amounts in thousands):


	Property	Maturity	Interest			31-Dec-14			31-Dec-13
		Date	Rate(1)
	Fixed Rate Debt:
	711 Third Avenue	Jun-15	4.99	%		$	120,000		$	120,000

	500 West Putnam Avenue	Jan-16	5.52	%		22,968			23,529

	Landmark Square	Dec-16	4	%		81,269			82,909

	485 Lexington Avenue	Feb-17	5.61	%		450,000			450,000

	120 West 45th Street	Feb-17	6.12	%		170,000			170,000

	762 Madison Avenue	Feb-17	3.75	%		8,045			8,211

	885 Third Avenue	Jul-17	6.26	%		267,650			267,650

	1745 Broadway(2)	Jun-18	4.81	%		16,000			—

	388-390 Greenwich Street(3)	Jun-18	2.99	%		1,004,000			—

	One Madison Avenue	May-20	5.91	%		565,742			587,336



	100 Church	Jul-22	4.68	%		228,612			230,000

	919 Third Avenue(4)	Jun-23	5.12	%		500,000			500,000

	400 East 57th Street	Feb-24	4.13	%		68,896			70,000

	400 East 58th Street	Feb-24	4.13	%		29,527			30,000

	420 Lexington Avenue(5)	Oct-24	5.95	%		300,000			182,641

	1515 Broadway(6)	Mar-25	3.93	%		900,000			900,000

	Series J Preferred Units(7)	Apr-51	3.75	%		4,000			—

	Other loan payable(8)					—			50,000

	609 Partners, LLC(9)					—			23

	125 Park Avenue(10)					—			146,250

	2 Herald Square(11)					—			191,250

	625 Madison Avenue(12)					—			120,830

	Total fixed rate debt					$	4,736,709		$	4,130,629

	Floating Rate Debt:
	Master repurchase agreement(13)	Dec-15	3.38	%		100,000			91,000

	180 Maiden Lane(14)	Nov-16	2.35	%		253,942			262,706

	388-390 Greenwich Street(3)	Jun-18	1.91	%		446,000			—

	248-252 Bedford Avenue(15)	Jun-19	1.93	%		29,000			22,000

	220 East 42nd Street	Oct-20	1.75	%		275,000			275,000

16 Court Street(16)					—			79,243

Total floating rate debt					$	1,103,942		$	729,949

Total mortgages and other loans payable					$	5,840,651		$	4,860,578

____________________________________________________________________

-1	Effective weighted average interest rate for the year ended December 31, 2014, taking into account interest rate hedges in effect during the period.

-2	In connection with our acquisition of Witkoff's interest in the unconsolidated joint venture which holds 1745 Broadway, we have assumed this partner loan.

-3	Simultaneous with the acquisition of our joint venture partner's interest, we refinanced the $1.1 billion floating rate mortgage with a $1.45 billion seven-year floating rate mortgage (including the as-of right extension option), and have consolidated the property. We assumed the existing derivative instruments, which swapped $504.0 million of the floating rate mortgage to a fixed rate mortgage which bears interest at 3.80% per annum. In October 2014, we entered into multiple swap agreements to hedge our interest rate exposure on the additional $500.0 million portion of this mortgage, which was swapped to a fixed rate of 2.69% per annum.

-4	We own a 51.0% controlling interest in the joint venture that is the borrower on this loan.

-5	In September 2014, we refinanced the previous mortgage and incurred a loss on early extinguishment of debt of $24.5 million. The new loan bears a fixed interest rate of 3.99% per annum.

-6	In February 2013, we refinanced the mortgage and incurred a loss on early extinguishment of debt of $18.5 million.

-7	In connection with the acquisition of a commercial real estate property, the Operating Partnership issued $4.0 million or 4,000 3.75% Series J Preferred Units of limited partnership interest, or the Series J Preferred Units, with a mandatory liquidation preference of $1,000.00 per unit. The Series J Preferred Units can be redeemed in cash by the Operating Partnership on the earlier of (i) the date of the sale of the property or (ii) April 30, 2051 or at the option of the unitholders as further prescribed in the related agreement.

-8	In November 2014, we repaid the loan.

-9	In April 2014, the remaining 22,658 Series E Preferred Units of the Operating Partnership were canceled.

-10	In October 2014, we repaid the loan at maturity.

-11	In November 2014, we sold the property and defeased the debt.

-12	In December 2014, we prepaid the loan and incurred a loss on early extinguishment of debt of $6.9 million.

-13	The Master Repurchase Agreement, or MRA, has a maximum facility capacity of $300.0 million. In December 2014, we extended the maturity date of the MRA to December 5, 2015.

-14	In connection with this consolidated joint venture obligation, we executed a master lease agreement. Our partner has executed a contribution agreement to reflect its pro rata share of the obligation under the master lease. This property was held for sale at December 31, 2014 and the related mortgage is included in liabilities related to assets held for sale. In January 2015, the property was sold and the debt was repaid.

-15	In June 2014, we refinanced the mortgage and incurred a loss on early extinguishment of debt of $0.5 million. In April 2014, we repaid the mortgage and incurred a loss on early extinguishment of d

Corporate_Indebtedness_Tables

Corporate Indebtedness (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Schedule of senior unsecured notes and other related disclosures by scheduled maturity date	The following table sets forth our senior unsecured notes and other related disclosures as of December 31, 2014 and 2013, respectively, by scheduled maturity date (dollars in thousands):


	Issuance		December 31,				December 31,				31-Dec-13			Coupon		Effective		Term		Maturity Date
			2014				2014				Accreted			Rate(1)		Rate		(in Years)
			Unpaid				Accreted				Balance
			Principal				Balance
			Balance
	March 31, 2006(2)		$	255,308			$	255,250			$	255,206		6	%	6	%	10		March 31, 2016

	October 12, 2010(3)		345,000				309,069				297,837			3	%	3	%	7		October 15, 2017

	August 5, 2011(4)		250,000				249,744				249,681			5	%	5	%	7		August 15, 2018

	March 16, 2010(4)		250,000				250,000				250,000			7.75	%	7.75	%	10		March 15, 2020

	November 15, 2012(4)		200,000				200,000				200,000			4.5	%	4.5	%	10		December 1, 2022

	June 27, 2005(2)(5)		7				7				7			4	%	4	%	20		June 15, 2025

	March 26, 2007(6)		10,008				10,008				10,701			3	%	3	%	20		March 30, 2027

	August 13, 2004(2)(7)		—				—				75,898

			$	1,310,323			$	1,274,078			$	1,339,330

	____________________________________________________________________

	-1	Interest on the senior unsecured notes is payable semi-annually with principal and unpaid interest due on the scheduled maturity dates.

	-2	Issued by ROP.

	-3	Issued by the Operating Partnership. Interest on these exchangeable notes is payable semi-annually on April 15 and October 15. The notes had an initial exchange rate representing an exchange price that was set at a 30.0% premium to the last reported sale price of SL Green's common stock on October 6, 2010, or $85.81. The initial exchange rate is subject to adjustment under certain circumstances. The current exchange rate is 12.1163 shares of SL Green's common stock per $1,000 principal amount of these notes. The notes are senior unsecured obligations of the Operating Partnership and are exchangeable upon the occurrence of specified events and during the period beginning on the twenty-second scheduled trading day prior to the maturity date and ending on the second business day prior to the maturity date, into cash or a combination of cash and shares of SL Green's common stock, if any, at our option. As a result of meeting specified events (as defined in the Indenture Agreement), these notes are exchangeable commencing January 1, 2015 and will remain exchangeable through March 31, 2015. The notes are guaranteed by ROP. On the issuance date, $78.3 million of the debt balance was recorded in equity. As of December 31, 2014, $35.9 million remained to be amortized into the debt balance.

	-4	Issued by the Company, the Operating Partnership and ROP, as co-obligors.

	-5	Exchangeable senior debentures which are currently callable at par. In addition, the debentures can be put to ROP, at the option of the holder at par plus accrued and unpaid interest, on June 15, 2015 and 2020 and upon the occurrence of certain change of control transactions. As a result of the acquisition of all outstanding shares of common stock of Reckson, or the Reckson Merger, the adjusted exchange rate for the debentures is 7.7461 shares of SL Green's common stock per $1,000 of principal amount of debentures and the adjusted reference dividend for the debentures is $1.3491.

	-6	Issued by the Operating Partnership. Interest on these remaining exchangeable notes is payable semi-annually on March 30 and September 30. The notes have an initial exchange rate representing an exchange price that was set at a 25.0% premium to the last reported sale price of the Company's common stock on March 20, 2007, or $173.30. The initial exchange rate is subject to adjustment under certain circumstances. The current exchange rate is 5.7952 shares of SL Green's common stock per $1,000 principal amount of these notes. The notes are senior unsecured obligations of the Operating Partnership and are exchangeable upon the occurrence of specified events and during the period beginning on the twenty-second scheduled trading day prior to the maturity date and ending on the second business day prior to the maturity date, into cash or a combination of cash and shares of SL Green's common stock, if any, at our option. The notes are currently redeemable at the Operating Partnership’s option. The Operating Partnership may be required to repurchase the notes on March 30, 2017 and 2022, and upon the occurrence of certain designated events.

	-7	In August 2014, these notes were repaid at maturity.
Schedule of combined aggregate principal maturities	Combined aggregate principal maturities of mortgages and other loans payable, 2012 credit facility, trust preferred securities, senior unsecured notes and our share of joint venture debt as of December 31, 2014, including as-of-right extension options and put options, were as follows (in thousands):


		Scheduled				Principal				Revolving			Unsecured Term Loan			Trust			Senior		Total		Joint
		Amortization				Repayments				Credit						Preferred			Unsecured				Venture
										Facility						Securities			Notes				Debt
	2015	$	39,353		-1	$	220,000			$	—		$	—		$	—		$	7	$	259,360	$	44,700

	2016	54,344			-1	338,465			-1	—			—			—			255,308		648,117		640,176

	2017	61,063				895,329				—			—			—			355,008		1,311,400		572,003

	2018	64,462				16,000				385,000			—			—			250,000		715,462		28

	2019	71,133				28,317				—			833,000			—			—		932,450		94,890

	Thereafter	203,098				3,849,087				—			—			100,000			450,000		4,602,185		266,191

		$	493,453		-1	$	5,347,198		-1	$	385,000		$	833,000		$	100,000		$	1,310,323	$	8,468,974	$	1,617,988

	____________________________________________________________________

	-1	Scheduled amortization and principal repayments include the mortgage at 180 Maiden Lane, which is included in liabilities related to assets held for sale. In January 2015, the property was sold and the debt was repaid.
Schedule of consolidated interest expense, excluding capitalized interest	Consolidated interest expense, excluding capitalized interest, was comprised of the following (in thousands):


		Year Ended December 31,
		2014				2013				2012
	Interest expense	$	319,898			$	312,897			$	311,235

	Interest income	(2,498		)		(2,003		)		(1,554		)
	Interest expense, net	$	317,400			$	310,894			$	309,681

	Interest capitalized	$	22,750			$	11,475			$	12,218

Related_Party_Transactions_Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Schedule of amounts due from/to related parties	Amounts due from related parties at December 31, 2014 and 2013 consisted of the following (in thousands):


		December 31,
		2014		2013
	Due from joint ventures	$	1,254	$	2,376

	Other	10,481		6,154

	Related party receivables	$	11,735	$	8,530

Noncontrolling_Interests_on_th1

Noncontrolling Interests on the Company's Consolidated Financial Statements (Tables)	12 Months Ended
	Dec. 31, 2014
Noncontrolling Interest [Abstract]
Schedule of Noncontrolling Interest	Below is the rollforward analysis of the activity relating to the noncontrolling interests in the Operating Partnership (in thousands) as of December 31, 2014 and 2013:


		December 31,
		2014			2013
	Balance at beginning of period	$	265,476		$	212,907

	Distributions	(7,849		)	(4,146		)
	Issuance of common units	56,469			24,750

	Redemption of common units	(31,653		)	(17,287		)
	Net income	18,467			3,023

	Accumulated other comprehensive income allocation	175			611

	Fair value adjustment	168,439			45,618

	Balance at end of period	$	469,524		$	265,476

Stockholders_Equity_of_the_Com1

Stockholders' Equity of the Company (Tables)	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Schedule of Earnings Per Share	SL Green's earnings per share for the years ended December 31, 2014, 2013 and 2012 are computed as follows (in thousands):


		Year Ended December 31,
	Numerator	2014			2013			2012
	Basic Earnings:
	Income attributable to SL Green common stockholders	$	503,104		$	101,330		$	155,984

	Effect of Dilutive Securities:
	Redemption of units to common shares	18,467			3,023			5,597

	Diluted Earnings:
	Income attributable to SL Green common stockholders	$	521,571		$	104,353		$	161,581



		Year Ended December 31,
	Denominator	2014		2013			2012
	Basic Shares:
	Weighted average common stock outstanding	95,774		92,269			89,319

	Effect of Dilutive Securities:
	Redemption of units to common shares	3,514		2,735			3,207

	Stock-based compensation plans	408		262			347

	Diluted weighted average common stock outstanding	99,696		95,266			92,873

Partners_Capital_of_the_Operat1

Partners' Capital of the Operating Partnership (Tables)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Schedule of calculation of numerator and denominator in earnings per unit	The Operating Partnership's earnings per unit for the years ended December 31, 2014, 2013 and 2012 are computed as follows (in thousands):


		Year Ended December 31,
	Numerator	2014			2013			2012
	Basic and Diluted Earnings:
	Income attributable to SLGOP common unitholders	$	521,571		$	104,353		$	161,581



		Year Ended December 31,
	Denominator	2014		2013			2012
	Basic units:
	Weighted average common units outstanding	99,288		95,004			92,526

	Effect of Dilutive Securities:
	Stock-based compensation plans	408		262			347

	Diluted weighted average common units outstanding	99,696		95,266			92,873

Sharebased_Compensation_Tables

Share-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of weighted average assumptions used to estimate the grant date fair value of options granted	The fair value of each stock option granted is estimated on the date of grant using the Black-Scholes option pricing model based on historical information with the following weighted average assumptions for grants during the years ended December 31, 2014, 2013 and 2012.


		2014			2013			2012
	Dividend yield	1.6	%		1.92	%		2	%
	Expected life of option	3.6 years			4.1 years			3.7 years

	Risk-free interest rate	1.29	%		0.96	%		0.46	%
	Expected stock price volatility	33.97	%		36.12	%		37.4	%
Summary of the status of stock options and changes during the period	A summary of the status of the Company's stock options as of December 31, 2014, 2013 and 2012 and changes during the years ended December 31, 2014, 2013 and 2012 are as follows:


		2014								2013					2012
		Options				Weighted				Options			Weighted		Options			Weighted
		Outstanding				Average				Outstanding			Average		Outstanding			Average
						Exercise							Exercise					Exercise
						Price							Price					Price
	Balance at beginning of year	1,765,034				$	83.24			1,201,000			$	75.05	1,277,200			$	63.37

	Granted	102,050				119.12				828,100			87.23		361,331			75.36

	Exercised	(348,156		)		72.76				(223,531		)	53.93		(382,612		)	36.65

	Lapsed or cancelled	(56,202		)		90.03				(40,535		)	83.94		(54,919		)	72.99

	Balance at end of year	1,462,726				$	87.98			1,765,034			$	83.24	1,201,000			$	75.05

	Options exercisable at end of year	428,951				$	90.32			461,458			$	89.38	479,913			$	86.85

	Weighted average fair value of options granted during the year	$	2,841,678							$	18,041,576				$	6,602,967

Summary of restricted stock and charges during the period	A summary of the Company's restricted stock as of December 31, 2014, 2013 and 2012 and charges during the years ended December 31, 2014, 2013 and 2012 are as follows:


		2014				2013				2012
	Balance at beginning of year	2,994,197				2,804,901				2,912,456

	Granted	9,550				192,563				92,729

	Cancelled	(2,768		)		(3,267		)		(200,284		)
	Balance at end of year	3,000,979				2,994,197				2,804,901

	Vested during the year	75,043				21,074				408,800

	Compensation expense recorded	$	9,658,019			$	6,713,155			$	6,930,381

	Weighted average fair value of restricted stock granted during the year	$	1,141,675			$	17,386,949			$	7,023,942

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Loss of the Company (Tables) (SL Green Realty Corp)	12 Months Ended
	Dec. 31, 2014
SL Green Realty Corp
Accumulated Other Comprehensive Income (Loss) [Line Items]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following tables set forth the changes in accumulated other comprehensive income (loss) by component as of December 31, 2014, 2013 and 2012 (in thousands):


		Net unrealized loss on derivative instruments(1)			SL Green’s share of joint venture net unrealized loss on derivative instruments(2)			Unrealized gain and (loss) on marketable securities			Total
	Balance at December 31, 2011	$	(17,510	)	$	(17,401	)	$	6,466		$	(28,445	)

	Other comprehensive loss before reclassifications	(1,124		)	(9,098		)	(4,879		)	(15,101		)
	Amounts reclassified from accumulated other comprehensive income	1,800			10,436			1,723			13,959

	Balance at December 31, 2012	(16,834		)	(16,063		)	3,310			(29,587		)

	Other comprehensive (loss) income before reclassifications	(168		)	6,267			1,474			7,573

	Amounts reclassified from accumulated other comprehensive income	1,877			4,926			—			6,803

	Balance at December 31, 2013	(15,125		)	(4,870		)	4,784			(15,211		)

	Other comprehensive (loss) income before reclassifications	(576		)	2,847			(2,692		)	(421		)

	Amounts reclassified from accumulated other comprehensive income	6,203			1,928			521			8,652

	Balance at December 31, 2014	$	(9,498	)	$	(95	)	$	2,613		$	(6,980	)

	____________________________________________________________________

	-1	Amount reclassified from accumulated other comprehensive income (loss) is included in interest expense in the respective consolidated statements of income. As of December 31, 2014, 2013 and 2012, the deferred net losses from these terminated hedges, which is included in accumulated other comprehensive loss relating to net unrealized loss on derivative instrument, was $11.8 million , $13.8 million and $15.0 million, respectively.

	-2	Amount reclassified from accumulated other comprehensive income (loss) is included in equity in net income from unconsolidated joint ventures in the respective consolidated statements of income.

Accumulated_Other_Comprehensiv3

Accumulated Other Comprehensive Loss of the Operating Partnership (Tables) (SL Green Operating Partnership)	12 Months Ended
	Dec. 31, 2014
SL Green Operating Partnership
Accumulated Other Comprehensive Income (Loss) [Line Items]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following tables set forth the changes in accumulated other comprehensive income (loss) by component as of December 31, 2014, 2013 and 2012 (in thousands):


		Net unrealized loss on derivative instruments(1)			SLGOP’s share of joint venture net unrealized loss on derivative instruments(2)			Unrealized gain and (loss) on marketable securities			Total
	Balance at December 31, 2011	$	(18,391	)	$	(17,814	)	$	7,086		$	(29,119	)

	Other comprehensive loss before reclassifications	(912		)	(9,637		)	(5,442		)	(15,991		)
	Amounts reclassified from accumulated other comprehensive income (loss)	1,865			10,811			1,785			$	14,461

	Balance at December 31, 2012	(17,438		)	(16,640		)	3,429			(30,649		)

	Other comprehensive (loss) income before reclassifications	(68		)	6,553			1,497			7,982

	Amounts reclassified from accumulated other comprehensive income	1,933			5,072			—			7,005

	Balance at December 31, 2013	(15,573		)	(5,015		)	4,926			(15,662		)

	Other comprehensive (loss) income before reclassifications	(703		)	2,916			(2,777		)	(564		)

	Amounts reclassified from accumulated other comprehensive income	6,431			1,999			540			8,970

	Balance at December 31, 2014	$	(9,845	)	$	(100	)	$	2,689		$	(7,256	)

	____________________________________________________________________

	-1	Amount reclassified from accumulated other comprehensive income (loss) is included in interest expense in the respective consolidated statements of income. As of December 31, 2014, 2013 and 2012, the deferred net losses from these terminated hedges, which is included in accumulated other comprehensive loss relating to net unrealized loss on derivative instrument, was $12.2 million, $14.2 million and $15.5 million, respectively.

	-2	Amount reclassified from accumulated other comprehensive income (loss) is included in equity in net income from unconsolidated joint ventures in the respective consolidated statements of income.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements, Recurring and Nonrecurring	The following tables set forth the assets and liabilities that we measure at fair value on a recurring and non-recurring basis by their levels in the fair value hierarchy at December 31, 2014 and 2013 (in thousands):


		December 31, 2014
		Total		Level 1		Level 2		Level 3
	Assets:
	Marketable securities	$	39,429	$	4,332	$	35,097	$	—

	Interest rate swap agreements (included in other assets)	$	2,174	$	—	$	2,174	$	—

	Liabilities:
	Interest rate swap agreements (included in accrued interest payable and other liabilities)	$	14,728	$	—	$	14,728	$	—



		December 31, 2013
		Total		Level 1		Level 2		Level 3
	Assets:
	Marketable securities	$	32,049	$	4,307	$	24,419	$	3,323

	Liabilities:
	Interest rate swap agreements (included in accrued interest payable and other liabilities)	$	1,329	—		$	1,329	—

Fair Value, by Balance Sheet Grouping	The following table provides the carrying value and fair value of these financial instruments as of December 31, 2014 and 2013 (in thousands):


		December 31, 2014				December 31, 2013
		Carrying Value		Fair Value		Carrying Value		Fair Value

	Debt and preferred equity investments	$	1,408,804	-1		$	1,304,839	-1



	Fixed rate debt	$	6,140,786	$	6,565,236	$	5,599,960	$	5,886,980

	Variable rate debt	2,291,943		2,315,952		1,319,948		1,327,422

		$	8,432,729	$	8,881,188	$	6,919,908	$	7,214,402

	____________________________________________________________________

	-1	At December 31, 2014, debt and preferred equity investments had an estimated fair value ranging between $1.5 billion and $1.8 billion. At December 31, 2013, debt and preferred equity investments had an estimated fair value ranging between $1.3 billion and $1.4 billion.

Financial_Instruments_Derivati1

Financial Instruments: Derivatives and Hedging (Tables)	12 Months Ended
Financial Instruments: Derivatives and Hedging (Tables)	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of notional and fair value of derivative financial instruments and foreign currency hedges	The following table summarizes the notional and fair value of our consolidated derivative financial instruments at December 31, 2014 based on Level 2 information. The notional value is an indication of the extent of our involvement in these instruments at that time, but does not represent exposure to credit, interest rate or market risks (amounts in thousands).


		Notional				Strike			Effective	Expiration		Balance Sheet Location	Fair
		Value				Rate			Date	Date		Balance Sheet Location	Value
	Interest Rate Cap - Sold	$	504,000			4.75	%		May-14	May-16		Other Assets	$	4
	Interest Rate Cap - Sold	$	504,000			4.75	%		May-14	May-16		Other Assets	$	4
	Interest Rate Cap	504,000				4.75	%		May-14	May-16		Other Liabilities	(4		)
	Interest Rate Cap	504,000				4.75	%		May-14	May-16		Other Liabilities	(4		)
	Interest Rate Cap	500,000				4.75	%		Oct-14	May-16		Other Assets	4
	Interest Rate Cap	500,000				4.75	%		Oct-14	May-16		Other Assets	4
	Interest Rate Cap - Sold	500,000				4.75	%		Nov-14	May-16		Other Liabilities	(4		)
	Interest Rate Cap - Sold	500,000				4.75	%		Nov-14	May-16		Other Liabilities	(4		)
	Interest Rate Cap	446,000				4.75	%		Oct-14	May-16		Other Assets	3
	Interest Rate Cap	446,000				4.75	%		Oct-14	May-16		Other Assets	3
	Interest Rate Cap	263,426				6	%		Nov-13	Nov-15		Other Assets	—
	Interest Rate Cap	263,426				6	%		Nov-13	Nov-15		Other Assets	—
	Interest Rate Cap	137,500				4	%		Oct-13	Sep-15		Other Assets	—
	Interest Rate Cap	137,500				4	%		Oct-13	Sep-15		Other Assets	—
	Interest Rate Swap	200,000				0.938	%		Oct-14	Dec-17		Other Assets	871
	Interest Rate Swap	200,000				0.938	%		Oct-14	Dec-17		Other Assets	871
	Interest Rate Swap	150,000				0.94	%		Oct-14	Dec-17		Other Assets	647
	Interest Rate Swap	150,000				0.94	%		Oct-14	Dec-17		Other Assets	647
	Interest Rate Swap	150,000				0.94	%		Oct-14	Dec-17		Other Assets	645
	Interest Rate Swap	150,000				0.94	%		Oct-14	Dec-17		Other Assets	645
	Interest Rate Swap	144,000				2.236	%		Dec-12	Dec-17		Other Liabilities	(4,757		)
	Interest Rate Swap	144,000				2.236	%		Dec-12	Dec-17		Other Liabilities	(4,757		)
	Interest Rate Swap	86,400				1.948	%		Dec-12	Dec-17		Other Liabilities	(2,124		)
	Interest Rate Swap	86,400				1.948	%		Dec-12	Dec-17		Other Liabilities	(2,124		)
	Interest Rate Swap	72,000				2.31	%		Dec-12	Dec-17		Other Liabilities	(2,533		)
	Interest Rate Swap	72,000				2.31	%		Dec-12	Dec-17		Other Liabilities	(2,533		)
	Interest Rate Swap	72,000				1.345	%		Dec-12	Dec-17		Other Liabilities	(506		)
	Interest Rate Swap	72,000				1.345	%		Dec-12	Dec-17		Other Liabilities	(506		)
	Interest Rate Swap	72,000				2.31	%		Dec-12	Dec-17		Other Liabilities	(2,534		)
	Interest Rate Swap	72,000				2.31	%		Dec-12	Dec-17		Other Liabilities	(2,534		)
	Interest Rate Swap	57,600				1.99	%		Dec-12	Dec-17		Other Liabilities	(1,487		)
	Interest Rate Swap	57,600				1.99	%		Dec-12	Dec-17		Other Liabilities	(1,487		)
	Interest Rate Swap	30,000				2.295	%		Jul-10	Jun-16		Other Liabilities	(774		)
	Interest Rate Swap	30,000				2.295	%		Jul-10	Jun-16		Other Liabilities	(774		)
	Interest Rate Swap	8,500				0.74	%		Feb-12	Feb-15		Other Liabilities	(5		)
	Interest Rate Swap	8,500				0.74	%		Feb-12	Feb-15		Other Liabilities	(5		)
													$	(12,554	)
Schedule of effect of derivative financial instruments on consolidated statements of income	The following table presents the effect of our derivative financial instruments and our share of our joint ventures' derivative financial instruments that are designated and qualify as hedging instruments on the consolidated statements of income for the years ended December 31, 2014, 2013 and 2012, respectively (in thousands):


			Amount of (Loss) or Gain										Location of Gain or (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income		Amount of Loss						Location of Gain Recognized in Income on Derivative	Amount of Gain
			Recognized in												Reclassified from							Recognized into Income
			Other Comprehensive												Accumulated Other							(Ineffective Portion)
			Loss												Comprehensive Loss into Income
			(Effective Portion)												(Effective Portion)
			Year Ended												Year Ended							Year Ended
			December 31,												December 31,							December 31,
	Derivative		2014				2013			2012					2014		2013		2012			2014		2013		2012
	Interest Rate Swaps/Caps		$	(703	)		$	(68	)	$	(912	)	Interest expense		$	6,431	$	1,933	$	1,865	Interest expense	$	4	$	3	$	3
	Interest Rate Swaps/Caps		$	(703	)		$	(68	)	$	(912	)	Interest expense		$	6,431	$	1,933	$	1,865	Interest expense	$	4	$	3	$	3
	Share of unconsolidated joint ventures' derivative instruments		2,916				6,553			(9,637		)	Equity in net income from unconsolidated joint ventures		1,999		5,072		10,811		Equity in net income from unconsolidated joint ventures	—		—		—
			2,916				6,553			(9,637		)	Equity in net income from unconsolidated joint ventures		1,999		5,072		10,811		Equity in net income from unconsolidated joint ventures	—		—		—
			$	2,213			$	6,485		$	(10,549	)			$	8,430	$	7,005	$	12,676		$	4	$	3	$	3
			$	2,213			$	6,485		$	(10,549	)			$	8,430	$	7,005	$	12,676		$	4	$	3	$	3

