SL Green Operating Partnership 10-Q 9 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Nov. 07, 2016
Document Information [Line Items]
Entity Registrant Name	SL GREEN REALTY CORP
Entity Central Index Key	1,040,971
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		101,322,189
SL Green Operating Partnership
Document Information [Line Items]
Entity Registrant Name	SL GREEN OPERATING PARTNERSHIP, LP.
Entity Central Index Key	1,492,869
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus (Q1,Q2,Q3,FY)	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		1,497,718

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Commercial real estate properties, at cost:
Land and land interests	$ 3,347,482	$ 4,779,159
Building and improvements	7,777,647	10,423,739
Building leasehold and improvements	1,436,287	1,431,259
Properties under capital lease	47,445	47,445
Total commercial real estate properties, at cost	12,608,861	16,681,602
Less: accumulated depreciation	(2,190,142)	(2,060,706)
Total commercial real estate properties, net	10,418,719	14,620,896
Assets held for sale	117,159	34,981
Cash and cash equivalents	405,896	255,399
Restricted cash	100,195	233,578
Investments in marketable securities	60,352	45,138
Tenant and other receivables, net of allowance of $18,278 and $17,618 in 2016 and 2015, respectively	55,976	63,491
Related party receivables	14,840	10,650
Deferred rents receivable, net of allowance of $24,922 and $21,730 in 2016 and 2015, respectively	430,642	498,776
Debt and preferred equity investments, net of discounts and deferred origination fees of $14,630 and $18,759 in 2016 and 2015, respectively	1,453,234	1,670,020
Investments in unconsolidated joint ventures	1,860,912	1,203,858
Deferred costs, net	252,179	239,920
Other assets	620,838	850,939
Total assets	15,790,942	19,727,646
Liabilities
Mortgages and other loans payable, net	3,954,155	6,881,920
Revolving credit facility, net	0	985,055
Term loan and senior unsecured notes, net	2,303,657	2,308,478
Accrued interest payable	30,734	42,406
Other liabilities	211,513	168,477
Accounts payable and accrued expenses	178,946	196,213
Deferred revenue	237,548	399,102
Capital lease obligations	41,951	41,360
Deferred land leases payable	2,419	1,783
Dividend and distributions payable	81,392	79,790
Security deposits	67,709	68,023
Liabilities related to assets held for sale	65,520	29,000
Junior subordinated deferrable interest debentures held by trusts that issued trust preferred securities	100,000	100,000
Total liabilities	7,275,544	11,301,607
Commitments and contingencies
Noncontrolling interests in Operating Partnership	490,440	424,206
Preferred units	302,310	282,516
Equity
Series I Preferred Stock, $0.01 par value, $25.00 liquidation preference, 9,200 issued and outstanding at both September 30, 2016 and December 31, 2015	221,932	221,932
Common stock, $0.01 par value, 160,000 shares authorized and 101,319 and 100,063 issued and outstanding at September 30, 2016 and December 31, 2015, respectively (including 1,055 and 87 shares held in treasury at September 30, 2016 and December 31, 2015, respectively)	1,013	1,001
Additional paid-in-capital	5,596,026	5,439,735
Treasury stock at cost	(124,049)	(10,000)
Accumulated other comprehensive loss	(14,074)	(8,749)
Retained earnings	1,612,707	1,643,546
Total SL Green stockholders' equity	7,293,555	7,287,465
Noncontrolling interests in other partnerships	429,093	431,852
Total equity	7,722,648	7,719,317
SL Green stockholders equity:
Total liabilities and equity/capital	15,790,942	19,727,646
SL Green Operating Partnership
Commercial real estate properties, at cost:
Land and land interests	3,347,482	4,779,159
Building and improvements	7,777,647	10,423,739
Building leasehold and improvements	1,436,287	1,431,259
Properties under capital lease	47,445	47,445
Total commercial real estate properties, at cost	12,608,861	16,681,602
Less: accumulated depreciation	(2,190,142)	(2,060,706)
Total commercial real estate properties, net	10,418,719	14,620,896
Assets held for sale	117,159	34,981
Cash and cash equivalents	405,896	255,399
Restricted cash	100,195	233,578
Investments in marketable securities	60,352	45,138
Tenant and other receivables, net of allowance of $18,278 and $17,618 in 2016 and 2015, respectively	55,976	63,491
Related party receivables	14,840	10,650
Deferred rents receivable, net of allowance of $24,922 and $21,730 in 2016 and 2015, respectively	430,642	498,776
Debt and preferred equity investments, net of discounts and deferred origination fees of $14,630 and $18,759 in 2016 and 2015, respectively	1,453,234	1,670,020
Investments in unconsolidated joint ventures	1,860,912	1,203,858
Deferred costs, net	252,179	239,920
Other assets	620,838	850,939
Total assets	15,790,942	19,727,646
Liabilities
Mortgages and other loans payable, net	3,954,155	6,881,920
Revolving credit facility, net	0	985,055
Term loan and senior unsecured notes, net	2,303,657	2,308,478
Accrued interest payable	30,734	42,406
Other liabilities	211,513	168,477
Accounts payable and accrued expenses	178,946	196,213
Deferred revenue	237,548	399,102
Capital lease obligations	41,951	41,360
Deferred land leases payable	2,419	1,783
Dividend and distributions payable	81,392	79,790
Security deposits	67,709	68,023
Liabilities related to assets held for sale	65,520	29,000
Junior subordinated deferrable interest debentures held by trusts that issued trust preferred securities	100,000	100,000
Total liabilities	7,275,544	11,301,607
Commitments and contingencies
Noncontrolling interests in Operating Partnership	490,440	424,206
Limited partner interests in SLGOP (4,495 and 3,746 limited partner common units outstanding at September 30, 2016 and December 31, 2015, respectively)	490,440	424,206
Preferred units	302,310	282,516
Equity
Accumulated other comprehensive loss	(14,074)	(8,749)
SL Green stockholders equity:
Series I Preferred Units, $25.00 liquidation preference, 9,200 issued and outstanding at both September 30, 2016 and December 31, 2015	221,932	221,932
SL Green partners' capital (1,047 and 1,035 general partner common units and 99,217 and 98,941 limited partner common units outstanding at September 30, 2016 and December 31, 2015, respectively)	7,085,697	7,074,282
Total SLGOP partners' capital	7,293,555	7,287,465
Noncontrolling interests in other partnerships	429,093	431,852
Total capital	7,722,648	7,719,317
Total liabilities and equity/capital	$ 15,790,942	$ 19,727,646

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Tenant and other receivables, allowance	$ 18,278	$ 17,618
Deferred rents receivable, allowance	24,922	21,730
Debt and preferred equity investments, discount and deferred origination fees	$ 14,630	$ 18,759
Preferred stock, par value (in dollars per share)	$ 0.01
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	160,000,000	160,000,000
Common stock, shares issued (in shares)	100,319,000	100,063,000
Common stock, shares outstanding (in shares)	100,319,000	100,063,000
Treasury stock, shares (in shares)	1,055,000	87,000
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 (in shares)	9,200,000	9,200,000
Preferred stock, shares outstanding (in shares)	9,200,000	9,200,000
SL Green Operating Partnership
Tenant and other receivables, allowance	$ 18,278	$ 17,618
Deferred rents receivable, allowance	24,922	21,730
Debt and preferred equity investments, discount and deferred origination fees	$ 14,630	$ 18,759
Limited partner interests in Operating Partnership, limited partner common units outstanding (shares)	4,495,000	3,746,000
SL Green partner's capital, general partner common units outstanding (shares)	1,047,000	1,035,000
SL Green partners' capital, limited partner common units outstanding (shares)	99,217,000	98,941,000
SL Green Operating Partnership | Series I Preferred Stock
Preferred units, liquidation preference (in dollars per share)	$ 25	$ 25
Preferred units, shares issued	9,200,000	9,200,000
Preferred units, shares outstanding	9,200,000	9,200,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenues
Rental revenue, net	$ 281,482	$ 318,465	$ 1,043,898	$ 926,020
Escalation and reimbursement	53,130	48,254	147,357	130,630
Investment income	75,396	49,328	174,347	136,588
Other income	6,673	16,019	124,137	44,201
Total revenues	416,681	432,066	1,489,739	1,237,439
Expenses
Operating expenses, including $5,042 and $15,171 in 2016 and $5,238 and $13,415 in 2015 of related party expenses	79,425	78,648	234,269	225,539
Real estate taxes	64,133	61,009	187,931	173,018
Ground rent	8,338	8,252	24,953	24,526
Interest expense, net of interest income	72,565	84,141	256,326	235,694
Amortization of deferred financing costs	4,815	7,160	20,180	19,727
Depreciation and amortization	112,665	146,185	717,015	454,087
Transaction related costs	2,593	5,829	5,987	10,039
Marketing, general and administrative	25,458	23,475	73,974	72,139
Total expenses	369,992	414,699	1,520,635	1,214,769
Income (loss) from continuing operations before equity in net (loss) income from unconsolidated joint ventures, equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain on sale of real estate, net, depreciable real estate reserves, loss on sale of investment in marketable securities and loss on early extinguishment of debt	46,689	17,367	(30,896)	22,670
Equity in net (loss) income from unconsolidated joint ventures	(3,968)	3,627	11,969	10,651
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	225	15,281	43,588	16,050
Gain on sale of real estate, net	397	159,704	210,750	159,704
Depreciable real estate reserves	0	(19,226)	(10,387)	(19,226)
Loss on sale of investment in marketable securities	0	0	(83)	0
Loss on early extinguishment of debt	0	0	0	(49)
Income from continuing operations	43,343	176,753	224,941	189,800
Net income from discontinued operations	0	0	0	427
Gain on sale of discontinued operations	0	0	0	12,983
Net income	43,343	176,753	224,941	203,210
Net income attributable to noncontrolling interests:
Noncontrolling interests in the Operating Partnership	(1,663)	(6,467)	(8,171)	(6,634)
Noncontrolling interests in other partnerships	(836)	(665)	(6,245)	(13,217)
Preferred units distributions	(2,854)	(2,225)	(8,382)	(4,316)
Net income (loss) attributable to SL Green/SLGOP	37,990	167,396	202,143	179,043
Perpetual preferred stock dividends	(3,738)	(3,738)	(11,213)	(11,214)
Amounts attributable to SL Green common stockholders:
Income (loss) from continuing operations before depreciable real estate reserves, gains on sale and discontinued operations	33,657	13,768	(43,041)	4,357
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	215	14,705	41,805	15,439
Net income from discontinued operations	0	0	0	411
Gain on sale of discontinued operations	0	0	0	12,489
Gain on sale of real estate	380	153,687	202,128	153,628
Depreciable real estate reserves	0	(18,502)	(9,962)	(18,495)
Net income attributable to SL Green common stockholders	$ 34,252	$ 163,658	$ 190,930	$ 167,829
Basic earnings per share:
Income (loss) from continuing operations before depreciable real estate reserves, gains on sale and discontinued operations (in usd per share)	$ 0.34	$ 0.14	$ (0.43)	$ 0.04
Equity in net gain on sale of interest in unconsolidated joint venture/real estate (usd per share)	0	0.15	0.42	0.16
Net income from discontinued operations (usd per share)	0	0	0	0
Gain on sale of discontinued operations (usd per share)	0	0	0	0.13
Gain on sale of real estate (in dollars per share)	0	1.54	2.02	1.55
Depreciable Real Estate Reserves, Effect on Earnings, Per Basic Share	0	(0.19)	(0.10)	(0.19)
Net income attributable to SL Green common stockholders (usd per share)	0.34	1.64	1.91	1.69
Diluted earnings per share:
Income (loss) from continuing operations before depreciable real estate reserves, gains on sale and discontinued operations (in usd per share)	0.34	0.14	(0.43)	0.04
Equity in net gain on sale of interest in unconsolidated joint venture/real estate (usd per share)	0	0.15	0.42	0.16
Net income from discontinued operations (in usd per share)	0	0	0	0
Gain on sale of discontinued operations (usd per share)	0	0	0	0.13
Gain on sale of real estate (in dollars per share)	0	1.54	2.01	1.54
Depreciable real estate reserves (in dollars per share)	0	(0.19)	(0.10)	(0.19)
Net income attributable to SL Green common stockholders (usd per share)	0.34	1.64	1.90	1.68
Dividends per share/unit (usd per share)	$ 0.72	$ 0.60	$ 2.16	$ 1.80
Basic weighted average common shares outstanding (in shares)	100,233	99,621	100,140	99,205
Diluted weighted average common shares and common share equivalents outstanding (in shares)	105,143	103,929	104,761	103,609
SL Green Operating Partnership
Revenues
Rental revenue, net	$ 281,482	$ 318,465	$ 1,043,898	$ 926,020
Escalation and reimbursement	53,130	48,254	147,357	130,630
Investment income	75,396	49,328	174,347	136,588
Other income	6,673	16,019	124,137	44,201
Total revenues	416,681	432,066	1,489,739	1,237,439
Expenses
Operating expenses, including $5,042 and $15,171 in 2016 and $5,238 and $13,415 in 2015 of related party expenses	79,425	78,648	234,269	225,539
Real estate taxes	64,133	61,009	187,931	173,018
Ground rent	8,338	8,252	24,953	24,526
Interest expense, net of interest income	72,565	84,141	256,326	235,694
Amortization of deferred financing costs	4,815	7,160	20,180	19,727
Depreciation and amortization	112,665	146,185	717,015	454,087
Transaction related costs	2,593	5,829	5,987	10,039
Marketing, general and administrative	25,458	23,475	73,974	72,139
Total expenses	369,992	414,699	1,520,635	1,214,769
Income (loss) from continuing operations before equity in net (loss) income from unconsolidated joint ventures, equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain on sale of real estate, net, depreciable real estate reserves, loss on sale of investment in marketable securities and loss on early extinguishment of debt	46,689	17,367	(30,896)	22,670
Equity in net (loss) income from unconsolidated joint ventures	(3,968)	3,627	11,969	10,651
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	225	15,281	43,588	16,050
Gain on sale of real estate, net	397	159,704	210,750	159,704
Depreciable real estate reserves	0	(19,226)	(10,387)	(19,226)
Loss on sale of investment in marketable securities	0	0	(83)	0
Loss on early extinguishment of debt	0	0	0	(49)
Income from continuing operations	43,343	176,753	224,941	189,800
Net income from discontinued operations	0	0	0	427
Gain on sale of discontinued operations	0	0	0	12,983
Net income	43,343	176,753	224,941	203,210
Net income attributable to noncontrolling interests:
Noncontrolling interests in the Operating Partnership			(8,171)
Noncontrolling interests in other partnerships	(836)	(665)	(6,245)	(13,217)
Preferred units distributions	(2,854)	(2,225)	(8,382)	(4,316)
Net income (loss) attributable to SL Green/SLGOP	39,653	173,863	210,314	185,677
Perpetual preferred unit distributions	(3,738)	(3,738)	(11,213)	(11,214)
Net income attributable to SLGOP common unitholders	35,915	170,125	199,101	174,463
Amounts attributable to SL Green common stockholders:
Income (loss) from continuing operations before depreciable real estate reserves, gains on sale and discontinued operations	35,293	14,366	(44,850)	4,525
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	225	15,281	43,588	16,050
Net income from discontinued operations	0	0	0	427
Gain on sale of discontinued operations	0	0	0	12,983
Gain on sale of real estate	397	159,704	210,750	159,704
Depreciable real estate reserves	$ 0	$ (19,226)	$ (10,387)	$ (19,226)
Basic earnings per share:
(Loss) income from continuing operations before gains on sale and discontinued operations (usd per share)	$ 0.34	$ 0.14	$ (0.43)	$ 0.04
Equity in net gain on sale of interest in unconsolidated joint venture/real estate (usd per share)	0	0.15	0.42	0.16
Net income from discontinued operations (usd per share)	0	0	0	0
Gain on sale of discontinued operations (usd per share)	0	0	0	0.13
Gain on sale of real estate (in dollars per share)	0	1.54	2.02	1.55
Depreciable Real Estate Reserves, Effect on Earnings, Per Basic Share	0	(0.19)	(0.10)	(0.19)
Net income attributable to SLGOP common unitholders (usd per share)	0.34	1.64	1.91	1.69
Diluted earnings per share:
(Loss) income from continuing operations before gains on sale and discontinued operations (in usd per share)	0.34	0.14	(0.43)	0.04
Equity in net gain on sale of interest in unconsolidated joint venture/real estate (usd per share)	0	0.15	0.42	0.16
Net income from discontinued operations (in usd per share)	0	0	0	0
Gain on sale of discontinued operations (usd per share)	0	0	0	0.13
Gain on sale of real estate (in dollars per share)	0	1.54	2.01	1.54
Depreciable real estate reserves (in dollars per share)	0	(0.19)	(0.10)	(0.19)
Net income attributable to SLGOP common unitholders (usd per share)	0.34	1.64	1.90	1.68
Dividends per share/unit (usd per share)	$ 0.72	$ 0.60	$ 2.16	$ 1.80
Basic weighted average common shares outstanding (in shares)	104,730	103,522	104,412	103,129
Basic weighted average common units outstanding (in shares)	104,730	103,522	104,412	103,129
Diluted weighted average common units and common unit equivalents outstanding (in shares)	105,143	103,929	104,761	103,609

Consolidated Statements of Ope5

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Operating expenses, paid to related parties	$ 5,042	$ 5,238	$ 15,171	$ 13,415
SL Green Operating Partnership
Operating expenses, paid to related parties	$ 5,042	$ 5,238	$ 15,171	$ 13,415

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net income	$ 43,343	$ 176,753	$ 224,941	$ 203,210
Other comprehensive income (loss):
Change in net unrealized gain (loss) on derivative instruments, including SL Green's/SLGOP's share of joint venture net unrealized (loss) gain on derivative instruments	2,632	(5,423)	(4,682)	(8,853)
Change in unrealized (loss) gain on marketable securities	(30)	317	(900)	(337)
Other comprehensive income (loss)	2,602	(5,106)	(5,582)	(9,190)
Comprehensive income	45,945	171,647	219,359	194,020
Net income attributable to noncontrolling interests and preferred units distributions	(5,353)	(9,357)	(22,798)	(24,167)
Net income attributable to noncontrolling interests	836	665	6,245	13,217
Other comprehensive (loss) income attributable to noncontrolling interests	(118)	191	257	349
Comprehensive income attributable to SL Green/SLGOP	40,474	162,481	196,818	170,202
SL Green Operating Partnership
Net income	43,343	176,753	224,941	203,210
Other comprehensive income (loss):
Change in net unrealized gain (loss) on derivative instruments, including SL Green's/SLGOP's share of joint venture net unrealized (loss) gain on derivative instruments	2,632	(5,423)	(4,682)	(8,853)
Change in unrealized (loss) gain on marketable securities	(30)	317	(900)	(337)
Other comprehensive income (loss)	2,602	(5,106)	(5,582)	(9,190)
Comprehensive income	45,945	171,647	219,359	194,020
Net income attributable to noncontrolling interests	836	665	6,245	13,217
Other comprehensive (loss) income attributable to noncontrolling interests	(118)	191	257	349
Comprehensive income attributable to SL Green/SLGOP	$ 44,991	$ 171,173	$ 213,371	$ 181,152