Rental_Income_Tables

Rental Income (Tables)	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Schedule of approximate future minimum rents to be received over the next five years and thereafter	Approximate future minimum rents to be received over the next five years and thereafter for non-cancelable operating leases in effect at December 31, 2014 for the consolidated properties, including consolidated joint venture properties, and our share of unconsolidated joint venture properties are as follows (in thousands):


		Consolidated		Unconsolidated
		Properties		Properties
	2015	$	975,025	$	157,438

	2016	964,428		157,514

	2017	941,014		152,226

	2018	879,727		146,605

	2019	799,744		134,451

	Thereafter	5,774,406		699,568

		$	10,334,344	$	1,447,802

Benefit_Plans_Tables

Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Schedule of contributions made to multi-employer plans	Contributions we made to the multi-employer plans for the years ended December 31, 2014, 2013 and 2012 are included in the table below (in thousands):


	Benefit Plan	2014		2013		2012
	Pension Plan	$	2,807	$	2,765	$	2,506

	Health Plan	8,470		8,522		8,020

	Other plans	5,838		6,006		6,025

	Total plan contributions	$	17,115	$	17,293	$	16,551

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Schedule of future minimum lease payments under capital leases and non cancellable operating leases	The following is a schedule of future minimum lease payments under capital leases and noncancellable operating leases with initial terms in excess of one year as of December 31, 2014 (in thousands):


		Capital lease			Non-cancellable
					operating leases
	2015	$	145		$	30,491

	2016	170			30,612

	2017	291			30,845

	2018	291			30,845

	2019	315			30,862

	Thereafter	56,569			720,698

	Total minimum lease payments	57,781			$	874,353

	Less amount representing interest	(36,959		)
	Capital lease obligations	$	20,822

Segment_Information_Tables

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Schedule of selected results of operations and selected asset information	Selected results of operations for the years ended December 31, 2014, 2013 and 2012, and selected asset information as of December 31, 2014 and 2013, regarding our operating segments are as follows (in thousands):


		Real			Debt and Preferred			Total
		Estate			Equity			Company
		Segment			Segment
	Total revenues
	Years ended:
	31-Dec-14	$	1,341,163		$	178,815		$	1,519,978

	31-Dec-13	1,177,222			193,843			1,371,065

	31-Dec-12	1,170,897			119,155			1,290,052

	Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate and purchase price fair value adjustment
	Years ended:
	31-Dec-14	$	22,178		$	150,852		$	173,030

	31-Dec-13	(49,793		)	159,193			109,400

	31-Dec-12	41,366			92,414			133,780

	Total assets
	As of:
	31-Dec-14	$	15,671,662		$	1,424,925		$	17,096,587

	31-Dec-13	13,641,727			1,317,274			14,959,001

Schedule of reconciliation of income from continuing operations to net income attributable to SL Green common stockholders	The table below reconciles income from continuing operations to net income for the years ended December 31, 2014, 2013 and 2012 (in thousands):


		Year ended December 31,
		2014			2013			2012
	Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate and purchase price fair value adjustment	$	173,030		$	109,400		$	133,780

	Equity in net gain on sale of interest in unconsolidated joint venture/real estate	123,253			3,601			37,053

	Purchase price fair value adjustment	67,446			(2,305		)	—

	Income from continuing operations	363,729			110,696			170,833

	Net income from discontinued operations	19,075			25,687			32,240

	Gain on sale of discontinued operations	163,059			14,900			6,627

	Net income	$	545,863		$	151,283		$	209,700

Quarterly_Financial_Data_unaud1

Quarterly Financial Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2014
SL Green Realty Corp
Condensed Income Statements, Captions [Line Items]
Schedule of Quarterly Financial Information	Summarized quarterly financial data for the years ended December 31, 2014 and 2013, which is reflective of the reclassification of the properties sold or held for sale during 2014 and 2013 as discontinued operations (see Note 4, "Properties Held for Sale and Dispositions"), was as follows (in thousands, except for per share amounts):


	2014 Quarter Ended	December 31			September 30			June 30			March 31
	Total revenues	$	386,627		$	390,274		$	380,631		$	362,446

	Income from continuing before equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, (loss) gain on early extinguishment of debt, loss on sale of investment in marketable securities, net of noncontrolling interests	$	40,379		$	46,863		$	47,035		$	39,416

	Equity in net gain on sale of interest in unconsolidated joint venture/real estate	673			16,496			1,444			104,640

	Purchase price fair value adjustment	—			(4,000		)	71,446			—

	(Loss) gain on early extinguishment of debt	(6,865		)	(24,475		)	(1,028		)	3

	Loss on sale of investment in marketable securities	3,895			—			—			—

	Net income from discontinued operations	3,626			4,035			5,645			5,769

	Gain on sale of discontinued operations	18,817			29,507			114,735			—

	Net income attributable to SL Green	60,525			68,426			239,277			149,828

	Preferred stock redemption costs	—			—			—			—

	Perpetual preferred stock dividends	(3,738		)	(3,738		)	(3,738		)	(3,738		)
	Net income attributable to SL Green common stockholders	$	56,787		$	64,688		$	235,539		$	146,090

	Net income attributable to common stockholders per common share—basic	$	0.59		$	0.68		$	2.47		$	1.54

	Net income attributable to common stockholders per common share—diluted	$	0.59		$	0.68		$	2.46		$	1.53



	2013 Quarter Ended	December 31			September 30			June 30			March 31
	Total revenues	$	350,451		$	338,782		$	340,888		$	340,944

	Income from continuing before equity in net gain (loss) on sale of interest in unconsolidated joint venture/real estate, gain (loss) on early extinguishment of debt, gain on sale of investment in marketable securities, net of noncontrolling interests	$	27,478		$	19,895		$	27,398		$	37,300

	Equity in net gain (loss) on sale of interest in unconsolidated joint venture/ real estate	7,538			(354		)	(3,583		)	—

	Purchase price fair value adjustment	—			—			(2,305		)	—

	Gain (loss) on early extinguishment of debt	5			—			(10		)	(18,513		)

	Gain on sale of investment in marketable securities	—			—			(8		)	(57		)

	Net income from discontinued operations	5,836			7,435			5,943			6,473

	Gain on sale of discontinued operations	—			13,787			—			1,113

	Net income attributable to SL Green	40,857			40,763			27,435			26,316

	Preferred stock redemption costs	—			—			(12,160		)	—

	Perpetual preferred stock dividends	(3,737		)	(3,738		)	(6,999		)	(7,407		)
	Net income attributable to SL Green common stockholders	$	37,120		$	37,025		$	8,276		$	18,909

	Net income attributable to common stockholders per common share—basic	$	0.39		$	0.4		$	0.09		$	0.21

	Net income attributable to common stockholders per common share—diluted	$	0.39		$	0.4		$	0.09		$	0.21

SL Green Operating Partnership
Condensed Income Statements, Captions [Line Items]
Schedule of Quarterly Financial Information	Summarized quarterly financial data for the years ended December 31, 2014 and 2013, which is reflective of the reclassification of the properties sold or held for sale during 2014 and 2013 as discontinued operations (see Note 4, "Properties Held for Sale and Dispositions"), was as follows (in thousands, except for per share amounts):


	2014 Quarter Ended	December 31			September 30			June 30			March 31
	Total revenues	$	386,627		$	390,274		$	380,631		$	362,446

	Income from continuing before equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, (loss) gain on early extinguishment of debt, loss on sale of investment in marketable securities, net of noncontrolling interests	$	42,837		$	49,499		$	55,680		$	44,144

	Equity in net gain on sale of interest in unconsolidated joint venture/real estate	673			16,496			1,444			104,640

	Purchase price fair value adjustment	—			(4,000		)	71,446			—

	(Loss) gain on early extinguishment of debt	(6,865		)	(24,475		)	(1,028		)	3

	Loss on sale of investment in marketable securities	3,895			—			—			—

	Net income from discontinued operations	3,626			4,035			5,645			5,769

	Gain on sale of discontinued operations	18,817			29,507			114,735			—

	Net income attributable to SLGOP	62,983			71,062			247,922			154,556

	Preferred unit redemption costs	—			—			—			—

	Perpetual preferred units distributions	(3,738		)	(3,738		)	(3,738		)	(3,738		)
	Net income attributable to SLGOP common unitholders	$	59,245		$	67,324		$	244,184		$	150,818

	Net income attributable to common unitholders per common unit—basic	$	0.59		$	0.68		$	2.47		$	1.54

	Net income attributable to common unitholders per common unit—diluted	$	0.59		$	0.68		$	2.46		$	1.53



	2013 Quarter Ended	December 31			September 30			June 30			March 31
	Total revenues	$	350,451		$	338,782		$	340,888		$	340,944

	Income from continuing before equity in net gain (loss) on sale of interest in unconsolidated joint venture/real estate, gain (loss) on early extinguishment of debt, gain on sale of investment in marketable securities, net of noncontrolling interests	$	28,592		$	21,005		$	27,642		$	37,855

	Equity in net gain (loss) on sale of interest in unconsolidated joint venture/ real estate	7,538			(354		)	(3,583		)	—

	Purchase price fair value adjustment	—			—			(2,305		)	—

	Gain (loss) on early extinguishment of debt	5			—			(10		)	(18,513		)

	Gain on sale of investment in marketable securities	—			—			(8		)	(57		)

	Net income from discontinued operations	5,836			7,435			5,943			6,473

	Gain on sale of discontinued operations	—			13,787			—			1,113

	Net income attributable to SLGOP	41,971			41,873			27,679			26,871

	Preferred unit redemption costs	—			—			(12,160		)	—

	Perpetual preferred distributions	(3,737		)	(3,738		)	(6,999		)	(7,407		)
	Net income attributable to SLGOP common unitholders	$	38,234		$	38,135		$	8,520		$	19,464

	Net income attributable to common unitholders per common unit—basic	$	0.39		$	0.4		$	0.09		$	0.21

	Net income attributable to common unitholders per common unit—diluted	$	0.39		$	0.4		$	0.09		$	0.21

Organization_and_Basis_of_Pres2

Organization and Basis of Presentation (Details) (SL Green Operating Partnership)	0 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Organization
Percentage of ownership in SL Green Management LLC owned by operating partnership (percent)	100.00%
Noncontrolling interest in the operating partnership (as a percent)	3.92%	3.92%	2.96%
Service Corporation
Organization
Economic interest in variable interest entity (as a percent)	95.00%

Organization_and_Basis_of_Pres3

Organization and Basis of Presentation (Details 2) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
	sqft
	building
Real estate properties
Number of properties (buildings)	101
Approximate Square Feet (sqft)	33,891,036
Weighted Average Occupancy (as a percent)	85.80%	[1]
Carrying Value, Net of Discounts and Deferred Origination Fees	$1,408,804		$1,304,839
Number of shares to be received on redemption of one unit of limited partnership interests (shares)	1
Residential
Real estate properties
Number of properties (buildings)	4
Approximate Square Feet (sqft)	802,198
Weighted Average Occupancy (as a percent)	95.20%	[1]
Managed office properties
Real estate properties
Approximate Square Feet (sqft)	336,201
Commercial properties
Real estate properties
Number of properties (buildings)	97
Approximate Square Feet (sqft)	33,088,838
Weighted Average Occupancy (as a percent)	85.50%	[1]
Consolidated properties
Real estate properties
Number of properties (buildings)	76
Approximate Square Feet (sqft)	26,894,770
Consolidated properties \| Residential
Real estate properties
Number of properties (buildings)	4
Approximate Square Feet (sqft)	802,198
Consolidated properties \| Commercial properties
Real estate properties
Number of properties (buildings)	72
Approximate Square Feet (sqft)	26,092,572
Unconsolidated properties
Real estate properties
Number of properties (buildings)	25
Approximate Square Feet (sqft)	6,996,266
Unconsolidated properties \| Residential
Real estate properties
Number of properties (buildings)	0
Approximate Square Feet (sqft)	0
Unconsolidated properties \| Commercial properties
Real estate properties
Number of properties (buildings)	25
Approximate Square Feet (sqft)	6,996,266
Manhattan
Real estate properties
Number of properties (buildings)	62
Approximate Square Feet (sqft)	27,298,697
Weighted Average Occupancy (as a percent)	86.30%	[1]
Manhattan \| Office
Real estate properties
Number of properties (buildings)	30
Approximate Square Feet (sqft)	21,905,160
Weighted Average Occupancy (as a percent)	95.30%	[1]
Manhattan \| Retail
Real estate properties
Number of properties (buildings)	16
Approximate Square Feet (sqft)	683,363
Weighted Average Occupancy (as a percent)	91.00%	[1]
Manhattan \| Development/Redevelopment
Real estate properties
Number of properties (buildings)	14
Approximate Square Feet (sqft)	3,926,644
Weighted Average Occupancy (as a percent)	32.60%	[1]
Manhattan \| Fee interest
Real estate properties
Number of properties (buildings)	2
Approximate Square Feet (sqft)	783,530
Weighted Average Occupancy (as a percent)	100.00%	[1]
Manhattan \| Residential
Real estate properties
Number of properties (buildings)	3
Approximate Square Feet (sqft)	735,587
Weighted Average Occupancy (as a percent)	95.60%	[1]
Manhattan \| Consolidated properties
Real estate properties
Number of properties (buildings)	43
Approximate Square Feet (sqft)	21,590,172
Manhattan \| Consolidated properties \| Office
Real estate properties
Number of properties (buildings)	23
Approximate Square Feet (sqft)	18,429,045
Manhattan \| Consolidated properties \| Retail
Real estate properties
Number of properties (buildings)	9	[2]
Approximate Square Feet (sqft)	403,735
Manhattan \| Consolidated properties \| Development/Redevelopment
Real estate properties
Number of properties (buildings)	9	[3]
Approximate Square Feet (sqft)	1,973,862
Manhattan \| Consolidated properties \| Fee interest
Real estate properties
Number of properties (buildings)	2
Approximate Square Feet (sqft)	783,530
Manhattan \| Consolidated properties \| Residential
Real estate properties
Number of properties (buildings)	3	[2]
Approximate Square Feet (sqft)	735,587
Manhattan \| Consolidated properties \| Dual property type, retail portion
Real estate properties
Approximate Square Feet (sqft)	270,132
Manhattan \| Consolidated properties \| Dual property type, residential portion
Real estate properties
Approximate Square Feet (sqft)	222,855
Manhattan \| Unconsolidated properties
Real estate properties
Number of properties (buildings)	19
Approximate Square Feet (sqft)	5,708,525
Manhattan \| Unconsolidated properties \| Office
Real estate properties
Number of properties (buildings)	7
Approximate Square Feet (sqft)	3,476,115
Manhattan \| Unconsolidated properties \| Retail
Real estate properties
Number of properties (buildings)	7
Approximate Square Feet (sqft)	279,628
Manhattan \| Unconsolidated properties \| Development/Redevelopment
Real estate properties
Number of properties (buildings)	5
Approximate Square Feet (sqft)	1,952,782
Manhattan \| Unconsolidated properties \| Fee interest
Real estate properties
Number of properties (buildings)	0
Approximate Square Feet (sqft)	0
Manhattan \| Unconsolidated properties \| Residential
Real estate properties
Number of properties (buildings)	0
Approximate Square Feet (sqft)	0
Suburban
Real estate properties
Number of properties (buildings)	35
Approximate Square Feet (sqft)	5,790,141
Weighted Average Occupancy (as a percent)	81.80%	[1]
Suburban \| Office
Real estate properties
Number of properties (buildings)	31
Approximate Square Feet (sqft)	5,587,500
Weighted Average Occupancy (as a percent)	82.40%	[1]
Suburban \| Retail
Real estate properties
Number of properties (buildings)	1
Approximate Square Feet (sqft)	52,000
Weighted Average Occupancy (as a percent)	100.00%	[1]
Suburban \| Development/Redevelopment
Real estate properties
Number of properties (buildings)	3
Approximate Square Feet (sqft)	150,641
Weighted Average Occupancy (as a percent)	54.20%	[1]
Suburban \| Residential
Real estate properties
Number of properties (buildings)	1
Approximate Square Feet (sqft)	66,611
Weighted Average Occupancy (as a percent)	89.60%	[1]
Suburban \| Consolidated properties
Real estate properties
Number of properties (buildings)	29
Approximate Square Feet (sqft)	4,502,400
Suburban \| Consolidated properties \| Office
Real estate properties
Number of properties (buildings)	27
Approximate Square Feet (sqft)	4,365,400
Suburban \| Consolidated properties \| Retail
Real estate properties
Number of properties (buildings)	1
Approximate Square Feet (sqft)	52,000
Suburban \| Consolidated properties \| Development/Redevelopment
Real estate properties
Number of properties (buildings)	1
Approximate Square Feet (sqft)	85,000
Suburban \| Consolidated properties \| Residential
Real estate properties
Number of properties (buildings)	1
Approximate Square Feet (sqft)	66,611
Suburban \| Unconsolidated properties
Real estate properties
Number of properties (buildings)	6
Approximate Square Feet (sqft)	1,287,741
Suburban \| Unconsolidated properties \| Office
Real estate properties
Number of properties (buildings)	4
Approximate Square Feet (sqft)	1,222,100
Suburban \| Unconsolidated properties \| Retail
Real estate properties
Number of properties (buildings)	0
Approximate Square Feet (sqft)	0
Suburban \| Unconsolidated properties \| Development/Redevelopment
Real estate properties
Number of properties (buildings)	2
Approximate Square Feet (sqft)	65,641
Suburban \| Unconsolidated properties \| Residential
Real estate properties
Number of properties (buildings)	0
Approximate Square Feet (sqft)	0

[1]	The weighted average occupancy for commercial properties represents the total occupied square feet divided by total available rentable square feet. The weighted average occupancy for residential properties represents the total occupied units divided by total available units.
[2]	As of DecemberB 31, 2014, we owned a building that was comprised of approximately 270,132 square feet (unaudited) of retail space and approximately 222,855 square feet (unaudited) of residential space. For the purpose of this report, we have included the building as part of retail properties and have shown the square footage under its respective classifications.
[3]	Includes one property which was held for sale as of DecemberB 31, 2014 and sold in January 2015.

Significant_Accounting_Policie3

Significant Accounting Policies (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Principles of Consolidation
Commercial real estate properties	$12,163,976	$10,687,540
Mortgages and other loans payable	5,586,709	4,860,578
Assets held for sale	462,430	0
Liabilities related to assets held for sale	266,873	0
Consolidated VIEs
Principles of Consolidation
Commercial real estate properties	198,400	605,900
Mortgages and other loans payable	106,500	370,900
Consolidated VIEs \| Commercial properties
Principles of Consolidation
Assets held for sale	445,000
Liabilities related to assets held for sale	$253,900

Significant_Accounting_Policie4

Significant Accounting Policies (Details 2) (USD $)	12 Months Ended			1 Months Ended
Significant Accounting Policies (Details 2) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2013	Apr. 30, 2013	31-May-14
Investment in Commercial Real Estate Properties
Depreciation expense (including amortization of the capital lease asset)	$338,800,000	$296,500,000	$287,500,000
Period from cessation of major construction to consider construction project as complete and available for occupancy, maximum	1 year
Weighted average amortization period for above-market leases	7 years 11 days
Weighted average amortization period for below-market leases	5 years 7 months 13 days
Weighted average amortization period for in-place lease costs	5 years 11 months 16 days
Increase in rental revenue from amortization of acquired leases	23,300,000	18,800,000	16,500,000
Write-off of above and in place market leases		6,800,000
Increase in rental revenue		25,600,000
Reduction in interest expense from amortization of above-market rate mortgages	-5,000,000	-5,000,000	-1,400,000
Identified intangible assets (included in other assets):
Gross amount	664,297,000	746,704,000
Accumulated amortization	-383,236,000	-343,339,000
Net	281,061,000	403,365,000
Identified intangible liabilities (included in deferred revenue):
Gross amount	655,755,000	671,380,000
Accumulated amortization	-483,948,000	-429,138,000
Net	171,807,000	242,242,000
Above-market leases \| Minimum
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets	1 year
Above-market leases \| Maximum
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets	14 years
In-place leases \| Minimum
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets	1 year
In-place leases \| Maximum
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets	14 years
Acquired below-market leases, net of acquired above-market leases
Estimated annual amortization
2015	1,978,000
2016	-592,000
2017	-1,303,000
2018	-3,135,000
2019	-3,994,000
All other identifiable assets
Estimated annual amortization
2015	9,150,000
2016	5,919,000
2017	4,442,000
2018	3,005,000
2019	2,467,000
300 Main Street
Investment in Commercial Real Estate Properties
Impairment charges recorded				2,200,000
16 Court Street
Investment in Commercial Real Estate Properties
Purchase price fair value adjustment					-2,300,000
Buildings (fee ownership)
Investment in Commercial Real Estate Properties
Estimated useful life	40 years
Building (leasehold interest) \| Maximum
Investment in Commercial Real Estate Properties
Estimated useful life	40 years
Furniture and fixtures \| Minimum
Investment in Commercial Real Estate Properties
Estimated useful life	4 years
Furniture and fixtures \| Maximum
Investment in Commercial Real Estate Properties
Estimated useful life	7 years
Building \| Minimum
Investment in Commercial Real Estate Properties
Estimated useful life	3 years
Building \| Maximum
Investment in Commercial Real Estate Properties
Estimated useful life	40 years
388-390 Greenwich Street
Investment in Commercial Real Estate Properties
Purchase price fair value adjustment recognized						$71,400,000

Significant_Accounting_Policie5

Significant Accounting Policies (Details 3) (USD $)	12 Months Ended
Significant Accounting Policies (Details 3) (USD $)	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2013
Investment in Marketable Securities
Marketable securities	$39,429,000		$32,049,000
Net proceeds on sale of marketable securities	4,400,000	6,800,000
Realized gain (loss) on investment in marketable securities	3,900,000	4,900,000
Commercial mortgage-backed securities
Investment in Marketable Securities
Cost basis	32,400,000		23,000,000
Rake bonds
Investment in Marketable Securities
Cost basis			3,600,000
Level 1
Investment in Marketable Securities
Marketable securities	4,332,000		4,307,000
Level 1 \| Equity marketable securities
Investment in Marketable Securities
Marketable securities	4,332,000		4,307,000
Level 2
Investment in Marketable Securities
Marketable securities	35,097,000		24,419,000
Level 2 \| Commercial mortgage-backed securities
Investment in Marketable Securities
Marketable securities	35,097,000		24,419,000
Level 3
Investment in Marketable Securities
Marketable securities	0		3,323,000
Level 3 \| Rake bonds
Investment in Marketable Securities
Marketable securities	0		3,323,000
Fair Value
Investment in Marketable Securities
Marketable securities	$39,429,000		$32,049,000

Significant_Accounting_Policie6

Significant Accounting Policies (Details 4) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Deferred Lease Costs
Portion of compensation capitalized	$15.10	$12.40	$11
Estimated average lease term	7 years
Joint venture
Investment in Unconsolidated Joint Ventures
Recourse debt	$18.40
Number of joint ventures with debt recourse (joint ventures)	1

Significant_Accounting_Policie7

Significant Accounting Policies (Details 5) (USD $)	12 Months Ended
Significant Accounting Policies (Details 5) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reserve for Possible Credit Losses
Days past due for income recognition on debt and preferred equity investments to be suspended	90 days
Loan loss reserves and charge offs	$0	$0	$564,000
Recoveries recorded	0	0	2,436,000
Income taxes
Federal, state and local tax provision	7,800,000	4,400,000	0
Debt and Preferred Equity Investments Held to Maturity
Reserve for Possible Credit Losses
Loan loss reserves and charge offs			$3,000,000

Significant_Accounting_Policie8

Significant Accounting Policies (Details 6)	12 Months Ended
Significant Accounting Policies (Details 6)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Workforce concentration
Concentration of Credit Risk
Number of collective bargaining agreements (agreement)	6
Annualized rent \| Customer concentration
Concentration of Credit Risk
Number of tenants (tenants)	3
Maximum percentage of annualized rent for any one tenant not individually disclosed (percent)	2.00%
Annualized rent \| 1515 Broadway \| Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	9.90%	10.60%	10.20%
Annualized rent \| 388 and 390 Greenwich Street \| Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	9.80%
Annualized rent \| 919 Third Avenue \| Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	7.50%	7.80%	8.00%
Annualized rent \| 1185 Avenue of the Americas \| Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	7.80%	7.70%	7.10%
Annualized rent \| One Madison Avenue \| Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)		6.40%	6.20%
Annualized rent \| Tenant 1 \| Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	10.90%
Annualized rent \| Tenant 2 \| Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	7.20%
Annualized rent \| Tenant 3 \| Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	5.60%
Collective bargaining arrangements \| Workforce concentration
Concentration of Credit Risk
Percentage of concentration (percent)	73.40%
Collective bargaining arrangements which expires in 2015 \| Workforce concentration
Concentration of Credit Risk
Percentage of concentration (percent)	77.60%

Property_Acquisitions_Details

Property Acquisitions (Details) (USD $)

1 Months Ended

12 Months Ended

1 Months Ended

Oct. 31, 2014

Sep. 30, 2014

Aug. 31, 2014

Jul. 31, 2014

31-May-14

Dec. 31, 2014

Dec. 31, 2013

Nov. 30, 2013

Apr. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Jan. 31, 2012

Recognized Identifiable Assets Acquired and Liabilities Assumed

Approximate Square Feet (sqft)

33,891,036

Fixed rate debt

$4,736,709,000

$4,130,629,000

Series J Preferred Units

Recognized Identifiable Assets Acquired and Liabilities Assumed

Fixed rate debt

4,000,000

[1]

102 Greene Street

Recognized Identifiable Assets Acquired and Liabilities Assumed

Land

11,288,000

[2]

Building and building leasehold

20,962,000

[2]

Above market lease value

[2]

Acquired in-place leases

[2]

Other assets, net of other liabilities

[2]

Assets acquired

32,250,000

[2]

Mark-to-market assumed debt

[2]

Below market lease value

[2]

Derivatives

[2]

Liabilities assumed

[2]

Purchase price allocation

32,250,000

[2]

Net consideration funded by us at closing, excluding consideration financed by debt

32,250,000

[2]

Equity and/or debt investment held

[2]

Debt assumed

[2]

635 Madison Avenue

Recognized Identifiable Assets Acquired and Liabilities Assumed

Land

153,745,000

[2],[3]

Building and building leasehold

[2],[3]

Above market lease value

[2],[3]

Acquired in-place leases

[2],[3]

Other assets, net of other liabilities

[2],[3]

Assets acquired

153,745,000

[2],[3]

Mark-to-market assumed debt

[2],[3]

Below market lease value

[2],[3]

Derivatives

[2],[3]

Liabilities assumed

[2],[3]

Purchase price allocation

153,745,000

[2],[3]

Net consideration funded by us at closing, excluding consideration financed by debt

153,745,000

[2],[3]

Equity and/or debt investment held

[2],[3]

Debt assumed

[2],[3]

635 Madison Avenue | Series J Preferred Units

Recognized Identifiable Assets Acquired and Liabilities Assumed

Issuance of aggregate liquidation preference of preferred units

4,000,000

752 Madison Avenue

Recognized Identifiable Assets Acquired and Liabilities Assumed

Land

282,415,000

[2],[4]

Building and building leasehold

[2],[4]

Above market lease value

[2],[4]

Acquired in-place leases

[2],[4]

Other assets, net of other liabilities

[2],[4]

Assets acquired

282,415,000

[2],[4]

Mark-to-market assumed debt

[2],[4]

Below market lease value

[2],[4]

Derivatives

[2],[4]

Liabilities assumed

[2],[4]

Purchase price allocation

282,415,000

[2],[4]

Net consideration funded by us at closing, excluding consideration financed by debt

282,415,000

[2],[4]

Equity and/or debt investment held

[2],[4]

Debt assumed

[2],[4]

Ownership interest in consolidated joint venture (as a percent)

80.00%

719 Seventh Avenue

Recognized Identifiable Assets Acquired and Liabilities Assumed

Land

14,402,000

[2],[5]

Building and building leasehold

26,747,000

[2],[5]

Above market lease value

[2],[5]

Acquired in-place leases

[2],[5]

Other assets, net of other liabilities

[2],[5]

Assets acquired

41,149,000

[2],[5]

Mark-to-market assumed debt

[2],[5]

Below market lease value

[2],[5]

Derivatives

[2],[5]

Liabilities assumed

[2],[5]

Purchase price allocation

41,149,000

[2],[5]

Net consideration funded by us at closing, excluding consideration financed by debt

41,149,000

[2],[5]

Equity and/or debt investment held

[2],[5]

Debt assumed

[2],[5]

Ownership interest in consolidated joint venture (as a percent)

75.00%

719 Seventh Avenue | Series L Preferred Units

Recognized Identifiable Assets Acquired and Liabilities Assumed

Issuance of aggregate liquidation preference of preferred units

14,100,000

719 Seventh Avenue | Series K Preferred Units

Recognized Identifiable Assets Acquired and Liabilities Assumed

Issuance of aggregate liquidation preference of preferred units

9,500,000

115 Spring Street

Recognized Identifiable Assets Acquired and Liabilities Assumed

Land

15,938,000

[2]

Building and building leasehold

37,187,000

[2]

Above market lease value

[2]

Acquired in-place leases

[2]

Other assets, net of other liabilities

[2]

Assets acquired

53,125,000

[2]

Mark-to-market assumed debt

[2]

Below market lease value

[2]

Derivatives

[2]

Liabilities assumed

[2]

Purchase price allocation

53,125,000

[2]

Net consideration funded by us at closing, excluding consideration financed by debt

53,125,000

[2]

Equity and/or debt investment held

[2]

Debt assumed

[2]

388-390 Greenwich Street

Recognized Identifiable Assets Acquired and Liabilities Assumed

Land

558,777,000

[2],[6]

Building and building leasehold

1,037,729,000

[2],[6]

Above market lease value

[2],[6]

Acquired in-place leases

[2],[6]

Other assets, net of other liabilities

6,495,000

[2],[6]

Assets acquired

1,603,001,000

[2],[6]

Mark-to-market assumed debt

[2],[6]

Below market lease value

[2],[6]

Derivatives

18,001,000

[2],[6]

Liabilities assumed

18,001,000

[2],[6]

Purchase price allocation

1,585,000,000

[2],[6]

Net consideration funded by us at closing, excluding consideration financed by debt

208,614,000

[2],[6]

Equity and/or debt investment held

148,025,000

[2],[6]

Debt assumed

1,162,379,000

[2],[6]

Economic interest

49.65%

Value of interest

1,585,000,000

Face amount of loan

1,450,000,000

Notional value

504,000,000

Purchase price fair value adjustment recognized

71,400,000

Business Acquisition, Pro Forma Information [Abstract]

Actual revenues since acquisition

1,519,978,000

Actual net income since acquisition

545,863,000

Pro forma revenues

1,562,206,000

1,481,021,000

Pro forma income from continuing operations

298,679,000

[7]

205,437,000

[7]

Pro forma basic earnings per share

$4.60

$2.10

Pro forma diluted earnings per share

$4.58

$2.09

Pro forma basic earnings per unit

4.6

2.1

Pro forma diluted earnings per unit

4.58

2.09

315 West 33rd Street

Recognized Identifiable Assets Acquired and Liabilities Assumed

Land

195,834,000

[8]

Building and building leasehold

164,429,000

[8]

Above market lease value

7,084,000

[8]

Acquired in-place leases

26,125,000

[8]

Other assets, net of other liabilities

1,142,000

[8]

Assets acquired

394,614,000

[8]

Mark-to-market assumed debt

[8]

Below market lease value

7,839,000

[8]

Liabilities assumed

7,839,000

[8]

Purchase price allocation

386,775,000

[8]

Net consideration funded by us at closing, excluding consideration financed by debt

386,775,000

[8]

Equity and/or debt investment held

[8]

Debt assumed

[8]

Assemblage of Retail Development Properties on Fifth Avenue

Recognized Identifiable Assets Acquired and Liabilities Assumed

Land

135,513,000

[8]

Building and building leasehold

10,487,000

[8]

Above market lease value

[8]

Acquired in-place leases

[8]

Other assets, net of other liabilities

[8]

Assets acquired

146,000,000

[8]

Mark-to-market assumed debt

[8]

Below market lease value

[8]

Liabilities assumed

[8]

Purchase price allocation

146,000,000

[8]

Net consideration funded by us at closing, excluding consideration financed by debt

146,000,000

[8]

Equity and/or debt investment held

[8]

Debt assumed

[8]

16 Court Street

Recognized Identifiable Assets Acquired and Liabilities Assumed

Land

19,217,000

[9]

Building and building leasehold

63,210,000

[9]

Above market lease value

5,122,000

[9]

Acquired in-place leases

9,422,000

[9]

Other assets, net of other liabilities

3,380,000

[9]

Assets acquired

100,351,000

[9]

Mark-to-market assumed debt

294,000

[9]

Below market lease value

3,885,000

[9]

Liabilities assumed

4,179,000

[9]

Purchase price allocation

96,172,000

[9]

Net consideration funded by us at closing, excluding consideration financed by debt

4,000,000

[9]

Equity and/or debt investment held

13,835,000

[9]

Debt assumed

84,642,000

[9]

Mortgage encumbering the property

84,600,000

Purchase price fair value adjustment

-2,300,000

248-252 Bedford Avenue

Recognized Identifiable Assets Acquired and Liabilities Assumed

Land

10,865,000

[10]

Building and building leasehold

44,035,000

[10]

Above market lease value

[10]

Acquired in-place leases

[10]

Other assets, net of other liabilities

[10]

Assets acquired

54,900,000

[10]

Mark-to-market assumed debt

[10]

Below market lease value

[10]

Liabilities assumed

[10]

Purchase price allocation

54,900,000

[10]

Net consideration funded by us at closing, excluding consideration financed by debt

21,782,000

[10]

Equity and/or debt investment held

[10]

Debt assumed

[10]

Face amount of loan

22,000,000

Stated interest rate of preferred partnership units issued (as a percent)

90.00%

131-137 Spring Street

Recognized Identifiable Assets Acquired and Liabilities Assumed

Land

27,021,000

Building and building leasehold

105,342,000

Above market lease value

179,000

Acquired in-place leases

7,046,000

Other assets, net of other liabilities

Assets acquired

139,588,000

Fair value adjustment to mortgage note payable

Below market lease value

17,288,000

Liabilities assumed

17,288,000

Purchase price allocation

122,300,000

Net consideration funded by us at closing, excluding consideration financed by debt

122,300,000

Equity and/or debt investment held

Debt assumed

985-987 Third Avenue

Recognized Identifiable Assets Acquired and Liabilities Assumed

Land

5,400,000

[11]

Building and building leasehold

12,600,000

[11]

Above market lease value

[11]

Acquired in-place leases

[11]

Other assets, net of other liabilities

[11]

Assets acquired

18,000,000

[11]

Fair value adjustment to mortgage note payable

[11]

Below market lease value

[11]

Liabilities assumed

[11]

Purchase price allocation

18,000,000

[11]

Net consideration funded by us at closing, excluding consideration financed by debt

18,000,000

[11]

Equity and/or debt investment held

[11]

Debt assumed

[11]

Approximate Square Feet (sqft)

13,678

[12]

635-641 Sixth Avenue

Recognized Identifiable Assets Acquired and Liabilities Assumed

Land

69,848,000

Building and building leasehold

104,474,000

Above market lease value

Acquired in-place leases

7,727,000

Other assets, net of other liabilities

Assets acquired

182,049,000

Fair value adjustment to mortgage note payable

Below market lease value

9,049,000

Liabilities assumed

9,049,000

Purchase price allocation

173,000,000

Net consideration funded by us at closing, excluding consideration financed by debt

173,000,000

Equity and/or debt investment held

Debt assumed

[13]

304 Park Avenue

Recognized Identifiable Assets Acquired and Liabilities Assumed

Land

54,189,000

[13]

Building and building leasehold

75,619,000

[13]

Above market lease value

2,824,000

[13]

Acquired in-place leases

8,265,000

[13]

Other assets, net of other liabilities

[13]

Assets acquired

140,897,000

[13]

Fair value adjustment to mortgage note payable

[13]

Below market lease value

5,897,000

[13]

Liabilities assumed

5,897,000

[13]

Purchase price allocation

135,000,000

[13]

Net consideration funded by us at closing, excluding consideration financed by debt

135,000,000

[13]

Equity and/or debt investment held

[13]

Consideration in cash

102,000,000

Value of preferred operating partnership units issued

33,000,000

Stonehenge Properties

Recognized Identifiable Assets Acquired and Liabilities Assumed

Land

65,533,000

[14]

Building and building leasehold

128,457,000

[14]

Above market lease value

594,000

[14]

Acquired in-place leases

9,573,000

[14]

Other assets, net of other liabilities

2,190,000

[14]

Assets acquired

206,347,000

[14]

Fair value adjustment to mortgage note payable

[14]

Below market lease value

13,239,000

[14]

Liabilities assumed

13,239,000

[14]

Net consideration funded by us at closing, excluding consideration financed by debt

78,121,000

[14]

Equity and/or debt investment held

[14]

Debt assumed

[14]

Ownership interest in consolidated joint venture (as a percent)

80.00%

Manhattan

Recognized Identifiable Assets Acquired and Liabilities Assumed

Price of acquisition

193,108,000

[14]

Manhattan | Series G Preferred Units

Recognized Identifiable Assets Acquired and Liabilities Assumed

Mortgage encumbering the property

47,600,000

Retail properties

Recognized Identifiable Assets Acquired and Liabilities Assumed

Fixed rate debt

8,500,000

Multifamily properties

Recognized Identifiable Assets Acquired and Liabilities Assumed

Number of units (unit)

385

Approximate Square Feet (sqft)

488,000

Fixed rate debt

$100,000,000

Interest rate, fixed rate debt (as a percent)

4.10%

Apartments | 248-252 Bedford Avenue

Recognized Identifiable Assets Acquired and Liabilities Assumed

Number of units (unit)

Townhouses | 248-252 Bedford Avenue

Recognized Identifiable Assets Acquired and Liabilities Assumed

Number of units (unit)

[1]

In connection with the acquisition of a commercial real estate property, the Operating Partnership issued $4.0 millionB orB 4,000B 3.75%B Series J Preferred Units of limited partnership interest, or the Series J Preferred Units, with a mandatory liquidation preference of $1,000.00B per unit. The Series J Preferred Units can be redeemed in cash by the Operating Partnership on the earlier of (i) the date of the sale of the property or (ii) April 30, 2051 or at the option of the unitholders as further prescribed in the related agreement.

[2]

We are currently in the process of analyzing the purchase price allocation and, as such, we have not allocated any value to intangible assets such as above- and below-market lease or in-place leases.

[3]

This property was acquired inclusive of the issuance of $4.0 million aggregate liquidation preference of Series J Preferred Units of limited partnership interest of the Operating Partnership.

[4]

In January 2012, a separate joint venture in which an SL Green entity holds anB 80%B interest acquired the ground tenancy position.

[5]

We, along with our joint venture partner, acquired this property inclusive of the issuance of $14.1 million aggregate liquidation preference of Series L Preferred Units of limited partnership interest of the Operating Partnership and $9.5 million aggregate liquidation preference of Series K Preferred Units of limited partnership interest of the Operating Partnership. We hold a 75.0% controlling interest in this joint venture.

[6]

In May 2014, we acquired Ivanhoe Cambridge, Inc.'sB 49.65%B economic interest in this property, thereby consolidating full ownership of the property. The transaction valued the consolidated interests atB $1.585 billion. Simultaneous with the closing, we refinanced theB previous mortgage with aB $1.45 billionB mortgage. We also assumed the existing derivative instruments, which swapped $504.0 millionB of the mortgage to fixed rate. We recognized a purchase price fair value adjustment ofB $71.4 millionB upon closing of this transaction. This property, which we initially acquired in December 2007, was previously accounted for as an investment in unconsolidated joint ventures.

[7]

The pro forma income from continuing operations for the years ended December 31, 2014 and 2013 includes the effect of the new financing necessary to complete the acquisition and the preliminary allocation of purchase price in connection with the changes in depreciation and amortization. In addition, the pro forma income from continuing operations for the year ended December 31, 2013 was adjusted to include the purchase price fair value adjustment, as though the acquisition was completed on January 1, 2013. The pro forma income from continuing operations for the year ended December 31, 2014 excludes this purchase price fair value adjustment.

[8]

During the year ended December 31, 2014, we finalized the purchase price allocation based on a third party appraisal and additional facts and circumstances that existed at the acquisition dates. These adjustments did not have a material impact to our consolidated statement of income for the year ended December 31, 2014.

[9]

In AprilB 2013, we acquired interests from our joint venture partner, City Investment Fund, or CIF, in 16 Court Street in Brooklyn for $4.0 million. We have consolidated the ownership of the building. The transaction valued the consolidated interest at $96.2 million, inclusive of the $84.6 million mortgage encumbering the property. In April 2014, we repaid the mortgage. We recognized a purchase price fair value adjustment of $(2.3) million upon the closing of this transaction. This property, which we initially acquired in JulyB 2007, was previously accounted for as an investment in unconsolidated joint ventures.

[10]

In March 2013, we, along with Magnum Real Estate Group, acquired 84 residential units, consisting of 72 apartment units and 12 townhouses, located at 248-252 Bedford Avenue, Williamsburg, Brooklyn for $54.9 million. Simultaneous with the closing on this property, the joint venture closed on a $22.0 million mortgage loan which was later refinanced in June 2014. The property is above a commercial property already owned by us. We hold a 90.0% controlling interest in this joint venture.

[11]

This property was subsequently sold in July 2014. See Note 4, "Properties Held for Sale and Dispositions."

[12]

The gain on sale for 2 Herald Square, 985-987 Third Avenue, 673 First Avenue, 333 West 34th Street, and 292 Madison Avenue are net of a $2.5 million, $1.3 million, $3.4 million, $3.0 million and $1.5 million employee compensation award, respectively, accrued in connection with the realization of this investment gain as a bonus to certain employees that were instrumental in realizing the gain on sale.

[13]

This property was acquired with $102.0 million in cash and $33.0 million in units of limited partnership interest of the Operating Partnership.

[14]

In January 2012, we acquired five retail and two multifamily properties in Manhattan for $193.1 million. This property was acquired inclusive of the issuance of $47.6 million aggregate liquidation preference of SeriesB G Preferred Units of limited partnership interest of the Operating Partnership. Simultaneous with the closing, we financed the multifamily component, which encompasses 385 units and approximately 488,000 square feet (unaudited), with an aggregate $100.0 million fixed rate mortgage which bears interest at 4.1% and one of the retail properties financed with an $8.5 million fixed rate mortgage. We hold an 80.0% interest in this joint venture which we consolidate as it is a VIE and we have been designated as the primary beneficiary. In February 2013, we sold one of the retail properties, which is further described in Note 4, "Properties Held for Sale and Dispositions."

Properties_Held_for_Sale_and_D2

Properties Held for Sale and Dispositions (Details) (USD $)	3 Months Ended									12 Months Ended			1 Months Ended														0 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013		Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Nov. 30, 2014		Jul. 31, 2014		31-May-14		Sep. 30, 2013		Aug. 31, 2013		Feb. 28, 2013		Feb. 29, 2012		Jan. 31, 2015
	sqft	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013		Jun. 30, 2013	Mar. 31, 2013	sqft	Dec. 31, 2013	Dec. 31, 2012	sqft		sqft		sqft		sqft		sqft		sqft		sqft		Jan. 31, 2015
Properties Sold [Abstract]
Area of property (sqft)	33,891,036									33,891,036
Gain (Loss) on Sale	$18,817,000	$29,507,000	$114,735,000	$0	$0	$13,787,000		$0	$1,113,000	$163,059,000	$14,900,000	$6,627,000
Revenues
Rental revenue										51,090,000	94,558,000	97,254,000
Escalation and reimbursement revenues										4,646,000	14,856,000	16,232,000
Other income										23,000	554,000	8,295,000
Total revenues										55,759,000	109,968,000	121,781,000
Operating expenses										7,772,000	20,568,000	23,166,000
Real estate taxes										7,156,000	16,521,000	16,190,000
Ground rent										3,001,000	7,975,000	6,362,000
Interest expense, net of interest income										12,652,000	19,782,000	22,298,000
Depreciable real estate reserves										0	2,150,000	0
Transaction related costs, net of recoveries										89,000	2,000	383,000
Depreciation and amortization										5,581,000	16,443,000	20,250,000
Amortization of deferred financing costs										433,000	840,000	892,000
Total expenses										36,684,000	84,281,000	89,541,000
Net income from discontinued operations	3,626,000	4,035,000	5,645,000	5,769,000	5,836,000	7,435,000		5,943,000	6,473,000	19,075,000	25,687,000	32,240,000
180 Maiden Lane
Properties Sold [Abstract]
Area of property (sqft)	1,090,000									1,090,000
2 Herald Square
Properties Sold [Abstract]
Area of property (sqft)													354,400	[1]
Sales Price													365,000,000	[1]
Gain (Loss) on Sale													18,800,000	[1]
Employee compensation award													2,500,000
985-987 Third Avenue
Properties Sold [Abstract]
Area of property (sqft)															13,678	[1]
Sales Price															68,700,000	[1]
Gain (Loss) on Sale															29,800,000	[1]
Employee compensation award															1,300,000
673 First Avenue
Properties Sold [Abstract]
Area of property (sqft)																	422,000	[1]
Sales Price																	145,000,000	[1]
Gain (Loss) on Sale																	117,600,000	[1]
Employee compensation award																	3,400,000
300 Main Street
Properties Sold [Abstract]
Area of property (sqft)						130,000	[1]												130,000	[1]
Sales Price																			13,500,000	[1]
Gain (Loss) on Sale																			-2,200,000	[1]
333 West 34th Street
Properties Sold [Abstract]
Area of property (sqft)																					345,400	[1]
Sales Price																					220,300,000	[1]
Gain (Loss) on Sale																					13,800,000	[1]
Employee compensation award																					3,000,000
44 West 55th Street
Properties Sold [Abstract]
Area of property (sqft)																							8,557	[1]
Sales Price																							6,300,000	[1]
Gain (Loss) on Sale																							1,100,000	[1]
292 Madison Avenue
Properties Sold [Abstract]
Area of property (sqft)																									203,800	[1]
Sales Price																									85,000,000	[1]
Gain (Loss) on Sale																									6,600,000	[1]
Employee compensation award																									1,500,000
Subsequent Event \| 180 Maiden Lane
Properties Sold [Abstract]
Sales Price																											$470,000,000

[1]	The gain on sale for 2 Herald Square, 985-987 Third Avenue, 673 First Avenue, 333 West 34th Street, and 292 Madison Avenue are net of a $2.5 million, $1.3 million, $3.4 million, $3.0 million and $1.5 million employee compensation award, respectively, accrued in connection with the realization of this investment gain as a bonus to certain employees that were instrumental in realizing the gain on sale.

Debt_and_Preferred_Equity_Inve2

Debt and Preferred Equity Investments (Details) (USD $)	12 Months Ended					3 Months Ended
Debt and Preferred Equity Investments (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Mar. 31, 2014	Dec. 31, 2011	Sep. 30, 2014
Debt investment
Increase in debt and preferred equity investments (net of discounts), including investments classified as held-for-sale	$680,100,000		$601,300,000
Decrease in debt and preferred equity investments (net of discounts), including investments classified as held-for-sale	576,100,000		644,900,000
Aggregate weighted average current yield (as a percent)	10.33%
Debt Investments Held [Abstract]
Carrying Value, Net of Discounts and Deferred Origination Fees	1,408,804,000		1,304,839,000
Loan loss reserve	0		-1,000,000		-7,000,000		-50,175,000
Origination of debt and preferred equity investments	617,090,000		555,137,000		645,229,000
Debt investment
Debt Investments Held [Abstract]
Future Funding Obligations	48,127,000
Senior Financing	5,693,315,000
Carrying Value, Net of Discounts and Deferred Origination Fees	1,275,809,000	[1]	936,475,000	[1]
Loan loss reserve	0	[1]	-1,000,000	[1]
Total, net of reserve	1,275,809,000	[1]	935,475,000	[1]
Total fixed rate
Debt Investments Held [Abstract]
Future Funding Obligations	16,424,000
Senior Financing	3,448,250,000
Carrying Value, Net of Discounts and Deferred Origination Fees	582,174,000	[1]	385,604,000	[1]
Total fixed rate \| Junior Mortgage Participation, March 2015
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	398,500,000
Carrying Value, Net of Discounts and Deferred Origination Fees	11,934,000	[1]	11,856,000	[1]
Total fixed rate \| Junior Mortgage Participation/Mezzanine Loan, February 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	205,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	70,688,000	[1]	68,319,000	[1]
Total fixed rate \| Other, Various
Debt Investments Held [Abstract]
Future Funding Obligations	0	[2]
Senior Financing	0	[2]
Carrying Value, Net of Discounts and Deferred Origination Fees	45,611,000	[1],[2]	44,742,000	[1],[2]
Total fixed rate \| Mezzanine Loan, May 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0	[3]
Senior Financing	177,000,000	[3]
Carrying Value, Net of Discounts and Deferred Origination Fees	14,068,000	[1],[3]	15,012,000	[1],[3]
Total fixed rate \| Junior Mortgage Participation, June 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	133,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	49,000,000	[1]	49,000,000	[1]
Total fixed rate \| Junior Mortgage Participation/Mezzanine Loan, March 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0	[4]
Senior Financing	1,109,000,000	[4]
Carrying Value, Net of Discounts and Deferred Origination Fees	98,934,000	[1],[4]	26,884,000	[1],[4]
Carrying Value, Net of Discounts and Deferred Origination Fees	30,000,000
Carrying amount of Notes defeased	66,700,000
Interest income recognized previously accrued						10,100,000
Origination of debt and preferred equity investments	67,300,000
Total fixed rate \| Other, March 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	65,770,000	[1]	54,099,000	[1]
Total fixed rate \| Mezzanine Loan, June 2017
Debt Investments Held [Abstract]
Future Funding Obligations	16,424,000	[5]
Senior Financing	521,750,000	[5]
Carrying Value, Net of Discounts and Deferred Origination Fees	24,608,000	[1],[5]	20,954,000	[1],[5]
Amount participated out	41,300,000
Total fixed rate \| Mezzanine Loan, July 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	539,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	49,629,000	[1]	0	[1]
Total fixed rate \| Mortgage Loan, February 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0	[6]
Senior Financing	0	[6]
Carrying Value, Net of Discounts and Deferred Origination Fees	26,209,000	[1],[6]	0	[1],[6]
Loan acquired								26,400,000
Discount amount								200,000
Total fixed rate \| Mortgage Loan, August 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	637,000	[1]	0	[1]
Total fixed rate \| Mezzanine Loan, September 2021
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	15,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	3,500,000	[1]	3,500,000	[1]
Total fixed rate \| Mezzanine Loan, November 2023
Debt Investments Held [Abstract]
Future Funding Obligations	0	[7]
Senior Financing	90,000,000	[7]
Carrying Value, Net of Discounts and Deferred Origination Fees	19,930,000	[1],[7]	19,926,000	[1],[7]
Amount participated out	5,000,000
Total fixed rate \| Mezzanine Loan, January 2025
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	95,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	30,000,000	[1]	0	[1]
Total fixed rate \| Mezzanine Loan, November 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	165,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	71,656,000	[1]	71,312,000	[1]
Total fixed rate \| Other Various, Junior Participation Loan
Debt Investments Held [Abstract]
Carrying amount of Notes defeased	22,600,000
Total fixed rate \| Other Various, Mezzanine Loan
Debt Investments Held [Abstract]
Carrying amount of Notes defeased	23,000,000
Total fixed rate \| Junior Mortgage Participation, Related To Mortgage Loan, February 2019
Debt Investments Held [Abstract]
Loan acquired								5,700,000
Discount amount								5,700,000
Total floating rate
Debt Investments Held [Abstract]
Future Funding Obligations	31,703,000
Senior Financing	2,245,065,000
Carrying Value, Net of Discounts and Deferred Origination Fees	693,635,000	[1]	550,871,000	[1]
Total floating rate \| Mezzanine Loan, April 2015
Debt Investments Held [Abstract]
Future Funding Obligations	7,785,000
Senior Financing	50,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	37,322,000	[1]	0	[1]
Total floating rate \| Mortgage Mezzanine Loan, June 2015
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	109,527,000	[1]	0	[1]
Total floating rate \| Mezzanine Loan, September 2015
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	110,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	49,614,000	[1]	49,110,000	[1]
Total floating rate \| Mezzanine Loan, December 2015
Debt Investments Held [Abstract]
Future Funding Obligations	7,249,000
Senior Financing	113,633,000
Carrying Value, Net of Discounts and Deferred Origination Fees	42,750,000	[1]	27,662,000	[1]
Total floating rate \| Mezzanine Loan, March 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	775,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	73,402,000	[1]	72,823,000	[1]
Total floating rate \| Mezzanine Loan, June 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0	[8]
Senior Financing	160,000,000	[8]
Carrying Value, Net of Discounts and Deferred Origination Fees	22,573,000	[1],[8]	22,526,000	[1],[8]
Amount participated out	7,400,000
Total floating rate \| Mezzanine Loan, July 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	115,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	24,910,000	[1]	25,590,000	[1]
Total floating rate \| Mezzanine Loan, November 2016
Debt Investments Held [Abstract]
Future Funding Obligations	3,641,000
Senior Financing	172,105,000
Carrying Value, Net of Discounts and Deferred Origination Fees	33,726,000	[1]	25,725,000	[1]
Total floating rate \| Mezzanine Loan, November 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	360,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	99,023,000	[1]	0	[1]
Total floating rate \| Mezzanine Loan, December 2016
Debt Investments Held [Abstract]
Future Funding Obligations	333,000
Senior Financing	33,833,000
Carrying Value, Net of Discounts and Deferred Origination Fees	11,835,000	[1]	11,798,000	[1]
Total floating rate \| Mezzanine Loan, January 2017
Debt Investments Held [Abstract]
Future Funding Obligations	9,053,000
Senior Financing	91,727,000
Carrying Value, Net of Discounts and Deferred Origination Fees	20,651,000	[1]	0	[1]
Total floating rate \| Mortgage/Mezzanine Loan, July 2017
Debt Investments Held [Abstract]
Future Funding Obligations	2,847,000
Senior Financing	110,767,000
Carrying Value, Net of Discounts and Deferred Origination Fees	38,524,000	[1]	0	[1]
Total floating rate \| Mortgage/Mezzanine Loan, July 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	22,803,000	[1]	0	[1]
Total floating rate \| Mortgage/Mezzanine Loan, September 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	16,848,000	[1]	0	[1]
Total floating rate \| Mezzanine Loan, November 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	60,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	14,859,000	[1]	0	[1]
Total floating rate \| Mortgage Mezzanine Loan, December 2017
Debt Investments Held [Abstract]
Future Funding Obligations	795,000	[9]
Senior Financing	0	[9]
Carrying Value, Net of Discounts and Deferred Origination Fees	14,845,000	[1],[9]	0	[1],[9]
Amount participated out	5,100,000
Total floating rate \| Junior Mortgage Participation/Mezzanine Loan, July 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	55,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	20,533,000	[1]	20,553,000	[1]
Total floating rate \| Mortgage Mezzanine Loan, February 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	18,083,000	[1]	0	[1]
Total floating rate \| Mezzanine Loan, March 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	38,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees	21,807,000	[1]	0	[1]
Total floating rate \| Mortgage Loan, Repaid in May 2014
Debt Investments Held [Abstract]
Future Funding Obligations	0	[10]
Senior Financing	0	[10]
Carrying Value, Net of Discounts and Deferred Origination Fees	0	[1],[10]	30,000,000	[1],[10]
Total floating rate \| Junior Mortgage Participation, Repaid In July 2014
Debt Investments Held [Abstract]
Future Funding Obligations	0	[11]
Senior Financing	0	[11]
Carrying Value, Net of Discounts and Deferred Origination Fees	0	[1],[11]	24,046,000	[1],[11]
Total floating rate \| Junior Mortgage Participation/Mezzanine Loan, Repaid In July 2014
Debt Investments Held [Abstract]
Future Funding Obligations	0	[11]
Senior Financing	0	[11]
Carrying Value, Net of Discounts and Deferred Origination Fees	0	[1],[11]	131,724,000	[1],[11]
Total floating rate \| Mezzanine Loan, Repaid in August 2014
Debt Investments Held [Abstract]
Future Funding Obligations	0	[12]
Senior Financing	0	[12]
Carrying Value, Net of Discounts and Deferred Origination Fees	0	[1],[12]	59,892,000	[1],[12]
Total floating rate \| Junior Mortgage Participation, Repaid In August 2014
Debt Investments Held [Abstract]
Future Funding Obligations	0	[12]
Senior Financing	0	[12]
Carrying Value, Net of Discounts and Deferred Origination Fees	0	[1],[12]	10,873,000	[1],[12]
Total floating rate \| Mezzanine Loan, Repaid In August 2014
Debt Investments Held [Abstract]
Future Funding Obligations	0	[12]
Senior Financing	0	[12]
Carrying Value, Net of Discounts and Deferred Origination Fees	$0	[1],[12]	$38,549,000	[1],[12]

[1]	Carrying value is net of discounts, premiums, original issue discounts and deferred origination fees.
[2]	During the fourth quarter of 2014, both our $22.6 million junior participation and our $23.0 mezzanine loan were defeased and are now collateralized by defeasance securities. In connection with the defeasance, the maturity date of the mortgage in which we are a junior participant was accelerated from the May 2016 to February 2016, per the terms of the loan agreement. The maturity date of the mezzanine loan was not changed in connection with the defeasance and will mature in May 2016.
[3]	This loan was repaid in February 2015.
[4]	During the first quarter of 2014, we recognized $10.1 million of previously unaccrued interest income which was deemed collectible as a result of the sale of the underlying property, which closed in June 2014. In connection with the sale of the underlying property, our existing $66.7 million mezzanine loan was defeased and is now shown separately, as it is collateralized by defeasance securities. The buyer assumed our $30.0 million participating interest in the mortgage and we acquired a $67.3 million participating interest in the new mezzanine loan.
[5]	Carrying value is net of $41.3 million that was participated out, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfer not meeting the conditions for sale accounting.
[6]	In September 2014, we acquired a $26.4 million mortgage loan at a $0.2 million discount and a $5.7 million junior mortgage participation at a $5.7 million discount. The junior mortgage participation was a nonperforming loan at acquisition and is currently on non-accrual status.
[7]	Carrying value is net of $5.0 million that was participated out, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfer not meeting the conditions for sale accounting.
[8]	Carrying value is net of $7.4 million that was participated out, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfer not meeting the conditions for sale accounting.
[9]	Carrying value is net of $5.1 million that was participated out, which is included in other assets and other liabilities on the consolidated balance sheets as a result of the transfer not meeting the conditions for sale accounting.
[10]	This loan was repaid in May 2014.
[11]	This loan was repaid in July 2014.
[12]	This loan was repaid in August 2014.