Consolidated Statement of Equit

Consolidated Statement of Equity - 9 months ended Sep. 30, 2016 - USD ($) shares in Thousands, $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid- In-Capital	Treasury Stock	Accumulated Other Comprehensive (Loss)	Retained Earnings	Noncontrolling Interests
Beginning Balance at Dec. 31, 2015	$ 7,719,317	$ 221,932	$ 1,001	$ 5,439,735	$ (10,000)	$ (8,749)	$ 1,643,546	$ 431,852
Beginning Balance (in shares) at Dec. 31, 2015			99,976
Increase (Decrease) in Stockholders' Equity
Net income	208,388						202,143	6,245
Other comprehensive loss	(5,325)					(5,325)
Preferred dividends	(11,213)						(11,213)
DRSPP proceeds (in shares)			1
DRSPP proceeds	146			146
Conversion of units of the Operating Partnership to common stock (in shares)			118
Conversion of units of the Operating Partnership to common stock	12,746		$ 1	12,745
Reallocation of noncontrolling interest in the Operating Partnership	(4,959)						(4,959)
Deferred compensation plan and stock award, net (in shares)			12
Deferred compensation plan and stock award, net	(2,086)			(2,086)
Amortization of deferred compensation plan	19,230			19,230
Issuance of common stock	(40)		$ 10	113,999	(114,049)
Proceeds from stock options exercised (in shares)			157
Proceeds from stock options exercised	12,258		$ 1	12,257
Contributions to consolidated joint venture interests	2,019							2,019
Cash distributions to noncontrolling interests	(11,023)							(11,023)
Cash distributions declared ($2.16 per common share, none of which represented a return of capital for federal income tax purposes)	(216,810)						(216,810)
Ending Balance at Sep. 30, 2016	$ 7,722,648	$ 221,932	$ 1,013	$ 5,596,026	$ (124,049)	$ (14,074)	$ 1,612,707	$ 429,093
Ending Balance (in shares) at Sep. 30, 2016			100,264

Consolidated Statement of Equi8

Consolidated Statement of Equity (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Stockholders' Equity [Abstract]
Cash distribution declared, per common share (in dollars per share)	$ 0.72	$ 0.60	$ 2.16	$ 1.80

Consolidated Statement of Capit

Consolidated Statement of Capital shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2016USD ($)shares
Increase (Decrease) in Partner's Capital
DRSPP proceeds	$ 146
Conversion of common units	12,746
Reallocation of noncontrolling interests in the operating partnership	(4,959)
Deferred compensation plan and stock award, net	(2,086)
Amortization of deferred compensation plan	19,230
Issuance of common stock	(40)
Contribution to consolidated joint venture interests	2,019
Cash distributions to noncontrolling interests	$ (11,023)
Common Stock
Increase (Decrease) in Partner's Capital
DRSPP proceeds (in shares) | shares	1
Conversion of common units	$ 1
Deferred compensation plan and stock award, net (in shares) | shares	12
Issuance of common stock	$ 10
Contributions - proceeds from stock options exercised (in shares) | shares	157
Noncontrolling Interests
Increase (Decrease) in Partner's Capital
Contribution to consolidated joint venture interests	$ 2,019
Cash distributions to noncontrolling interests	(11,023)
SL Green Operating Partnership
Increase (Decrease) in Partner's Capital
Beginning Balance	7,719,317
Net income	208,388
Other comprehensive (loss)	(5,325)
Preferred distributions	(11,213)
DRSPP proceeds	146
Conversion of common units	12,746
Reallocation of noncontrolling interests in the operating partnership	(4,959)
Deferred compensation plan and stock award, net	(2,086)
Amortization of deferred compensation plan	19,230
Issuance of common stock	(40)
Contribution to consolidated joint venture interests	2,019
Contributions - proceeds from stock options exercised	12,258
Cash distributions to noncontrolling interests	(11,023)
Cash distributions declared ($2.16 per common unit, none of which represented a return of capital for federal income tax purposes)	(216,810)
Ending Balance	7,722,648
SL Green Operating Partnership | Preferred Units
Increase (Decrease) in Partner's Capital
Beginning Balance	221,932
Ending Balance	221,932
SL Green Operating Partnership | Common Stock | Partners' Interest
Increase (Decrease) in Partner's Capital
Beginning Balance	$ 7,074,282
Beginning Balance (units) | shares	99,976
Net income	$ 202,143
Preferred distributions	$ (11,213)
DRSPP proceeds (in shares) | shares	1
DRSPP proceeds	$ 146
Conversion of common units (in shares) | shares	118
Conversion of common units	$ 12,746
Reallocation of noncontrolling interests in the operating partnership	$ (4,959)
Deferred compensation plan and stock award, net (in shares) | shares	12
Deferred compensation plan and stock award, net	$ (2,086)
Amortization of deferred compensation plan	19,230
Issuance of common stock	$ (40)
Contributions - proceeds from stock options exercised (in shares) | shares	157
Contributions - proceeds from stock options exercised	$ 12,258
Cash distributions declared ($2.16 per common unit, none of which represented a return of capital for federal income tax purposes)	(216,810)
Ending Balance	$ 7,085,697
Ending Balance (units) | shares	100,264
SL Green Operating Partnership | Accumulated Other Comprehensive (Loss)
Increase (Decrease) in Partner's Capital
Beginning Balance	$ (8,749)
Other comprehensive (loss)	(5,325)
Ending Balance	(14,074)
SL Green Operating Partnership | Noncontrolling Interests
Increase (Decrease) in Partner's Capital
Beginning Balance	431,852
Net income	6,245
Contribution to consolidated joint venture interests	2,019
Cash distributions to noncontrolling interests	(11,023)
Ending Balance	$ 429,093

Consolidated Statement of Cap10

Consolidated Statement of Capital (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Cash distribution declared, per common share (in dollars per share)	$ 0.72	$ 0.60	$ 2.16	$ 1.80
SL Green Operating Partnership
Cash distribution declared, per common share (in dollars per share)	$ 0.72	$ 0.60	$ 2.16	$ 1.80

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016		Sep. 30, 2015
Operating Activities
Net income	$ 224,941		$ 203,210
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	737,195		473,817
Equity in net income from unconsolidated joint ventures	(11,969)		(10,651)
Distributions of cumulative earnings from unconsolidated joint ventures	19,311		33,141
Equity in net gain on sale of interest in unconsolidated joint venture interest/real estate	(43,588)		(16,050)
Depreciable real estate reserves	10,387		19,226
Gain on sale of real estate	(210,750)		(159,704)
Gain on sale of discontinued operations	0		(12,983)
Loss on sale of investment in marketable securities	83		0
Loss on early extinguishment of debt	0		49
Deferred rents receivable	40,056		(99,015)
Other non-cash adjustments	(155,558)	[1]	(16,140)
Changes in operating assets and liabilities:
Restricted cash—operations	(12,855)		(23,437)
Tenant and other receivables	2,714		(8,498)
Related party receivables	(4,167)		646
Deferred lease costs	(47,036)		(46,673)
Other assets	(30,899)		(43,736)
Accounts payable, accrued expenses and other liabilities and security deposits	(28,089)		6,119
Deferred revenue and land leases payable	19,016		23,678
Net cash provided by operating activities	508,792		322,999
Investing Activities
Acquisitions of real estate property	(38,005)		(2,574,687)
Additions to land, buildings and improvements	(269,182)		(219,760)
Escrowed cash—capital improvements/acquisition deposits/deferred purchase price	85,983		(117,026)
Investments in unconsolidated joint ventures	(69,422)		(127,783)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	171,472		89,059
Net proceeds from disposition of real estate/joint venture interest	2,419,841		1,072,175
Proceeds from sale of marketable securities	6,868		432
Purchases of marketable securities	(23,062)		(7,769)
Other investments	8,232		(11,894)
Origination of debt and preferred equity investments	(554,803)		(461,257)
Repayments or redemption of debt and preferred equity investments	667,251		372,084
Net cash provided by (used in) investing activities	2,405,173		(1,986,426)
Financing Activities
Proceeds from mortgages and other loans payable	256,207		1,706,018
Repayments of mortgages and other loans payable	(1,786,034)		(681,286)
Proceeds from revolving credit facility and senior unsecured notes	1,260,300		2,130,000
Repayments of revolving credit facility and senior unsecured notes	(2,269,604)		(1,466,007)
Proceeds from stock options exercised and DRIP issuance	12,404		112,399
Proceeds from sale of common stock	0		124,794
Redemption of preferred stock	(2,999)		(200)
Distributions to noncontrolling interests in other partnerships	(11,023)		(113,595)
Contributions from noncontrolling interests in other partnerships	2,019		11,931
Distributions to noncontrolling interests in the Operating Partnership	(9,245)		(7,017)
Dividends/Distributions paid on common and preferred stock/units	(234,801)		(191,920)
Other obligations related to mortgage loan participations	59,150		25,000
Deferred loan costs and capitalized lease obligation	(39,842)		(23,739)
Net cash (used in) provided by financing activities	(2,763,468)		1,626,378
Net increase (decrease) in cash and cash equivalents	150,497		(37,049)
Cash and cash equivalents at beginning of year	255,399		281,409
Cash and cash equivalents at end of period	405,896		244,360
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of units in the Operating Partnership relating to the investment in unconsolidated joint ventures	51,647		0
Redemption of units in the Operating Partnership for stock	12,746		41,605
Exchange of debt investment for equity in joint venture	68,581		10,151
Transfer of restricted cash to operating cash and cash equivalents as a result of sale	0		21,578
Acquisition of subsidiary interest from noncontrolling interest	0		20,630
Tenant improvements and capital expenditures payable	4,281		14,470
Fair value adjustment to noncontrolling interest in Operating Partnership	4,959		31,664
Capital lease assets	0		20,000
Reclassification of development costs from other assets to real estate	0		47,519
Transfer of assets related to assets held for sale	2,048,376		117,885
Transfer of liabilities related to assets held for sale	1,677,528		94
Deferred leasing payable	1,208		6,176
Removal of fully depreciated commercial real estate properties	22,179		0
Deconsolidation of a subsidiary (2)	1,173,570	[2]	27,435
Issuance of common stock to consolidated joint venture	114,049		10,000
Contribution to consolidated joint venture by noncontrolling interest	0		22,504
Receivable from sale of unconsolidated joint venture interest	0		15,129
SL Green Operating Partnership
Operating Activities
Net income	224,941		203,210
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	737,195		473,817
Equity in net income from unconsolidated joint ventures	(11,969)		(10,651)
Distributions of cumulative earnings from unconsolidated joint ventures	19,311		33,141
Equity in net gain on sale of interest in unconsolidated joint venture interest/real estate	(43,588)		(16,050)
Depreciable real estate reserves	10,387		19,226
Gain on sale of real estate	(210,750)		(159,704)
Gain on sale of discontinued operations	0		(12,983)
Loss on sale of investment in marketable securities	83		0
Loss on early extinguishment of debt	0		49
Deferred rents receivable	40,056		(99,015)
Other non-cash adjustments	(155,558)		(16,140)
Changes in operating assets and liabilities:
Restricted cash—operations	(12,855)		(23,437)
Tenant and other receivables	2,714		(8,498)
Related party receivables	(4,167)		646
Deferred lease costs	(47,036)		(46,673)
Other assets	(30,899)		(43,736)
Accounts payable, accrued expenses and other liabilities and security deposits	(28,089)		6,119
Deferred revenue and land leases payable	19,016		23,678
Net cash provided by operating activities	508,792		322,999
Investing Activities
Acquisitions of real estate property	(38,005)		(2,574,687)
Additions to land, buildings and improvements	(269,182)		(219,760)
Escrowed cash—capital improvements/acquisition deposits/deferred purchase price	85,983		(117,026)
Investments in unconsolidated joint ventures	(69,422)		(127,783)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	171,472		89,059
Net proceeds from disposition of real estate/joint venture interest	2,419,841		1,072,175
Proceeds from sale of marketable securities	6,868		432
Purchases of marketable securities	(23,062)		(7,769)
Other investments	8,232		(11,894)
Origination of debt and preferred equity investments	(554,803)		(461,257)
Repayments or redemption of debt and preferred equity investments	667,251		372,084
Net cash provided by (used in) investing activities	2,405,173		(1,986,426)
Financing Activities
Proceeds from mortgages and other loans payable	256,207		1,706,018
Repayments of mortgages and other loans payable	(1,786,034)		(681,286)
Proceeds from revolving credit facility and senior unsecured notes	1,260,300		2,130,000
Repayments of revolving credit facility and senior unsecured notes	(2,269,604)		(1,466,007)
Proceeds from stock options exercised and DRIP issuance	12,404		112,399
Proceeds from sale of common stock	0		124,794
Redemption of preferred stock	(2,999)		(200)
Distributions to noncontrolling interests in other partnerships	(11,023)		(113,595)
Contributions from noncontrolling interests in other partnerships	2,019		11,931
Dividends/Distributions paid on common and preferred stock/units	(244,046)		(198,937)
Other obligations related to mortgage loan participations	59,150		25,000
Deferred loan costs and capitalized lease obligation	(39,842)		(23,739)
Net cash (used in) provided by financing activities	(2,763,468)		1,626,378
Net increase (decrease) in cash and cash equivalents	150,497		(37,049)
Cash and cash equivalents at beginning of year	255,399		281,409
Cash and cash equivalents at end of period	405,896		244,360
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of units in the Operating Partnership relating to the investment in unconsolidated joint ventures	51,647		0
Redemption of units in the Operating Partnership for stock	12,746		41,605
Exchange of debt investment for equity in joint venture	68,581		10,151
Transfer of restricted cash to operating cash and cash equivalents as a result of sale	0		21,578
Acquisition of subsidiary interest from noncontrolling interest	0		20,630
Tenant improvements and capital expenditures payable	4,281		14,470
Capital lease assets	0		20,000
Reclassification of development costs from other assets to real estate	0		47,519
Transfer of assets related to assets held for sale	2,048,376		117,885
Transfer of liabilities related to assets held for sale	1,677,528		94
Deferred leasing payable	1,208		6,176
Removal of fully depreciated commercial real estate properties	22,179		0
Deconsolidation of a subsidiary (2)	1,173,570	[2]	27,435
Issuance of common stock to consolidated joint venture	114,049		10,000
Contribution to consolidated joint venture by noncontrolling interest	0		22,504
Receivable from sale of unconsolidated joint venture interest	0		15,129
Common Stock
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of stock/units	0		2,228
Common Stock | SL Green Operating Partnership
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of stock/units	0		2,228
Preferred Units
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of preferred units relating to a real estate acquisition	22,793		211,601
Preferred Units | SL Green Operating Partnership
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Issuance of preferred units relating to a real estate acquisition	$ 22,793		$ 211,601
[1]	Included in Other non-cash adjustments is $172.4 million for the nine months ended September 30, 2016 for the amortization of the below-market lease at 388-390 Greenwich Street as a result of the tenant exercising their option to purchase the property and entering into an agreement to accelerate the sale
[2]	The 2016 amount relates to 11 Madison for which in August 2016 we closed on the sale of a 40% interest. The sale did not meet the criteria for sale accounting and as a result the property is being accounted for under the profit sharing method.

Consolidated Statements of Ca12

Consolidated Statements of Cash Flows (Parenthetical) - USD ($)	1 Months Ended	9 Months Ended
	Aug. 31, 2016	Sep. 30, 2016
Amortization of acquired leases		$ 191,400,000
388-390 Greenwich Street
Amortization of acquired leases		172,400,000
SL Green Operating Partnership | 388-390 Greenwich Street
Amortization of acquired leases		$ 172,400,000
11 Madison Avenue
Ownership percentage in disposed asset	40.00%
11 Madison Avenue | SL Green Operating Partnership
Ownership percentage in disposed asset	40.00%

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2016
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. All of the management, leasing and construction services that are provided to the properties that are wholly-owned by us and that are provided to certain joint ventures 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 all of our operations are conducted through, the Operating Partnership. The Company is the sole managing general partner of the Operating Partnership. As of September 30, 2016 , noncontrolling investors held, in the aggregate, a 4.29% limited partnership interest in the Operating Partnership. We refer to these interests as the noncontrolling interests in the Operating Partnership. The Operating Partnership is considered a variable interest entity, or VIE, in which we are the primary beneficiary. 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 SL Green Realty Corp. As of September 30, 2016 , we owned the following interests in properties 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 Property 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 24 16,054,606 7 6,558,139 31 22,612,745 95.4 % Retail 10 (2) 418,093 9 347,970 19 766,063 87.6 % Development/Redevelopment 3 42,635 3 767,311 6 809,946 35.5 % Fee Interest 1 176,530 1 26,926 2 203,456 86.8 % 38 16,691,864 20 7,700,346 58 24,392,210 93.2 % Suburban Office 25 4,113,800 2 640,000 27 4,753,800 82.0 % Retail 1 52,000 — — 1 52,000 100.0 % Development/Redevelopment 1 1,000 1 — 2 1,000 100.0 % 27 4,166,800 3 640,000 30 4,806,800 82.2 % Total commercial properties 65 20,858,664 23 8,340,346 88 29,199,010 91.4 % Residential: Manhattan Residential 4 (2)(3) 762,587 17 2,957,282 21 3,719,869 81.4 % Suburban Residential — — — — — — — % Total residential properties 4 762,587 17 2,957,282 21 3,719,869 81.4 % Total portfolio (3) 69 21,621,251 40 11,297,628 109 32,918,879 90.3 % (1) The weighted average occupancy for commercial properties represents the total occupied square feet divided by the total acquisition square footage. The weighted average occupancy for residential properties represents the total occupied units divided by the total available units. (2) As of September 30, 2016 , 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 in the retail properties count and have bifurcated the square footage into the retail and residential components. (3) Includes the property at 400 East 57th Street, which is classified as held for sale at September 30, 2016 . As of September 30, 2016 , we also managed an office building of approximately 336,000 square foot (unaudited), which is owned by a third party and held debt and preferred equity investments with a book value of $1.8 billion , including $0.3 billion of debt and preferred equity investments and other financing receivables that are included in other balance sheet line items. 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. Basis of Quarterly Presentation The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and notes required by accounting principles generally accepted in the United States for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for the fair presentation of the financial position of the Company and the Operating Partnership at September 30, 2016 and the results of operations for the periods presented have been included. The operating results for the period presented are not necessarily indicative of the results that may be expected for the year ending December 31, 2016 . These financial statements should be read in conjunction with the financial statements and accompanying notes included in the Annual Report on Form 10-K for the year ended December 31, 2015 of the Company and the Operating Partnership. The consolidated balance sheets at December 31, 2015 have been derived from the audited financial statements as of that date but do not include all the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2016
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. 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 September 30, 2016 and December 31, 2015 are $1.6 billion and $200.7 million , respectively, related to our consolidated VIEs. Included in mortgages and other loans payable on our consolidated balance sheets as of September 30, 2016 and December 31, 2015 are $605.8 million and $101.1 million , respectively, collateralized by the real estate assets of the related consolidated VIEs. As of September 30, 2016 , assets held for sale and liabilities related to assets held for sale on the consolidated balance sheets did not include amounts related to 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 is 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, 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 requiring 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 On a periodic basis, we assess whether there are any indications that the value of our real estate properties may be other than temporarily 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) 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 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 either their carrying value or fair value less costs to sell. We do not believe that there were any indicators of impairment at any of our consolidated properties at September 30, 2016 . 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. We recognized $(0.2) million and $191.4 million of rental revenue for the three and nine months ended September 30, 2016 , and $10.2 million and $32.9 million of rental revenue for the three and nine months ended September 30, 2015 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. Included in rental revenue is zero and $172.4 million for the three and nine months ended September 30, 2016 for the amortization of the below-market lease at 388-390 Greenwich Street as a result of the tenant exercising their option to purchase the property and entering into an agreement to accelerate the sale. For the three and nine months ended September 30, 2016 , we recognized as a reduction to interest expense the amortization of the above-market rate mortgages assumed of $0.7 million and $2.0 million , respectively. For the three and nine months ended September 30, 2015 , we recognized as a reduction to interest expense the amortization of the above-market rate mortgages assumed of $0.6 million and $1.7 million , 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 September 30, 2016 and December 31, 2015 (in thousands): September 30, 2016 December 31, 2015 Identified intangible assets (included in other assets): Gross amount $ 624,557 $ 939,518 Accumulated amortization (397,148 ) (403,747 ) Net (1) $ 227,409 $ 535,771 Identified intangible liabilities (included in deferred revenue): Gross amount $ 648,583 $ 866,561 Accumulated amortization (455,568 ) (486,928 ) Net (1) $ 193,015 $ 379,633 (1) As of September 30, 2016 and December 31, 2015, $0.3 million and $0.2 million , respectively and $0.8 million and $0.1 million , respectively, of net intangible assets and net intangible liabilities, were reclassified to assets held for sale and liabilities related to assets held for sale. In February 2016, we closed on the sale of 885 Third Avenue but did not meet the criteria for sale accounting under the full accrual method in ASC 360-20, Property, Plant and Equipment - Real Estate Sales. As a result the property remains on our consolidated balance sheet until the criteria is met. Fair Value Measurements See Note 16, "Fair Value Measurements." Investment in Marketable Securities We designate a security as held-to-maturity, available-for-sale, or trading at acquisition. As of September 30, 2016 , we did not have any securities designated as held-to-maturity or trading. We account for our available-for-sale securities at fair value pursuant to Accounting Standards Codification, or ASC, 820-10, with the net unrealized gains or losses reported as a component of accumulated other comprehensive income or loss. Any 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 September 30, 2016 and December 31, 2015 , we held the following marketable securities (in thousands): September 30, 2016 December 31, 2015 Equity marketable securities $ 23,213 $ 4,704 Commercial mortgage-backed securities 37,139 40,434 Total marketable securities available-for-sale $ 60,352 $ 45,138 The cost basis of the commercial mortgage-backed securities was $36.1 million and $38.7 million at September 30, 2016 and December 31, 2015 , respectively. These securities mature at various times through 2049. During the three and nine months ended September 30, 2016 , we disposed of marketable securities for aggregate net proceeds of $1.7 million and $6.9 million , respectively. During the three and nine months ended September 30, 2015 , we disposed of marketable securities for aggregate net proceeds of $0.1 million , and $0.4 million , respectively. 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 ventures' projected discounted cash flows. We do not believe that the values of any of our equity investments were impaired at September 30, 2016 . We may originate loans for real estate acquisition, development and construction, where we expect to receive some 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. 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 provided that we have no substantial economic involvement with the buyer. Interest income on debt and preferred equity investments is accrued based on the contractual terms of the instruments and when, in the opinion of management, it is deemed collectible. Some 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 an adjustment 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 the loans individually. When a transaction meets the criteria for 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, original issue discounts, 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 operations. 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. 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 include geographic trends, product diversification, the size of the portfolio and current economic conditions. Based upon these factors, we establish a provision for possible credit loss 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 additional information reflects increased recovery of our investment, we will adjust our reserves accordingly. There were no loan reserves recorded during the three and nine months ended September 30, 2016 and 2015. 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. 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, SL Green 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 operations 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 three and nine months ended September 30, 2016 , we recorded Federal, state and local tax provisions of $0.9 million and $1.9 million , respectively. During the three and nine months ended September 30, 2015 , we recorded Federal, state and local tax provisions of $1.1 million and $2.5 million , respectively. 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. 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 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. 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 or loss 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 or loss 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 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 revenue and the costs associated with re-tenanting a space. 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 two tenants, who account for 7.8% and 6.8% of our share of annualized cash rent, no other tenant in our portfolio accounted for more than 5.0% of our share of annualized cash rent, including our share of joint venture annualized rent, at September 30, 2016 . For the three months ended September 30, 2016 , 9.7% , 7.9% , 7.5% , 6.6% , 5.7% , and 5.1% of our share of annualized cash rent for consolidated properties was attributable to 1515 Broadway, 919 Third Avenue, 1185 Avenue of the Americas, 420 Lexington Avenue, One Madison Avenue and 485 Lexington Avenue, respectively. Annualized cash rent for all other consolidated properties was below 5.0% . Reclassification Certain prior year balances have been reclassified to conform to our current year presentation. Accounting Standards Updates In August 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. The ASU provides final guidance on eight cash flow issues, including debt prepayment or debt extinguishment costs, contingent consideration payments made after a business combination, distributions received from equity method investees, separately identifiable cash flows and application of the predominance principle, and others. The amendments in the ASU are effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. The Company has not yet adopted this new guidance and is currently evaluating the impact of adopting this new accounting standard on the Company’s consolidated financial statements. In June 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The guidance changes how entities will measure credit losses for most financial assets and certain other instruments that aren’t measured at fair value through net income. The guidance replaces the current ‘incurred loss’ model with an ‘expected loss’ approach. The guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted after December 2018. The Company has not yet adopted this new guidance and is currently evaluating the impact of adopting this new accounting standard on the Company’s consolidated financial statements. In March 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The guidance simplifies the accounting for share-based payment award transactions including: income tax conseq

Property Acquisitions

Property Acquisitions	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Property Acquisitions	Property Acquisitions 2016 Acquisitions During the nine months ended September 30, 2016 , the property listed below was acquired from a third party. The following summarizes our preliminary allocation of the purchase price of the assets acquired and liabilities assumed upon the closing of this acquisition (in thousands): 183 Broadway (1) Acquisition Date March 2016 Ownership Type Fee Interest Property Type Retail/Residential Purchase Price Allocation: Land $ 26,640 Building and building leasehold 2,960 Above-market lease value — Acquired in-place leases — Other assets, net of other liabilities — Assets acquired 29,600 Mark-to-market assumed debt — Below-market lease value — Derivatives — Liabilities assumed — Purchase price $ 29,600 Net consideration funded by us at closing, excluding consideration financed by debt $ 29,600 Equity and/or debt investment held $ — Debt assumed $ — (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. 2015 Acquisitions During nine months ended September 30, 2016 , we finalized the purchase price allocations based on facts and circumstances that existed at the acquisition dates for the following 2015 acquisitions (in thousands): 187 Broadway and 5 & 7 Dey Street (1) 110 Greene Street (1) Upper Eastside Residential (1) 11 Madison Avenue (1) 1640 Flatbush Avenue (1) Acquisition Date August 2015 July 2015 June 2015 August 2015 March 2015 Ownership Type Fee Interest Fee Interest Fee Interest Fee Interest Fee Interest Property Type Residential/Retail Office Residential/Retail Office Retail Purchase Price Allocation: Land $ 20,266 $ 45,120 $ 48,152 $ 675,776 $ 6,226 Building and building leasehold 42,468 215,470 — 1,553,602 501 Above-market lease value 17 — — 19,764 — Acquired in-place leases 3,621 8,967 1,922 366,949 146 Other assets, net of other liabilities — — — — — Assets acquired 66,372 269,557 50,074 2,616,091 6,873 Mark-to-market assumed debt — — — — — Below-market lease value (3,226 ) (14,557 ) — (187,732 ) (73 ) Derivatives — — — — — Liabilities assumed (3,226 ) (14,557 ) — (187,732 ) (73 ) Purchase price $ 63,146 $ 255,000 $ 50,074 $ 2,428,359 $ 6,800 Net consideration funded by us at closing, excluding consideration financed by debt $ — $ — $ — $ — $ — Equity and/or debt investment held $ — $ — $ — $ — $ — Debt assumed $ — $ — $ — $ — $ — (1) Based on our preliminary analysis of the purchase price, we had allocated $22.1 million and $41.0 million to land and building, respectively, at 187 Broadway and 5 & 7 Dey Street, $89.3 million and $165.8 million to land and building, respectively, at 110 Greene Street, $17.5 million and $32.5 million to land and building, respectively, at the Upper Eastside Residential Property, $849.9 million and $1.6 billion to land and building, respectively, at 11 Madison Avenue, and $6.1 million and $0.7 million to land and building, respectively, at 1640 Flatbush Avenue. The impact to our consolidated statement of operations for the nine months ended September 30, 2016 to adjust for the finalized purchase price allocations was $8.0 million in rental revenue for the amortization of aggregate below-market leases and $17.9 million of depreciation expense.

Properties Held for Sale and Pr

Properties Held for Sale and Property Dispositions	9 Months Ended
	Sep. 30, 2016
Discontinued Operations and Disposal Groups [Abstract]
Properties Held for Sale and Property Dispositions	Properties Held for Sale and Property Dispositions Properties Held for Sale During the three months ended September 30, 2016 , we determined that the held for sale criteria was met for 400 East 57th Street. In October we closed on the sale of a 49% interest in the property, in which we previously held a 90% interest. Property Dispositions The following table summarizes the properties sold during the nine months ended September 30, 2016 : Property Disposition Date Property Type Approximate Square Feet Sales Price (1) (in millions) Gain on Sale (2) (in millions) 248-252 Bedford Avenue February 2016 Residential 66,611 $ 55.0 $ 15.3 885 Third Avenue (3) February 2016 Land 607,000 453.0 — 7 International Drive May 2016 Land 31 Acres 20.0 (6.9 ) 388 Greenwich June 2016 Office 2,635,000 2,002.3 206.5 500 West Putnam July 2016 Office 121,500 41.0 (10.4 ) 11 Madison Avenue (4) August 2016 Office 2,314,000 2,600.0 — (1) Sales price represents the gross sales price for a property or the gross asset valuation for interests in a property. (2) The gain on sale for 248-252 Bedford Avenue and 388 Greenwich are net of $1.3 million and $1.6 million , respectively in employee compensation awards accrued in connection with the realization of the investment gain as a bonus to certain employees that were instrumental in realizing the gain on sale. Additionally, amounts do not include adjustments for expenses recorded in subsequent periods. (3) In February 2016, we closed on the sale of 885 Third Avenue. The sale did not meet the criteria for sale accounting and, as a result, the property remains on our consolidated balance sheet until the criteria is met. An estimated loss relating to the sale of $6.6 million was recorded in December 2015. We expect to meet the criteria for sale accounting in 2017 at which time we will recognize the sale and start recognizing investment income on our $135.0 million 5.75% senior equity investment in the property. (4) In August 2016, we sold an 40% interest in 11 Madison Avenue. The sale did not meet the criteria for sale accounting and, as a result, the property is being accounted for under the profit sharing method. See Note 6, "Investments in Unconsolidated Joint Ventures." Discontinued Operations The Company adopted ASU 2014-08 effective January 1, 2015 which raised the threshold for disposals to qualify as discontinued operations to include only dispositions that represent a strategic shift in an entity’s operations. The guidance was applied prospectively for new disposals. As a result, the results of operations for 400 East 57th Street, which was classified as held for sale at September 30, 2016 along with 570-574 Fifth Avenue and 140-150 Grand Street, which were classified as held for sale at September 30, 2015, are included in continuing operations for all periods presented. Discontinued operations for the nine months ended September 30, 2016 included the results of operations of 180 Maiden Lane, which was held for sale at December 31, 2014 and sold in January 2015, as follows (in thousands): Nine Months Ended September 30, 2015 Revenues Rental revenue $ 236 Escalation and reimbursement revenues (127 ) Total revenues 109 Operating expenses (631 ) Real estate taxes 250 Transaction related costs (49 ) Depreciable real estate reserves 109 Interest expense, net of interest income 3 Total expenses (318 ) Net income from discontinued operations $ 427

Debt and Preferred Equity Inves

Debt and Preferred Equity Investments	9 Months Ended
	Sep. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Debt and Preferred Equity Investments	Debt and Preferred Equity Investments During the nine months ended September 30, 2016 and 2015 , our debt and preferred equity investments, net of discounts and deferred origination fees, increased $590.4 million and $464.9 million , respectively, due to originations, purchases, advances under future funding obligations, discount and fee amortization, and paid-in-kind interest, net of premium amortization. We recorded repayments, participations and sales of $807.2 million and $372.1 million during the nine months ended September 30, 2016 and 2015 , respectively, which offset the increases in debt and preferred equity investments. Certain debt investments that were participated out but did not meet the conditions for sale accounting are included in other assets and other liabilities on the consolidated balance sheets. Debt Investments As of September 30, 2016 and December 31, 2015 we held the following debt investments with an aggregate weighted average current yield of 9.29% at September 30, 2016 (in thousands): Loan Type September 30, 2016 Future Funding Obligations September 30, 2016 Senior Financing September 30, 2016 Carrying Value (1) December 31, 2015 Carrying Value (1) Maturity Date (2) Fixed Rate Investments: Jr. Mortgage Participation/Mezzanine Loan $ — $ 1,109,000 $ 189,250 $ 104,661 March 2017 Mezzanine Loan (3a) 5,000 502,100 61,059 41,115 June 2017 Mortgage Loan (4) — — 26,297 26,262 February 2019 Mortgage Loan — — 414 513 August 2019 Mezzanine Loan — 15,000 3,500 3,500 September 2021 Mezzanine Loan (3b) — 88,944 12,691 19,936 November 2023 Mezzanine Loan (3c) — 115,000 12,923 24,916 June 2024 Mezzanine Loan — 95,000 30,000 30,000 January 2025 Mezzanine Loan (5) — — — 72,102 Mezzanine Loan (6) — — — 49,691 Jr. Mortgage Participation (7) — — — 49,000 Other (7)(8) — — — 23,510 Other (7)(8) — — — 66,183 Total fixed rate $ 5,000 $ 1,925,044 $ 336,134 $ 511,389 Floating Rate Investments: Mezzanine Loan — 360,000 99,945 99,530 November 2016 Mezzanine Loan 7,939 144,008 53,405 49,751 December 2016 Mezzanine Loan 281 39,201 11,024 13,731 December 2016 Mortgage/Mezzanine Loan (3d) 40,086 — 140,920 134,264 January 2017 Mezzanine Loan 1,127 118,949 28,834 28,551 January 2017 Mezzanine Loan (3e)(9) — 40,000 15,290 68,977 June 2017 Mortgage/Mezzanine Loan — — 32,763 — June 2017 Mortgage/Mezzanine Loan — — 22,939 22,877 July 2017 Mortgage/Mezzanine Loan — — 16,946 16,901 September 2017 Mortgage/Mezzanine Loan 4,038 — 19,834 19,282 October 2017 Mezzanine Loan — 60,000 14,944 14,904 November 2017 Mezzanine Loan (3f) — 85,000 15,075 29,505 December 2017 Mezzanine Loan (3g) — 65,000 14,598 28,563 December 2017 Mortgage/Mezzanine Loan (3h) 795 — 15,024 14,942 December 2017 Jr. Mortgage Participation — 40,000 19,896 19,846 April 2018 Mezzanine Loan — 175,000 34,814 34,725 April 2018 Mortgage/Mezzanine Loan (10) 523 24,818 10,846 31,210 August 2018 Mortgage Loan — — 19,815 — August 2018 Mezzanine Loan — 65,000 14,862 — August 2018 Mezzanine Loan — — 14,599 — September 2018 Mezzanine Loan 2,325 45,025 34,411 — October 2018 Loan Type September 30, 2016 Future Funding Obligations September 30, 2016 Senior Financing September 30, 2016 Carrying Value (1) December 31, 2015 Carrying Value (1) Maturity Date (2) Mezzanine Loan — 33,000 26,831 26,777 December 2018 Mezzanine Loan 4,097 156,383 55,264 52,774 December 2018 Mezzanine Loan 18,883 246,758 59,917 49,625 December 2018 Mezzanine Loan 6,383 16,383 5,387 — January 2019 Mezzanine Loan — 38,000 21,880 21,845 March 2019 Mezzanine Loan — 265,000 24,677 — April 2019 Mortgage/Jr. Mortgage Participation Loan 34,500 180,740 64,549 — August 2019 Mezzanine Loan 2,500 187,500 37,307 — September 2019 Mortgage/Mezzanine Loan 87,620 — 107,060 — September 2019 Jr. Mortgage Participation/Mezzanine Loan — 30,000 15,599 — July 2021 Mortgage/Mezzanine Loan (11) — — — 94,901 Jr. Mortgage Participation/Mezzanine Loan (5) — — — 20,510 Mezzanine Loan (12) — — — 22,625 Mezzanine Loan (13) — — — 74,700 Mezzanine Loan (14) — — — 66,398 Jr. Mortgage Participation/Mezzanine Loan (7) — — — 18,395 Mezzanine Loan (15) — — — 40,346 Total floating rate $ 211,097 $ 2,415,765 $ 1,069,255 $ 1,116,455 Total $ 216,097 $ 4,340,809 $ 1,405,389 $ 1,627,844 (1) Carrying value is net of discounts, premiums, original issue discounts and deferred origination fees. (2) Represents contractual maturity, excluding any unexercised extension options. (3) Carrying value is net of the following amounts that were participated out, which are included in other assets and other liabilities on the consolidated balance sheets as a result of the transfers not meeting the conditions for sale accounting: (a) $41.3 million , (b) $5.0 million , (c) $12.0 million , (d) $36.3 million , (e) $14.5 million , (f) $14.6 million , (g) $14.1 million , and (h) $5.1 million . (4) 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. (5) These loans were repaid in July 2016. (6) In April 2016, we closed on an option to acquire a 20% interest in the underlying asset at a previously agreed upon purchase option valuation, and our mezzanine loan was simultaneously repaid. (7) These loans were repaid in March 2016. (8) These loans were collateralized by defeasance securities. (9) In March 2016, the mortgage was sold. (10) In January 2016, the loans were modified. In March 2016, the mortgage was sold. (11) This loan was repaid in September 2016. (12) This loan was repaid in June 2016. (13) This loan was repaid in May 2016. (14) In March 2016, we contributed our interest in the loan in exchange for a joint venture interest which is now accounted for under the equity method of accounting. It is included in unconsolidated joint ventures on the consolidated balance sheets. (15) This loan was repaid in February 2016. Preferred Equity Investments As of September 30, 2016 and December 31, 2015 , we held the following preferred equity investments with an aggregate weighted average current yield of 7.32% at September 30, 2016 (in thousands): Type September 30, 2016 Future Funding Obligations September 30, 2016 Senior Financing September 30, 2016 Carrying Value (1) December 31, 2015 (1) Initial Mandatory Redemption Preferred Equity $ — $ 71,486 $ 9,978 $ 9,967 March 2018 Preferred Equity — 59,034 37,867 32,209 November 2018 Total $ — $ 130,520 $ 47,845 $ 42,176 (1) Carrying value is net of deferred origination fees. At September 30, 2016 and December 31, 2015 , 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 September 30, 2016 and 2015 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 $101.4 million and $121.5 million at September 30, 2016 and December 31, 2015 , respectively. No financing receivables were 90 days past due at September 30, 2016 .