Debt_and_Preferred_Equity_Inve3

Debt and Preferred Equity Investments (Details 2) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Preferred equity investment
Aggregate weighted average current yield (as a percent)	10.33%
Carrying Value, Net of Discounts and Deferred Origination Fees	$1,408,804		$1,304,839
Preferred Equity, July 2015
Preferred equity investment
Senior Financing	550,000	[1]
Carrying Value, Net of Discounts and Deferred Origination Fees	123,041	[1],[2]	115,198	[1],[2]
Preferred Equity, November 2017
Preferred equity investment
Senior Financing	70,000
Carrying Value, Net of Discounts and Deferred Origination Fees	9,954	[2]	9,940	[2]
Preferred Equity, Repaid April 2014
Preferred equity investment
Senior Financing	0	[3]
Carrying Value, Net of Discounts and Deferred Origination Fees	0	[2],[3]	25,896	[2],[3]
Preferred Equity, Repaid November 2014
Preferred equity investment
Senior Financing	0	[1],[4]
Carrying Value, Net of Discounts and Deferred Origination Fees	0	[1],[2],[4]	218,330	[1],[2],[4]
Preferred equity investments
Preferred equity investment
Aggregate weighted average current yield (as a percent)	10.89%
Senior Financing	620,000
Carrying Value, Net of Discounts and Deferred Origination Fees	$132,995	[2]	$369,364	[2]

[1]	The difference between the pay and accrual rates is included as an addition to the principal balance outstanding.
[2]	Carrying value is net of discounts and deferred origination fees.
[3]	This preferred equity investment was redeemed in April 2014.
[4]	This preferred equity investment was redeemed in November 2014.

Debt_and_Preferred_Equity_Inve4

Debt and Preferred Equity Investments (Details 3) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Loan loss reserve activity
Balance at beginning of year	$1,000	$7,000	$50,175
Expensed	0	0	3,000
Recoveries	0	0	-2,436
Charge-offs and reclassifications	-1,000	-6,000	-43,739
Balance at end of period	$0	$1,000	$7,000

Debt_and_Preferred_Equity_Inve5

Debt and Preferred Equity Investments (Details 4) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
	segment	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]
Number of portfolio segments of financial receivables (segment)	1
Additional amount of financing receivables included in other assets	$133,500,000	$172,800,000
Unpaid Principal Balance
With no related allowance recorded		0
With an allowance recorded		10,750,000	[1]
Unpaid Principal Balance		10,750,000
Recorded Investment
With no related allowance recorded		0
With an allowance recorded		10,750,000	[1]
Recorded Investment		10,750,000
Allowance Allocated		1,000,000	[1]
Average recorded investment in impaired loans		10,900,000
Investment income recognized		$7,100,000

[1]	This loan was repaid during the year ended December 31, 2014.

Investment_in_Unconsolidated_J1

Investment in Unconsolidated Joint Ventures (Details) (USD $)	3 Months Ended											12 Months Ended					1 Months Ended
	Dec. 31, 2014		Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Jun. 30, 2012	Dec. 31, 2014		Oct. 31, 2014	Nov. 30, 2014	Mar. 31, 2014		Dec. 31, 2013		Nov. 30, 2012	Oct. 01, 2012	Sep. 30, 2012
	sqft		Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	sqft		Dec. 31, 2013		Dec. 31, 2012	Jun. 30, 2012	sqft		Oct. 31, 2014	Nov. 30, 2014	Mar. 31, 2014		Dec. 31, 2013		Nov. 30, 2012	Oct. 01, 2012	Sep. 30, 2012
General information on each joint venture
Net equity investment in VIEs in which the entity is not primary beneficiary	$146,200,000						$310,700,000					$146,200,000		$310,700,000				$146,200,000						$310,700,000
Approximate Square Feet (sqft)	33,891,036											33,891,036						33,891,036
Gain on Sale	673,000		16,496,000	1,444,000	104,640,000		7,538,000		-354,000	-3,583,000	0	123,253,000		3,601,000		37,053,000
Carrying Value, Net of Discounts and Deferred Origination Fees	1,408,804,000						1,304,839,000					1,408,804,000		1,304,839,000				1,408,804,000						1,304,839,000
100 Park Avenue
General information on each joint venture
Ownership Percentage	49.90%											49.90%						49.90%
Economic Interest (as a percent)	49.90%											49.90%						49.90%
Approximate Square Feet (sqft)	834,000											834,000						834,000
Acquisition Price	95,800,000	[1]										95,800,000	[1]					95,800,000	[1]
717 Fifth Avenue
General information on each joint venture
Ownership Percentage	10.92%	[2]										10.92%	[2]					10.92%	[2]
Economic Interest (as a percent)	10.92%	[2]										10.92%	[2]					10.92%	[2]
Approximate Square Feet (sqft)	119,500	[2]										119,500	[2]					119,500	[2]
Acquisition Price	251,900,000	[1],[2]										251,900,000	[1],[2]					251,900,000	[1],[2]
Proceeds from sale of equity method investments																	67,900,000
Gain on Sale																	3,000,000
Beneficial interest sold (as a percent)																	50.00%
800 Third Avenue
General information on each joint venture
Ownership Percentage	42.95%											42.95%						42.95%
Economic Interest (as a percent)	42.95%											42.95%						42.95%
Approximate Square Feet (sqft)	526,000											526,000						526,000
Acquisition Price	285,000,000	[1]										285,000,000	[1]					285,000,000	[1]
1745 Broadway
General information on each joint venture
Ownership Percentage	56.88%	[3]										56.88%	[3]					56.88%	[3]
Economic Interest (as a percent)	56.88%	[3]										56.88%	[3]					56.88%	[3]
Approximate Square Feet (sqft)	674,000	[3]										674,000	[3]					674,000	[3]
Acquisition Price	520,000,000	[1],[3]										520,000,000	[1],[3]					520,000,000	[1],[3]
Mortgage on properties assumed																		16,000,000
Accrued interest	7,000,000											7,000,000						7,000,000
Jericho Plaza
General information on each joint venture
Ownership Percentage	20.26%											20.26%						20.26%
Economic Interest (as a percent)	20.26%											20.26%						20.26%
Approximate Square Feet (sqft)	640,000											640,000						640,000
Acquisition Price	210,000,000	[1]										210,000,000	[1]					210,000,000	[1]
The Meadows
General information on each joint venture
Ownership Percentage	50.00%											50.00%						50.00%
Economic Interest (as a percent)	50.00%											50.00%						50.00%
Approximate Square Feet (sqft)	582,100											582,100						582,100
Acquisition Price	111,500,000	[1]										111,500,000	[1]					111,500,000	[1]
600 Lexington Avenue
General information on each joint venture
Ownership Percentage	55.00%											55.00%						55.00%
Economic Interest (as a percent)	55.00%											55.00%						55.00%
Approximate Square Feet (sqft)	303,515											303,515						303,515
Acquisition Price	193,000,000	[1]										193,000,000	[1]					193,000,000	[1]
11 West 34th Street
General information on each joint venture
Ownership Percentage	30.00%											30.00%						30.00%
Economic Interest (as a percent)	30.00%											30.00%						30.00%
Approximate Square Feet (sqft)	17,150											17,150						17,150
Acquisition Price	10,800,000	[1]										10,800,000	[1]					10,800,000	[1]
7 Renaissance
General information on each joint venture
Ownership Percentage	50.00%											50.00%						50.00%
Economic Interest (as a percent)	50.00%											50.00%						50.00%
Approximate Square Feet (sqft)	65,641											65,641						65,641
Acquisition Price	4,000,000	[1]										4,000,000	[1]					4,000,000	[1]
3 Columbus Circle
General information on each joint venture
Ownership Percentage	48.90%	[4]										48.90%	[4]					48.90%	[4]
Economic Interest (as a percent)	48.90%	[4]										48.90%	[4]					48.90%	[4]
Approximate Square Feet (sqft)	741,500	[4]										741,500	[4]					741,500	[4]
Acquisition Price	500,000,000	[1],[4]										500,000,000	[1],[4]					500,000,000	[1],[4]
280 Park Avenue
General information on each joint venture
Ownership Percentage	50.00%	[5]										50.00%	[5]					50.00%	[5]
Economic Interest (as a percent)	50.00%	[5]										50.00%	[5]					50.00%	[5]
Approximate Square Feet (sqft)	1,219,158	[5]										1,219,158	[5]					1,219,158	[5]
Acquisition Price	400,000,000	[1],[5]										400,000,000	[1],[5]					400,000,000	[1],[5]
Interest Of Minority Shareholders, Acquired																				11,000,000
1552 Broadway
General information on each joint venture
Approximate Square Feet (sqft)	13,045											13,045						13,045
1552-1560 Broadway
General information on each joint venture
Ownership Percentage	50.00%	[6]										50.00%	[6]					50.00%	[6]
Economic Interest (as a percent)	50.00%	[6]										50.00%	[6]					50.00%	[6]
Approximate Square Feet (sqft)	35,897	[6]										35,897	[6]					35,897	[6]
Acquisition Price	136,550,000	[1],[6]										136,550,000	[1],[6]					136,550,000	[1],[6]
724 Fifth Avenue
General information on each joint venture
Ownership Percentage	50.00%											50.00%						50.00%
Economic Interest (as a percent)	50.00%											50.00%						50.00%
Approximate Square Feet (sqft)	65,040											65,040						65,040
Acquisition Price	223,000,000	[1]										223,000,000	[1]					223,000,000	[1]
10 East 53rd Street
General information on each joint venture
Ownership Percentage	55.00%											55.00%						55.00%
Economic Interest (as a percent)	55.00%											55.00%						55.00%
Approximate Square Feet (sqft)	354,300											354,300						354,300
Acquisition Price	252,500,000	[1]										252,500,000	[1]					252,500,000	[1]
33 Beekman
General information on each joint venture
Ownership Percentage	45.90%	[7]										45.90%	[7]					45.90%	[7]
Economic Interest (as a percent)	45.90%	[7]										45.90%	[7]					45.90%	[7]
Approximate Square Feet (sqft)	0	[7]										0	[7]					0	[7]
Acquisition Price	31,000,000	[1],[7]										31,000,000	[1],[7]					31,000,000	[1],[7]
Number of floors of student housing (floors)	30											30						30
521 Fifth Avenue
General information on each joint venture
Ownership Percentage	50.50%	[8]										50.50%	[8]					50.50%	[8]
Economic Interest (as a percent)	50.50%	[8]										50.50%	[8]					50.50%	[8]
Approximate Square Feet (sqft)	460,000	[8]										460,000	[8]					460,000	[8]
Acquisition Price	315,000,000	[1],[8]										315,000,000	[1],[8]					315,000,000	[1],[8]
Gain on Sale														2,800,000
21 East 66th Street
General information on each joint venture
Ownership Percentage	32.28%	[9]										32.28%	[9]					32.28%	[9]
Economic Interest (as a percent)	32.28%	[9]										32.28%	[9]					32.28%	[9]
Approximate Square Feet (sqft)	16,736	[9]										16,736	[9]					16,736	[9]
Acquisition Price	75,000,000	[1],[9]										75,000,000	[1],[9]					75,000,000	[1],[9]
Gain on Sale																				700,000
315 West 36th Street
General information on each joint venture
Ownership Percentage	35.50%											35.50%						35.50%
Economic Interest (as a percent)	35.50%											35.50%						35.50%
Approximate Square Feet (sqft)	147,619											147,619						147,619
Acquisition Price	45,000,000	[1]										45,000,000	[1]					45,000,000	[1]
650 Fifth Avenue
General information on each joint venture
Ownership Percentage	50.00%	[10]										50.00%	[10]					50.00%	[10]
Economic Interest (as a percent)	50.00%	[10]										50.00%	[10]					50.00%	[10]
Approximate Square Feet (sqft)	32,324	[10]										32,324	[10]					32,324	[10]
Acquisition Price	0	[1],[10]										0	[1],[10]					0	[1],[10]
121 Greene Street
General information on each joint venture
Ownership Percentage	50.00%											50.00%						50.00%
Economic Interest (as a percent)	50.00%											50.00%						50.00%
Approximate Square Feet (sqft)	7,131											7,131						7,131
Acquisition Price	27,400,000	[1]										27,400,000	[1]					27,400,000	[1]
175-225 Third Street
General information on each joint venture
Ownership Percentage	95.00%	[11]										95.00%	[11]					95.00%	[11]
Economic Interest (as a percent)	95.00%	[11]										95.00%	[11]					95.00%	[11]
Approximate Square Feet (sqft)	0	[11]										0	[11]					0	[11]
Acquisition Price	74,600,000	[1],[11]										74,600,000	[1],[11]					74,600,000	[1],[11]
55 West 46th Street
General information on each joint venture
Ownership Percentage	25.00%	[12]										25.00%	[12]					25.00%	[12]		25.00%
Economic Interest (as a percent)	25.00%	[12]										25.00%	[12]					25.00%	[12]
Approximate Square Feet (sqft)	347,000	[12]										347,000	[12]					347,000	[12]
Acquisition Price	295,000,000	[1],[12]										295,000,000	[1],[12]					295,000,000	[1],[12]
Partnership interest sold to Harel by joint venture (as a percent)																					75.00%
West Coast office portfolio
General information on each joint venture
Ownership Percentage					42.02%	[13]	42.04%	[13]						42.04%	[13]							42.02%	[13]	42.04%	[13]		27.63%	63.18%
Economic Interest (as a percent)							43.74%							43.74%										43.74%
Gain on Sale																						85,600,000	[13],[14]	2,100,000	[13],[14]
521 Fifth Avenue
General information on each joint venture
Partnership interest sold to Harel by joint venture (as a percent)																										49.50%
Mortgage Loan \| Joint venture \| 521 Fifth Avenue
General information on each joint venture
Gain on Sale																										19,400,000
Lehman Bros \| 1745 Broadway
General information on each joint venture
Remaining percentage of interest acquired in joint venture (percent)																					7.37%
Witkoff \| 1745 Broadway
General information on each joint venture
Remaining percentage of interest acquired in joint venture (percent)																		14.79%
Wells Fargo \| 1745 Broadway
General information on each joint venture
Remaining percentage of interest acquired in joint venture (percent)																		2.46%
Three Retail and Two Residential Units \| 21 East 66th Street
General information on each joint venture
Ownership Percentage	32.28%											32.28%						32.28%
Number of Stores	3											3						3
Number Of Residential Units	2											2						2
Three Residential Units \| 21 East 66th Street
General information on each joint venture
Ownership Percentage	16.14%											16.14%						16.14%
Number Of Residential Units	3											3						3
Participating Financing Due March 2016
General information on each joint venture
Loans Receivable, Gross, Commercial, Acquisition	99,600,000				100,000,000							99,600,000						99,600,000				100,000,000
Carrying Value, Net of Discounts and Deferred Origination Fees					40,000,000																	40,000,000
Participating Financing Due March 2016 \| Mezzanine loans
General information on each joint venture
Carrying Value, Net of Discounts					60,000,000																	60,000,000
Participating Financing Due February 2022
General information on each joint venture
Loans Receivable, Gross, Commercial, Acquisition	$46,200,000											$46,200,000						$46,200,000		$45,800,000

[1]	Acquisition price represents the actual or implied gross purchase price for the joint venture.
[2]	In June 2012, we recognized $67.9 million of additional cash income, equivalent to profit, due to the distribution of refinancing proceeds and a gain on sale of $3.0 million, on the sale of 50.0% of our remaining interest.
[3]	In November 2014, we acquired Lehman Bros.' 7.37% interest in 1745 Broadway. In December 2014, we additionally acquired Witkoff's 14.79% interest and Wells Fargo's 2.46% interest in the property. In connection with the acquisition of Witkoff's interest, we assumed a partner loan of $16.0 million, which is included in mortgages and other loans payable in the consolidated balance sheet, and $7.0 million of accrued interest.
[4]	As a result of the sale of a condominium interest in SeptemberB 2012, YoungB & Rubicam,B Inc., or Y&R, owns a portion of the property, generally floors three through eight referred to as Y&R units. Because the joint venture has an option to repurchase the Y&R units, the gain associated with this sale was deferred.
[5]	In October 2014, we, along with Vornado, acquired equally the interest of minority shareholders for $11.0 million.
[6]	The purchase price represents only the purchase of the 1552 Broadway interest which comprised approximatelyB 13,045B square feet (unaudited). The joint venture also owns a long-term leasehold interest in the retail space and certain other spaces at 1560 Broadway, which is adjacent to 1552 Broadway.
[7]	The property is currently being developed into a 30B story dormitory building, which will be conveyed to Pace University upon its completion under a long-term ground lease arrangement.
[8]	In November 2012, we refinanced the previous mortgage and sold 49.5% of our partnership interest. We recognized a gain of $19.4 million on the sale. Due to lack of control, we deconsolidated the entity effective NovemberB 30, 2012 and adopted the equity method of accounting thereafter. During the year ended December 31, 2013, we recognized additional post closing costs of $2.8 million as an adjustment to the gain.
[9]	In October 2014, the joint venture sold one of the residential units at the property. We recognized a gain of $0.7 million on the sale. As of December 31, 2014, we hold aB 32.28%B interest inB threeB retail andB twoB residential units at the property and aB 16.14%B interest inB threeB residential units at the property.
[10]	The joint venture owns a long-term leasehold interest in the retail space at 650 Fifth Avenue. In connection with the ground lease obligation, SLG provided a performance guaranty and Sutton executed a contribution agreement to reflect its pro rata obligation. In the event the property is converted into a condominium unit and the landlord elects the purchase option, the joint venture shall be obligated to acquire the unit at the then fair value.
[11]	In October 2014, we, along with our joint venture partners, acquired a development site at 175-225 Third Street in Brooklyn, New York. The property is being managed by our joint venture partners. We did not consolidate the property as a result of multiple partners having substantive participating rights.
[12]	In October 2014, we acquired the vacant commercial condominium units on floors 2 and 22-34 in the building located at 55 West 46th Street for $295.0 million. We also acquired a retail space on 46th Street and the buildingbs parking garage and fitness center. We consolidated the property from acquisition through October 31, 2014. In November 2014, we, together with Prudential, formed a joint venture for the ownership of the condominium units. We sold 75.00% of our interest to Prudential and retained 25.00% interest in the joint venture. As a result of Prudential having substantive participating rights, we deconsolidated the property and adopted the equity method of accounting subsequently thereafter.
[13]	Prior to the recapitalization, we consolidated the investment for the months of August and September 2012 as a result of our 63.18% ownership interest and control over its activities. Immediately following the recapitalization in September 2012, our investment was 27.63%. The change in ownership resulted in a change in accounting from consolidating the investment to accounting for the joint venture under the equity method of accounting. During the year ended December 31, 2013, the joint venture sold three properties, the proceeds of which were used primarily to repay a portion of the debt. Also during the year ended December 31, 2013, we acquired in aggregate 14.39% ownership interest of two of our joint venture partners. As a result, we had a 42.04% effective ownership interest (43.74% effective economic interest) in the West Coast portfolio as of December 31, 2013. During the year ended December 31, 2014, we sold our ownership interest in the joint venture.
[14]	Represents the Company's share of the gain.

Investment_in_Unconsolidated_J2

Investment in Unconsolidated Joint Ventures (Details 2) (USD $)

3 Months Ended

12 Months Ended

1 Months Ended

Dec. 31, 2014

Sep. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Sep. 30, 2014

31-May-14

Mar. 31, 2014

Dec. 31, 2013

Jan. 31, 2014

Jul. 31, 2012

Apr. 30, 2012

Mar. 31, 2012

Oct. 01, 2012

Sep. 30, 2012

sqft

Investments in Unconsolidated Joint Ventures [Abstract]

Gain on Sale

$673,000

$16,496,000

$1,444,000

$104,640,000

$7,538,000

($354,000)

($3,583,000)

$123,253,000

$3,601,000

$37,053,000

Total floating rate debt

1,103,942,000

729,949,000

1,103,942,000

729,949,000

Approximate Square Feet (sqft)

33,891,036

Mortgage assigned to joint venture

150,000,000

180 Broadway

Investments in Unconsolidated Joint Ventures [Abstract]

Ownership Percentage

25.50%

[1]

25.50%

[1]

Implied Sales Price

222,500,000

[1],[2]

222,500,000

[1],[2]

Gain on Sale

16,500,000

[1],[3]

Promote recognized

3,300,000

747 Madison Avenue

Investments in Unconsolidated Joint Ventures [Abstract]

Ownership Percentage

33.33%

[4]

Implied Sales Price

160,000,000

[2],[4]

Gain on Sale

[3],[4]

Promote recognized

10,300,000

Preferred equity investment

30,000,000

Deferred gain on sale

13,100,000

West Coast office portfolio

Investments in Unconsolidated Joint Ventures [Abstract]

Ownership Percentage

42.02%

[5]

42.04%

[5]

42.04%

[5]

42.02%

[5]

42.04%

[5]

27.63%

63.18%

Implied Sales Price

756,000,000

[2],[5]

224,300,000

[2],[5]

224,300,000

[2],[5]

756,000,000

[2],[5]

224,300,000

[2],[5]

Gain on Sale

85,600,000

[3],[5]

2,100,000

[3],[5]

Economic interest

43.74%

West Coast Office Portfolio, Two Joint Venture Partners

Investments in Unconsolidated Joint Ventures [Abstract]

Ownership Percentage

14.39%

21-25 West 34th Street

Investments in Unconsolidated Joint Ventures [Abstract]

Ownership Percentage

49.90%

[6]

Implied Sales Price

114,900,000

[2],[6]

Gain on Sale

20,900,000

[3],[6]

Approximate Square Feet (sqft)

91,300

27-29 West 34th Street

Investments in Unconsolidated Joint Ventures [Abstract]

Ownership Percentage

50.00%

[7]

50.00%

[7]

50.00%

[7]

Implied Sales Price

70,100,000

[2],[7]

70,100,000

[2],[7]

70,100,000

[2],[7]

Gain on Sale

7,600,000

[3],[7]

Accrued employee compensation award

1,500,000

One Court Square

Investments in Unconsolidated Joint Ventures [Abstract]

Ownership Percentage

30.00%

[8]

Implied Sales Price

481,100,000

[2],[8]

Gain on Sale

1,000,000

[3],[8]

Mortgage assigned to joint venture

315,000,000

379 West Broadway

Investments in Unconsolidated Joint Ventures [Abstract]

Ownership Percentage

45.00%

[9]

Implied Sales Price

48,500,000

[2],[9]

Gain on Sale

6,500,000

[3],[9]

Fees Position Acquired

13,500,000

141 Fifth Avenue

Investments in Unconsolidated Joint Ventures [Abstract]

Ownership Percentage

50.00%

[10]

Implied Sales Price

46,000,000

[10],[2]

Gain on Sale

7,300,000

[10],[3]

Employee compensation award

1,500,000

Joint venture

Investment in Unconsolidated Joint Ventures

Maximum amount of loan recourse to entity

18,400,000

Investments in Unconsolidated Joint Ventures [Abstract]

Total floating rate debt

$1,713,440,000

$1,842,815,000

$1,713,440,000

$1,842,815,000

Preferred equity | Herald Center

Investments in Unconsolidated Joint Ventures [Abstract]

Interest rate (as a percent)

8.75%

[1]

In connection with the sale of the property, we also recognized a promote ofB $3.3 million.

[2]

Represents implied gross valuation for the joint venture or sales price of the property.

[3]

Represents the Company's share of the gain.

[4]

We sold our ownership interest in the joint venture, which owns 100% interest as tenant-in-common in 30 East 65th Street Corporation and the related proprietary lease of five cooperative apartment units in the property. We also recognized a promote ofB $10.3 millionB and originated aB $30.0 millionB preferred equity investment. Given our continuing involvement as a preferred equity holder, we deferred the gain on sale ofB $13.1 millionB as we did not meet the requirements of a sale under the full accrual method. We, along with our joint venture partners, retained one apartment unit at this property.

[5]

Prior to the recapitalization, we consolidated the investment for the months of August and September 2012 as a result of our 63.18% ownership interest and control over its activities. Immediately following the recapitalization in September 2012, our investment was 27.63%. The change in ownership resulted in a change in accounting from consolidating the investment to accounting for the joint venture under the equity method of accounting. During the year ended December 31, 2013, the joint venture sold three properties, the proceeds of which were used primarily to repay a portion of the debt. Also during the year ended December 31, 2013, we acquired in aggregate 14.39% ownership interest of two of our joint venture partners. As a result, we had a 42.04% effective ownership interest (43.74% effective economic interest) in the West Coast portfolio as of December 31, 2013. During the year ended December 31, 2014, we sold our ownership interest in the joint venture.