Investments in Unconsolidated J

Investments in Unconsolidated Joint Ventures	9 Months Ended
	Sep. 30, 2016
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. As of September 30, 2016 , 650 Fifth Avenue, 800 Third Avenue, 21 East 66th Street, 605 West 42 nd Street, 333 East 22nd Street, and certain properties within the Stonehenge Portfolio are VIEs in which we are not the primary beneficiary. Our net equity investment in these VIEs was $ 220.7 million as of September 30, 2016 . As of December 31, 2015 , 650 Fifth Avenue and 33 Beekman were VIEs in which we were not the primary beneficiary. Our net equity investment in these VIEs was $39.7 million as of December 31, 2015 . Our maximum loss is limited to the amount of our equity investment in these VIEs. All other investments below are voting interest entities. 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 September 30, 2016 : Property Partner Ownership Interest Economic Interest Approximate Square Feet Acquisition Date Acquisition Price (1) (in thousands) 100 Park Avenue Prudential Real Estate Investors 49.90% 49.90% 834,000 January 2000 $ 95,800 717 Fifth Avenue Jeff Sutton/Private Investor 10.92% 10.92% 119,500 September 2006 251,900 800 Third Avenue Private Investors 60.52% 60.52% 526,000 December 2006 285,000 1745 Broadway Ivanhoe Cambridge, Inc. 56.88% 56.88% 674,000 April 2007 520,000 Jericho Plaza (2) Onyx Equities/Private Investor 11.67% 11.67% 640,000 April 2007 210,000 11 West 34th Street Private Investor/ Jeff Sutton 30.00% 30.00% 17,150 December 2010 10,800 3 Columbus Circle (3) The Moinian Group 48.90% 48.90% 741,500 January 2011 500,000 280 Park Avenue Vornado Realty Trust 50.00% 50.00% 1,219,158 March 2011 400,000 1552-1560 Broadway (4) Jeff Sutton 50.00% 50.00% 35,897 August 2011 136,550 724 Fifth Avenue Jeff Sutton 50.00% 50.00% 65,040 January 2012 223,000 10 East 53rd Street Canadian Pension Plan Investment Board 55.00% 55.00% 354,300 February 2012 252,500 521 Fifth Avenue Plaza Global Real Estate Partners LP 50.50% 50.50% 460,000 November 2012 315,000 21 East 66th Street (5) Private Investors 32.28% 32.28% 16,736 December 2012 75,000 650 Fifth Avenue (6) Jeff Sutton 50.00% 50.00% 32,324 November 2013 121 Greene Street Jeff Sutton 50.00% 50.00% 7,131 September 2014 27,400 175-225 Third Street Brooklyn, New York KCLW 3rd Street LLC/LIVWRK LLC 95.00% 95.00% — October 2014 74,600 55 West 46th Street Prudential Real Estate Investors 25.00% 25.00% 347,000 November 2014 295,000 Stonehenge Portfolio Various Various Various 2,046,733 Various 36,668 131-137 Spring Street Invesco Real Estate 20.00% 20.00% 68,342 August 2015 277,750 76 11th Avenue (7) Oxford/Vornado 33.33% 36.58% 764,000 March 2016 138,240 605 West 42nd Street (8) The Moinian Group 20.00% 20.00% 927,358 April 2016 759,000 11 Madison Avenue (9) PGIM Real Estate 60.00% 60.00% 2,314,000 August 2016 2,605,000 333 East 22nd Street (10) Private Investors 33.33% 33.33% 26,926 August 2016 — (1) Acquisition price represents the actual or implied gross purchase price for the joint venture, which is not adjusted for subsequent acquisitions of additional interests. (2) Our ownership percentage was reduced in the first quarter of 2016, from 77.78% to 11.67% , upon completion of the restructuring of the joint venture. (3) As a result of the sale of a condominium interest in September 2012, Young & Rubicam, Inc., or Y&R, owns floors three through eight at the property. Because the joint venture has an option to repurchase these floors, the gain associated with this sale was deferred. (4) The purchase price represents only the purchase of the 1552 Broadway interest which comprised approximately 13,045 square feet. 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. (5) 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. (6) 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 our joint venture partner 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. (7) The joint venture owns two mezzanine notes secured by interests in the entity that owns 76 11th Avenue. The difference between our ownership interest and our economic interest results from our right to 50% of the total exit fee while each of our partners is entitled to receive 25% of the total exit fee. (8) The Company was granted an option to purchase the interest at an agreed upon valuation in July 2014 when it originated a $50.0 million mezzanine loan to the project's developer. The mezzanine loan was repaid prior to the closing of the Company's acquisition of its joint venture interest. (9) In August 2016, we closed on the sale of a 40% interest in 11 Madison. The sale did not meet the criteria for sale accounting and as a result the property is being accounted for under the profit sharing method. Under the profit sharing method the Company recognizes its share of the operations of the property and also recognizes the other partner's share of depreciation. Included in equity in net income from unconsolidated joint ventures is $4.7 million of depreciation for the three and nine months ended September 30, 2016 representing the other partner's share of depreciation. Included in Investment in Unconsolidated Joint Ventures at September 30, 2016 are $2.7 billion of assets net of $1.5 billion of liabilities, net of the $482.0 million consideration received at closing for this property. Sale accounting will be met upon the lender group consenting to certain modifications to the mortgage on the property which we expect will be granted during the fourth quarter of 2016. If the modification is not obtained this may result in the Company repurchasing the sold interest from PGIM Real Estate at the sale price. The achievement of sale accounting will discontinue recognition of PGIM Real Estate's share of depreciation from that date and will have no effect on the balance sheet presentation of the investment. (10) The joint venture entered into a ground lease for the property commencing in October 2016. Acquisition, Development and Construction Arrangements Based on the characteristics of the following arrangements, which are similar to those of an investment, combined with the expected residual profit of not greater than 50% , we have accounted for these debt and preferred equity investments under the equity method. As of September 30, 2016 and December 31, 2015, the carrying value for acquisition, development and construction arrangements were as follows (in thousands): Loan Type September 30, 2016 December 31, 2015 Initial Maturity Date Mezzanine Loan and Preferred Equity $ 100,000 $ 99,936 March 2017 Mezzanine Loan 24,119 — July 2036 (1) Mezzanine Loan (2) 45,675 45,942 February 2022 $ 169,794 $ 145,878 (1) The Company has the ability to convert this loan into an equity position starting in 2021 and the borrower is able to force this conversion in 2024. (2) We have an option to convert our loan to an equity interest subject to certain conditions. We have determined that our option to convert the loan to equity is not a derivative financial instrument pursuant to GAAP. Sale of Joint Venture Interest or Property The following table summarizes the investments in unconsolidated joint ventures sold during the nine months ended September 30, 2016 : Property Ownership Percentage Disposition Date Type of Sale Gross Asset Valuation (in thousands) (1) Gain on Sale (in thousands) (2) 1 Jericho Plaza (3) 66.11% February 2016 Office $ 95,200 $ 3,300 7 Renaissance Square 50.00% March 2016 Office 20,700 4,200 EOP Denver 4.79% March 2016 Office 180,700 2,800 33 Beekman (4) 45.90% May 2016 Residential 196,000 33,000 EOP Denver 0.48% September 2016 Office 180,700 300 (1) Represents implied gross valuation for the joint venture or sales price of the property. (2) Represents the Company's share of the gain. The gain on sale is net of $1.1 million employee compensation awards accrued in connection with the realization of these investment gains as a bonus to certain employees that were instrumental in realizing the gains on sale. (3) Our ownership percentage was reduced in the first quarter of 2016, from 77.78% to 11.67% , upon completion of the restructuring of the joint venture. (4) In connection with the sale of the property, we also recognized a promote of $10.8 million . 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 September 30, 2016 and December 31, 2015 , respectively, are as follows (amounts in thousands): Property Maturity Date Interest Rate (1) September 30, 2016 December 31, 2015 Fixed Rate Debt: 1745 Broadway January 2017 5.68 % $ 340,000 $ 340,000 521 Fifth Avenue November 2019 3.73 % 170,000 170,000 717 Fifth Avenue (2) July 2022 4.45 % 300,000 300,000 717 Fifth Avenue (2) July 2022 5.50 % 355,328 325,704 Property Maturity Date Interest Rate (1) September 30, 2016 December 31, 2015 21 East 66th Street April 2023 3.60 % 12,000 12,000 3 Columbus Circle March 2025 3.61 % 350,000 350,000 11 Madison Avenue September 2025 3.84 % 1,400,000 — 800 Third Avenue February 2026 3.37 % 177,000 20,910 Stonehenge Portfolio (3) Various 4.19 % 364,255 430,627 280 Park Avenue — 692,963 7 Renaissance Square — 2,927 Total fixed rate debt $ 3,468,583 $ 2,645,131 Floating Rate Debt: 175-225 Third Street (4) December 2016 4.50 % $ 40,000 $ 40,000 10 East 53rd Street February 2017 2.99 % 125,000 125,000 724 Fifth Avenue April 2017 2.91 % 275,000 275,000 1552 Broadway (5) April 2017 4.71 % 185,410 190,409 55 West 46th Street (6) October 2017 2.79 % 151,536 150,000 Jericho Plaza (7) March 2018 4.64 % 76,993 163,750 605 West 42nd Street July 2018 2.85 % 539,000 — 650 Fifth Avenue (8) August 2018 4.17 % 65,000 65,000 280 Park Avenue June 2019 2.49 % 900,000 30,000 121 Greene Street November 2019 1.99 % 15,000 15,000 131-137 Spring Street August 2020 2.04 % 141,000 141,000 11 West 34th Street January 2021 1.94 % 23,000 23,000 100 Park Avenue February 2021 2.24 % 360,000 360,000 21 East 66th Street June 2033 3.00 % 1,746 1,805 Stonehenge Portfolio (9) Various 5.81 % 65,664 10,500 33 Beekman — 73,518 Total floating rate debt $ 2,964,349 $ 1,663,982 Total joint venture mortgages and other loans payable $ 6,432,932 $ 4,309,113 Deferred financing costs, net (100,426 ) (42,565 ) Total joint venture mortgages and other loans payable, net $ 6,332,506 $ 4,266,548 (1) Effective weighted average interest rate for the three months ended September 30, 2016 , taking into account interest rate hedges in effect during the period. (2) These loans are comprised of a $300.0 million fixed rate mortgage loan and $355.3 million mezzanine loan. The mezzanine loan is subject to accretion based on the difference between contractual interest rate and contractual pay rate. (3) Amount is comprised of $13.2 million , $34.6 million , $140.3 million , and $176.1 million in fixed-rate mortgages that mature in April 2017, November 2017, August 2019, and June 2024, respectively. (4) In October 2016, the loan was extended to December 2017. (5) These loans are comprised of a $145.0 million mortgage loan and a $41.5 million mezzanine loan. As of September 30, 2016 , $0.6 million of the mortgage loan and $0.5 million of the mezzanine loan were unfunded. (6) This loan has a committed amount of $190.0 million , of which $38.5 million was unfunded as of September 30, 2016 . (7) We hold an 11.67% non-controlling interest in the joint venture and the property secures a two year $100.0 million loan, of which $77.0 million is currently outstanding. (8) This loan has a committed amount of $97.0 million , of which $32.0 million was unfunded as of September 30, 2016 . (9) Amount is comprised of $55.3 million and $10.3 million in floating-rate mortgages that mature in June 2017 and December 2017, respectively. 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, 21 East 66th Street, 175-225 Third Street, 605 West 42nd Street and the Stonehenge Portfolio. We are entitled to receive fees for providing management, leasing, construction supervision and asset management services to certain of our joint ventures. We earned $2.0 million and $4.5 million from these services for the three and nine months ended September 30, 2016 , respectively. We earned $1.9 million and $6.8 million from these services for the three and nine months ended September 30, 2015 , 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 September 30, 2016 and December 31, 2015 are as follows (in thousands): September 30, 2016 December 31, 2015 Assets Commercial real estate property, net $ 8,927,385 $ 6,122,468 Cash and restricted cash 320,318 258,564 Tenant and other receivables, related party receivables, and deferred rents receivable, net of allowance 227,937 208,802 Debt and preferred equity investments, net 332,506 145,878 Other assets 670,665 248,474 Total assets $ 10,478,811 $ 6,984,186 Liabilities and members' equity Mortgages and other loans payable, net $ 6,332,506 $ 4,266,548 Deferred revenue/gain 367,873 209,095 Other liabilities 374,198 314,065 Members' equity 3,404,234 2,194,478 Total liabilities and members' equity $ 10,478,811 $ 6,984,186 Company's investments in unconsolidated joint ventures $ 1,860,912 $ 1,203,858 The combined statements of operations for the unconsolidated joint ventures, from acquisition date through the three and nine months ended September 30, 2016 and 2015 , are as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Total revenues $ 184,221 $ 150,638 $ 498,308 $ 423,089 Operating expenses 34,727 27,647 89,147 79,478 Ground rent 3,744 4,677 10,670 9,841 Real estate taxes 30,814 23,494 79,356 65,205 Interest expense, net of interest income 51,789 51,430 147,876 147,152 Amortization of deferred financing costs 7,155 3,473 17,667 9,628 Transaction related costs 5,359 604 5,359 615 Depreciation and amortization 56,890 38,144 132,035 109,022 Total expenses 190,478 149,469 482,110 420,941 Loss on early extinguishment of debt — (248 ) (1,606 ) (1,081 ) Net (loss) income before gain on sale $ (6,257 ) $ 921 $ 14,592 $ 1,067 Company's equity in net (loss) income from unconsolidated joint ventures $ (3,968 ) $ 3,627 $ 11,969 $ 10,651

Deferred Costs

Deferred Costs	9 Months Ended
	Sep. 30, 2016
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred Costs	Deferred Costs Deferred costs at September 30, 2016 and December 31, 2015 consisted of the following (in thousands): September 30, 2016 December 31, 2015 Deferred leasing $ 450,192 $ 415,406 Less: accumulated amortization (198,013 ) (175,486 ) Deferred costs, net $ 252,179 $ 239,920