[6]

We sold our ownership interest in the joint venture. We, along with our joint venture partner, retained approximatelyB 91,300B square feet (unaudited) of development rights at the property.

[7]

We sold our ownership interest in the joint venture. The gain on the sale of this investment is net of a $1.5 million employee compensation award, accrued in connection with the realization of this investment gain as a bonus to certain employees that were instrumental in realizing the gain on this sale. Simultaneously, we, along with Sutton, also formed a new joint venture and retained the air rights at this property.

[8]

We, along with our joint venture partner, sold the property, which included the assumption by the purchaser of $315.0 million of existing debt.

[9]

We, along with our joint venture partner, sold the property, inclusive of the fee position, which was acquired for $13.5 million.

[10]

We, along with our joint venture partner, sold the property. The gain on the sale of this investment is net of a $1.5 million employee compensation award, accrued in connection with the realization of this investment gain as a bonus to certain employees that were instrumental in realizing the gain on this sale.

Investment_in_Unconsolidated_J3

Investment in Unconsolidated Joint Ventures (Details 3) (USD $)

3 Months Ended

12 Months Ended

1 Months Ended

Dec. 31, 2014

Sep. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

31-May-14

Feb. 28, 2014

Nov. 30, 2014

Oct. 31, 2014

Debt Instrument [Line Items]

Total fixed rate debt

$4,736,709,000

$4,130,629,000

$4,736,709,000

$4,130,629,000

Total floating rate debt

1,103,942,000

729,949,000

1,103,942,000

729,949,000

Total mortgages and other loans payable

5,840,651,000

4,860,578,000

5,840,651,000

4,860,578,000

Loss on early extinguishment of debt

-6,865,000

-24,475,000

-1,028,000

3,000

5,000

-10,000

-18,513,000

-32,365,000

-18,518,000

-6,978,000

1745 Broadway

Debt Instrument [Line Items]

Total fixed rate debt

16,000,000

[1]

16,000,000

[1]

388-390 Greenwich Street

Debt Instrument [Line Items]

Total fixed rate debt

1,004,000,000

[2]

1,004,000,000

[2]

Total floating rate debt

446,000,000

[2]

446,000,000

[2]

Joint venture

Debt Instrument [Line Items]

Total fixed rate debt

2,065,264,000

3,223,895,000

2,065,264,000

3,223,895,000

Total floating rate debt

1,713,440,000

1,842,815,000

1,713,440,000

1,842,815,000

Total mortgages and other loans payable

3,778,704,000

5,066,710,000

3,778,704,000

5,066,710,000

Maximum amount of loan recourse to entity

18,400,000

Joint venture | 7 Renaissance

Debt Instrument [Line Items]

Total fixed rate debt

2,147,000

1,276,000

2,147,000

1,276,000

Joint venture | 11 West 34th Street

Debt Instrument [Line Items]

Total fixed rate debt

16,905,000

17,205,000

16,905,000

17,205,000

Joint venture | 280 Park Avenue

Debt Instrument [Line Items]

Total fixed rate debt

700,171,000

706,886,000

700,171,000

706,886,000

Joint venture | 1745 Broadway

Debt Instrument [Line Items]

Total fixed rate debt

340,000,000

Joint venture | Jericho Plaza

Debt Instrument [Line Items]

Total fixed rate debt

163,750,000

Joint venture | 800 Third Avenue

Debt Instrument [Line Items]

Total fixed rate debt

20,910,000

Joint venture | 315 West 36th Street

Debt Instrument [Line Items]

Total fixed rate debt

25,000,000

Joint venture | 521 Fifth Avenue

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

3.73%

Total fixed rate debt

170,000,000

[3]

170,000,000

[3]

Total floating rate debt

[3]

170,000,000

[3]

170,000,000

[3]

Joint venture | 717 Fifth Avenue | Mortgage loan

Debt Instrument [Line Items]

Committed amount

300,000,000

Joint venture | 717 Fifth Avenue | Mezzanine loans

Debt Instrument [Line Items]

Committed amount

290,000,000

Joint venture | 21 East 66th Street

Debt Instrument [Line Items]

Total fixed rate debt

12,000,000

Total floating rate debt

1,883,000

1,959,000

1,883,000

1,959,000

Joint venture | 388-390 Greenwich Street

Debt Instrument [Line Items]

Total fixed rate debt

[4]

996,082,000

[4]

996,082,000

[4]

Total floating rate debt

[4]

142,297,000

[4]

142,297,000

[4]

Loss on early extinguishment of debt

-2,400,000

Joint venture | 100 Park Avenue

Debt Instrument [Line Items]

Total fixed rate debt

[5]

209,786,000

[5]

209,786,000

[5]

Total floating rate debt

360,000,000

[5]

360,000,000

[5]

Loss on early extinguishment of debt

-3,200,000

Joint venture | 21 West 34th Street

Debt Instrument [Line Items]

Total fixed rate debt

[6]

100,000,000

[6]

100,000,000

[6]

Joint venture | 1604-1610 Broadway

Debt Instrument [Line Items]

Total fixed rate debt

[7]

27,000,000

[7]

27,000,000

[7]

Incentive income

7,700,000

Joint venture | The Meadows

Debt Instrument [Line Items]

Total floating rate debt

67,350,000

Joint venture | 3 Columbus Circle

Debt Instrument [Line Items]

Total floating rate debt

230,974,000

[8]

239,233,000

[8]

230,974,000

[8]

239,233,000

[8]

Possible increase in mortgage based on meeting certain performance hurdles

40,000,000

Joint venture | 1552 Broadway

Debt Instrument [Line Items]

Total floating rate debt

184,210,000

[9]

158,690,000

[9]

184,210,000

[9]

158,690,000

[9]

Joint venture | 1552 Broadway | Mortgage loan

Debt Instrument [Line Items]

Committed amount

150,000,000

Unfunded amount

3,900,000

Joint venture | 1552 Broadway | Mezzanine loans

Debt Instrument [Line Items]

Committed amount

41,500,000

Unfunded amount

3,400,000

Joint venture | Other loan payable

Debt Instrument [Line Items]

Total floating rate debt

30,000,000

Joint venture | 650 Fifth Avenue

Debt Instrument [Line Items]

Total floating rate debt

65,000,000

[10]

65,000,000

[10]

Joint venture | 650 Fifth Avenue | Mortgage loan

Debt Instrument [Line Items]

Committed amount

97,000,000

Unfunded amount

32,000,000

Joint venture | 175-225 Third Street

Debt Instrument [Line Items]

Total floating rate debt

40,000,000

Joint venture | 10 East 53rd Street

Debt Instrument [Line Items]

Total floating rate debt

125,000,000

Joint venture | 724 Fifth Avenue

Debt Instrument [Line Items]

Total floating rate debt

275,000,000

[11]

120,000,000

[11]

275,000,000

[11]

120,000,000

[11]

Joint venture | 724 Fifth Avenue | Mezzanine loans

Debt Instrument [Line Items]

Loss on early extinguishment of debt

-1,200,000

Joint venture | 33 Beekman

Debt Instrument [Line Items]

Total floating rate debt

52,283,000

[12]

18,362,000

[12]

52,283,000

[12]

18,362,000

[12]

Maximum amount of loan recourse to entity

75,000,000

Joint venture | 600 Lexington Avenue

Debt Instrument [Line Items]

Total floating rate debt

116,740,000

120,616,000

116,740,000

120,616,000

Joint venture | 55 West 46th Street

Debt Instrument [Line Items]

Total floating rate debt

150,000,000

[13]

150,000,000

[13]

Joint venture | 55 West 46th Street | Mortgage loan

Debt Instrument [Line Items]

Committed amount

190,000,000

Unfunded amount

40,000,000

Joint venture | 121 Greene Street

Debt Instrument [Line Items]

Total floating rate debt

15,000,000

Joint venture | 747 Madison Avenue

Debt Instrument [Line Items]

Total floating rate debt

33,125,000

Joint venture | West Coast office portfolio

Debt Instrument [Line Items]

Total floating rate debt

[14]

526,290,000

[14]

526,290,000

[14]

Joint venture | 180/182 Broadway

Debt Instrument [Line Items]

Total floating rate debt

[15]

89,893,000

[15]

89,893,000

[15]

Initial Maturity July 2022 | Joint venture | 717 Fifth Avenue

Debt Instrument [Line Items]

Total fixed rate debt

300,000,000

[16]

300,000,000

[16]

300,000,000

[16]

300,000,000

[16]

Initial Maturity July 2024 | Joint venture | 717 Fifth Avenue

Debt Instrument [Line Items]

Total fixed rate debt

$314,381,000

[16]

$304,000,000

[16]

$314,381,000

[16]

$304,000,000

[16]

Weighted Average | 1745 Broadway

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

4.81%

[1],[17]

4.81%

[1],[17]

Weighted Average | 388-390 Greenwich Street

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

2.99%

[17],[2]

2.99%

[17],[2]

Interest rate, floating rate debt (as a percent)

1.91%

[17],[2]

1.91%

[17],[2]

Weighted Average | Joint venture | 7 Renaissance

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

10.00%

[17]

10.00%

[17]

Weighted Average | Joint venture | 11 West 34th Street

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

4.82%

[17]

4.82%

[17]

Weighted Average | Joint venture | 280 Park Avenue

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

6.57%

[17]

6.57%

[17]

Weighted Average | Joint venture | 1745 Broadway

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

5.68%

[17]

5.68%

[17]

Weighted Average | Joint venture | Jericho Plaza

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

5.65%

[17]

5.65%

[17]

Weighted Average | Joint venture | 800 Third Avenue

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

6.00%

[17]

6.00%

[17]

Weighted Average | Joint venture | 315 West 36th Street

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

3.16%

[17]

3.16%

[17]

Weighted Average | Joint venture | 521 Fifth Avenue

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

2.48%

[17],[3]

2.48%

[17],[3]

Interest rate, floating rate debt (as a percent)

0.00%

[17],[3]

0.00%

[17],[3]

Weighted Average | Joint venture | 21 East 66th Street

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

3.60%

[17]

3.60%

[17]

Interest rate, floating rate debt (as a percent)

2.88%

[17]

2.88%

[17]

Weighted Average | Joint venture | 388-390 Greenwich Street

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

0.00%

[17],[4]

0.00%

[17],[4]

Interest rate, floating rate debt (as a percent)

0.00%

[17],[4]

0.00%

[17],[4]

Weighted Average | Joint venture | 100 Park Avenue

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

0.00%

[17],[5]

0.00%

[17],[5]

Interest rate, floating rate debt (as a percent)

2.36%

[17],[5]

2.36%

[17],[5]

Weighted Average | Joint venture | 21 West 34th Street

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

0.00%

[17],[6]

0.00%

[17],[6]

Weighted Average | Joint venture | 1604-1610 Broadway

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

0.00%

[17],[7]

0.00%

[17],[7]

Weighted Average | Joint venture | The Meadows

Debt Instrument [Line Items]

Interest rate, floating rate debt (as a percent)

7.75%

[17]

7.75%

[17]

Weighted Average | Joint venture | 3 Columbus Circle

Debt Instrument [Line Items]

Interest rate, floating rate debt (as a percent)

2.33%

[17],[8]

2.33%

[17],[8]

Weighted Average | Joint venture | 1552 Broadway

Debt Instrument [Line Items]

Interest rate, floating rate debt (as a percent)

4.25%

[17],[9]

4.25%

[17],[9]

Weighted Average | Joint venture | Other loan payable

Debt Instrument [Line Items]

Interest rate, floating rate debt (as a percent)

1.05%

[17]

1.05%

[17]

Weighted Average | Joint venture | 650 Fifth Avenue

Debt Instrument [Line Items]

Interest rate, floating rate debt (as a percent)

3.66%

[10],[17]

3.66%

[10],[17]

Weighted Average | Joint venture | 175-225 Third Street

Debt Instrument [Line Items]

Interest rate, floating rate debt (as a percent)

4.25%

[17]

4.25%

[17]

Weighted Average | Joint venture | 10 East 53rd Street

Debt Instrument [Line Items]

Interest rate, floating rate debt (as a percent)

2.65%

[17]

2.65%

[17]

Weighted Average | Joint venture | 724 Fifth Avenue

Debt Instrument [Line Items]

Interest rate, floating rate debt (as a percent)

2.57%

[11],[17]

2.57%

[11],[17]

Weighted Average | Joint venture | 33 Beekman

Debt Instrument [Line Items]

Interest rate, floating rate debt (as a percent)

2.90%

[12],[17]

2.90%

[12],[17]

Weighted Average | Joint venture | 600 Lexington Avenue

Debt Instrument [Line Items]

Interest rate, floating rate debt (as a percent)

2.23%

[17]

2.23%

[17]

Weighted Average | Joint venture | 55 West 46th Street

Debt Instrument [Line Items]

Interest rate, floating rate debt (as a percent)

2.45%

[13],[17]

2.45%

[13],[17]

Weighted Average | Joint venture | 121 Greene Street

Debt Instrument [Line Items]

Interest rate, floating rate debt (as a percent)

1.67%

[17]

1.67%

[17]

Weighted Average | Joint venture | 747 Madison Avenue

Debt Instrument [Line Items]

Interest rate, floating rate debt (as a percent)

0.00%

[17]

0.00%

[17]

Weighted Average | Joint venture | West Coast office portfolio

Debt Instrument [Line Items]

Interest rate, floating rate debt (as a percent)

0.00%

[14],[17]

0.00%

[14],[17]

Weighted Average | Joint venture | 180/182 Broadway

Debt Instrument [Line Items]

Interest rate, floating rate debt (as a percent)

0.00%

[15],[17]

0.00%

[15],[17]

Weighted Average | Initial Maturity July 2022 | Joint venture | 717 Fifth Avenue

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

4.45%

[16],[17]

4.45%

[16],[17]

Weighted Average | Initial Maturity July 2024 | Joint venture | 717 Fifth Avenue

Debt Instrument [Line Items]

Interest rate, fixed rate debt (as a percent)

9.00%

[16],[17]

9.00%

[16],[17]

[1]

In connection with our acquisition of Witkoff's interest in the unconsolidated joint venture which holds 1745 Broadway, we have assumed this partner loan.

[2]

Simultaneous with the acquisition of our joint venture partner's interest, we refinanced theB $1.1 billionB floating rate mortgage with aB $1.45 billionB seven-year floating rate mortgage (including the as-of right extension option), and have consolidated the property. We assumed the existing derivative instruments, which swapped $504.0 million of the floating rate mortgage to a fixed rate mortgage which bears interest at 3.80% per annum. In October 2014, we entered into multiple swap agreements to hedge our interest rate exposure on the additional $500.0 million portion of this mortgage, which was swapped to a fixed rate of 2.69% per annum.

[3]

This loan became a 3.73% fixed rate mortgage upon the effectivity of the interest rate swap in November 2014.

[4]

In May 2014, we acquired the interest of our joint venture partner, thereby consolidating the entity. Simultaneous with the acquisition, we refinanced the mortgage and incurred a net loss on early extinguishment of debt of $2.4 million.

[5]

In February 2014, the joint venture refinanced the previous mortgage and incurred a net loss on early extinguishment of debt of $3.2 million.

[6]

In January 2014, we sold our interest in the joint venture, inclusive of our share of the joint venture debt.

[7]

This loan was in default since NovemberB 2009 due to the non-payment of debt service. In January 2014, the joint venture surrendered its ground lease position to the lender. During the year ended DecemberB 31, 2014, we recognized $7.7 million of incentive income, which is included in other income on the consolidated statements of income.

[8]

The joint venture has the ability to increase the mortgage by $40.0 million based on meeting certain performance hurdles. In connection with this obligation, we executed a master lease agreement and our joint venture partner executed a contribution agreement to reflect its pro rata obligation under the master lease. The lien on the mortgage and the master lease excludes the condominium interest owned by Y&R. See Note 4 of the first table.

[9]

These loans are comprised of a $150.0 million mortgage loan and a $41.5 million mezzanine loan. As of DecemberB 31, 2014, $3.9 million of the mortgage loan and $3.4 million of the mezzanine loan remained unfunded.

[10]

In October 2014, the joint venture closed on a $97.0 million leasehold mortgage, of which $32.0 million remained unfunded as of DecemberB 31, 2014.

[11]

In April 2014, the joint venture refinanced the previous mortgage and incurred a net loss on early extinguishment of debt of $1.2 million.

[12]

This loan has a committed amount of $75.0 million, of which $18.4 million is recourse to us. Our partner has indemnified us for its pro rata share of the recourse guarantee. A portion of the guarantee terminates upon the joint venture reaching certain milestones. We believe it is unlikely that we will be required to perform under this guarantee.

[13]

This loan has a committed amount of $190.0 million, of which $40.0 million remained unfunded as of DecemberB 31, 2014.

[14]

In March 2014, we sold our interest in the joint venture, inclusive of our share in the joint venture debt.

[15]

In September 2014, the joint venture sold the property and repaid the debt.

[16]

These loans are comprised of a $300.0 million fixed rate mortgage loan and $290.0 million mezzanine loan. The mezzanine loan is subject to accretion based on the difference between contractual interest rate and contractual pay rate.

[17]

Effective weighted average interest rate for the year ended DecemberB 31, 2014, taking into account interest rate hedges in effect during the period.

Investment_in_Unconsolidated_J4

Investment in Unconsolidated Joint Ventures (Details 4) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Assets
Commercial real estate property, net	$12,163,976	$10,687,540
Other assets	647,333	750,123
Liabilities and members' equity
Mortgages and other loans payable	5,586,709	4,860,578
Company's investments in unconsolidated joint ventures	1,172,020	1,113,218
Combined statements of income for the unconsolidated joint ventures
Operating expenses	282,283	276,589	275,872
Ground rent	32,307	31,951	31,504
Real estate taxes	217,843	203,076	194,371
Interest expense, net of interest income	317,400	310,894	309,681
Amortization of deferred financing costs	22,377	15,855	18,558
Transaction related costs, net of recoveries	8,707	3,985	5,402
Depreciation and amortization	400,001	357,599	351,539
Total expenses	1,345,015	1,253,003	1,230,652
Company's equity in net income from unconsolidated joint ventures	26,537	9,921	76,418
Joint venture
Assets
Commercial real estate property, net	5,275,632	6,846,021
Other assets	810,567	827,282
Total assets	6,086,199	7,673,303
Liabilities and members' equity
Mortgages and other loans payable	3,778,704	5,066,710
Other liabilities	485,572	596,960
Members' equity	1,821,923	2,009,633
Total liabilities and members' equity	6,086,199	7,673,303
Company's investments in unconsolidated joint ventures	1,172,020	1,113,218
Combined statements of income for the unconsolidated joint ventures
Total revenues	522,132	628,649	511,157
Operating expenses	82,436	114,633	80,722
Ground rent	9,898	2,863	2,975
Real estate taxes	64,217	71,755	53,613
Interest expense, net of interest income	178,743	225,765	221,476
Amortization of deferred financing costs	12,395	17,092	9,739
Transaction related costs, net of recoveries	535	808	2,044
Depreciation and amortization	137,793	192,504	166,336
Total expenses	486,017	625,420	536,905
(Loss) gain on early extinguishment of debt	-6,743	0	21,421
Net income (loss) before gain on sale	29,372	3,229	-4,327
Company's equity in net income from unconsolidated joint ventures	$26,537	$9,921	$76,418

Investments_in_Unconsolidated_1

Investments in Unconsolidated Joint Ventures Investment in Unconsolidated Joint Ventures- Additional Information (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
717 Fifth Avenue
Investment in Unconsolidated Joint Ventures
Other income recognized on distribution			$67,900,000
Joint venture
Investment in Unconsolidated Joint Ventures
Management fees, base revenue	16,900,000	4,700,000	7,900,000
The Meadows \| Joint venture
Investment in Unconsolidated Joint Ventures
Loss on early extinguishment of debt			$10,800,000

Deferred_Costs_Details

Deferred Costs (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred Costs [Abstract]
Deferred leasing	$385,555	$326,379
Deferred financing	193,776	157,088
Deferred costs, gross	579,331	483,467
Less accumulated amortization	-251,369	-216,409
Deferred costs, net	$327,962	$267,058

Mortgages_and_Other_Loans_Paya2

Mortgages and Other Loans Payable (Details) (USD $)	3 Months Ended										12 Months Ended					1 Months Ended
Mortgages and Other Loans Payable (Details) (USD $)	Dec. 31, 2014		Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Sep. 30, 2014	Feb. 28, 2013	Dec. 31, 2014		Jun. 30, 2014	Apr. 30, 2014	Nov. 30, 2012	Oct. 31, 2014
Debt Instrument [Line Items]
Total fixed rate debt	$4,736,709,000					$4,130,629,000					$4,736,709,000		$4,130,629,000					$4,736,709,000
Total floating rate debt	1,103,942,000					729,949,000					1,103,942,000		729,949,000					1,103,942,000
Total mortgages and other loans payable	5,840,651,000					4,860,578,000					5,840,651,000		4,860,578,000					5,840,651,000
Loss on early extinguishment of debt	6,865,000		24,475,000	1,028,000	-3,000	-5,000		0	10,000	18,513,000	32,365,000		18,518,000		6,978,000
Junior subordinate deferrable interest debentures held by trusts																						1,600,000,000
Book value of collateral	8,200,000,000					8,000,000,000					8,200,000,000		8,000,000,000					8,200,000,000
Series J Preferred Stock
Debt Instrument [Line Items]
Total fixed rate debt	4,000,000	[1]				0	[1]				4,000,000	[1]	0	[1]				4,000,000	[1]
Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest	4,000,000										4,000,000							4,000,000
Preferred Units, shares outstanding (shares)	4,000										4,000							4,000
Preferred Units (as a percent)											3.75%
Preferred Units, liquidation preference (in dollars per share)	$1,000										$1,000							$1,000
Master repurchase
Debt Instrument [Line Items]
Total floating rate debt	100,000,000	[2]				91,000,000	[2]				100,000,000	[2]	91,000,000	[2]				100,000,000	[2]
711 Third Avenue
Debt Instrument [Line Items]
Total fixed rate debt	120,000,000					120,000,000					120,000,000		120,000,000					120,000,000
500 West Putnam Avenue
Debt Instrument [Line Items]
Total fixed rate debt	22,968,000					23,529,000					22,968,000		23,529,000					22,968,000
Landmark Square
Debt Instrument [Line Items]
Total fixed rate debt	81,269,000					82,909,000					81,269,000		82,909,000					81,269,000
485 Lexington Avenue
Debt Instrument [Line Items]
Total fixed rate debt	450,000,000					450,000,000					450,000,000		450,000,000					450,000,000
120 West 45th Street
Debt Instrument [Line Items]
Total fixed rate debt	170,000,000					170,000,000					170,000,000		170,000,000					170,000,000
762 Madison Avenue
Debt Instrument [Line Items]
Total fixed rate debt	8,045,000					8,211,000					8,045,000		8,211,000					8,045,000
885 Third Avenue
Debt Instrument [Line Items]
Total fixed rate debt	267,650,000					267,650,000					267,650,000		267,650,000					267,650,000
1745 Broadway
Debt Instrument [Line Items]
Total fixed rate debt	16,000,000	[3]				0	[3]				16,000,000	[3]	0	[3]				16,000,000	[3]
388-390 Greenwich Street
Debt Instrument [Line Items]
Total fixed rate debt	1,004,000,000	[4]				0	[4]				1,004,000,000	[4]	0	[4]				1,004,000,000	[4]
Total floating rate debt	446,000,000	[4]				0	[4]				446,000,000	[4]	0	[4]				446,000,000	[4]
Extinguishment of debt											1,100,000,000
Refinanced mortgage loan	1,450,000,000										1,450,000,000							1,450,000,000
Term											7 years
388-390 Greenwich Street \| Swap One
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.80%										3.80%							3.80%
Total fixed rate debt	504,000,000										504,000,000							504,000,000
388-390 Greenwich Street \| Swap Two
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)																							2.69%
Total fixed rate debt																							500,000,000
One Madison Avenue
Debt Instrument [Line Items]
Total fixed rate debt	565,742,000					587,336,000					565,742,000		587,336,000					565,742,000
100 Church
Debt Instrument [Line Items]
Total fixed rate debt	228,612,000					230,000,000					228,612,000		230,000,000					228,612,000
919 Third Avenue
Debt Instrument [Line Items]
Total fixed rate debt	500,000,000	[5]				500,000,000	[5]				500,000,000	[5]	500,000,000	[5]				500,000,000	[5]
Interest in property (as a percent)	51.00%										51.00%							51.00%
400 East 57th Street
Debt Instrument [Line Items]
Total fixed rate debt	68,896,000					70,000,000					68,896,000		70,000,000					68,896,000
400 East 58th Street
Debt Instrument [Line Items]
Total fixed rate debt	29,527,000					30,000,000					29,527,000		30,000,000					29,527,000
420 Lexington Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.99%										3.99%							3.99%
Total fixed rate debt	300,000,000	[6]				182,641,000	[6]				300,000,000	[6]	182,641,000	[6]				300,000,000	[6]
Loss on early extinguishment of debt																24,500,000
1515 Broadway
Debt Instrument [Line Items]
Total fixed rate debt	900,000,000	[7]				900,000,000	[7]				900,000,000	[7]	900,000,000	[7]				900,000,000	[7]
Loss on early extinguishment of debt																	18,500,000
Other loan payable
Debt Instrument [Line Items]
Total fixed rate debt	0	[8]				50,000,000	[8]				0	[8]	50,000,000	[8]				0	[8]
609 Partners, LLC
Debt Instrument [Line Items]
Total fixed rate debt	0	[9]				23,000	[9]				0	[9]	23,000	[9]				0	[9]
609 Partners, LLC \| Series E preferred units
Debt Instrument [Line Items]
Preferred Units, shares outstanding (shares)																					22,658
125 Park Avenue
Debt Instrument [Line Items]
Total fixed rate debt	0	[10]				146,250,000	[10]				0	[10]	146,250,000	[10]				0	[10]
2 Herald Square
Debt Instrument [Line Items]
Total fixed rate debt	0	[11]				191,250,000	[11]				0	[11]	191,250,000	[11]				0	[11]
625 Madison Avenue
Debt Instrument [Line Items]
Total fixed rate debt	0					120,830,000					0		120,830,000					0
Loss on early extinguishment of debt																		6,900,000
Master repurchase
Debt Instrument [Line Items]
Junior subordinate deferrable interest debentures held by trusts	300,000,000										300,000,000							300,000,000
180 Maiden Lane
Debt Instrument [Line Items]
Total floating rate debt	253,942,000	[12]				262,706,000	[12]				253,942,000	[12]	262,706,000	[12]				253,942,000	[12]
248-252 Bedford Avenue
Debt Instrument [Line Items]
Total floating rate debt	29,000,000	[13]				22,000,000	[13]				29,000,000	[13]	22,000,000	[13]				29,000,000	[13]
Loss on early extinguishment of debt																				500,000
220 East 42nd Street
Debt Instrument [Line Items]
Total floating rate debt	275,000,000					275,000,000					275,000,000		275,000,000					275,000,000
16 Court Street
Debt Instrument [Line Items]
Total floating rate debt	0	[14]				79,243,000	[14]				0	[14]	79,243,000	[14]				0	[14]
Loss on early extinguishment of debt																					$500,000
Weighted Average \| Series J Preferred Stock
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.75%	[1],[15]									3.75%	[1],[15]						3.75%	[1],[15]
Weighted Average \| Master repurchase
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	3.38%	[15],[2]									3.38%	[15],[2]						3.38%	[15],[2]
Weighted Average \| 711 Third Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	4.99%	[15]									4.99%	[15]						4.99%	[15]
Weighted Average \| 500 West Putnam Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	5.52%	[15]									5.52%	[15]						5.52%	[15]
Weighted Average \| Landmark Square
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	4.00%	[15]									4.00%	[15]						4.00%	[15]
Weighted Average \| 485 Lexington Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	5.61%	[15]									5.61%	[15]						5.61%	[15]
Weighted Average \| 120 West 45th Street
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	6.12%	[15]									6.12%	[15]						6.12%	[15]
Weighted Average \| 762 Madison Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.75%	[15]									3.75%	[15]						3.75%	[15]
Weighted Average \| 885 Third Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	6.26%	[15]									6.26%	[15]						6.26%	[15]
Weighted Average \| 1745 Broadway
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	4.81%	[15],[3]									4.81%	[15],[3]						4.81%	[15],[3]
Weighted Average \| 388-390 Greenwich Street
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	2.99%	[15],[4]									2.99%	[15],[4]						2.99%	[15],[4]
Interest rate, floating rate debt (as a percent)	1.91%	[15],[4]									1.91%	[15],[4]						1.91%	[15],[4]
Weighted Average \| One Madison Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	5.91%	[15]									5.91%	[15]						5.91%	[15]
Weighted Average \| 100 Church
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	4.68%	[15]									4.68%	[15]						4.68%	[15]
Weighted Average \| 919 Third Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	5.12%	[15],[5]									5.12%	[15],[5]						5.12%	[15],[5]
Weighted Average \| 400 East 57th Street
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	4.13%	[15]									4.13%	[15]						4.13%	[15]
Weighted Average \| 400 East 58th Street
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	4.13%	[15]									4.13%	[15]						4.13%	[15]
Weighted Average \| 420 Lexington Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	5.95%	[15],[6]									5.95%	[15],[6]						5.95%	[15],[6]
Weighted Average \| 1515 Broadway
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.93%	[15],[7]									3.93%	[15],[7]						3.93%	[15],[7]
Weighted Average \| 180 Maiden Lane
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	2.35%	[12],[15]									2.35%	[12],[15]						2.35%	[12],[15]
Weighted Average \| 248-252 Bedford Avenue
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	1.93%	[13],[15]									1.93%	[13],[15]						1.93%	[13],[15]
Weighted Average \| 220 East 42nd Street
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	1.75%	[15]									1.75%	[15]						1.75%	[15]