Mortgages and Other Loans Payab

Mortgages and Other Loans Payable	9 Months Ended
	Sep. 30, 2016
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 or debt investments at September 30, 2016 and December 31, 2015 , respectively, were as follows (amounts in thousands): Property Maturity Date Interest Rate (1) September 30, 2016 December 31, 2015 Fixed Rate Debt: Landmark Square December 2016 4.00 % $ 78,236 $ 79,562 FHLB Facility January 2017 1.03 % 105,000 — FHLB Facility January 2017 0.80 % 100,000 — 485 Lexington Avenue February 2017 5.61 % 450,000 450,000 762 Madison Avenue February 2017 3.86 % 7,739 7,872 Unsecured Loan June 2018 4.81 % 16,000 16,000 One Madison Avenue May 2020 5.91 % 524,814 542,817 100 Church Street July 2022 4.68 % 222,390 225,099 919 Third Avenue (2) June 2023 5.12 % 500,000 500,000 400 East 57th Street (3) February 2024 4.13 % 66,779 67,644 400 East 58th Street February 2024 4.13 % 28,620 28,990 420 Lexington Avenue October 2024 3.99 % 300,000 300,000 1515 Broadway March 2025 3.93 % 892,457 900,000 Series J Preferred Units (4) April 2051 3.75 % 4,000 4,000 885 Third Avenue (5) 6.26 % 267,650 267,650 11 Madison Avenue (6) — 1,400,000 388-390 Greenwich Street (7) — 1,004,000 500 West Putnam Avenue (8) — 22,376 Total fixed rate debt $ 3,563,685 $ 5,816,010 Floating Rate Debt: FHLB Facility December 2016 0.77 % $ 24,000 $ 45,750 719 Seventh Avenue February 2018 3.54 % 32,823 — 183, 187 Broadway & 5-7 Dey Street May 2018 3.19 % 58,000 40,000 Master Repurchase Agreement July 2018 3.01 % 134,642 253,424 1080 Amsterdam November 2018 4.24 % 3,525 3,525 220 East 42nd Street October 2020 2.09 % 275,000 275,000 One Vanderbilt Avenue (9) September 2021 4.03 % — — 600 Lexington Avenue — 112,795 388-390 Greenwich Street (7) — 446,000 248-252 Bedford Avenue (10) — 29,000 Total floating rate debt $ 527,990 $ 1,205,494 Total fixed rate and floating rate debt $ 4,091,675 $ 7,021,504 Mortgages reclassed to liabilities related to assets held for sale (3)(7)(10) (66,779 ) (29,000 ) Total mortgages and other loans payable $ 4,024,896 $ 6,992,504 Deferred financing costs, net of amortization (70,741 ) (110,584 ) Total mortgages and other loans payable, net $ 3,954,155 $ 6,881,920 (1) Effective weighted average interest rate for the quarter ended September 30, 2016 , taking into account interest rate hedges in effect during the period. (2) We own a 51.0% controlling interest in the consolidated joint venture that is the borrower on this loan. (3) In October 2016, we closed on the sale of an interest in 400 East 57th Street. At September 30, 2016, this property was classified as a held for sale property and the related mortgage, net of deferred financing costs, net of amortization of $2.1 million , was included in liabilities related to assets held for sale. (4) In connection with the acquisition of a commercial real estate property, the Operating Partnership issued $4.0 million , 3.75% Series J Preferred Units of limited partnership interest, or the Series J Preferred Units, with a mandatory liquidation preference of $1,000 per unit. The Series J Preferred Units are accounted for as debt because they 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 provided for in the related agreement. (5) In February 2016, we closed on the sale of 885 Third Avenue. The sale did not meet the criteria for sale accounting and as a result the property remains on our consolidated balance sheet until the criteria is met. The maturity date of the mortgage on the property, which was assumed by the buyer, is July 2017. (6) In August 2016, we closed on the sale of a 40.0% interest on 11 Madison Avenue. This property is now classified within unconsolidated joint ventures. (7) In June 2016, we closed on the sale of 388-390 Greenwich Street. At March 31, 2016, this property was classified as a held for sale property and the related mortgage, net of deferred financing costs, net of amortization of $24.5 million , was included in liabilities related to assets held for sale. (8) In January 2016, the mortgage was repaid. (9) In September 2016, we closed on a $1.5 billion construction facility in connection with the development of One Vanderbilt Avenue. This facility bears interest at 350 basis points over 30-day LIBOR, with reductions based on meeting certain conditions, and has an initial five -year term with two one -year extension options. Advances under the loan are subject to incurred costs, funded equity, loan to value thresholds, and entering into construction contracts. (10) The property at 248-252 Bedford Avenue in Brooklyn, New York was sold in February 2016. At December 31, 2015 this property was held for sale and the related mortgage, net of deferred financing, net of amortization costs of $0.9 million , was included in liabilities related to assets held for sale. Federal Home Loan Bank of New York Facility The Company’s wholly-owned subsidiary, Belmont Insurance Company, or Belmont, a New York licensed captive insurance company, is a member of the Federal Home Loan Bank of New York, or FHLBNY. As a member, Belmont may borrow funds from the FHLBNY in the form of secured advances. As of September 30, 2016 , we had $229.0 million in outstanding secured advances with a weighted average borrowing rate of 0.90% . On January 12, 2016, the Federal Housing Finance Agency, or FHFA, adopted a final regulation on Federal Home Loan Bank, or FHLB, membership. The rule excludes captive insurance entities from FHLB membership on a going-forward basis and provides termination rules for current captive insurance members. Unless the final rule is modified, Belmont's membership will terminate on February 19, 2017, at which point we would be required to repay all funds borrowed from the FHLBNY. Master Repurchase Agreement The Master Repurchase Agreement, or MRA, provides us with the ability to sell certain debt investments with a simultaneous agreement to repurchase the same at a certain date or on demand. This MRA has a maximum facility capacity of $300.0 million and bears interest ranging from 225 and 400 basis points over 30-day LIBOR depending on the pledged collateral. Since December 6, 2015, we have been required to pay monthly in arrears a 25 basis point fee on the excess of $150.0 million over the average daily balance during the period if the average daily balance is less than $150.0 million . We seek to mitigate risks associated with our repurchase agreement by managing the credit quality of our assets, early repayments, interest rate volatility, liquidity, and market value. The margin call provisions under our repurchase facility permit valuation adjustments based on capital markets activity, and are not limited to collateral-specific credit marks. To monitor credit risk associated with our debt investments, our asset management team regularly reviews our investment portfolio and is in contact with our borrowers in order to monitor the collateral and enforce our rights as necessary. The risk associated with potential margin calls is further mitigated by our ability to recollateralize the facility with additional assets from our portfolio of debt investments, our ability to satisfy margin calls with cash or cash equivalents and access to additional liquidity through the 2012 credit facility, as defined below. At September 30, 2016 and December 31, 2015 , the gross book value of the properties and debt and preferred equity investments collateralizing the mortgages and other loans payable, not including assets held for sale, was approximately $6.4 billion and $10.8 billion , respectively.

Corporate Indebtedness

Corporate Indebtedness	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Corporate Indebtedness	Corporate Indebtedness 2012 Credit Facility In August 2016, we entered into an amendment to the credit facility that was originally entered into by the Company in November 2012, referred to as the 2012 credit facility. As of September 30, 2016 , the 2012 credit facility, as amended, consisted of a $1.6 billion revolving credit facility and a $1.2 billion term loan, with a maturity date of March 29, 2019 and June 30, 2019, respectively. The revolving credit facility has an as-of-right extension to March 29, 2020. We also have an option, subject to customary conditions, to increase the capacity under the revolving credit facility to $3.0 billion at any time prior to the maturity date for the revolving credit facility without the consent of existing lenders, by obtaining additional commitments from our existing lenders and other financial institutions. As of September 30, 2016 , the 2012 credit facility bore interest at a spread over LIBOR ranging from (i) 87.5 basis points to 155 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 September 30, 2016 , the applicable spread was 125 basis points for the revolving credit facility and 140 basis points for the term loan facility. At September 30, 2016 , the effective interest rate was 1.73% for the revolving credit facility and 2.25% for the term loan facility. We are required to pay quarterly in arrears a 12.5 to 30 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 September 30, 2016 , the facility fee was 25 basis points. As of September 30, 2016 , we had $56.5 million of outstanding letters of credit, zero drawn under the revolving credit facility and $1.2 billion outstanding under the term loan facility, with total undrawn capacity of $1.5 billion under the 2012 credit facility. At September 30, 2016 and December 31, 2015 the revolving credit facility had a carrying value of $(6.9) million , representing deferred financing costs presented within other liabilities, and $985.1 million , respectively, net of deferred financing costs. At September 30, 2016 and December 31, 2015, the term loan facility had a carrying value of $1.2 billion and $929.5 million , respectively, net of deferred financing costs. 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). Senior Unsecured Notes The following table sets forth our senior unsecured notes and other related disclosures as of September 30, 2016 and December 31, 2015 , respectively, by scheduled maturity date (dollars in thousands): Issuance September 30, September 30, December 31, 2015 Accreted Balance Coupon Rate (1) Effective Rate Term (in Years) Maturity Date October 12, 2010 (2) $ 345,000 $ 330,754 $ 321,130 3.00 % 3.00 % 7 October 2017 August 5, 2011 (3) 250,000 249,862 249,810 5.00 % 5.00 % 7 August 2018 March 16, 2010 (3) 250,000 250,000 250,000 7.75 % 7.75 % 10 March 2020 November 15, 2012 (3) 200,000 200,000 200,000 4.50 % 4.50 % 10 December 2022 December 17, 2015 (3) 100,000 100,000 100,000 4.27 % 4.27 % 10 December 2025 March 26, 2007 (4) — — 10,008 March 31, 2006 (5) — — 255,296 $ 1,145,000 $ 1,130,616 $ 1,386,244 Deferred financing costs, net (6,163 ) (7,280 ) $ 1,145,000 $ 1,124,453 $ 1,378,964 (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 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 12.5697 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 became exchangeable commencing January 1, 2016 and remained exchangeable through March 31, 2016. The notes are guaranteed by ROP. On the issuance date, $78.3 million of the debt balance was recorded in equity. As of September 30, 2016 , $14.2 million remained to be amortized into the debt balance. (3) Issued by the Company, the Operating Partnership and ROP, as co-obligors. (4) Balance was repaid in September 2016. (5) Issued by ROP, balance was repaid in March 2016. 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 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 September 30, 2016 and 2015 , we were in compliance with all such covenants. Junior Subordinated 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 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 September 30, 2016 , including as-of-right extension options and put options, were as follows (in thousands): Scheduled Amortization Principal Revolving Credit Facility Unsecured Term Loan Trust Preferred Securities Senior Unsecured Notes Total Joint Venture Debt Remaining 2016 $ 12,694 $ 101,936 $ — $ — $ — $ — $ 114,630 $ 38,253 2017 53,467 930,329 — — — 345,000 1,328,796 534,720 2018 56,320 244,990 — — — 250,000 551,310 41,933 2019 62,048 — — 1,183,000 — — 1,245,048 554,686 2020 44,162 679,531 — — — 250,000 973,693 30,298 Thereafter 124,818 1,781,380 — — 100,000 300,000 2,306,198 1,494,287 $ 353,509 $ 3,738,166 $ — $ 1,183,000 $ 100,000 $ 1,145,000 $ 6,519,675 $ 2,694,177 Consolidated interest expense, excluding capitalized interest, was comprised of the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Interest expense before capitalized interest $ 78,715 $ 92,244 $ 276,437 $ 261,343 Interest capitalized (6,084 ) (7,327 ) (18,135 ) (23,496 ) Interest income (66 ) (776 ) (1,976 ) (2,153 ) Interest expense, net $ 72,565 $ 84,141 $ 256,326 $ 235,694

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2016
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Cleaning/ Security/ Messenger and Restoration Services Alliance Building Services, or Alliance, and its affiliates are partially owned by Gary Green, a son of Stephen L. Green, the chairman of SL Green's board of directors, and provide services to certain properties owned by us. Alliance’s affiliates include First Quality Maintenance, L.P., or First Quality, Classic Security LLC, Bright Star Couriers LLC and Onyx Restoration Works, and provide cleaning, extermination, security, messenger, and restoration services, respectively. 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 operations, was $0.8 million and $2.6 million for the three and nine months ended September 30, 2016 , respectively, and was $0.9 million and $2.9 million for the three and nine months ended September 30, 2015 respectively. We also recorded expenses for these services, inclusive of capitalized expenses, of $5.3 million and $16.1 million for the three and nine months ended September 30, 2016 , respectively, (excluding services provided directly to tenants), and $5.7 million and $14.3 million for the three and nine months ended September 30, 2015 respectively. 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 this entity of $0.1 million and $0.3 million for the three and nine months ended September 30, 2016 . We received management fees from this entity of $0.1 million and $0.4 million for the three and nine months ended September 30, 2015 . Other Amounts due from related parties at September 30, 2016 and December 31, 2015 consisted of the following (in thousands): September 30, 2016 December 31, 2015 Due from joint ventures $ 1,727 $ 1,334 Other 13,113 9,316 Related party receivables $ 14,840 $ 10,650

Noncontrolling Interests on the

Noncontrolling Interests on the Company's Consolidated Financial Statements	9 Months Ended
	Sep. 30, 2016
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 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 September 30, 2016 and December 31, 2015 , the noncontrolling interest unit holders owned 4.29% , or 4,495,410 units, and 3.61% , or 3,745,766 units, of the Operating Partnership, respectively. As of September 30, 2016 , 4,495,410 shares of SL Green's common stock were reserved for issuance upon the 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 as of September 30, 2016 and December 31, 2015 (in thousands): September 30, 2016 December 31, 2015 Balance at beginning of period $ 424,206 $ 469,524 Distributions (9,245 ) (9,710 ) Issuance of common units 75,352 30,506 Redemption of common units (12,746 ) (55,697 ) Net income 8,171 10,565 Accumulated other comprehensive income allocation (257 ) (67 ) Fair value adjustment 4,959 (20,915 ) Balance at end of period $ 490,440 $ 424,206 Preferred Units of Limited Partnership Interest in the Operating Partnership The Operating Partnership has 1,902,000 4.50% 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 3.50% 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 any time, 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. The Operating Partnership has authorized up to 1,600,000 3.75% Series M Preferred Units of limited partnership interest, or the Series M Preferred Units, with a liquidation preference of $25.00 per unit. In February 2015, the Company issued 1,600,000 Series M Preferred Units in conjunction with the acquisition of ownership interests in and relating to certain residential and retail real estate properties. The Series M Preferred unitholders receive annual dividends of $0.9375 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Series M Preferred Units can be redeemed at any time at par for cash at the option of the unitholder. The Operating Partnership has authorized up to 552,303 3.00% Series N Preferred Units of limited partnership interest, or the Series N Preferred Units, with a liquidation preference of $25.00 per unit. In June 2015, the Company issued 552,303 Series N Preferred Units in conjunction with an acquisition. The Series N Preferred unitholders receive annual dividends of $0.75 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Series N Preferred Units can be redeemed at any time at par for cash at the option of the unitholder. The Operating Partnership has authorized an aggregate of one 6.25% Series O Preferred Unit of limited partnership interest, or the Series O Preferred Unit. In June 2015, the Company issued the Series O Preferred Unit in connection with an acquisition. The Operating Partnership has authorized up to 200,000 4.00% Series P Preferred Units of limited partnership interest, or the Series P Preferred Units, with a liquidation preference of $25.00 per unit. In July 2015, the Company issued 200,000 Series P Preferred Units in conjunction with an acquisition. The Series P 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 P Preferred Units can be redeemed at any time at par for cash at the option of the unitholder. The Operating Partnership has authorized up to 268,000 3.50% Series Q Preferred Units of limited partnership interest, or the Series Q Preferred Units, with a liquidation preference of $25.00 per unit. In July 2015, the Company issued 268,000 Series Q Preferred Units in conjunction with an acquisition. The Series Q 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 Q Preferred Units can be redeemed at any time, 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) $148.95 . The Operating Partnership has authorized up to 400,000 3.50% Series R Preferred Units of limited partnership interest, or the Series R Preferred Units, with a liquidation preference of $25.00 per unit. In August 2015, the Company issued 400,000 Series R Preferred Units in conjunction with an acquisition. The Series R 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 R Preferred Units can be redeemed at any time, 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) $154.89 . The Operating Partnership has authorized up to 1,077,280 4.00% Series S Preferred Units of limited partnership interest, or the Series S Preferred Units, with a liquidation preference of $25.00 per unit. In August 2015, the Company issued 1,077,280 Series S Preferred Units in conjunction with an acquisition. The Series S 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 S Preferred Units can be redeemed at any time at par for cash at the option of the unitholder. The Operating Partnership has authorized up to 230,000 2.75% Series T Preferred Units of limited partnership interest, or the Series T Preferred Units, with a liquidation preference of $25.00 per unit. In March 2016, the Company issued 230,000 Series T Preferred Units in conjunction with an acquisition. The Series T Preferred unitholders receive annual dividends of $0.6875 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Series T Preferred Units can be redeemed at any time, 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) $119.02 . The Operating Partnership has authorized up to 680,000 4.50% Series U Preferred Units of limited partnership interest, or the Series U Preferred Units, with a liquidation preference of $25.00 per unit. In March 2016, the Company issued 680,000 Series U Preferred Units in conjunction with an acquisition. The Series U Preferred unitholders initially receive annual dividends of $1.125 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The annual dividend is subject to reduction upon the occurence of certain circumstances set forth in the terms of the Series U Preferred Units. The minimum annual dividend is $0.75 per unit. The Series U Preferred Units can be redeemed at any time at par for cash at the option of the unitholder. T hrough a consolidated subsidiary, we have authorized up to 109,161 3.5% Series A Preferred Units of limited partnership interest, or the Greene Series A Preferred Units, with a liquidation preference of $1,000.00 per unit. In August 2015, the Company issued 109,161 Greene Series A Preferred Units in conjunction with an acquisition. The Greene Series A Preferred unitholders receive annual dividends of $35.00 per unit paid on a quarterly basis and dividends are cumulative, subject to certain provisions. The Greene Series A Preferred Units can be redeemed at any time, at the option of the unitholder, either for cash or are convertible on a one-for-one basis, into the Series B Preferred Units of limited partnership interest, or the Greene Series B Preferred Units. The Greene Series B Preferred Units can be converted at any time, at the option of the unitholder, into a number of common stock equal to 6.71348 shares of common stock for each Greene Series B Preferred Unit. As of September 30, 2016 , no Greene Series B Preferred Units have been issued. Below is the rollforward analysis of the activity relating to the preferred units in the Operating Partnership as of September 30, 2016 and December 31, 2015 (in thousands): September 30, 2016 December 31, 2015 Balance at beginning of period $ 282,516 $ 71,115 Issuance of preferred units 22,793 211,601 Redemption of preferred units (2,999 ) (200 ) Balance at end of period $ 302,310 $ 282,516

Stockholders' Equity of the Com

Stockholders' Equity of the Company	9 Months Ended
	Sep. 30, 2016
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 September 30, 2016 , 100,264,253 shares of common stock and no shares of excess stock were issued and outstanding. In August 2016, our board of directors approved a stock repurchase plan under which we can buy up to $1.0 billion of shares of our common stock. As of September 30, 2016, we have not repurchased any shares under the plan. At-The-Market Equity Offering Program In March 2015, the Company, along with the Operating Partnership, entered into a new "at-the-market" equity offering program, or ATM Program, to sell an aggregate of $300.0 million of SL Green's common stock. During the year ended December 31, 2015, we sold 91,180 shares of our common stock for aggregate net proceeds of $12.0 million . The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 91,180 units of limited partnership interest of the Operating Partnership. The Company did not make any sales of its common stock under an ATM program in the first nine months of 2016. 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. Dividend Reinvestment and Stock Purchase Plan In February 2015, 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. Earnings per Share SL Green's earnings per share for the three and nine months ended September 30, 2016 and 2015 are computed as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Numerator 2016 2015 2016 2015 Basic Earnings: Income attributable to SL Green common stockholders $ 34,252 $ 163,658 $ 190,930 $ 167,829 Effect of Dilutive Securities: Redemption of units to common shares 1,663 6,467 8,171 6,634 Diluted Earnings: Income attributable to SL Green common stockholders $ 35,915 $ 170,125 $ 199,101 $ 174,463 Three Months Ended September 30, Nine Months Ended September 30, Denominator 2016 2015 2016 2015 Basic Shares: Weighted average common stock outstanding 100,233 99,621 100,140 99,205 Effect of Dilutive Securities: Operating Partnership units redeemable for common shares 4,497 3,901 4,272 3,924 Stock-based compensation plans 413 407 349 480 Diluted weighted average common stock outstanding 105,143 103,929 104,761 103,609 SL Green has excluded 673,298 and 753,344 common stock equivalents from the diluted shares outstanding for the three and nine months ended September 30, 2016 , respectively, as they were anti-dilutive. SL Green has excluded 263,236 and 231,970 common stock equivalents from the diluted shares outstanding for the three and nine months ended September 30, 2015 , as they were anti-dilutive.

Partners' Capital of the Operat

Partners' Capital of the Operating Partnership	9 Months Ended
	Sep. 30, 2016
Stockholders' Equity
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 September 30, 2016 , 100,264,253 shares of common stock and no shares of excess stock were issued and outstanding. In August 2016, our board of directors approved a stock repurchase plan under which we can buy up to $1.0 billion of shares of our common stock. As of September 30, 2016, we have not repurchased any shares under the plan. At-The-Market Equity Offering Program In March 2015, the Company, along with the Operating Partnership, entered into a new "at-the-market" equity offering program, or ATM Program, to sell an aggregate of $300.0 million of SL Green's common stock. During the year ended December 31, 2015, we sold 91,180 shares of our common stock for aggregate net proceeds of $12.0 million . The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 91,180 units of limited partnership interest of the Operating Partnership. The Company did not make any sales of its common stock under an ATM program in the first nine months of 2016. 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. Dividend Reinvestment and Stock Purchase Plan In February 2015, 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. Earnings per Share SL Green's earnings per share for the three and nine months ended September 30, 2016 and 2015 are computed as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Numerator 2016 2015 2016 2015 Basic Earnings: Income attributable to SL Green common stockholders $ 34,252 $ 163,658 $ 190,930 $ 167,829 Effect of Dilutive Securities: Redemption of units to common shares 1,663 6,467 8,171 6,634 Diluted Earnings: Income attributable to SL Green common stockholders $ 35,915 $ 170,125 $ 199,101 $ 174,463 Three Months Ended September 30, Nine Months Ended September 30, Denominator 2016 2015 2016 2015 Basic Shares: Weighted average common stock outstanding 100,233 99,621 100,140 99,205 Effect of Dilutive Securities: Operating Partnership units redeemable for common shares 4,497 3,901 4,272 3,924 Stock-based compensation plans 413 407 349 480 Diluted weighted average common stock outstanding 105,143 103,929 104,761 103,609 SL Green has excluded 673,298 and 753,344 common stock equivalents from the diluted shares outstanding for the three and nine months ended September 30, 2016 , respectively, as they were anti-dilutive. SL Green has excluded 263,236 and 231,970 common stock equivalents from the diluted shares outstanding for the three and nine months ended September 30, 2015 , as they were anti-dilutive.
SL Green Operating Partnership
Stockholders' Equity
Partners' Capital of the Operating Partnership	Partners' Capital of the Operating Partnership The Company is the sole general partner of the Operating Partnership and at September 30, 2016 owned 100,264,253 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 September 30, 2016 , limited partners other than SL Green owned 4.29% , or 4,495,410 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 three and nine months ended September 30, 2016 and 2015 , respectively are computed as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Numerator 2016 2015 2016 2015 Basic and Diluted Earnings: Net income attributable to SLGOP common unitholders $ 35,915 $ 170,125 $ 199,101 $ 174,463 Three Months Ended September 30, Nine Months Ended September 30, Denominator 2016 2015 2016 2015 Basic units: Weighted average common units outstanding 104,730 103,522 104,412 103,129 Effect of Dilutive Securities: Stock-based compensation plans 413 407 349 480 Diluted weighted average common units outstanding 105,143 103,929 104,761 103,609 The Operating Partnership has excluded 673,298 and 753,344 common stock equivalents from the diluted shares outstanding for the three and nine months ended September 30, 2016 , respectively, as they were anti-dilutive. SL Green has excluded 263,236 and 231,970 common unit equivalents from the diluted units outstanding for the three and nine months ended September 30, 2015 , respectively, as they were anti-dilutive.

Share-based Compensation

Share-based Compensation	9 Months Ended
	Sep. 30, 2016
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. Fourth Amended and Restated 2005 Stock Option and Incentive Plan The Fourth Amended and Restated 2005 Stock Option and Incentive Plan, or the 2005 Plan, was approved by the Company's board of directors in April 2016 and its stockholders in June 2016 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, cash-based awards and other equity-based awards. Subject to adjustments upon certain corporate transactions or events, awards with respect to up to a maximum of 27,030,000 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) granted after the effective date of the Fourth Amendment 2005 Plan counting as 3.74 Fungible Units per share subject to such awards, (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 0.73 fungible units per share subject to such awards, and (3) all other awards (e.g., ten -year stock options) counting as 1.0 fungible units per share subject to such awards. Awards granted under the 2005 Plan prior to the approval of the fourth amendment and restatement in June 2016 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 27,030,000 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 2, 2026, which is the tenth anniversary of the date that the 2005 Plan was most recently approved by the Company's stockholders. As of September 30, 2016 , 10.3 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 nine months ended September 30, 2016 and the year ended December 31, 2015 . September 30, 2016 December 31, 2015 Dividend yield 2.30 % 1.97 % Expected life of option 4.2 years 3.6 years Risk-free interest rate 1.08 % 1.43 % Expected stock price volatility 29.08 % 32.34 % A summary of the status of the Company's stock options as of September 30, 2016 and December 31, 2015 , and changes during the nine months ended September 30, 2016 and year ended December 31, 2015 are as follows: September 30, 2016 December 31, 2015 Options Outstanding Weighted Average Exercise Price Options Outstanding Weighted Average Exercise Price Balance at beginning of period $ 1,595,007 $ 95.52 $ 1,462,726 $ 87.98 Granted 109,500 99.65 389,836 112.54 Exercised (157,361 ) 77.90 (217,438 ) 74.69 Lapsed or cancelled (48,117 ) 110.81 (40,117 ) 98.61 Balance at end of period $ 1,499,029 $ 97.18 $ 1,595,007 $ 95.52 Options exercisable at end of period 794,797 $ 90.29 589,055 $ 89.85 Weighted average fair value of options granted during the period $ 2,258,336 $ 9,522,613 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 3.4 years and the remaining average contractual life of the options exercisable was 2.7 years. During the three and nine months ended September 30, 2016 , we recognized compensation expense for these options of $2.5 million and $6.4 million , respectively. During the three and nine months ended September 30, 2015 , we recognized compensation expense for these options of $1.9 million and $5.8 million , respectively. As of September 30, 2016 , there was $9.8 million of total unrecognized compensation cost related to unvested stock options, which is expected to be recognized over a weighted average period of 1.4 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 September 30, 2016 and December 31, 2015 and charges during the nine months ended September 30, 2016 and the year ended December 31, 2015 , are as follows: September 30, 2016 December 31, 2015 Balance at beginning of period 3,137,881 3,000,979 Granted 14,550 143,053 Cancelled (34,600 ) (6,151 ) Balance at end of period 3,117,831 3,137,881 Vested during the period 83,822 87,081 Compensation expense recorded $ 5,275,799 $ 7,540,747 Weighted average fair value of restricted stock granted during the period $ 1,613,846 $ 16,061,201 The fair value of restricted stock that vested during the nine months ended September 30, 2016 and the year ended December 31, 2015 was $7.6 million and $7.4 million , respectively. As of September 30, 2016 there was $13.6 million of total unrecognized compensation cost related to restricted stock, which is expected to be recognized over a weighted average period of 2.1 years . For the three and nine months ended September 30, 2016 , $1.5 million , $4.4 million , respectively, was capitalized to assets associated with compensation expense related to our long-term compensation plans, restricted stock and stock options. For the three and nine months ended September 30, 2015 , $1.5 million and $4.9 million , respectively, was capitalized to assets associated with compensation expense related to our long-term compensation plans, restricted stock and stock options. We have granted LTIP Units, which include bonus, time-based and performance based awards, with a fa ir value of $28.1 million and $25.4 million as of September 30, 2016 and December 31, 2015, respectively. 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 September 30, 2016 , there was $6.0 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 1.2 years years. During the three and nine months ended September 30, 2016 , we recorded compensation expense related to bonus, time-based and performance based awards of $2.3 million and $15.1 million , respectively. During the three and nine months ended September 30, 2015 , we recorded compensation expense related to bonus, time-based and performance based awards of $2.7 million and $19.0 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, 385,583 LTIP Units, 327,416 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 of January 1, 2015. 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 were subject to vesting requirements, with 50% of any awards earned vested on August 31, 2014 and the remaining 50% vesting on August 31, 2015, based on 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 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 ( $26.7 million , subject to forfeitures) was amortized into earnings through the final vesting period. We recorded no compensation expense during the three and nine months ended September 30, 2016 , and $0.6 million, and $4.5 million during the three and nine months ended September 30, 2015 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 ( $27.9 million , subject to forfeitures), based on the portion of the 2014 Outperformance Plan granted as of September 30, 2016 , will be amortized into earnings through the final vesting period. We recorded compensation expense of $1.8 million and $6.6 million , during the three and nine months ended September 30, 2016 , respectively, related to the 2014 Outperformance Plan. We recorded compensation expense of $1.5 million , and $4.4 million during the three and nine months ended September 30, 2015 , respectively, 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 the 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 nine months ended September 30, 2016 , 8,136 phantom stock units were earned and 9,014 shares of common stock were issued to our board of directors. We recorded compensation expense of $0.1 million , $1.9 million during the three and nine months ended September 30, 2016 related to the Deferred Compensation Plan. We recorded compensation expense of $0.1 million , and $1.8 million during the three and nine months ended September 30, 2015 related to the Deferred Compensation Plan. As of September 30, 2016 , there were 88,902 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 September 30, 2016 , 93,288 shares of SL Green's common stock had been issued under the ESPP.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	9 Months Ended
	Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Loss of the Company/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 September 30, 2016 , 100,264,253 shares of common stock and no shares of excess stock were issued and outstanding. In August 2016, our board of directors approved a stock repurchase plan under which we can buy up to $1.0 billion of shares of our common stock. As of September 30, 2016, we have not repurchased any shares under the plan. At-The-Market Equity Offering Program In March 2015, the Company, along with the Operating Partnership, entered into a new "at-the-market" equity offering program, or ATM Program, to sell an aggregate of $300.0 million of SL Green's common stock. During the year ended December 31, 2015, we sold 91,180 shares of our common stock for aggregate net proceeds of $12.0 million . The net proceeds from these offerings were contributed to the Operating Partnership in exchange for 91,180 units of limited partnership interest of the Operating Partnership. The Company did not make any sales of its common stock under an ATM program in the first nine months of 2016. 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. Dividend Reinvestment and Stock Purchase Plan In February 2015, 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. Earnings per Share SL Green's earnings per share for the three and nine months ended September 30, 2016 and 2015 are computed as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Numerator 2016 2015 2016 2015 Basic Earnings: Income attributable to SL Green common stockholders $ 34,252 $ 163,658 $ 190,930 $ 167,829 Effect of Dilutive Securities: Redemption of units to common shares 1,663 6,467 8,171 6,634 Diluted Earnings: Income attributable to SL Green common stockholders $ 35,915 $ 170,125 $ 199,101 $ 174,463 Three Months Ended September 30, Nine Months Ended September 30, Denominator 2016 2015 2016 2015 Basic Shares: Weighted average common stock outstanding 100,233 99,621 100,140 99,205 Effect of Dilutive Securities: Operating Partnership units redeemable for common shares 4,497 3,901 4,272 3,924 Stock-based compensation plans 413 407 349 480 Diluted weighted average common stock outstanding 105,143 103,929 104,761 103,609 SL Green has excluded 673,298 and 753,344 common stock equivalents from the diluted shares outstanding for the three and nine months ended September 30, 2016 , respectively, as they were anti-dilutive. SL Green has excluded 263,236 and 231,970 common stock equivalents from the diluted shares outstanding for the three and nine months ended September 30, 2015 , as they were anti-dilutive.
SL Green Realty Corp
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Loss of the Company/Operating Partnership	Accumulated Other Comprehensive Loss The following tables set forth the changes in accumulated other comprehensive income (loss) by component as of September 30, 2016 (in thousands): Net unrealized (loss) gain on derivative instruments ( 1 ) SL Green’s share of joint venture net unrealized (loss) gain on derivative instruments ( 2 ) Unrealized gain (loss) on marketable securities Total Balance at December 31, 2015 $ (10,160 ) $ (592 ) $ 2,003 $ (8,749 ) Other comprehensive loss before reclassifications (7,810 ) (7,409 ) (869 ) (16,088 ) Amounts reclassified from accumulated other comprehensive income 7,862 2,901 — 10,763 Balance at September 30, 2016 $ (10,108 ) $ (5,100 ) $ 1,134 $ (14,074 ) (1) Amount reclassified from accumulated other comprehensive income (loss) is included in interest expense in the respective consolidated statements of operations. As of September 30, 2016 and December 31, 2015 , 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 $8.1 million and $9.7 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 operations.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2016
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 consists 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 September 30, 2016 and December 31, 2015 (in thousands): September 30, 2016 Total Level 1 Level 2 Level 3 Assets: Marketable securities $ 60,352 $ 23,213 $ 37,139 $ — Interest rate cap and swap agreements (included in other assets) $ 4 $ — $ 4 $ — Liabilities: Interest rate cap and swap agreements (included in accrued interest payable and other liabilities) $ 2,127 $ — $ 2,127 $ — Interest rate cap and swap agreements (included in liabilities related to assets held for sale) $ — $ — $ — $ — December 31, 2015 Total Level 1 Level 2 Level 3 Assets: Marketable securities $ 45,138 $ 4,704 $ 40,434 $ — Interest rate cap and swap agreements (included in other assets) $ 204 $ — $ 204 $ — Liabilities: Interest rate cap and swap agreements (included in accrued interest payable and other liabilities) $ 10,776 $ — $ 10,776 $ — We determine other than temporary 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. 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, 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 September 30, 2016 and December 31, 2015 (in thousands): September 30, 2016 December 31, 2015 Carrying Value (1) Fair Value Carrying Value (1) Fair Value Debt and preferred equity investments $ 1,453,234 (2) $ 1,670,020 (2) Fixed rate debt $ 5,494,301 $ 5,922,120 $ 7,232,254 $ 7,591,388 Variable rate debt 1,010,990 1,014,458 3,202,494 3,179,186 $ 6,505,291 $ 6,936,578 $ 10,434,748 $ 10,770,574 (1) Amounts exclude net deferred financing costs. (2) At September 30, 2016 , debt and preferred equity investments had an estimated fair value ranging between $1.5 billion and $1.6 billion . At December 31, 2015, debt and preferred equity investments had an estimated fair value ranging between $1.7 billion and $1.8 billion . Disclosure about fair value of financial instruments was based on pertinent information available to us as of September 30, 2016 and December 31, 2015 . 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	9 Months Ended
	Sep. 30, 2016
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 value at inception and fair value of our consolidated derivative financial instruments at September 30, 2016 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 Value Strike Rate Effective Date Expiration Date Balance Sheet Location Fair Value Interest Rate Swap $ 200,000 0.938 % October 2014 December 2017 Other Liabilities $ (551 ) Interest Rate Swap 150,000 0.940 % October 2014 December 2017 Other Liabilities (417 ) Interest Rate Swap 150,000 0.940 % October 2014 December 2017 Other Liabilities (417 ) Interest Rate Cap 117,392 6.000 % October 2014 October 2016 Other Liabilities — Interest Rate Swap 14,409 0.500 % January 2015 January 2017 Other Assets 4 Interest Rate Swap 8,018 0.852 % February 2015 February 2017 Other Liabilities (7 ) Interest Rate Cap 137,500 4.000 % September 2015 September 2017 Other Assets — Interest Rate Cap 1,450,000 4.750 % May 2016 May 2017 Other Assets — Interest Rate Swap 200,000 1.131 % July 2016 July 2023 Other Liabilities (361 ) Interest Rate Swap 100,000 1.161 % July 2016 July 2023 Other Liabilities (374 ) Interest Rate Cap 23,199 4.500 % October 2016 October 2017 Other Assets — Total $ (2,123 ) During the three and nine months ended September 30, 2016 , we recorded a $0.1 million loss and $0.5 million gain, respectively on the changes in the fair value, which is included in interest expense on the consolidated statements of operations. During both the three and nine months ended September 30, 2015 , we recorded a gain on the changes in the fair value of $0.1 million , which is included in interest expense on the consolidated statements of operations. 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 September 30, 2016 , 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 $2.2 million . As of September 30, 2016 , 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 $2.1 million at September 30, 2016 . Gains and losses on terminated hedges are included in 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 $4.9 million of the current balance held in accumulated other comprehensive loss will be reclassified into interest expense and $1.7 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 operations for the three months ended September 30, 2016 and 2015 , respectively (in thousands): Amount of Gain Location of (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income Amount of Loss Location of (Loss) or Gain Recognized in Income on Derivative Amount of (Loss) Gain Three Months Ended September 30, Three Months Ended September 30, Three Months Ended September 30, Derivative 2016 2015 2016 2015 2016 2015 Interest Rate Swaps/Caps $ (7 ) $ (6,921 ) Interest expense $ 1,442 $ 2,737 Interest expense $ — $ (31 ) Share of unconsolidated joint ventures' derivative instruments (222 ) (1,526 ) Equity in net income from unconsolidated joint ventures 547 287 Equity in net income from unconsolidated joint ventures 830 (21 ) $ (229 ) $ (8,447 ) $ 1,989 $ 3,024 $ 830 $ (52 ) 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 operations for the nine months ended September 30, 2016 and 2015 , respectively (in thousands): Amount of Gain Location of (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income Amount of Loss Location of (Loss) or Gain Recognized in Income on Derivative Amount of Loss Nine Months Ended September 30, Nine Months Ended September 30, Nine Months Ended September 30, Derivative 2016 2015 2016 2015 2016 2015 Interest Rate Swaps/Caps $ (8,112 ) $ (15,537 ) Interest expense $ 8,073 $ 8,221 Interest expense $ (38 ) $ (455 ) Share of unconsolidated joint ventures' derivative instruments (5,992 ) (2,486 ) Equity in net income from unconsolidated joint ventures 1,465 949 Equity in net income from unconsolidated joint ventures (206 ) (21 ) $ (14,104 ) $ (18,023 ) $ 9,538 $ 9,170 $ (244 ) $ (476 )

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings As of September 30, 2016 , 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 which if adversely determined could have a material adverse impact on us. Environmental Matters The Company believes that its 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. Capital and Ground Leases Arrangements The following is a schedule of future minimum lease payments under capital leases and non-cancellable operating leases with initial terms in excess of one year as of September 30, 2016 (in thousands): Capital lease Non-cancellable operating leases Remaining 2016 $ 585 $ 7,835 2017 2,387 31,374 2018 2,387 31,455 2019 2,411 31,716 2020 2,620 32,086 Thereafter 825,483 983,213 Total minimum lease payments $ 835,873 $ 1,117,679 Amount representing interest (793,922 ) Capital lease obligations $ 41,951