[1]	In connection with the acquisition of a commercial real estate property, the Operating Partnership issued $4.0 millionB orB 4,000B 3.75%B Series J Preferred Units of limited partnership interest, or the Series J Preferred Units, with a mandatory liquidation preference of $1,000.00B per unit. The Series J Preferred Units can be redeemed in cash by the Operating Partnership on the earlier of (i) the date of the sale of the property or (ii) April 30, 2051 or at the option of the unitholders as further prescribed in the related agreement.
[2]	The Master Repurchase Agreement, or MRA, has a maximum facility capacity of $300.0 million. In December 2014, we extended the maturity date of the MRA to December 5, 2015.
[3]	In connection with our acquisition of Witkoff's interest in the unconsolidated joint venture which holds 1745 Broadway, we have assumed this partner loan.
[4]	Simultaneous with the acquisition of our joint venture partner's interest, we refinanced theB $1.1 billionB floating rate mortgage with aB $1.45 billionB seven-year floating rate mortgage (including the as-of right extension option), and have consolidated the property. We assumed the existing derivative instruments, which swapped $504.0 million of the floating rate mortgage to a fixed rate mortgage which bears interest at 3.80% per annum. In October 2014, we entered into multiple swap agreements to hedge our interest rate exposure on the additional $500.0 million portion of this mortgage, which was swapped to a fixed rate of 2.69% per annum.
[5]	We own a 51.0% controlling interest in the joint venture that is the borrower on this loan.
[6]	In September 2014, we refinanced the previous mortgage and incurred a loss on early extinguishment of debt of $24.5 million. The new loan bears a fixed interest rate of 3.99% per annum.
[7]	In FebruaryB 2013, we refinanced the mortgage and incurred a loss on early extinguishment of debt of $18.5 million.
[8]	The joint venture has the ability to increase the mortgage by $40.0 million based on meeting certain performance hurdles. In connection with this obligation, we executed a master lease agreement and our joint venture partner executed a contribution agreement to reflect its pro rata obligation under the master lease. The lien on the mortgage and the master lease excludes the condominium interest owned by Y&R. See Note 4 of the first table.
[9]	In April 2014, the remaining 22,658 Series E Preferred Units of the Operating Partnership were canceled.
[10]	In October 2014, we repaid the loan at maturity.
[11]	In December 2014, we prepaid the loan and incurred a loss on early extinguishment of debt ofB $6.9 million.
[12]	In connection with this consolidated joint venture obligation, we executed a master lease agreement. Our partner has executed a contribution agreement to reflect its pro rata share of the obligation under the master lease. This property was held for sale at DecemberB 31, 2014 and the related mortgage is included in liabilities related to assets held for sale. In January 2015, the property was sold and the debt was repaid.
[13]	In June 2014, we refinanced the mortgage and incurred a loss on early extinguishment of debt ofB $0.5 million. In April 2014, we repaid the mortgage and incurred a loss on early extinguishment of debt ofB $0.5 million.
[14]	il 2014, we repaid the mortgage and incurred a loss on early extinguishment of de
[15]	Effective weighted average interest rate for the year ended DecemberB 31, 2014, taking into account interest rate hedges in effect during the period.

Corporate_Indebtedness_Details

Corporate Indebtedness (Details) (USD $)	12 Months Ended	1 Months Ended			12 Months Ended	1 Months Ended
Corporate Indebtedness (Details) (USD $)	Dec. 31, 2014	Nov. 30, 2014	Mar. 31, 2014	Jan. 31, 2015	Dec. 31, 2013	Jun. 30, 2005	Nov. 30, 2012
Corporate Indebtedness
Credit facility, maximum borrowing capacity							$1,600,000,000
Outstanding under line of credit facility	385,000,000				220,000,000
2012 Credit Facility
Corporate Indebtedness
Letters of credit	113,200,000
Ability to borrow under line of credit facility	701,800,000
Debt origination	3,000,000
Revolving credit facility
Corporate Indebtedness
Credit facility, maximum borrowing capacity							1,200,000,000
Maximum borrowing capacity, optional expansion							1,500,000,000
Effective rate (as a percent)	1.61%
Outstanding under line of credit facility	385,000,000
Revolving credit facility \| Maximum
Corporate Indebtedness
Unused balance fee	0.35%
Revolving credit facility \| Minimum
Corporate Indebtedness
Facility fee	0.30%
Unused balance fee	0.15%
Revolving credit facility \| LIBOR
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.45%
Revolving credit facility \| LIBOR \| Maximum
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.75%
Revolving credit facility \| LIBOR \| Minimum
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.00%
Term loan
Corporate Indebtedness
Credit facility, maximum borrowing capacity	833,000,000	833,000,000	783,000,000
Increase in credit facility		50,000,000	383,000,000
Decrease in basis points			0.25%
Effective rate (as a percent)	1.67%
Term loan \| LIBOR
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.40%
Term loan \| LIBOR \| Maximum
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.90%
Term loan \| LIBOR \| Minimum
Corporate Indebtedness
Interest rate added to base rate (as a percent)	0.95%
Term loan \| Subsequent Event
Corporate Indebtedness
Decrease in basis points				0.20%
Facility fee				0.05%
2011 Revolving Credit Facility
Corporate Indebtedness
Credit facility, maximum borrowing capacity	1,500,000,000
2011 Revolving Credit Facility \| Maximum
Corporate Indebtedness
Unused balance fee					0.45%
2011 Revolving Credit Facility \| Minimum
Corporate Indebtedness
Unused balance fee					0.18%
2011 Revolving Credit Facility \| LIBOR \| Maximum
Corporate Indebtedness
Interest rate added to base rate (as a percent)					1.85%
2011 Revolving Credit Facility \| LIBOR \| Minimum
Corporate Indebtedness
Interest rate added to base rate (as a percent)					1.00%
Trust Preferred Securities
Corporate Indebtedness
Debt instrument issued, value						$100,000,000
Interest rate (as a percent)	5.61%
Number of years for which securities will bear fixed rate of interest						10 years
Trust Preferred Securities \| LIBOR
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.25%

Corporate_Indebtedness_Details1

Corporate Indebtedness (Details 2) (USD $)	12 Months Ended
Corporate Indebtedness (Details 2) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Oct. 06, 2010	Mar. 20, 2007
Debt disclosures by scheduled maturity date
Accreted Balance	$2,107,078,000		$1,739,330,000
Senior unsecured notes
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	1,310,323,000
Accreted Balance	1,274,078,000		1,339,330,000
Senior unsecured notes \| 6.00% Senior unsecured notes maturing on March 31, 2016
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	255,308,000	[1]
Accreted Balance	255,250,000	[1]	255,206,000	[1]
Coupon Rate (as a percent)	6.00%	[1],[2]
Effective rate (as a percent)	6.00%	[1]
Term	10 years	[1]
Senior unsecured notes \| 3.00% Senior unsecured notes maturing on October 15, 2017
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	345,000,000	[3]
Accreted Balance	309,069,000	[3]	297,837,000	[3]
Coupon Rate (as a percent)	3.00%	[2],[3]
Effective rate (as a percent)	3.00%	[3]
Term	7 years	[3]
Premium on sale price to calculate exchange price of notes (as a percent)					30.00%
Exchange price (in dollars per share)					$85.81
Adjusted exchange rate for the debentures (in shares)	12.1163
Amount of convertible debt recorded in equity					78,300,000
Debt Instrument, Unamortized Discount	35,900,000
Senior unsecured notes \| 5.00% Senior unsecured notes maturing on August 15, 2018
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	250,000,000	[4]
Accreted Balance	249,744,000	[4]	249,681,000	[4]
Coupon Rate (as a percent)	5.00%	[2],[4]
Effective rate (as a percent)	5.00%	[4]
Term	7 years	[4]
Senior unsecured notes \| 7.75% Senior unsecured notes maturing on March 15, 2020
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	250,000,000	[4]
Accreted Balance	250,000,000	[4]	250,000,000	[4]
Coupon Rate (as a percent)	7.75%	[2],[4]
Effective rate (as a percent)	7.75%	[4]
Term	10 years	[4]
Senior unsecured notes \| 4.50% Senior unsecured notes maturing on December 1, 2022
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	200,000,000	[4]
Accreted Balance	200,000,000	[4]	200,000,000	[4]
Coupon Rate (as a percent)	4.50%	[2],[4]
Effective rate (as a percent)	4.50%	[4]
Term	10 years	[4]
Senior unsecured notes \| 4.00% Senior unsecured notes maturing on June 15, 2025
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	7,000	[1],[5]
Accreted Balance	7,000	[1],[5]	7,000	[1],[5]
Coupon Rate (as a percent)	4.00%	[1],[2],[5]
Effective rate (as a percent)	4.00%	[1],[5]
Term	20 years	[1],[5]
Exchange price (in dollars per share)	$1.35
Adjusted exchange rate for the debentures (in shares)	7.7461
Senior unsecured notes \| 3.00% Senior unsecured notes maturing on March 30, 2027
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	10,008,000	[6]
Accreted Balance	10,008,000	[6]	10,701,000	[6]
Coupon Rate (as a percent)	3.00%	[2],[6]
Effective rate (as a percent)	3.00%	[6]
Term	20 years	[6]
Premium on sale price to calculate exchange price of notes (as a percent)						25.00%
Exchange price (in dollars per share)						$173.30
Adjusted exchange rate for the debentures (in shares)	5.7952
Senior unsecured notes \| Senior unsecured notes due August 15, 2014
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	0	[1],[7]
Accreted Balance	$0	[1],[7]	$75,898,000	[1],[7]
Coupon Rate (as a percent)		[1],[2],[7]
Effective rate (as a percent)		[1],[7]
Term		[1],[7]

[1]	Issued by ROP.
[2]	Interest on the senior unsecured notes is payable semi-annually with principal and unpaid interest due on the scheduled maturity dates.
[3]	Issued by the Operating Partnership. Interest on these exchangeable notes is payable semi-annually on AprilB 15 and OctoberB 15. The notes had an initial exchange rate representing an exchange price that was set at aB 30.0%B premium to the last reported sale price of SL Green's common stock on OctoberB 6, 2010, orB $85.81. The initial exchange rate is subject to adjustment under certain circumstances. The current exchange rate isB 12.1163B shares of SL Green's common stock per $1,000 principal amount of these notes. The notes are senior unsecured obligations of the Operating Partnership and are exchangeable upon the occurrence of specified events and during the period beginning on the twenty-second scheduled trading day prior to the maturity date and ending on the second business day prior to the maturity date, into cash or a combination of cash and shares of SL Green's common stock, if any, at our option. As a result of meeting specified events (as defined in the Indenture Agreement), these notes are exchangeable commencing January 1, 2015 and will remain exchangeable through March 31, 2015. The notes are guaranteed by ROP. On the issuance date,B $78.3 millionB of the debt balance was recorded in equity. As ofB DecemberB 31, 2014,B $35.9 millionB remained to be amortized into the debt balance.
[4]	Issued by the Company, the Operating Partnership and ROP, as co-obligors.
[5]	Exchangeable senior debentures which are currently callable at par. In addition, the debentures can be put to ROP, at the option of the holder at par plus accrued and unpaid interest, on JuneB 15, 2015 and 2020 and upon the occurrence of certain change of control transactions. As a result of the acquisition of all outstanding shares of common stock of Reckson, or the Reckson Merger, the adjusted exchange rate for the debentures isB 7.7461B shares of SL Green's common stock perB $1,000B of principal amount of debentures and the adjusted reference dividend for the debentures isB $1.3491.
[6]	Issued by the Operating Partnership. Interest on these remaining exchangeable notes is payable semi-annually on MarchB 30 and SeptemberB 30. The notes have an initial exchange rate representing an exchange price that was set at aB 25.0%B premium to the last reported sale price of the Company's common stock on MarchB 20, 2007, orB $173.30. The initial exchange rate is subject to adjustment under certain circumstances. The current exchange rate is 5.7952 shares of SL Green's common stock per $1,000 principal amount of these notes. The notes are senior unsecured obligations of the Operating Partnership and are exchangeable upon the occurrence of specified events and during the period beginning on the twenty-second scheduled trading day prior to the maturity date and ending on the second business day prior to the maturity date, into cash or a combination of cash and shares of SL Green's common stock, if any, at our option. The notes are currently redeemable at the Operating Partnershipbs option. The Operating Partnership may be required to repurchase the notes on MarchB 30, 2017 and 2022, and upon the occurrence of certain designated events.
[7]	In August 2014, these notes were repaid at maturity.

Corporate_Indebtedness_Details2

Corporate Indebtedness (Details 3) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified	Dec. 31, 2014
Scheduled Amortization and Principal Repayments
2015	$259,360
2016	648,117
2017	1,311,400
2018	715,462
2019	932,450
Thereafter	4,602,185
Total amortization of debt and principal repayments	8,468,974
Mortgages and other loans payable
Scheduled Amortization
2015	39,353	[1]
2016	54,344	[1]
2017	61,063
2018	64,462
2019	71,133
Thereafter	203,098
Total amortization of debt	493,453	[1]
Principal Repayments
2015	220,000
2016	338,465	[1]
2017	895,329
2018	16,000
2019	28,317
Thereafter	3,849,087
Total principal repayments	5,347,198	[1]
Term loan
Scheduled Amortization and Principal Repayments
2015	0
2016	0
2017	0
2018	0
2019	833,000
Thereafter	0
Total amortization of debt and principal repayments	833,000
2011 Revolving Credit Facility
Scheduled Amortization and Principal Repayments
2015	0
2016	0
2017	0
2018	385,000
2019	0
Thereafter	0
Total amortization of debt and principal repayments	385,000
Term Loans and Trust Preferred Securities
Scheduled Amortization and Principal Repayments
2015	0
2016	0
2017	0
2018	0
2019	0
Thereafter	100,000
Total amortization of debt and principal repayments	100,000
Senior Unsecured Notes
Scheduled Amortization and Principal Repayments
2015	7
2016	255,308
2017	355,008
2018	250,000
2019	0
Thereafter	450,000
Total amortization of debt and principal repayments	1,310,323
Joint venture
Principal Repayments
2015	44,700
2016	640,176
2017	572,003
2018	28
2019	94,890
Thereafter	266,191
Total principal repayments	$1,617,988

[1]	Scheduled amortization and principal repayments include the mortgage at 180 Maiden Lane, which is included in liabilities related to assets held for sale. In January 2015, the property was sold and the debt was repaid.

Corporate_Idebtedness_Details_

Corporate Idebtedness (Details 4) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Interest expense
Interest expense	$319,898	$312,897	$311,235
Interest income	-2,498	-2,003	-1,554
Interest expense, net	317,400	310,894	309,681
Interest capitalized	$22,750	$11,475	$12,218

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	12 Months Ended
Related Party Transactions (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Amounts due from/to related parties
Due from joint ventures	$1,254,000	$2,376,000
Other	10,481,000	6,154,000
Related party receivables	11,735,000	8,530,000
Alliance Building Services
Related Party Transactions
Profit participation from related party	3,800,000	3,500,000	4,000,000
Payments made for services	21,500,000	23,400,000	20,500,000
Entity with Stephen L Green ownership interest
Related Party Transactions
Property management fees from related party	$444,300	$441,100	$384,900

Noncontrolling_Interests_on_th2

Noncontrolling Interests on the Company's Consolidated Financial Statements (Details) (USD $)	12 Months Ended			1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 31, 2012	Aug. 31, 2014	Oct. 31, 2014
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Balance at beginning of period	$265,476,000
Distributions	-7,019,000	-14,623,000	-21,946,000
Net income	18,467,000	3,023,000	5,597,000
Accumulated other comprehensive income allocation	175,000	611,000	-388,000
Balance at end of period	469,524,000	265,476,000
SL Green Operating Partnership
Organization
Noncontrolling interest in the operating partnership (as a percent)	3.92%	2.96%
Number of units of operating partnership owned by the noncontrolling interest unit holders (shares)	3,973,016	2,902,317
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares)	3,973,016
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Balance at beginning of period	265,476,000	212,907,000
Distributions	-7,849,000	-4,146,000
Issuance of common units	56,469,000	24,750,000
Redemption of common units	-31,653,000	-17,287,000
Net income	18,467,000	3,023,000
Accumulated other comprehensive income allocation	175,000	611,000
Fair value adjustment	168,439,000	45,618,000
Balance at end of period	469,524,000	265,476,000
SL Green Operating Partnership \| Series G Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares)				1,902,000
Dividend rate preferred units (as a percent)				4.50%
Liquidation preference of preferred units (in dollars per share)				$25
Annual dividends on preferred units (in dollars per share)				$1.13
Operating partnership common stock value use for conversion of preferred units (in dollars per share)				$88.50
Number of company common stock issue on redemption of operation partnership common units				1
SL Green Operating Partnership \| Series F Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares)	60
Mandatory liquidation preference	$1,000
SL Green Operating Partnership \| Series K Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares)					563,954
Dividend rate preferred units (as a percent)					3.50%
Liquidation preference of preferred units (in dollars per share)					$25
Annual dividends on preferred units (in dollars per share)					$0.88
Operating partnership common stock value use for conversion of preferred units (in dollars per share)					$134.67
Preferred Units, Authorized					700,000
SL Green Operating Partnership \| Series L Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares)					378,634
Dividend rate preferred units (as a percent)					4.00%
Liquidation preference of preferred units (in dollars per share)					$25
Annual dividends on preferred units (in dollars per share)					$1
Preferred Units, Authorized					500,000
SL Green Operating Partnership \| Series H Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares)						80,000
Dividend rate preferred units (as a percent)						6.00%
Liquidation preference of preferred units (in dollars per share)						$25
Annual dividends on preferred units (in dollars per share)						$0.06

Stockholders_Equity_of_the_Com2

Stockholders' Equity of the Company (Details) (USD $)	1 Months Ended	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Nov. 30, 2013	Dec. 31, 2014	Dec. 31, 2013
Stockholders' Equity Note [Abstract]
Authorized capital stock (in shares)		260,000,000
Authorized shares, par value (in dollars per share)		$0.01
Common stock, shares authorized (shares)		160,000,000	160,000,000
Common stock, par value (in dollars per share)	$0.01	$0.01	$0.01
Excess stock, shares authorized (shares)		75,000,000
Excess stock, par value (in dollars per share)		$0.01
Preferred stock, shares authorized (shares)		25,000,000
Preferred stock, par value (in dollars per share)		$0.01
Shares issued (shares)		97,325,200
Excess shares issued (shares)		0
Excess shares outstanding (shares)		0
Issuance of common stock (shares)	2,600,000
Share Price	$95.94
Issuance of common stock	$248,900	$185,321	$290,699

Stockholders_Equity_of_the_Com3

Stockholders' Equity of the Company (Details 2) (USD $)	1 Months Ended	3 Months Ended								12 Months Ended			1 Months Ended			6 Months Ended
Stockholders' Equity of the Company (Details 2) (USD $)	Nov. 30, 2013	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Aug. 31, 2012	Jun. 30, 2013	Sep. 30, 2012	Jun. 30, 2013	Jul. 31, 2011	Mar. 31, 2012
Stockholders' Equity
Net proceeds from sale of common stock										$185,321,000	$290,699,000	$201,279,000
Issuance of common stock (shares)	2,600,000
Net proceeds from sale of preferred stock										0	0	221,965,000
Preferred stock redemption costs		0	0	0	0	0	0	12,160,000	0	0	12,160,000	10,010,000
Common stock, shares authorized (shares)		160,000,000				160,000,000				160,000,000	160,000,000
At-the-market equity offering programs
Stockholders' Equity
Aggregate value of the shares of common stock to be sold																	250,000,000
Net proceeds from sale of common stock										2,800,000
Issuance of common stock (shares)										25,659
New At-the-Market Equity offering programs
Stockholders' Equity
Aggregate value of the shares of common stock to be sold				300,000,000
Net proceeds from sale of common stock										182,900,000
Issuance of common stock (shares)										1,626,999
Series I Preferred Stock
Stockholders' Equity
Preferred stock, shares outstanding (shares)		9,200,000				9,200,000				9,200,000	9,200,000
Dividend rate preferred units (as a percent)										6.50%
Perpetual Preferred stock, liquidation preference (in dollars per share)		$25				$25				$25	$25
Perpetual Preferred stock, annual dividends per share (in dollars per share)										$1.63
Net proceeds from sale of preferred stock													221,900,000
Series C Preferred Stock
Stockholders' Equity
Preferred stock, shares outstanding (shares)								7,700,000					11,700,000	7,700,000		7,700,000
Dividend rate preferred units (as a percent)														7.63%		7.63%
Perpetual Preferred stock, liquidation preference (in dollars per share)								$25						$25		$25
Perpetual Preferred stock, annual dividends per share (in dollars per share)														$0.35	$0.37	$1.91
Preferred stock redemption costs														12,200,000	6,300,000
Preferred stock redeemed (in shares)															4,000,000
Preferred stock Redemption (in dollars per share)															$25
Dividend Reinvestment and Stock Purchase Plan (DRIP)
Stockholders' Equity
Net proceeds from sale of common stock										$63,720	$66,600	$99,600,000
Issuance of common stock (shares)										608	761	1,300,000
Common stock, shares authorized (shares)																		3,500,000

Stockholders_Equity_of_the_Com4

Stockholders' Equity of the Company (Details 3) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Basic Earnings:
Net income attributable to SL Green common stockholders	$56,787	$64,688	$235,539	$146,090	$37,120	$37,025	$8,276	$18,909	$503,104	$101,330	$155,984
Diluted Earnings:
Income attributable to SLGOP common unitholders									521,571	104,353	161,581
Basic Shares:
Basic weighted average common shares outstanding (in shares)									95,774,000	92,269,000	89,319,000
Effect of Dilutive Securities:
Redemption of units to common shares (shares)									3,514,000	2,735,000	3,207,000
Stock-based compensation plans (in shares)									408,000	262,000	347,000
Diluted weighted average common stock outstanding (shares)									99,696,000	95,266,000	92,873,000
Common stock shares excluded from the diluted shares outstanding									737,361	964,789	627,000
Common Stock
Effect of Dilutive Securities:
Redemption of units to common shares									$18,467	$3,023	$5,597

Partners_Capital_of_the_Operat2

Partners' Capital of the Operating Partnership (Details)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Common Stock
Stockholders' Equity
Units outstanding (units)	97,325,000	94,993,000	91,250,000	85,783,000
SL Green Operating Partnership
Stockholders' Equity
Noncontrolling interest in the operating partnership (as a percent)	3.92%	2.96%
Number of units of operating partnership owned by the noncontrolling interest unit holders (units)	3,973,016	2,902,317
SL Green Operating Partnership \| Series I Preferred Units
Stockholders' Equity
Units outstanding (units)	9,200,000
SL Green Operating Partnership \| Common Stock
Stockholders' Equity
Units outstanding (units)	97,325,200

Partners_Capital_of_the_Operat3

Partners' Capital of the Operating Partnership-EPS (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stockholders' Equity
Net income attributable to SL Green common stockholders	$56,787	$64,688	$235,539	$146,090	$37,120	$37,025	$8,276	$18,909	$503,104	$101,330	$155,984
Basic weighted average common shares outstanding (in shares)									95,774,000	92,269,000	89,319,000
Common stock shares excluded from the diluted shares outstanding									737,361	964,789	627,000
SL Green Operating Partnership
Stockholders' Equity
Net income attributable to SL Green common stockholders									$521,571	$104,353	$161,581
Basic weighted average common shares outstanding (in shares)									99,288,000	95,004,000	92,526,000
Stock-based compensation plans (shares)									408,000	262,000	347,000
Diluted weighted average common units outstanding (shares)									99,696,000	95,266,000	92,873,000
Common stock shares excluded from the diluted shares outstanding									737,361	964,789	627,000

Sharebased_Compensation_Detail

Share-based Compensation (Details) (USD $)	12 Months Ended
Share-based Compensation (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock options
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Dividend yield (as a percent)	1.60%	1.92%	2.00%
Expected life of option	3 years 7 months 6 days	4 years 1 month 6 days	3 years 8 months 12 days
Risk-free interest rate (as a percent)	1.29%	0.96%	0.46%
Expected stock price volatility (as a percent)	33.97%	36.12%	37.40%
Options Outstanding
Balance at beginning of year (in shares)	1,765,034	1,201,000	1,277,200
Granted (in shares)	102,050	828,100	361,331
Exercised (in shares)	-348,156	-223,531	-382,612
Lapsed or cancelled (in shares)	-56,202	-40,535	-54,919
Balance at end of period (in shares)	1,462,726	1,765,034	1,201,000
Options exercisable at end of period (in shares)	428,951	461,458	479,913
Weighted average fair value of award granted during the year	$2,841,678	$18,041,576	$6,602,967
Weighted Average Exercise Price
Balance at beginning of year (in dollars per share)	$83.24	$75.05	$63.37
Granted (in dollars per share)	$119.12	$87.23	$75.36
Exercised (in dollars per share)	$72.76	$53.93	$36.65
Lapsed or cancelled (in dollars per share)	$90.03	$83.94	$72.99
Balance at end of period (in dollars per share)	$87.98	$83.24	$75.05
Options exercisable at end of period (in dollars per share)	$90.32	$89.38	$86.85
Restricted Stock Awards
Options Outstanding
Weighted average fair value of award granted during the year	1,141,675	17,386,949	7,023,942
Summary of restricted stock
Balance at beginning of year (in shares)	2,994,197	2,804,901	2,912,456
Granted (in shares)	9,550	192,563	92,729
Cancelled (in shares)	-2,768	-3,267	-200,284
Balance at end of period (in shares)	3,000,979	2,994,197	2,804,901
Vested during the period (in shares)	75,043	21,074	408,800
Compensation expense recorded	$9,658,019	$6,713,155	$6,930,381

Sharebased_CompensationAdditio

Share-based Compensation-Additional Information (Details) (USD $)

12 Months Ended

1 Months Ended

3 Months Ended

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Sep. 30, 2014

Mar. 31, 2014

Dec. 31, 2011

Dec. 11, 2013

Dec. 17, 2012

Dec. 31, 2010

Jun. 30, 2014

Aug. 31, 2011

Sep. 01, 2014

Aug. 31, 2014

Jan. 31, 2008

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Cost of the plan, subject to adjustment for forfeitures