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2016
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, redevelopment, financing, construction and maintenance in the New York Metropolitan area 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 consolidated results of operations for the three and nine months ended September 30, 2016 and 2015 , and selected asset information as of September 30, 2016 and December 31, 2015 , regarding our operating segments are as follows (in thousands): Real Estate Segment Debt and Preferred Equity Segment Total Company Total revenues Three months ended: September 30, 2016 $ 335,652 $ 81,029 $ 416,681 September 30, 2015 375,623 56,443 432,066 Nine months ended: September 30, 2016 1,300,082 189,657 1,489,739 September 30, 2015 1,085,870 151,569 1,237,439 (Loss) Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain on sale of real estate, depreciable real estate reserves net of recoveries, and loss on sale of investment in marketable securities Three months ended: September 30, 2016 $ (33,613 ) $ 76,334 $ 42,721 September 30, 2015 (29,577 ) 50,571 20,994 Nine months ended: September 30, 2016 (190,633 ) 171,706 (18,927 ) September 30, 2015 (96,333 ) 129,605 33,272 Total assets As of: September 30, 2016 $ 13,992,319 $ 1,798,623 $ 15,790,942 December 31, 2015 17,814,787 1,912,859 19,727,646 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 includes actual costs incurred for investments collateralizing the MRA. Interest is imputed on the remaining investments using our corporate 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 to the debt and preferred equity segment since the use of personnel and resources is dependent on transaction volume between the two segments and varies period over period. For the three and nine months ended September 30, 2016 , marketing, general and administrative expenses totaled $25.5 million and $74.0 million , respectively. For the three and nine months ended September 30, 2015 , marketing, general and administrative expenses totaled $23.5 million and $72.1 million , respectively. 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 three and nine months ended September 30, 2016 , and 2015 (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Income (Loss) from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain on sale of real estate, depreciable real estate reserves net of recoveries, and loss on sale of investment in marketable securities $ 42,721 $ 20,994 $ (18,927 ) $ 33,272 Equity in net gain on sale of interest in unconsolidated joint venture/real estate 225 15,281 43,588 16,050 Gain on sale of real estate, net 397 159,704 210,750 159,704 Depreciable real estate reserves — (19,226 ) (10,387 ) (19,226 ) Loss on sale of investment in marketable securities — — (83 ) — Income from continuing operations 43,343 176,753 224,941 189,800 Net income from discontinued operations — — — 427 Gain on sale of discontinued operations — — — 12,983 Net income $ 43,343 $ 176,753 $ 224,941 $ 203,210

Significant Accounting Polici32

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2016
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. 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 September 30, 2016 and December 31, 2015 are $1.6 billion and $200.7 million , respectively, related to our consolidated VIEs. Included in mortgages and other loans payable on our consolidated balance sheets as of September 30, 2016 and December 31, 2015 are $605.8 million and $101.1 million , respectively, collateralized by the real estate assets of the related consolidated VIEs. As of September 30, 2016 , assets held for sale and liabilities related to assets held for sale on the consolidated balance sheets did not include amounts related to 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 is 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, 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 requiring 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 On a periodic basis, we assess whether there are any indications that the value of our real estate properties may be other than temporarily 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) 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 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 either their carrying value or fair value less costs to sell. We do not believe that there were any indicators of impairment at any of our consolidated properties at September 30, 2016 . 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.
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 consists 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. We determine other than temporary 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. 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, 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.
Investment in Marketable Securities	Investment in Marketable Securities We designate a security as held-to-maturity, available-for-sale, or trading at acquisition. As of September 30, 2016 , we did not have any securities designated as held-to-maturity or trading. We account for our available-for-sale securities at fair value pursuant to Accounting Standards Codification, or ASC, 820-10, with the net unrealized gains or losses reported as a component of accumulated other comprehensive income or loss. Any 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.
Investments in Unconsolidated Joint Ventures	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 ventures' projected discounted cash flows. We do not believe that the values of any of our equity investments were impaired at September 30, 2016 . We may originate loans for real estate acquisition, development and construction, where we expect to receive some 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.
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 provided that we have no substantial economic involvement with the buyer. Interest income on debt and preferred equity investments is accrued based on the contractual terms of the instruments and when, in the opinion of management, it is deemed collectible. Some 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 an adjustment 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 the loans individually. When a transaction meets the criteria for 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, original issue discounts, 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 operations. 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.
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 include geographic trends, product diversification, the size of the portfolio and current economic conditions. Based upon these factors, we establish a provision for possible credit loss 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 additional information reflects increased recovery of our investment, we will adjust our reserves accordingly. There were no loan reserves recorded during the three and nine months ended September 30, 2016 and 2015. 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.
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, SL Green 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 operations 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 three and nine months ended September 30, 2016 , we recorded Federal, state and local tax provisions of $0.9 million and $1.9 million , respectively. During the three and nine months ended September 30, 2015 , we recorded Federal, state and local tax provisions of $1.1 million and $2.5 million , respectively. 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.
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 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.
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 or loss 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 or loss 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.
Concentrations 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 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 revenue and the costs associated with re-tenanting a space. 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.
Reclassification	Reclassification Certain prior year balances have been reclassified to conform to our current year presentation.
Accounting Standards Updates	Accounting Standards Updates In August 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments. The ASU provides final guidance on eight cash flow issues, including debt prepayment or debt extinguishment costs, contingent consideration payments made after a business combination, distributions received from equity method investees, separately identifiable cash flows and application of the predominance principle, and others. The amendments in the ASU are effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. The Company has not yet adopted this new guidance and is currently evaluating the impact of adopting this new accounting standard on the Company’s consolidated financial statements. In June 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The guidance changes how entities will measure credit losses for most financial assets and certain other instruments that aren’t measured at fair value through net income. The guidance replaces the current ‘incurred loss’ model with an ‘expected loss’ approach. The guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted after December 2018. The Company has not yet adopted this new guidance and is currently evaluating the impact of adopting this new accounting standard on the Company’s consolidated financial statements. In March 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The guidance simplifies the accounting for share-based payment award transactions including: income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. The guidance is effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. Early adoption is permitted. The Company has not yet adopted this new guidance and is currently evaluating the impact of adopting this new accounting standard on the Company’s consolidated financial statements. In March 2016, the FASB issued ASU 2016-07, Investments Equity Method and Joint Ventures (Topic 323). The guidance eliminates the requirement that an entity retroactively adopt the equity method of accounting if an investment qualifies for use of the equity method as a result of an increase in the level of ownership or degree of influence. The amendments require that the equity method investor add the cost of acquiring the additional interest in the investee to the current basis of the investor’s previously held interest and adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting. The guidance is effective for all entities for fiscal years beginning after 15 December 2016 and interim periods within those years. Early adoption is permitted in any interim or annual period. The Company has not yet adopted this new guidance and is currently evaluating the impact of adopting this new accounting standard on the Company’s consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases. The guidance requires lessees to recognize lease assets and lease liabilities for those leases classified as operating leases under the previous standard. The accounting applied by a lessor is largely unchanged from that applied under the previous standard. The Guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. The Company has not yet adopted this new guidance and is currently evaluating the impact of adopting this new accounting standard on the Company’s consolidated financial statements. In January 2016, the FASB issued ASU 2016-01 (ASU825-10), Recognition and Measurement of Financial Assets and Financial Liabilities. The guidance requires entities to measure equity investments that do not result in consolidation and are not accounted for under the equity method at fair value and to record changes in instruments-specific credit risk for financial liabilities measured under the fair value option in other comprehensive income. The guidance is effective for fiscal years beginning after December 15, 2017, and for interim periods therein. The Company has not yet adopted this new guidance and is currently evaluating the impact of adopting this new accounting standard on the Company’s consolidated financial statements. In April 2015, the FASB issued final guidance to simplify the presentation of debt issuance costs by requiring debt issuance costs to be presented as a deduction from the corresponding debt liability (ASU 2015-03). The guidance requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability. The Company adopted the guidance effective January 1, 2016. Accordingly, as of September 30, 2016 and December 31, 2015, $101.5 million and $130.3 million , respectively, of deferred debt issuance cost, net of amortization are presented as a direct reduction within Mortgages and other loans payable, Revolving credit facility, Term loan and senior unsecured notes on the Company's consolidated balance sheets. In February 2015, the FASB issued guidance that amends the current consolidation guidance, including introducing a separate consolidation analysis specific to limited partnerships and other similar entities (ASU 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 Company adopted the guidance effective January 1, 2016. Under the revised guidance, certain entities, including the Operating Partnership, now qualify as variable interest entities while some of our entities originally classified as variable interest entities no longer meet the criteria. The change in designation did not have a material impact on our consolidated financial statements and did not change the consolidation conclusion on these entities. 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 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. In March 2016, the FASB issued implementation guidance which clarifies principal versus agent considerations in reporting revenue gross versus net (ASU 2016-08). In April 2016, the FASB issued implementation guidance which clarifies the identification of performance obligations (ASU 2016-10). In April 2016, the FASB amended its new revenue recognition guidance on identifying performance obligations to allow entities to disregard items that are immaterial and clarify when a good or service is separately identifiable (ASU 2016-10). In May 2016, the FASB issued implementation guidance relating to transition, collectability, noncash consideration and presentation matters (ASU 2016-12). These ASUs are effective for annual and interim periods beginning after December 15, 2017. Early adoption is permitted, but not before interim and annual reporting periods beginning after December 15, 2016. 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 has not yet adopted this guidance and is currently evaluating the new guidance to determine the impact it may have on our consolidated financial statements.

Organization and Basis of Pre33

Organization and Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of commercial office properties	As of September 30, 2016 , we owned the following interests in properties 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 Property 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 24 16,054,606 7 6,558,139 31 22,612,745 95.4 % Retail 10 (2) 418,093 9 347,970 19 766,063 87.6 % Development/Redevelopment 3 42,635 3 767,311 6 809,946 35.5 % Fee Interest 1 176,530 1 26,926 2 203,456 86.8 % 38 16,691,864 20 7,700,346 58 24,392,210 93.2 % Suburban Office 25 4,113,800 2 640,000 27 4,753,800 82.0 % Retail 1 52,000 — — 1 52,000 100.0 % Development/Redevelopment 1 1,000 1 — 2 1,000 100.0 % 27 4,166,800 3 640,000 30 4,806,800 82.2 % Total commercial properties 65 20,858,664 23 8,340,346 88 29,199,010 91.4 % Residential: Manhattan Residential 4 (2)(3) 762,587 17 2,957,282 21 3,719,869 81.4 % Suburban Residential — — — — — — — % Total residential properties 4 762,587 17 2,957,282 21 3,719,869 81.4 % Total portfolio (3) 69 21,621,251 40 11,297,628 109 32,918,879 90.3 % (1) The weighted average occupancy for commercial properties represents the total occupied square feet divided by the total acquisition square footage. The weighted average occupancy for residential properties represents the total occupied units divided by the total available units. (2) As of September 30, 2016 , 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 in the retail properties count and have bifurcated the square footage into the retail and residential components. (3) Includes the property at 400 East 57th Street, which is classified as held for sale at September 30, 2016 .

Significant Accounting Polici34

Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
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 September 30, 2016 and December 31, 2015 (in thousands): September 30, 2016 December 31, 2015 Identified intangible assets (included in other assets): Gross amount $ 624,557 $ 939,518 Accumulated amortization (397,148 ) (403,747 ) Net (1) $ 227,409 $ 535,771 Identified intangible liabilities (included in deferred revenue): Gross amount $ 648,583 $ 866,561 Accumulated amortization (455,568 ) (486,928 ) Net (1) $ 193,015 $ 379,633 (1) As of September 30, 2016 and December 31, 2015, $0.3 million and $0.2 million , respectively and $0.8 million and $0.1 million , respectively, of net intangible assets and net intangible liabilities, were reclassified to assets held for sale and liabilities related to assets held for sale.
Schedule of marketable securities	At September 30, 2016 and December 31, 2015 , we held the following marketable securities (in thousands): September 30, 2016 December 31, 2015 Equity marketable securities $ 23,213 $ 4,704 Commercial mortgage-backed securities 37,139 40,434 Total marketable securities available-for-sale $ 60,352 $ 45,138

Property Acquisitions (Tables)

Property Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2016
2016 Acquisitions
Property Acquisitions
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	During the nine months ended September 30, 2016 , the property listed below was acquired from a third party. The following summarizes our preliminary allocation of the purchase price of the assets acquired and liabilities assumed upon the closing of this acquisition (in thousands): 183 Broadway (1) Acquisition Date March 2016 Ownership Type Fee Interest Property Type Retail/Residential Purchase Price Allocation: Land $ 26,640 Building and building leasehold 2,960 Above-market lease value — Acquired in-place leases — Other assets, net of other liabilities — Assets acquired 29,600 Mark-to-market assumed debt — Below-market lease value — Derivatives — Liabilities assumed — Purchase price $ 29,600 Net consideration funded by us at closing, excluding consideration financed by debt $ 29,600 Equity and/or debt investment held $ — Debt assumed $ — (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.
2015 Acquisitions
Property Acquisitions
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	During nine months ended September 30, 2016 , we finalized the purchase price allocations based on facts and circumstances that existed at the acquisition dates for the following 2015 acquisitions (in thousands): 187 Broadway and 5 & 7 Dey Street (1) 110 Greene Street (1) Upper Eastside Residential (1) 11 Madison Avenue (1) 1640 Flatbush Avenue (1) Acquisition Date August 2015 July 2015 June 2015 August 2015 March 2015 Ownership Type Fee Interest Fee Interest Fee Interest Fee Interest Fee Interest Property Type Residential/Retail Office Residential/Retail Office Retail Purchase Price Allocation: Land $ 20,266 $ 45,120 $ 48,152 $ 675,776 $ 6,226 Building and building leasehold 42,468 215,470 — 1,553,602 501 Above-market lease value 17 — — 19,764 — Acquired in-place leases 3,621 8,967 1,922 366,949 146 Other assets, net of other liabilities — — — — — Assets acquired 66,372 269,557 50,074 2,616,091 6,873 Mark-to-market assumed debt — — — — — Below-market lease value (3,226 ) (14,557 ) — (187,732 ) (73 ) Derivatives — — — — — Liabilities assumed (3,226 ) (14,557 ) — (187,732 ) (73 ) Purchase price $ 63,146 $ 255,000 $ 50,074 $ 2,428,359 $ 6,800 Net consideration funded by us at closing, excluding consideration financed by debt $ — $ — $ — $ — $ — Equity and/or debt investment held $ — $ — $ — $ — $ — Debt assumed $ — $ — $ — $ — $ — (1) Based on our preliminary analysis of the purchase price, we had allocated $22.1 million and $41.0 million to land and building, respectively, at 187 Broadway and 5 & 7 Dey Street, $89.3 million and $165.8 million to land and building, respectively, at 110 Greene Street, $17.5 million and $32.5 million to land and building, respectively, at the Upper Eastside Residential Property, $849.9 million and $1.6 billion to land and building, respectively, at 11 Madison Avenue, and $6.1 million and $0.7 million to land and building, respectively, at 1640 Flatbush Avenue. The impact to our consolidated statement of operations for the nine months ended September 30, 2016 to adjust for the finalized purchase price allocations was $8.0 million in rental revenue for the amortization of aggregate below-market leases and $17.9 million of depreciation expense.

Properties Held for Sale and 36

Properties Held for Sale and Property Dispositions (Tables)	9 Months Ended
	Sep. 30, 2016
Discontinued Operations and Disposal Groups [Abstract]
Summary of properties sold and income from discontinued operations	Discontinued operations for the nine months ended September 30, 2016 included the results of operations of 180 Maiden Lane, which was held for sale at December 31, 2014 and sold in January 2015, as follows (in thousands): Nine Months Ended September 30, 2015 Revenues Rental revenue $ 236 Escalation and reimbursement revenues (127 ) Total revenues 109 Operating expenses (631 ) Real estate taxes 250 Transaction related costs (49 ) Depreciable real estate reserves 109 Interest expense, net of interest income 3 Total expenses (318 ) Net income from discontinued operations $ 427 The following table summarizes the properties sold during the nine months ended September 30, 2016 : Property Disposition Date Property Type Approximate Square Feet Sales Price (1) (in millions) Gain on Sale (2) (in millions) 248-252 Bedford Avenue February 2016 Residential 66,611 $ 55.0 $ 15.3 885 Third Avenue (3) February 2016 Land 607,000 453.0 — 7 International Drive May 2016 Land 31 Acres 20.0 (6.9 ) 388 Greenwich June 2016 Office 2,635,000 2,002.3 206.5 500 West Putnam July 2016 Office 121,500 41.0 (10.4 ) 11 Madison Avenue (4) August 2016 Office 2,314,000 2,600.0 — (1) Sales price represents the gross sales price for a property or the gross asset valuation for interests in a property. (2) The gain on sale for 248-252 Bedford Avenue and 388 Greenwich are net of $1.3 million and $1.6 million , respectively in employee compensation awards accrued in connection with the realization of the investment gain as a bonus to certain employees that were instrumental in realizing the gain on sale. Additionally, amounts do not include adjustments for expenses recorded in subsequent periods. (3) In February 2016, we closed on the sale of 885 Third Avenue. The sale did not meet the criteria for sale accounting and, as a result, the property remains on our consolidated balance sheet until the criteria is met. An estimated loss relating to the sale of $6.6 million was recorded in December 2015. We expect to meet the criteria for sale accounting in 2017 at which time we will recognize the sale and start recognizing investment income on our $135.0 million 5.75% senior equity investment in the property. (4) In August 2016, we sold an 40% interest in 11 Madison Avenue. The sale did not meet the criteria for sale accounting and, as a result, the property is being accounted for under the profit sharing method. See Note 6, "Investments in Unconsolidated Joint Ventures."