$6,800,000

$4,500,000

$4,100,000

Stock options

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Period of commencement of option vesting, from date of grant

1 year

Exercise price of options granted, low end of the range (in dollars per share)

$20.67

Exercise price of options granted, high end of the range (in dollars per share)

$137.18

Remaining weighted average contractual life of the options outstanding

4 years 0 months 22 days

Remaining weighted average contractual life of the options exercisable

3 years 9 months 28 days

Total unrecognized compensation cost related to unvested stock awards

14,100,000

Weighted average period for recognition of compensation cost related to unvested stock awards

3 years

Weighted average fair value of award granted during the year

2,841,678

18,041,576

6,602,967

Stock options | Minimum

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Award expiration period

5 years

Options vesting period

1 year

Stock options | Maximum

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Award expiration period

10 years

Options vesting period

5 years

Restricted Stock Awards

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation expense

9,658,019

6,713,155

6,930,381

Total unrecognized compensation cost related to unvested stock awards

11,700,000

Weighted average period for recognition of compensation cost related to unvested stock awards

2 years 1 month

Annual award vesting rate, low end of range (as a percent)

15.00%

Annual award vesting rate, high end of range (as a percent)

35.00%

Fair value of restricted stock vested during the period

5,500,000

1,600,000

22,400,000

Weighted average fair value of award granted during the year

1,141,675

17,386,949

7,023,942

Awards granted (in shares)

9,550

192,563

92,729

Awards outstanding (in shares)

3,000,979

2,994,197

2,804,901

2,912,456

LTIP units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Weighted average fair value of award granted during the year

33,200,000

27,100,000

Performance Shares

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Total unrecognized compensation cost related to unvested stock awards

7,100,000

Weighted average period for recognition of compensation cost related to unvested stock awards

1 year 6 months

Share-based Compensation

31,400,000

27,300,000

12,600,000

2010 Notional Unit Long-Term Compensation Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation expense

2,700,000

4,500,000

10,700,000

Cost of the plan, subject to adjustment for forfeitures

31,700,000

Approximate amount of awards that may be earned by recipients after beginning of the second year if maximum performance achieved

25,000,000

Approximate amount of awards that may be earned by recipients after beginning of the third year if maximum performance achieved

25,000,000

Minimum stock price appreciation to earn maximum amount of awards (as a percent)

50.00%

LTIP units earned (in shares)

327,416

385,583

366,815

Percentage of LTIP Units earned, vested on December 17, 2012 (percent)

25.00%

50.00%

2010 Notional Unit Long-Term Compensation Plan | Minimum

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Approximate amount of LTIP units that may be earned by the recipients based on stock price appreciation

15,000,000

2010 Notional Unit Long-Term Compensation Plan | Maximum

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Approximate amount of LTIP units that may be earned by the recipients based on stock price appreciation

75,000,000

Third Amendment and Restated 2005 Stock Option and Incentive Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Maximum fungible units that may be granted (in shares)

17,130,000

Fungible units per share (fungible units)

2.76

Shares that may be issued if equal to fungible units (shares)

17,130,000

Fungible units

2,600,000

Third Amendment and Restated 2005 Stock Option and Incentive Plan | Stock options

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation expense

8,100,000

6,500,000

5,100,000

Stock options, stock appreciation rights and other awards

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Fungible units per share (fungible units)

0.77

Award expiration period

5 years

All other awards

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Fungible units per share (fungible units)

Award expiration period

10 years

2011 Outperformance Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation expense

8,600,000

8,000,000

5,500,000

Cost of the plan, subject to adjustment for forfeitures

27,000,000

Approximate amount of LTIP units that may be earned by the recipients based on stock price appreciation

85,000,000

LTIP units earned (in shares)

280,454

560,908

Value of LTIP Units that could be earned expressed as percentage of outperformance amount in excess of the 30% benchmark (percent)

10.00%

Duration period return to stockholders exceeds 25%

3 years

Cumulative return to stockholders (percent)

25.00%

Return to stockholders

85,000,000

Portion of earned LTIP Units vested

one-third

Percentage of LTIP Units earned, vesting on August 31, 2014 (percent)

50.00%

Percentage of LTIP Units earned, vesting on August 31, 2015 (percent)

50.00%

2014 Outperformance Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation expense

200,000

Cost of the plan, subject to adjustment for forfeitures

17,100,000

LTIP units earned (in shares)

610,000

Award period

3 years

Percentage awarded

0.6667

Deferred Stock Compensation Plan for Directors

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation expense

$1,600,000

Maximum percentage of the annual retainer fee, chairman fees and meeting fees that may be deferred by non-employee directors (percent)

100.00%

Awards granted (in shares)

9,305

Shares issued (in shares)

7,701

Awards outstanding (in shares)

75,649

Employee Stock Purchase Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Shares of common stock available for issuance (shares)

500,000

Duration of each offering period starting the first day of each calendar quarter

3 months

Purchase price as a percentage of market value of the common stock (percent)

85.00%

Shares of common stock issued (shares)

80,437

Share-based compensation award, tranche 3 | 2014 Outperformance Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Percentage of units vested

50.00%

Share-based compensation award, tranche 4 | 2014 Outperformance Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Percentage of units vested

50.00%

Period One Vesting | 2011 Outperformance Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Percentage of units vested

33.33%

Period Two Vesting | 2011 Outperformance Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Percentage of units vested

66.67%

Accumulated_Other_Comprehensiv4

Accumulated Other Comprehensive Loss of the Company (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Ending Balance	($6,980,000)		($15,211,000)
Deferred net losses from terminated hedges	11,800,000		13,800,000		15,000,000
SL Green Realty Corp
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	-15,211,000		-29,587,000		-28,445,000
Other comprehensive loss before reclassifications	-421,000		7,573,000		-15,101,000
Amounts reclassified from accumulated other comprehensive income	8,652,000		6,803,000		13,959,000
Ending Balance	-6,980,000		-15,211,000		-29,587,000
SL Green Realty Corp \| Net unrealized loss on derivative instruments
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	-15,125,000	[1]	-16,834,000	[1]	-17,510,000	[1]
Other comprehensive loss before reclassifications	-576,000	[1]	-168,000	[1]	-1,124,000	[1]
Amounts reclassified from accumulated other comprehensive income	6,203,000	[1]	1,877,000	[1]	1,800,000	[1]
Ending Balance	-9,498,000	[1]	-15,125,000	[1]	-16,834,000	[1]
SL Green Realty Corp \| Unrealized gain and (loss) on marketable securities
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	4,784,000		3,310,000		6,466,000
Other comprehensive loss before reclassifications	-2,692,000		1,474,000		-4,879,000
Amounts reclassified from accumulated other comprehensive income	521,000		0		1,723,000
Ending Balance	2,613,000		4,784,000		3,310,000
SL Green Realty Corp \| Joint venture \| Net unrealized loss on derivative instruments
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	-4,870,000	[2]	-16,063,000	[2]	-17,401,000	[2]
Other comprehensive loss before reclassifications	2,847,000	[2]	6,267,000	[2]	-9,098,000	[2]
Amounts reclassified from accumulated other comprehensive income	1,928,000	[2]	4,926,000	[2]	10,436,000	[2]
Ending Balance	($95,000)	[2]	($4,870,000)	[2]	($16,063,000)	[2]

[1]	Amount reclassified from accumulated other comprehensive income (loss) is included in interest expense in the respective consolidated statements of income. As of DecemberB 31, 2014, 2013 and 2012, the deferred net losses from these terminated hedges, which is included in accumulated other comprehensive loss relating to net unrealized loss on derivative instrument, was $11.8 million , $13.8 million and $15.0 million, respectively.
[2]	Amount reclassified from accumulated other comprehensive income (loss) is included in equity in net income from unconsolidated joint ventures in the respective consolidated statements of income.

Accumulated_Other_Comprehensiv5

Accumulated Other Comprehensive Loss of the Operating Partnership (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) of the Operating Partnership [Roll Forward]
Ending Balance	($6,980,000)		($15,211,000)
Deferred net losses from terminated hedges	11,800,000		13,800,000		15,000,000
SL Green Operating Partnership
Accumulated Other Comprehensive Income (Loss) of the Operating Partnership [Roll Forward]
Beginning Balance	-15,662,000		-30,649,000		-29,119,000
Other comprehensive loss before reclassifications	-564,000		7,982,000		-15,991,000
Amounts reclassified from accumulated other comprehensive income	8,970,000		7,005,000		14,461,000
Ending Balance	-7,256,000		-15,662,000		-30,649,000
Deferred net losses from terminated hedges	12,200,000		14,200,000		15,500,000
Unrealized gain and (loss) on marketable securities \| SL Green Operating Partnership
Accumulated Other Comprehensive Income (Loss) of the Operating Partnership [Roll Forward]
Beginning Balance	-15,573,000	[1]	-17,438,000	[1]	-18,391,000	[1]
Other comprehensive loss before reclassifications	-703,000	[1]	-68,000	[1]	-912,000	[1]
Amounts reclassified from accumulated other comprehensive income	6,431,000	[1]	1,933,000	[1]	1,865,000	[1]
Ending Balance	-9,845,000	[1]	-15,573,000	[1]	-17,438,000	[1]
Net unrealized loss on derivative instruments \| SL Green Operating Partnership
Accumulated Other Comprehensive Income (Loss) of the Operating Partnership [Roll Forward]
Beginning Balance	4,926,000		3,429,000		7,086,000
Other comprehensive loss before reclassifications	-2,777,000		1,497,000		-5,442,000
Amounts reclassified from accumulated other comprehensive income	540,000		0		1,785,000
Ending Balance	2,689,000		4,926,000		3,429,000
Joint venture \| Unrealized gain and (loss) on marketable securities \| SL Green Operating Partnership
Accumulated Other Comprehensive Income (Loss) of the Operating Partnership [Roll Forward]
Beginning Balance	-5,015,000	[2]	-16,640,000	[2]	-17,814,000	[2]
Other comprehensive loss before reclassifications	2,916,000	[2]	6,553,000	[2]	-9,637,000	[2]
Amounts reclassified from accumulated other comprehensive income	1,999,000	[2]	5,072,000	[2]	10,811,000	[2]
Ending Balance	($100,000)	[2]	($5,015,000)	[2]	($16,640,000)	[2]

[1]	(1)Amount reclassified from accumulated other comprehensive income (loss) is included in interest expense in the respective consolidated statements of income. As of DecemberB 31, 2014, 2013 and 2012, the deferred net losses from these terminated hedges, which is included in accumulated other comprehensive loss relating to net unr
[2]	Amount reclassified from accumulated other comprehensive income (loss) is included in equity in net income from unconsolidated joint ventures in the respective consolidated statements of income.

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
Fair Value of Financial Instruments
Marketable securities	$39,429,000		$32,049,000
Interest rate swap agreements (included in other assets)	2,174,000
Interest rate swap agreements (included in accrued interest payable and other liabilities)	14,728,000		1,329,000
Carrying Value, Net of Discounts and Deferred Origination Fees	1,408,804,000		1,304,839,000
Carrying Value
Fair Value of Financial Instruments
Fixed rate debt	6,140,786,000		5,599,960,000
Variable rate debt	2,291,943,000		1,319,948,000
Total	8,432,729,000		6,919,908,000
Fair Value
Fair Value of Financial Instruments
Total	8,881,188,000		7,214,402,000
Estimated fair value of debt and preferred equity investments, low end of range	1,500,000,000		1,300,000,000
Estimated fair value of debt and preferred equity investments, high end of range	1,800,000,000		1,400,000,000
Level 1
Fair Value of Financial Instruments
Marketable securities	4,332,000		4,307,000
Interest rate swap agreements (included in other assets)	0
Interest rate swap agreements (included in accrued interest payable and other liabilities)	0		0
Level 2
Fair Value of Financial Instruments
Marketable securities	35,097,000		24,419,000
Interest rate swap agreements (included in other assets)	2,174,000
Interest rate swap agreements (included in accrued interest payable and other liabilities)	14,728,000		1,329,000
Level 3
Fair Value of Financial Instruments
Marketable securities	0		3,323,000
Interest rate swap agreements (included in other assets)	0
Interest rate swap agreements (included in accrued interest payable and other liabilities)	0		0
Level 3 \| Carrying Value
Fair Value of Financial Instruments
Carrying Value, Net of Discounts and Deferred Origination Fees	1,408,804,000	[1]	1,304,839,000	[1]
Level 3 \| Fair Value
Fair Value of Financial Instruments
Fixed rate debt	6,565,236,000		5,886,980,000
Variable rate debt	$2,315,952,000		$1,327,422,000

[1]	At DecemberB 31, 2014, debt and preferred equity investments had an estimated fair value ranging between $1.5 billion and $1.8 billion. At DecemberB 31, 2013, debt and preferred equity investments had an estimated fair value ranging between $1.3 billion and $1.4 billion.

Financial_Instruments_Derivati2

Financial Instruments: Derivatives and Hedging (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Financial Instruments: Derivatives and Hedging
Fair Value	$2,174,000
Fair Value	-14,728,000	-1,329,000
Derivative, Fair Value, Net	-12,554,000
Loss from settlement of hedges included in accumulated other comprehensive loss	61,000	16,000	770,000
Fair value of derivatives in a net liability position	13,400,000
Aggregate termination value	13,400,000
Estimated current balance held in accumulated other comprehensive loss to be reclassified into earnings within the next 12 months	9,400,000
Share of joint venture of accumulated other comprehensive loss reclassified into equity in net income from unconsolidated joint ventures within the next 12 months	1,200,000
Amount of (Loss) or Gain Recognized in Other Comprehensive Loss (Effective Portion)	2,213,000	6,485,000	-10,549,000
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	8,430,000	7,005,000	12,676,000
Amount of Gain Recognized into Income (Ineffective Portion)	4,000	3,000	3,000
Level 2
Financial Instruments: Derivatives and Hedging
Fair Value	2,174,000
Fair Value	-14,728,000	-1,329,000
Joint venture
Financial Instruments: Derivatives and Hedging
Amount of (Loss) or Gain Recognized in Other Comprehensive Loss (Effective Portion)	2,916,000	6,553,000	-9,637,000
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	1,999,000	5,072,000	10,811,000
Amount of Gain Recognized into Income (Ineffective Portion)	0	0	0
Interest Rate Cap- Sold Expiring in May 2016
Financial Instruments: Derivatives and Hedging
Notional Value	504,000,000
Strike Rate (as a percent)	4.75%
Fair Value	4,000
Interest Rate Cap Expiring in May 2016
Financial Instruments: Derivatives and Hedging
Notional Value	504,000,000
Strike Rate (as a percent)	4.75%
Fair Value	-4,000
Interest Rate Cap Expiring In May 2016
Financial Instruments: Derivatives and Hedging
Notional Value	500,000,000
Strike Rate (as a percent)	4.75%
Fair Value	4,000
Interest Rate Cap- Sold Expiring in May 2016
Financial Instruments: Derivatives and Hedging
Notional Value	500,000,000
Strike Rate (as a percent)	4.75%
Fair Value	-4,000
Interest Rate Cap Expiring In May 2016
Financial Instruments: Derivatives and Hedging
Notional Value	446,000,000
Strike Rate (as a percent)	4.75%
Fair Value	3,000
Interest Rate Cap Expiring in November, 2015
Financial Instruments: Derivatives and Hedging
Notional Value	263,426,000
Strike Rate (as a percent)	6.00%
Fair Value	0
Interest Rate Cap Expiring in September 2015
Financial Instruments: Derivatives and Hedging
Notional Value	137,500,000
Strike Rate (as a percent)	4.00%
Fair Value	0
Interest Rate Swap
Financial Instruments: Derivatives and Hedging
Amount of (Loss) or Gain Recognized in Other Comprehensive Loss (Effective Portion)	-703,000	-68,000	-912,000
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	6,431,000	1,933,000	1,865,000
Amount of Gain Recognized into Income (Ineffective Portion)	4,000	3,000	3,000
Interest Rate Swap Expiring in December 2017
Financial Instruments: Derivatives and Hedging
Notional Value	200,000,000
Strike Rate (as a percent)	0.94%
Fair Value	871,000
Interest Rate Swap Expiring in December 2017
Financial Instruments: Derivatives and Hedging
Notional Value	150,000,000
Strike Rate (as a percent)	0.94%
Fair Value	647,000
Interest Rate Swap Expiring in December 2017
Financial Instruments: Derivatives and Hedging
Notional Value	150,000,000
Strike Rate (as a percent)	0.94%
Fair Value	645,000
Interest Rate Swap Expiring in December 2017
Financial Instruments: Derivatives and Hedging
Notional Value	144,000,000
Strike Rate (as a percent)	2.24%
Fair Value	-4,757,000
Interest Rate Swap Expiring in December 2017
Financial Instruments: Derivatives and Hedging
Notional Value	86,400,000
Strike Rate (as a percent)	1.95%
Fair Value	-2,124,000
Interest Rate Swap Expiring in December 2017
Financial Instruments: Derivatives and Hedging
Notional Value	72,000,000
Strike Rate (as a percent)	2.31%
Fair Value	-2,533,000
Interest Rate Swap Expiring in December 2017
Financial Instruments: Derivatives and Hedging
Notional Value	72,000,000
Strike Rate (as a percent)	1.35%
Fair Value	-506,000
Interest Rate Swap Expiring in December 2017
Financial Instruments: Derivatives and Hedging
Notional Value	72,000,000
Strike Rate (as a percent)	2.31%
Fair Value	-2,534,000
Interest Rate Swap Expiring in December 2017
Financial Instruments: Derivatives and Hedging
Notional Value	57,600,000
Strike Rate (as a percent)	1.99%
Fair Value	-1,487,000
Interest Rate Swap Expiring in June 2016
Financial Instruments: Derivatives and Hedging
Notional Value	30,000,000
Strike Rate (as a percent)	2.30%
Fair Value	-774,000
Interest Rate Swap Expiring in February, 2015
Financial Instruments: Derivatives and Hedging
Notional Value	8,500,000
Strike Rate (as a percent)	0.74%
Fair Value	-5,000
Interest Rate Swap Expiring in February, 2015 \| Level 2
Financial Instruments: Derivatives and Hedging
Loss from settlement of hedges included in accumulated other comprehensive loss			($700,000)

Rental_Income_Details

Rental Income (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified	Dec. 31, 2014
Consolidated properties
Approximate future minimum rents to be received over the next five years and thereafter for non-cancelable operating leases
2015	$975,025
2016	964,428
2017	941,014
2018	879,727
2019	799,744
Thereafter	5,774,406
Total minimum lease payments	10,334,344
Unconsolidated properties
Approximate future minimum rents to be received over the next five years and thereafter for non-cancelable operating leases
2015	157,438
2016	157,514
2017	152,226
2018	146,605
2019	134,451
Thereafter	699,568
Total minimum lease payments	$1,447,802

Benefit_Plans_Details

Benefit Plans (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2000
Multi-employer plans
Plan contributions	$17,115	$17,293	$16,551
401 (K) Plan
Employee contribution limit per calendar year (percent)	15.00%
Employer match of employee contributions of first specified percentage of annual compensation (percent)	50.00%	50.00%	50.00%	50.00%
Percentage of eligible compensation matched by employer (percent)	6.00%	6.00%	6.00%	4.00%
Matching contribution	550	550	561
Pension Plan
Multi-employer plans
Plan contributions	224,500	221,900	212,700
Health Plan
Multi-employer plans
Plan contributions		923,500	893,300
Contributions by company (less than)	5.00%
Pension Plan
Multi-employer plans
Plan contributions	2,807	2,765	2,506
Health Plan
Multi-employer plans
Plan contributions	8,470	8,522	8,020
Other plans
Multi-employer plans
Plan contributions	$5,838	$6,006	$6,025

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)	12 Months Ended	10 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Oct. 31, 2012	Dec. 31, 2013
Commitments and Contingencies.
Employment agreements with certain executives, minimum cash-based compensation for next fiscal year	$4.60
Employment agreements with certain executives, grant date value of deferred compensation awards	1.3
Number of property insurance portfolios for which all-risk property and rental value coverage is maintained (portfolio)	3
TRIPRA 2015
Commitments and Contingencies.
Program trigger	100
Per annum increase	20
Belmont
Commitments and Contingencies.
Loss reserves	6.1		7
Property and rental value coverage
Commitments and Contingencies.
Blanket limit per occurrence maintained under first property portfolio (up to $950 million)	950
Limit per occurrence maintained under property portfolio	700
Amount of flood coverage (up to $100 million)	100
Limit per occurrence and in aggregate per location under liability policies (up to $201 million)		201
Residential assets coverage
Commitments and Contingencies.
Limit per occurrence maintained under property portfolio	$380

Commitments_and_Contingencies_2

Commitments and Contingencies (Details 2) (USD $)	12 Months Ended	1 Months Ended
	Dec. 31, 2014	Oct. 31, 2012	Jul. 31, 2011	Dec. 31, 2013
	extenstion_option	Oct. 31, 2012	Jul. 31, 2011	Dec. 31, 2013
Commitments and Contingencies
Cost basis	$27,445,000			$50,310,000
420 Lexington Avenue
Commitments and Contingencies
Number of renewal options available (extension option)	2
Annual ground lease payments through December 2019	10,900,000
Annual ground lease payments through December 2029	11,200,000
Annual ground lease payments due thereafter	12,300,000
Value of land as a percentage of the fair market value of the property (percent)	6.00%
1080 Amsterdam Avenue
Commitments and Contingencies
Value of land as a percentage of the fair market value of the property (percent)		40.00%
Prepayment of ground lease rent		13,000,000
Cost basis	27,400,000
Cumulative amortization	400,000
711 Third Avenue
Commitments and Contingencies
Percentage of fee not owned by the entity (percent)			50.00%
461 Fifth Avenue
Commitments and Contingencies
Number of renewal options available (extension option)	2
Required annual ground lease payments	2,100,000
Term of first renewal option	21 years
Term of second renewal option	21 years
Term of third renewal option	15 years
625 Madison Avenue
Commitments and Contingencies
Number of renewal options available (extension option)	2
Required annual ground lease payments	4,600,000
Term of first renewal option	23 years
Term of second renewal option	23 years
1185 Avenue of the Americas
Commitments and Contingencies
Required annual ground lease payments	6,900,000
Term of first renewal option	23 years
Through July 2016 \| 711 Third Avenue
Commitments and Contingencies
Required annual ground lease payments	5,250,000
After July 2016 \| 711 Third Avenue
Commitments and Contingencies
Required annual ground lease payments	$5,500,000

Commitments_and_Contingencies_3

Commitments and Contingencies (Details 3) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Initial term of non cancellable operating leases, minimum	1 year
Capital lease
2015	$145
2016	170
2017	291
2018	291
2019	315
Thereafter	56,569
Total minimum lease payments	57,781
Less amount representing interest	-36,959
Capital lease obligations	20,822
Non-cancellable operating leases
2015	30,491
2016	30,612
2017	30,845
2018	30,845
2019	30,862
Thereafter	720,698
Total minimum lease payments	$874,353

Segment_Information_Details

Segment Information (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	segment	Dec. 31, 2013	Dec. 31, 2012
Segment information
Number of reportable segments (segment)									2
Total revenues	$386,627,000	$390,274,000	$380,631,000	$362,446,000	$350,451,000	$338,782,000	$340,888,000	$340,944,000	$1,519,978,000	$1,371,065,000	$1,290,052,000
Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate and purchase price fair value adjustment									173,030,000	109,400,000	133,780,000
Total assets	17,096,587,000				14,959,001,000				17,096,587,000	14,959,001,000
Leverage rate assumption (as a percent)									100.00%
Marketing, general and administrative expenses and transaction related costs									92,500,000	86,200,000	82,800,000
Real Estate Segment
Segment information
Total revenues									1,341,163,000	1,177,222,000	1,170,897,000
Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate and purchase price fair value adjustment									22,178,000	-49,793,000	41,366,000
Total assets	15,671,662,000				13,641,727,000				15,671,662,000	13,641,727,000
Debt and Preferred Equity Segment
Segment information
Total revenues									178,815,000	193,843,000	119,155,000
Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate and purchase price fair value adjustment									150,852,000	159,193,000	92,414,000
Total assets	$1,424,925,000				$1,317,274,000				$1,424,925,000	$1,317,274,000

Segment_Information_Details_2

Segment Information (Details 2) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of income from continuing operations to net income attributable to SL Green common stockholders
Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate and purchase price fair value adjustment									$173,030	$109,400	$133,780
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	673	16,496	1,444	104,640	7,538	-354	-3,583	0	123,253	3,601	37,053
Purchase price fair value adjustment									67,446	-2,305	0
Income from continuing operations									363,729	110,696	170,833
Net income from discontinued operations	3,626	4,035	5,645	5,769	5,836	7,435	5,943	6,473	19,075	25,687	32,240
Gain on sale of discontinued operations	18,817	29,507	114,735	0	0	13,787	0	1,113	163,059	14,900	6,627
Net income									$545,863	$151,283	$209,700

Quarterly_Financial_Data_unaud2

Quarterly Financial Data (unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Total revenues	$386,627	$390,274	$380,631	$362,446	$350,451	$338,782	$340,888	$340,944	$1,519,978	$1,371,065	$1,290,052
Income from continuing before equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, (loss) gain on early extinguishment of debt, loss on sale of investment in marketable securities, net of noncontrolling interests	40,379	46,863	47,035	39,416	27,478	19,895	27,398	37,300	174,963	118,062	59,400
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	673	16,496	1,444	104,640	7,538	-354	-3,583	0	123,253	3,601	37,053
Purchase price fair value adjustment	0	-4,000	71,446	0	0	0	-2,305	0	65,059	-2,239	0
(Loss) gain on early extinguishment of debt	-6,865	-24,475	-1,028	3	5	0	-10	-18,513	-32,365	-18,518	-6,978
Gain (loss) on sale of investment in marketable securities	3,895	0	0	0	0	0	-8	-57	3,895	-65	4,940
Net income (loss) from discontinued operations	3,626	4,035	5,645	5,769	5,836	7,435	5,943	6,473	19,075	25,687	32,240
Gain on sale of discontinued operations	18,817	29,507	114,735	0	0	13,787	0	1,113	163,059	14,900	6,627
Net income attributable to SL Green	60,525	68,426	239,277	149,828	40,857	40,763	27,435	26,316	518,056	135,371	196,405
Preferred stock redemption costs	0	0	0	0	0	0	-12,160	0	0	-12,160	-10,010
Perpetual preferred stock dividends	-3,738	-3,738	-3,738	-3,738	-3,737	-3,738	-6,999	-7,407	-14,952	-21,881	-30,411
Net income attributable to SL Green common stockholders	56,787	64,688	235,539	146,090	37,120	37,025	8,276	18,909	503,104	101,330	155,984
Net income per common share-Basic (usd per share)	$0.59	$0.68	$2.47	$1.54	$0.39	$0.40	$0.09	$0.21	$5.25	$1.10	$1.75
Net income per common share-Diluted (usd per share)	$0.59	$0.68	$2.46	$1.53	$0.39	$0.40	$0.09	$0.21	$5.23	$1.10	$1.74
SL Green Operating Partnership
Condensed Financial Statements, Captions [Line Items]
Total revenues	386,627	390,274	380,631	362,446	350,451	338,782	340,888	340,944	1,519,978	1,371,065	1,290,052
Income from continuing before equity in net gain on sale of interest in unconsolidated joint venture/real estate, purchase price fair value adjustment, (loss) gain on early extinguishment of debt, loss on sale of investment in marketable securities, net of noncontrolling interests	42,837	49,499	55,680	44,144	28,592	21,005	27,642	37,855	174,963	118,062	59,400
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	673	16,496	1,444	104,640	7,538	-354	-3,583	0	123,253	3,601	37,053
Purchase price fair value adjustment	0	-4,000	71,446	0	0	0	-2,305	0
(Loss) gain on early extinguishment of debt	-6,865	-24,475	-1,028	3	5	0	-10	-18,513	-32,365	-18,518	-6,978
Gain (loss) on sale of investment in marketable securities	3,895	0	0	0	0	0	-8	-57	3,895	-65	4,940
Net income (loss) from discontinued operations	3,626	4,035	5,645	5,769	5,836	7,435	5,943	6,473	19,075	25,687	32,240
Gain on sale of discontinued operations	18,817	29,507	114,735	0	0	13,787	0	1,113	163,059	14,900	6,627
Net income attributable to SL Green	62,983	71,062	247,922	154,556	41,971	41,873	27,679	26,871	536,523	138,394	202,002
Preferred stock redemption costs	0	0	0	0	0	0	-12,160	0
Perpetual preferred stock dividends	-3,738	-3,738	-3,738	-3,738	-3,737	-3,738	-6,999	-7,407
Net income attributable to SLGOP common unitholders	$59,245	$67,324	$244,184	$150,818	$38,234	$38,135	$8,520	$19,464	$521,571	$104,353	$161,581
Net income per common share-Basic (usd per share)	$0.59	$0.68	$2.47	$1.54	$0.39	$0.40	$0.09	$0.21
Net income per common share-Diluted (usd per share)	$0.59	$0.68	$2.46	$1.53	$0.39	$0.40	$0.09	$0.21

Subsequent_Events_Details

Subsequent Events (Details) (USD $)	12 Months Ended			1 Months Ended
Subsequent Events (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2014	Jan. 31, 2015	Nov. 30, 2012	Nov. 30, 2014
Subsequent Event [Line Items]
Credit facility, maximum borrowing capacity						$1,600,000,000
Net proceeds from sale of common stock	185,321,000	290,699,000	201,279,000
Term loan
Subsequent Event [Line Items]
Credit facility, maximum borrowing capacity	833,000,000			783,000,000			833,000,000
Decrease in basis points				0.25%
Term loan \| Subsequent Event
Subsequent Event [Line Items]
Decrease in basis points					0.20%
Facility fee					0.05%
At-the-market equity offering programs
Subsequent Event [Line Items]
Net proceeds from sale of common stock	2,800,000
At-the-market equity offering programs \| Subsequent Event
Subsequent Event [Line Items]
Aggregate gross proceeds from shares sold					895,956
Net proceeds from sale of common stock					113,400,000

Schedule_IIValuation_and_Quali1

Schedule II-Valuation and Qualifying Accounts (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Tenant and other receivablesballowance
Changes in valuation allowance
Balance at Beginning of Year	$17,325	$14,341	$11,326
Additions Charged Against Operations	13,533	13,425	17,232
Uncollectible Accounts Written-off/Recovery	-12,790	-10,441	-14,217
Balance at End of Year	18,068	17,325	14,341
Deferred rent receivableballowance
Changes in valuation allowance
Balance at Beginning of Year	30,333	29,580	29,156
Additions Charged Against Operations	4,140	7,563	7,153
Uncollectible Accounts Written-off/Recovery	-7,062	-6,810	-6,729
Balance at End of Year	$27,411	$30,333	$29,580

Schedule_IIIReal_Estate_And_Ac1

Schedule III-Real Estate And Accumulated Depreciation (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Real Estate And Accumulated Depreciation
Encumbrances	$5,466,709
Initial Cost
Land	3,685,380
Building & Improvements	8,919,315
Cost Capitalized Subsequent To Acquisition
Land	159,138
Building & Improvements	1,305,308
Gross Amount at Which Carried at Close of Period
Land	3,844,518
Building & Improvements	10,224,623
Total	14,069,141		12,333,780	11,662,953	11,147,151
Accumulated Depreciation	1,905,165		1,646,240	1,393,323	1,136,603
420 Lexington Avenue
Real Estate And Accumulated Depreciation
Encumbrances	300,000	[1]
Initial Cost
Building & Improvements	107,832	[1]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	221,171	[1]
Gross Amount at Which Carried at Close of Period
Building & Improvements	329,003	[1]
Total	329,003	[1]
Accumulated Depreciation	107,652	[1]
711 Third Avenue
Real Estate And Accumulated Depreciation
Encumbrances	120,000	[1],[2]
Initial Cost
Land	19,844	[1],[2]
Building & Improvements	42,499	[1],[2]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	40,907	[1],[2]
Gross Amount at Which Carried at Close of Period
Land	19,844	[1],[2]
Building & Improvements	83,406	[1],[2]
Total	103,250	[1],[2]
Accumulated Depreciation	30,035	[1],[2]
Interest in property (as a percent)	50.00%
555 W. 57th Street
Initial Cost
Land	18,846	[1]
Building & Improvements	78,704	[1]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	47,933	[1]
Gross Amount at Which Carried at Close of Period
Land	18,846	[1]
Building & Improvements	126,637	[1]
Total	145,483	[1]
Accumulated Depreciation	48,659	[1]
317 Madison Avenue
Initial Cost
Land	21,205	[1]
Building & Improvements	85,559	[1]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	35,572	[1]
Gross Amount at Which Carried at Close of Period
Land	21,205	[1]
Building & Improvements	121,131	[1]
Total	142,336	[1]
Accumulated Depreciation	53,779	[1]
220 East 42nd Street
Real Estate And Accumulated Depreciation
Encumbrances	275,000	[1]
Initial Cost
Land	50,373	[1]
Building & Improvements	203,727	[1]
Cost Capitalized Subsequent To Acquisition
Land	635	[1]
Building & Improvements	57,876	[1]
Gross Amount at Which Carried at Close of Period
Land	51,008	[1]
Building & Improvements	261,603	[1]
Total	312,611	[1]
Accumulated Depreciation	81,045	[1]
461 Fifth Avenue
Initial Cost
Building & Improvements	62,695	[1]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	9,626	[1]
Gross Amount at Which Carried at Close of Period
Building & Improvements	72,321	[1]
Total	72,321	[1]
Accumulated Depreciation	21,838	[1]
750 Third Avenue
Initial Cost
Land	51,093	[1]
Building & Improvements	205,972	[1]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	35,951	[1]
Gross Amount at Which Carried at Close of Period
Land	51,093	[1]
Building & Improvements	241,923	[1]
Total	293,016	[1]
Accumulated Depreciation	70,362	[1]
625 Madison Avenue
Initial Cost
Building & Improvements	246,673	[1]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	35,576	[1]
Gross Amount at Which Carried at Close of Period
Building & Improvements	282,249	[1]
Total	282,249	[1]
Accumulated Depreciation	77,982	[1]
485 Lexington Avenue
Real Estate And Accumulated Depreciation
Encumbrances	450,000	[1]
Initial Cost
Land	77,517	[1]
Building & Improvements	326,825	[1]
Cost Capitalized Subsequent To Acquisition
Land	765	[1]
Building & Improvements	89,417	[1]
Gross Amount at Which Carried at Close of Period
Land	78,282	[1]
Building & Improvements	416,242	[1]
Total	494,524	[1]
Accumulated Depreciation	127,566	[1]
609 Fifth Avenue
Initial Cost
Land	36,677	[1]
Building & Improvements	145,954	[1]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	7,814	[1]
Gross Amount at Which Carried at Close of Period
Land	36,677	[1]
Building & Improvements	153,768	[1]
Total	190,445	[1]
Accumulated Depreciation	32,939	[1]
120 West 45th Street
Real Estate And Accumulated Depreciation
Encumbrances	170,000	[1]
Initial Cost
Land	60,766	[1]
Building & Improvements	250,922	[1]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	22,227	[1]
Gross Amount at Which Carried at Close of Period
Land	60,766	[1]
Building & Improvements	273,149	[1]
Total	333,915	[1]
Accumulated Depreciation	58,601	[1]
810 Seventh Avenue
Initial Cost
Land	114,077	[1]
Building & Improvements	476,386	[1]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	54,441	[1]
Gross Amount at Which Carried at Close of Period
Land	114,077	[1]
Building & Improvements	530,827	[1]
Total	644,904	[1]
Accumulated Depreciation	114,957	[1]
919 Third Avenue
Real Estate And Accumulated Depreciation
Encumbrances	500,000	[1],[3]
Initial Cost
Land	223,529	[1],[3]
Building & Improvements	1,033,198	[1],[3]
Cost Capitalized Subsequent To Acquisition
Land	35,410	[1],[3]
Building & Improvements	22,564	[1],[3]
Gross Amount at Which Carried at Close of Period
Land	258,939	[1],[3]
Building & Improvements	1,055,762	[1],[3]
Total	1,314,701	[1],[3]
Accumulated Depreciation	216,685	[1],[3]
Interest in property (as a percent)	51.00%
1185 Avenue of the Americas
Initial Cost
Building & Improvements	728,213	[1]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	35,260	[1]
Gross Amount at Which Carried at Close of Period
Building & Improvements	763,473	[1]
Total	763,473	[1]
Accumulated Depreciation	175,368	[1]
1350 Avenue of the Americas
Initial Cost
Land	91,038	[1]
Building & Improvements	380,744	[1]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	29,132	[1]
Gross Amount at Which Carried at Close of Period
Land	91,038	[1]
Building & Improvements	409,876	[1]
Total	500,914	[1]
Accumulated Depreciation	90,325	[1]
1100 King Street - 1-7 International Drive
Initial Cost
Land	49,392	[4]
Building & Improvements	104,376	[4]
Cost Capitalized Subsequent To Acquisition
Land	2,473	[4]
Building & Improvements	19,385	[4]
Gross Amount at Which Carried at Close of Period
Land	51,865	[4]
Building & Improvements	123,761	[4]
Total	175,626	[4]
Accumulated Depreciation	31,003	[4]
520 White Plains Road
Initial Cost
Land	6,324	[4]
Building & Improvements	26,096	[4]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	4,785	[4]
Gross Amount at Which Carried at Close of Period
Land	6,324	[4]
Building & Improvements	30,881	[4]
Total	37,205	[4]
Accumulated Depreciation	7,755	[4]
115-117 Stevens Avenue
Initial Cost
Land	5,933	[4]
Building & Improvements	23,826	[4]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	6,334	[4]
Gross Amount at Which Carried at Close of Period
Land	5,933	[4]
Building & Improvements	30,160	[4]
Total	36,093	[4]
Accumulated Depreciation	7,967	[4]
100 Summit Lake Drive
Initial Cost
Land	10,526	[4]
Building & Improvements	43,109	[4]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	7,213	[4]
Gross Amount at Which Carried at Close of Period
Land	10,526	[4]
Building & Improvements	50,322	[4]
Total	60,848	[4]
Accumulated Depreciation	11,863	[4]
200 Summit Lake Drive
Initial Cost
Land	11,183	[4]
Building & Improvements	47,906	[4]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	7,217	[4]
Gross Amount at Which Carried at Close of Period
Land	11,183	[4]
Building & Improvements	55,123	[4]
Total	66,306	[4]
Accumulated Depreciation	12,600	[4]
500 Summit Lake Drive
Initial Cost
Land	9,777	[4]
Building & Improvements	39,048	[4]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	5,643	[4]
Gross Amount at Which Carried at Close of Period
Land	9,777	[4]
Building & Improvements	44,691	[4]
Total	54,468	[4]
Accumulated Depreciation	9,495	[4]
140 Grand Street
Initial Cost
Land	6,865	[4]
Building & Improvements	28,264	[4]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	4,606	[4]
Gross Amount at Which Carried at Close of Period
Land	6,865	[4]
Building & Improvements	32,870	[4]
Total	39,735	[4]
Accumulated Depreciation	7,734	[4]
360 Hamilton Avenue
Initial Cost
Land	29,497	[4]
Building & Improvements	118,250	[4]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	12,851	[4]
Gross Amount at Which Carried at Close of Period
Land	29,497	[4]
Building & Improvements	131,101	[4]
Total	160,598	[4]
Accumulated Depreciation	29,031	[4]
1-6 Landmark Square
Real Estate And Accumulated Depreciation
Encumbrances	81,269	[5]
Initial Cost
Land	50,947	[5]
Building & Improvements	195,167	[5]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	30,206	[5]
Gross Amount at Which Carried at Close of Period
Land	50,947	[5]
Building & Improvements	225,373	[5]
Total	276,320	[5]
Accumulated Depreciation	48,469	[5]
7 Landmark Square
Initial Cost
Land	2,088	[5]
Building & Improvements	7,748	[5]
Cost Capitalized Subsequent To Acquisition
Land	-367	[5]
Building & Improvements	-133	[5]
Gross Amount at Which Carried at Close of Period
Land	1,721	[5]
Building & Improvements	7,615	[5]
Total	9,336	[5]
Accumulated Depreciation	600	[5]
680 Washington Boulevard
Initial Cost
Land	11,696	[3],[5]
Building & Improvements	45,364	[3],[5]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	4,561	[3],[5]
Gross Amount at Which Carried at Close of Period
Land	11,696	[3],[5]
Building & Improvements	49,925	[3],[5]
Total	61,621	[3],[5]
Accumulated Depreciation	11,118	[3],[5]
Interest in property (as a percent)	51.00%
750 Washington Boulevard
Initial Cost
Land	16,916	[3],[5]
Building & Improvements	68,849	[3],[5]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	7,433	[3],[5]
Gross Amount at Which Carried at Close of Period
Land	16,916	[3],[5]
Building & Improvements	76,282	[3],[5]
Total	93,198	[3],[5]
Accumulated Depreciation	16,313	[3],[5]
Interest in property (as a percent)	51.00%
1010 Washington Boulevard
Initial Cost
Land	7,747	[5]
Building & Improvements	30,423	[5]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	5,058	[5]
Gross Amount at Which Carried at Close of Period
Land	7,747	[5]
Building & Improvements	35,481	[5]
Total	43,228	[5]
Accumulated Depreciation	7,695	[5]
500 West Putnam Avenue
Real Estate And Accumulated Depreciation
Encumbrances	22,968	[5]
Initial Cost
Land	11,210	[5]
Building & Improvements	44,782	[5]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	4,734	[5]
Gross Amount at Which Carried at Close of Period
Land	11,210	[5]
Building & Improvements	49,516	[5]
Total	60,726	[5]
Accumulated Depreciation	10,272	[5]
150 Grand Street
Initial Cost
Land	1,371	[4]
Building & Improvements	5,446	[4]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	11,225	[4]
Gross Amount at Which Carried at Close of Period
Land	1,371	[4]
Building & Improvements	16,671	[4]
Total	18,042	[4]
Accumulated Depreciation	1,770	[4]
400 Summit Lake Drive
Initial Cost
Land	38,889	[4]
Cost Capitalized Subsequent To Acquisition
Land	285	[4]
Building & Improvements	1	[4]
Gross Amount at Which Carried at Close of Period
Land	39,174	[4]
Building & Improvements	1	[4]
Total	39,175	[4]
Accumulated Depreciation	1	[4]
331 Madison Avenue
Initial Cost
Land	14,763	[1]
Building & Improvements	65,241	[1]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	2,681	[1]
Gross Amount at Which Carried at Close of Period
Land	14,763	[1]
Building & Improvements	67,922	[1]
Total	82,685	[1]
Accumulated Depreciation	13,923	[1]
1055 Washington Boulevard
Initial Cost
Land	13,516	[5]
Building & Improvements	53,228	[5]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	3,492	[5]
Gross Amount at Which Carried at Close of Period
Land	13,516	[5]
Building & Improvements	56,720	[5]
Total	70,236	[5]
Accumulated Depreciation	12,515	[5]
One Madison Avenue
Real Estate And Accumulated Depreciation
Encumbrances	565,742	[1]
Initial Cost
Land	172,641	[1]
Building & Improvements	654,394	[1]
Cost Capitalized Subsequent To Acquisition
Land	905	[1]
Building & Improvements	15,297	[1]
Gross Amount at Which Carried at Close of Period
Land	173,546	[1]
Building & Improvements	669,691	[1]
Total	843,237	[1]
Accumulated Depreciation	124,795	[1]
125 Chubb Way
Initial Cost
Land	5,884	[6]
Building & Improvements	25,958	[6]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	23,832	[6]
Gross Amount at Which Carried at Close of Period
Land	5,884	[6]
Building & Improvements	49,790	[6]
Total	55,674	[6]
Accumulated Depreciation	5,263	[6]
100 Church
Real Estate And Accumulated Depreciation
Encumbrances	228,612	[1]
Initial Cost
Land	32,494	[1]
Building & Improvements	79,996	[1]
Cost Capitalized Subsequent To Acquisition
Land	2,500	[1]
Building & Improvements	84,235	[1]
Gross Amount at Which Carried at Close of Period
Land	34,994	[1]
Building & Improvements	164,231	[1]
Total	199,225	[1]
Accumulated Depreciation	27,245	[1]
125 Park Avenue
Initial Cost
Land	120,900	[1]
Building & Improvements	189,714	[1]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	42,165	[1]
Gross Amount at Which Carried at Close of Period
Land	120,900	[1]
Building & Improvements	231,879	[1]
Total	352,779	[1]
Accumulated Depreciation	34,869	[1]
885 Third Avenue
Real Estate And Accumulated Depreciation
Encumbrances	267,650	[1]
Initial Cost
Land	131,766	[1]
Cost Capitalized Subsequent To Acquisition
Land	110,771	[1]
Gross Amount at Which Carried at Close of Period
Land	242,537	[1]
Total	242,537	[1]
Williamsburg
Initial Cost
Land	3,677	[7]
Building & Improvements	14,708	[7]
Cost Capitalized Subsequent To Acquisition
Land	2,523	[7]
Building & Improvements	-4,550	[7]
Gross Amount at Which Carried at Close of Period
Land	6,200	[7]
Building & Improvements	10,158	[7]
Total	16,358	[7]
Accumulated Depreciation	1,082	[7]
1515 Broadway
Real Estate And Accumulated Depreciation
Encumbrances	900,000	[1]
Initial Cost
Land	462,700	[1]
Building & Improvements	707,938	[1]
Cost Capitalized Subsequent To Acquisition
Land	1,145	[1]
Building & Improvements	68,978	[1]
Gross Amount at Which Carried at Close of Period
Land	463,845	[1]
Building & Improvements	776,916	[1]
Total	1,240,761	[1]
Accumulated Depreciation	88,018	[1]
110 East 42nd Street
Initial Cost
Land	34,000	[1]
Building & Improvements	46,411	[1]
Cost Capitalized Subsequent To Acquisition
Land	2,354	[1]
Building & Improvements	17,179	[1]
Gross Amount at Which Carried at Close of Period
Land	36,354	[1]
Building & Improvements	63,590	[1]
Total	99,944	[1]
Accumulated Depreciation	9,194	[1]
51 East 42nd Street
Initial Cost
Land	44,095	[1]
Building & Improvements	33,470	[1]
Cost Capitalized Subsequent To Acquisition
Land	5	[1]
Building & Improvements	5,607	[1]
Gross Amount at Which Carried at Close of Period
Land	44,100	[1]
Building & Improvements	39,077	[1]
Total	83,177	[1]
Accumulated Depreciation	3,278	[1]
400 East 57th Street
Real Estate And Accumulated Depreciation
Encumbrances	68,896	[1],[8]
Initial Cost
Land	39,780	[1],[8]
Building & Improvements	69,895	[1],[8]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	10,786	[1],[8]
Gross Amount at Which Carried at Close of Period
Land	39,780	[1],[8]
Building & Improvements	80,681	[1],[8]
Total	120,461	[1],[8]
Accumulated Depreciation	5,536	[1],[8]
Interest in property (as a percent)	80.00%
400 East 58th Street
Real Estate And Accumulated Depreciation
Encumbrances	29,527	[1],[8]
Initial Cost
Land	17,549	[1],[8]
Building & Improvements	30,916	[1],[8]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	4,673	[1],[8]
Gross Amount at Which Carried at Close of Period
Land	17,549	[1],[8]
Building & Improvements	35,589	[1],[8]
Total	53,138	[1],[8]
Accumulated Depreciation	2,402	[1],[8]
Interest in property (as a percent)	80.00%
752 Madison Avenue
Initial Cost
Land	282,415	[1],[8]
Building & Improvements	7,131	[1],[8]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	10	[1],[8]
Gross Amount at Which Carried at Close of Period
Land	282,415	[1],[8]
Building & Improvements	7,141	[1],[8]
Total	289,556	[1],[8]
Accumulated Depreciation	644	[1],[8]
Interest in property (as a percent)	80.00%
762 Madison Avenue
Real Estate And Accumulated Depreciation
Encumbrances	8,045	[1],[8]
Initial Cost
Land	6,153	[1],[8]
Building & Improvements	10,461	[1],[8]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	90	[1],[8]
Gross Amount at Which Carried at Close of Period
Land	6,153	[1],[8]
Building & Improvements	10,551	[1],[8]
Total	16,704	[1],[8]
Accumulated Depreciation	805	[1],[8]
Interest in property (as a percent)	80.00%
19-21 East 65th Street
Initial Cost
Building & Improvements	7,389	[1],[8]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	159	[1],[8]
Gross Amount at Which Carried at Close of Period
Building & Improvements	7,548	[1],[8]
Total	7,548	[1],[8]
Accumulated Depreciation	559	[1],[8]
Interest in property (as a percent)	80.00%
304 Park Avenue
Initial Cost
Land	54,189	[1]
Building & Improvements	75,619	[1]
Cost Capitalized Subsequent To Acquisition
Land	300	[1]
Building & Improvements	6,336	[1]
Gross Amount at Which Carried at Close of Period
Land	54,489	[1]
Building & Improvements	81,955	[1]
Total	136,444	[1]
Accumulated Depreciation	7,465	[1]
635 Sixth Avenue
Initial Cost
Land	24,180	[1]
Building & Improvements	37,158	[1]
Cost Capitalized Subsequent To Acquisition
Land	163	[1]
Building & Improvements	38,104	[1]
Gross Amount at Which Carried at Close of Period
Land	24,343	[1]
Building & Improvements	75,262	[1]
Total	99,605	[1]
641 Sixth Avenue
Initial Cost
Land	45,668	[1]
Building & Improvements	67,316	[1]
Cost Capitalized Subsequent To Acquisition
Land	308	[1]
Building & Improvements	793	[1]
Gross Amount at Which Carried at Close of Period
Land	45,976	[1]
Building & Improvements	68,109	[1]
Total	114,085	[1]
Accumulated Depreciation	5,076	[1]
1080 Amsterdam
Initial Cost
Building & Improvements	27,445	[1],[9]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	20,182	[1],[9]
Gross Amount at Which Carried at Close of Period
Building & Improvements	47,627	[1],[9]
Total	47,627	[1],[9]
Interest in property (as a percent)	87.50%
131-137 Spring Street
Initial Cost
Land	27,021	[1]
Building & Improvements	105,342	[1]
Cost Capitalized Subsequent To Acquisition
Land	154	[1]
Building & Improvements	3,384	[1]
Gross Amount at Which Carried at Close of Period
Land	27,175	[1]
Building & Improvements	108,726	[1]
Total	135,901	[1]
Accumulated Depreciation	5,606	[1]
248-252 Bedford Avenue
Real Estate And Accumulated Depreciation
Encumbrances	29,000	[10],[7]
Initial Cost
Land	10,865	[10],[7]
Building & Improvements	44,035	[10],[7]
Cost Capitalized Subsequent To Acquisition
Land	-2,194	[10],[7]
Building & Improvements	-6,784	[10],[7]
Gross Amount at Which Carried at Close of Period
Land	8,671	[10],[7]
Building & Improvements	37,251	[10],[7]
Total	45,922	[10],[7]
Accumulated Depreciation	1,490	[10],[7]
Interest in property (as a percent)	90.00%
16 Court Street
Initial Cost
Land	19,217	[7]
Building & Improvements	63,210	[7]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	4,954	[7]
Gross Amount at Which Carried at Close of Period
Land	19,217	[7]
Building & Improvements	68,164	[7]
Total	87,381	[7]
Accumulated Depreciation	4,604	[7]
315 West 33rd Street
Initial Cost
Land	195,834	[1]
Building & Improvements	164,429	[1]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	3,180	[1]
Gross Amount at Which Carried at Close of Period
Land	195,834	[1]
Building & Improvements	167,609	[1]
Total	363,443	[1]
Accumulated Depreciation	5,396	[1]
Fifth Avenue Retail Assemblage
Initial Cost
Land	135,513	[1]
Building & Improvements	10,487	[1]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	3,356	[1]
Gross Amount at Which Carried at Close of Period
Land	135,513	[1]
Building & Improvements	13,843	[1]
Total	149,356	[1]
Accumulated Depreciation	1,364	[1]
388-390 Greenwich Street
Real Estate And Accumulated Depreciation
Encumbrances	1,450,000	[1]
Initial Cost
Land	558,731	[1]
Building & Improvements	1,037,729	[1]
Cost Capitalized Subsequent To Acquisition
Building & Improvements	68,780	[1]
Gross Amount at Which Carried at Close of Period
Land	558,731	[1]
Building & Improvements	1,106,509	[1]
Total	1,665,240	[1]
Accumulated Depreciation	18,308	[1]
719 Seventh Avenue
Initial Cost
Land	14,402	[1],[11]
Building & Improvements	26,866	[1],[11]
Gross Amount at Which Carried at Close of Period
Land	14,402	[1],[11]
Building & Improvements	26,866	[1],[11]
Total	41,268	[1],[11]
Accumulated Depreciation	334	[1],[11]
Interest in property (as a percent)	75.00%
115 Spring Street
Initial Cost
Land	15,938	[1]
Building & Improvements	37,309	[1]
Gross Amount at Which Carried at Close of Period
Land	15,938	[1]
Building & Improvements	37,309	[1]
Total	53,247	[1]
635 Madison Avenue
Initial Cost
Land	153,745	[1]
Gross Amount at Which Carried at Close of Period
Land	153,745	[1]
Total	153,745	[1]
102 Greene Street
Initial Cost
Land	11,288	[1]
Building & Improvements	20,963	[1]
Gross Amount at Which Carried at Close of Period
Land	11,288	[1]
Building & Improvements	20,963	[1]
Total	32,251	[1]
Accumulated Depreciation	131	[1]
Other
Initial Cost
Land	1,130	[12]
Cost Capitalized Subsequent To Acquisition
Land	1,003	[12]
Building & Improvements	11,803	[12]
Gross Amount at Which Carried at Close of Period
Land	2,133	[12]
Building & Improvements	11,803	[12]
Total	13,936	[12]
Accumulated Depreciation	$3,194	[12]

[1]	Property located in New York, New York.
[2]	We own a 50.0% interest in this property.
[3]	We own a 51.0% interest in this property.
[4]	Property located in Westchester County, New York.
[5]	Property located in Connecticut.
[6]	Property located in New Jersey.
[7]	Property located in Brooklyn, New York.
[8]	We own an 80.0% interest in this property.
[9]	We own an 87.5% interest in this property.
[10]	We own a 90.0% interest in this property.
[11]	We own a 75.0% interest in this property.
[12]	Other includes tenant improvements at eEmerge, capitalized interest and corporate improvements.

Schedule_IIIReal_Estate_And_Ac2

Schedule III-Real Estate And Accumulated Depreciation (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Changes in real estate
Balance at beginning of year	$12,333,780,000	$11,662,953,000	$11,147,151,000
Property acquisitions	2,428,259,000	702,717,000	649,445,000
Improvements	379,295,000	199,141,000	146,410,000
Retirements/disposals/deconsolidation	-1,072,193,000	-231,031,000	-280,053,000
Balance at end of year	14,069,141,000	12,333,780,000	11,662,953,000
Aggregate cost of land, buildings and improvements, before depreciation, for Federal income tax purposes	10,400,000,000
Changes in accumulated depreciation, exclusive of amounts relating to equipment, autos, and furniture and fixtures
Balance at beginning of year	1,646,240,000	1,393,323,000	1,136,603,000
Depreciation for year	307,823,000	286,776,000	288,560,000
Retirements/disposals/deconsolidation	-48,898,000	-33,859,000	-31,840,000
Balance at end of year	$1,905,165,000	$1,646,240,000	$1,393,323,000