Debt and Preferred Equity Inv37

Debt and Preferred Equity Investments (Tables)	9 Months Ended
	Sep. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Summary of debt investments	As of September 30, 2016 and December 31, 2015 we held the following debt investments with an aggregate weighted average current yield of 9.29% at September 30, 2016 (in thousands): Loan Type September 30, 2016 Future Funding Obligations September 30, 2016 Senior Financing September 30, 2016 Carrying Value (1) December 31, 2015 Carrying Value (1) Maturity Date (2) Fixed Rate Investments: Jr. Mortgage Participation/Mezzanine Loan $ — $ 1,109,000 $ 189,250 $ 104,661 March 2017 Mezzanine Loan (3a) 5,000 502,100 61,059 41,115 June 2017 Mortgage Loan (4) — — 26,297 26,262 February 2019 Mortgage Loan — — 414 513 August 2019 Mezzanine Loan — 15,000 3,500 3,500 September 2021 Mezzanine Loan (3b) — 88,944 12,691 19,936 November 2023 Mezzanine Loan (3c) — 115,000 12,923 24,916 June 2024 Mezzanine Loan — 95,000 30,000 30,000 January 2025 Mezzanine Loan (5) — — — 72,102 Mezzanine Loan (6) — — — 49,691 Jr. Mortgage Participation (7) — — — 49,000 Other (7)(8) — — — 23,510 Other (7)(8) — — — 66,183 Total fixed rate $ 5,000 $ 1,925,044 $ 336,134 $ 511,389 Floating Rate Investments: Mezzanine Loan — 360,000 99,945 99,530 November 2016 Mezzanine Loan 7,939 144,008 53,405 49,751 December 2016 Mezzanine Loan 281 39,201 11,024 13,731 December 2016 Mortgage/Mezzanine Loan (3d) 40,086 — 140,920 134,264 January 2017 Mezzanine Loan 1,127 118,949 28,834 28,551 January 2017 Mezzanine Loan (3e)(9) — 40,000 15,290 68,977 June 2017 Mortgage/Mezzanine Loan — — 32,763 — June 2017 Mortgage/Mezzanine Loan — — 22,939 22,877 July 2017 Mortgage/Mezzanine Loan — — 16,946 16,901 September 2017 Mortgage/Mezzanine Loan 4,038 — 19,834 19,282 October 2017 Mezzanine Loan — 60,000 14,944 14,904 November 2017 Mezzanine Loan (3f) — 85,000 15,075 29,505 December 2017 Mezzanine Loan (3g) — 65,000 14,598 28,563 December 2017 Mortgage/Mezzanine Loan (3h) 795 — 15,024 14,942 December 2017 Jr. Mortgage Participation — 40,000 19,896 19,846 April 2018 Mezzanine Loan — 175,000 34,814 34,725 April 2018 Mortgage/Mezzanine Loan (10) 523 24,818 10,846 31,210 August 2018 Mortgage Loan — — 19,815 — August 2018 Mezzanine Loan — 65,000 14,862 — August 2018 Mezzanine Loan — — 14,599 — September 2018 Mezzanine Loan 2,325 45,025 34,411 — October 2018 Loan Type September 30, 2016 Future Funding Obligations September 30, 2016 Senior Financing September 30, 2016 Carrying Value (1) December 31, 2015 Carrying Value (1) Maturity Date (2) Mezzanine Loan — 33,000 26,831 26,777 December 2018 Mezzanine Loan 4,097 156,383 55,264 52,774 December 2018 Mezzanine Loan 18,883 246,758 59,917 49,625 December 2018 Mezzanine Loan 6,383 16,383 5,387 — January 2019 Mezzanine Loan — 38,000 21,880 21,845 March 2019 Mezzanine Loan — 265,000 24,677 — April 2019 Mortgage/Jr. Mortgage Participation Loan 34,500 180,740 64,549 — August 2019 Mezzanine Loan 2,500 187,500 37,307 — September 2019 Mortgage/Mezzanine Loan 87,620 — 107,060 — September 2019 Jr. Mortgage Participation/Mezzanine Loan — 30,000 15,599 — July 2021 Mortgage/Mezzanine Loan (11) — — — 94,901 Jr. Mortgage Participation/Mezzanine Loan (5) — — — 20,510 Mezzanine Loan (12) — — — 22,625 Mezzanine Loan (13) — — — 74,700 Mezzanine Loan (14) — — — 66,398 Jr. Mortgage Participation/Mezzanine Loan (7) — — — 18,395 Mezzanine Loan (15) — — — 40,346 Total floating rate $ 211,097 $ 2,415,765 $ 1,069,255 $ 1,116,455 Total $ 216,097 $ 4,340,809 $ 1,405,389 $ 1,627,844 (1) Carrying value is net of discounts, premiums, original issue discounts and deferred origination fees. (2) Represents contractual maturity, excluding any unexercised extension options. (3) Carrying value is net of the following amounts that were participated out, which are included in other assets and other liabilities on the consolidated balance sheets as a result of the transfers not meeting the conditions for sale accounting: (a) $41.3 million , (b) $5.0 million , (c) $12.0 million , (d) $36.3 million , (e) $14.5 million , (f) $14.6 million , (g) $14.1 million , and (h) $5.1 million . (4) 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. (5) These loans were repaid in July 2016. (6) In April 2016, we closed on an option to acquire a 20% interest in the underlying asset at a previously agreed upon purchase option valuation, and our mezzanine loan was simultaneously repaid. (7) These loans were repaid in March 2016. (8) These loans were collateralized by defeasance securities. (9) In March 2016, the mortgage was sold. (10) In January 2016, the loans were modified. In March 2016, the mortgage was sold. (11) This loan was repaid in September 2016. (12) This loan was repaid in June 2016. (13) This loan was repaid in May 2016. (14) In March 2016, we contributed our interest in the loan in exchange for a joint venture interest which is now accounted for under the equity method of accounting. It is included in unconsolidated joint ventures on the consolidated balance sheets. (15) This loan was repaid in February 2016.
Summary of preferred equity investments	As of September 30, 2016 and December 31, 2015 , we held the following preferred equity investments with an aggregate weighted average current yield of 7.32% at September 30, 2016 (in thousands): Type September 30, 2016 Future Funding Obligations September 30, 2016 Senior Financing September 30, 2016 Carrying Value (1) December 31, 2015 (1) Initial Mandatory Redemption Preferred Equity $ — $ 71,486 $ 9,978 $ 9,967 March 2018 Preferred Equity — 59,034 37,867 32,209 November 2018 Total $ — $ 130,520 $ 47,845 $ 42,176 (1) Carrying value is net of deferred origination fees.

Investments in Unconsolidated38

Investments in Unconsolidated Joint Ventures (Tables)	9 Months Ended
	Sep. 30, 2016
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 September 30, 2016 : Property Partner Ownership Interest Economic Interest Approximate Square Feet Acquisition Date Acquisition Price (1) (in thousands) 100 Park Avenue Prudential Real Estate Investors 49.90% 49.90% 834,000 January 2000 $ 95,800 717 Fifth Avenue Jeff Sutton/Private Investor 10.92% 10.92% 119,500 September 2006 251,900 800 Third Avenue Private Investors 60.52% 60.52% 526,000 December 2006 285,000 1745 Broadway Ivanhoe Cambridge, Inc. 56.88% 56.88% 674,000 April 2007 520,000 Jericho Plaza (2) Onyx Equities/Private Investor 11.67% 11.67% 640,000 April 2007 210,000 11 West 34th Street Private Investor/ Jeff Sutton 30.00% 30.00% 17,150 December 2010 10,800 3 Columbus Circle (3) The Moinian Group 48.90% 48.90% 741,500 January 2011 500,000 280 Park Avenue Vornado Realty Trust 50.00% 50.00% 1,219,158 March 2011 400,000 1552-1560 Broadway (4) Jeff Sutton 50.00% 50.00% 35,897 August 2011 136,550 724 Fifth Avenue Jeff Sutton 50.00% 50.00% 65,040 January 2012 223,000 10 East 53rd Street Canadian Pension Plan Investment Board 55.00% 55.00% 354,300 February 2012 252,500 521 Fifth Avenue Plaza Global Real Estate Partners LP 50.50% 50.50% 460,000 November 2012 315,000 21 East 66th Street (5) Private Investors 32.28% 32.28% 16,736 December 2012 75,000 650 Fifth Avenue (6) Jeff Sutton 50.00% 50.00% 32,324 November 2013 121 Greene Street Jeff Sutton 50.00% 50.00% 7,131 September 2014 27,400 175-225 Third Street Brooklyn, New York KCLW 3rd Street LLC/LIVWRK LLC 95.00% 95.00% — October 2014 74,600 55 West 46th Street Prudential Real Estate Investors 25.00% 25.00% 347,000 November 2014 295,000 Stonehenge Portfolio Various Various Various 2,046,733 Various 36,668 131-137 Spring Street Invesco Real Estate 20.00% 20.00% 68,342 August 2015 277,750 76 11th Avenue (7) Oxford/Vornado 33.33% 36.58% 764,000 March 2016 138,240 605 West 42nd Street (8) The Moinian Group 20.00% 20.00% 927,358 April 2016 759,000 11 Madison Avenue (9) PGIM Real Estate 60.00% 60.00% 2,314,000 August 2016 2,605,000 333 East 22nd Street (10) Private Investors 33.33% 33.33% 26,926 August 2016 — (1) Acquisition price represents the actual or implied gross purchase price for the joint venture, which is not adjusted for subsequent acquisitions of additional interests. (2) Our ownership percentage was reduced in the first quarter of 2016, from 77.78% to 11.67% , upon completion of the restructuring of the joint venture. (3) As a result of the sale of a condominium interest in September 2012, Young & Rubicam, Inc., or Y&R, owns floors three through eight at the property. Because the joint venture has an option to repurchase these floors, the gain associated with this sale was deferred. (4) The purchase price represents only the purchase of the 1552 Broadway interest which comprised approximately 13,045 square feet. 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. (5) 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. (6) 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 our joint venture partner 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. (7) The joint venture owns two mezzanine notes secured by interests in the entity that owns 76 11th Avenue. The difference between our ownership interest and our economic interest results from our right to 50% of the total exit fee while each of our partners is entitled to receive 25% of the total exit fee. (8) The Company was granted an option to purchase the interest at an agreed upon valuation in July 2014 when it originated a $50.0 million mezzanine loan to the project's developer. The mezzanine loan was repaid prior to the closing of the Company's acquisition of its joint venture interest. (9) In August 2016, we closed on the sale of a 40% interest in 11 Madison. The sale did not meet the criteria for sale accounting and as a result the property is being accounted for under the profit sharing method. Under the profit sharing method the Company recognizes its share of the operations of the property and also recognizes the other partner's share of depreciation. Included in equity in net income from unconsolidated joint ventures is $4.7 million of depreciation for the three and nine months ended September 30, 2016 representing the other partner's share of depreciation. Included in Investment in Unconsolidated Joint Ventures at September 30, 2016 are $2.7 billion of assets net of $1.5 billion of liabilities, net of the $482.0 million consideration received at closing for this property. Sale accounting will be met upon the lender group consenting to certain modifications to the mortgage on the property which we expect will be granted during the fourth quarter of 2016. If the modification is not obtained this may result in the Company repurchasing the sold interest from PGIM Real Estate at the sale price. The achievement of sale accounting will discontinue recognition of PGIM Real Estate's share of depreciation from that date and will have no effect on the balance sheet presentation of the investment. (10) The joint venture entered into a ground lease for the property commencing in October 2016. As of September 30, 2016 and December 31, 2015, the carrying value for acquisition, development and construction arrangements were as follows (in thousands): Loan Type September 30, 2016 December 31, 2015 Initial Maturity Date Mezzanine Loan and Preferred Equity $ 100,000 $ 99,936 March 2017 Mezzanine Loan 24,119 — July 2036 (1) Mezzanine Loan (2) 45,675 45,942 February 2022 $ 169,794 $ 145,878 (1) The Company has the ability to convert this loan into an equity position starting in 2021 and the borrower is able to force this conversion in 2024. (2) We have an option to convert our loan to an equity interest subject to certain conditions. We have determined that our option to convert the loan to equity is not a derivative financial instrument pursuant to GAAP. The following table summarizes the investments in unconsolidated joint ventures sold during the nine months ended September 30, 2016 : Property Ownership Percentage Disposition Date Type of Sale Gross Asset Valuation (in thousands) (1) Gain on Sale (in thousands) (2) 1 Jericho Plaza (3) 66.11% February 2016 Office $ 95,200 $ 3,300 7 Renaissance Square 50.00% March 2016 Office 20,700 4,200 EOP Denver 4.79% March 2016 Office 180,700 2,800 33 Beekman (4) 45.90% May 2016 Residential 196,000 33,000 EOP Denver 0.48% September 2016 Office 180,700 300 (1) Represents implied gross valuation for the joint venture or sales price of the property. (2) Represents the Company's share of the gain. The gain on sale is net of $1.1 million employee compensation awards accrued in connection with the realization of these investment gains as a bonus to certain employees that were instrumental in realizing the gains on sale. (3) Our ownership percentage was reduced in the first quarter of 2016, from 77.78% to 11.67% , upon completion of the restructuring of the joint venture. (4) In connection with the sale of the property, we also recognized a promote of $10.8 million .
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 September 30, 2016 and December 31, 2015 , respectively, are as follows (amounts in thousands): Property Maturity Date Interest Rate (1) September 30, 2016 December 31, 2015 Fixed Rate Debt: 1745 Broadway January 2017 5.68 % $ 340,000 $ 340,000 521 Fifth Avenue November 2019 3.73 % 170,000 170,000 717 Fifth Avenue (2) July 2022 4.45 % 300,000 300,000 717 Fifth Avenue (2) July 2022 5.50 % 355,328 325,704 Property Maturity Date Interest Rate (1) September 30, 2016 December 31, 2015 21 East 66th Street April 2023 3.60 % 12,000 12,000 3 Columbus Circle March 2025 3.61 % 350,000 350,000 11 Madison Avenue September 2025 3.84 % 1,400,000 — 800 Third Avenue February 2026 3.37 % 177,000 20,910 Stonehenge Portfolio (3) Various 4.19 % 364,255 430,627 280 Park Avenue — 692,963 7 Renaissance Square — 2,927 Total fixed rate debt $ 3,468,583 $ 2,645,131 Floating Rate Debt: 175-225 Third Street (4) December 2016 4.50 % $ 40,000 $ 40,000 10 East 53rd Street February 2017 2.99 % 125,000 125,000 724 Fifth Avenue April 2017 2.91 % 275,000 275,000 1552 Broadway (5) April 2017 4.71 % 185,410 190,409 55 West 46th Street (6) October 2017 2.79 % 151,536 150,000 Jericho Plaza (7) March 2018 4.64 % 76,993 163,750 605 West 42nd Street July 2018 2.85 % 539,000 — 650 Fifth Avenue (8) August 2018 4.17 % 65,000 65,000 280 Park Avenue June 2019 2.49 % 900,000 30,000 121 Greene Street November 2019 1.99 % 15,000 15,000 131-137 Spring Street August 2020 2.04 % 141,000 141,000 11 West 34th Street January 2021 1.94 % 23,000 23,000 100 Park Avenue February 2021 2.24 % 360,000 360,000 21 East 66th Street June 2033 3.00 % 1,746 1,805 Stonehenge Portfolio (9) Various 5.81 % 65,664 10,500 33 Beekman — 73,518 Total floating rate debt $ 2,964,349 $ 1,663,982 Total joint venture mortgages and other loans payable $ 6,432,932 $ 4,309,113 Deferred financing costs, net (100,426 ) (42,565 ) Total joint venture mortgages and other loans payable, net $ 6,332,506 $ 4,266,548 (1) Effective weighted average interest rate for the three months ended September 30, 2016 , taking into account interest rate hedges in effect during the period. (2) These loans are comprised of a $300.0 million fixed rate mortgage loan and $355.3 million mezzanine loan. The mezzanine loan is subject to accretion based on the difference between contractual interest rate and contractual pay rate. (3) Amount is comprised of $13.2 million , $34.6 million , $140.3 million , and $176.1 million in fixed-rate mortgages that mature in April 2017, November 2017, August 2019, and June 2024, respectively. (4) In October 2016, the loan was extended to December 2017. (5) These loans are comprised of a $145.0 million mortgage loan and a $41.5 million mezzanine loan. As of September 30, 2016 , $0.6 million of the mortgage loan and $0.5 million of the mezzanine loan were unfunded. (6) This loan has a committed amount of $190.0 million , of which $38.5 million was unfunded as of September 30, 2016 . (7) We hold an 11.67% non-controlling interest in the joint venture and the property secures a two year $100.0 million loan, of which $77.0 million is currently outstanding. (8) This loan has a committed amount of $97.0 million , of which $32.0 million was unfunded as of September 30, 2016 . (9) Amount is comprised of $55.3 million and $10.3 million in floating-rate mortgages that mature in June 2017 and December 2017, respectively.
Schedule of combined balance sheets for the unconsolidated joint ventures	The combined balance sheets for the unconsolidated joint ventures, at September 30, 2016 and December 31, 2015 are as follows (in thousands): September 30, 2016 December 31, 2015 Assets Commercial real estate property, net $ 8,927,385 $ 6,122,468 Cash and restricted cash 320,318 258,564 Tenant and other receivables, related party receivables, and deferred rents receivable, net of allowance 227,937 208,802 Debt and preferred equity investments, net 332,506 145,878 Other assets 670,665 248,474 Total assets $ 10,478,811 $ 6,984,186 Liabilities and members' equity Mortgages and other loans payable, net $ 6,332,506 $ 4,266,548 Deferred revenue/gain 367,873 209,095 Other liabilities 374,198 314,065 Members' equity 3,404,234 2,194,478 Total liabilities and members' equity $ 10,478,811 $ 6,984,186 Company's investments in unconsolidated joint ventures $ 1,860,912 $ 1,203,858
Schedule of combined statements of income for the unconsolidated joint ventures	The combined statements of operations for the unconsolidated joint ventures, from acquisition date through the three and nine months ended September 30, 2016 and 2015 , are as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Total revenues $ 184,221 $ 150,638 $ 498,308 $ 423,089 Operating expenses 34,727 27,647 89,147 79,478 Ground rent 3,744 4,677 10,670 9,841 Real estate taxes 30,814 23,494 79,356 65,205 Interest expense, net of interest income 51,789 51,430 147,876 147,152 Amortization of deferred financing costs 7,155 3,473 17,667 9,628 Transaction related costs 5,359 604 5,359 615 Depreciation and amortization 56,890 38,144 132,035 109,022 Total expenses 190,478 149,469 482,110 420,941 Loss on early extinguishment of debt — (248 ) (1,606 ) (1,081 ) Net (loss) income before gain on sale $ (6,257 ) $ 921 $ 14,592 $ 1,067 Company's equity in net (loss) income from unconsolidated joint ventures $ (3,968 ) $ 3,627 $ 11,969 $ 10,651

Deferred Costs (Tables)

Deferred Costs (Tables)	9 Months Ended
	Sep. 30, 2016
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of components of deferred costs	Deferred costs at September 30, 2016 and December 31, 2015 consisted of the following (in thousands): September 30, 2016 December 31, 2015 Deferred leasing $ 450,192 $ 415,406 Less: accumulated amortization (198,013 ) (175,486 ) Deferred costs, net $ 252,179 $ 239,920

Mortgages and Other Loans Pay40

Mortgages and Other Loans Payable (Tables)	9 Months Ended
	Sep. 30, 2016
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 or debt investments at September 30, 2016 and December 31, 2015 , respectively, were as follows (amounts in thousands): Property Maturity Date Interest Rate (1) September 30, 2016 December 31, 2015 Fixed Rate Debt: Landmark Square December 2016 4.00 % $ 78,236 $ 79,562 FHLB Facility January 2017 1.03 % 105,000 — FHLB Facility January 2017 0.80 % 100,000 — 485 Lexington Avenue February 2017 5.61 % 450,000 450,000 762 Madison Avenue February 2017 3.86 % 7,739 7,872 Unsecured Loan June 2018 4.81 % 16,000 16,000 One Madison Avenue May 2020 5.91 % 524,814 542,817 100 Church Street July 2022 4.68 % 222,390 225,099 919 Third Avenue (2) June 2023 5.12 % 500,000 500,000 400 East 57th Street (3) February 2024 4.13 % 66,779 67,644 400 East 58th Street February 2024 4.13 % 28,620 28,990 420 Lexington Avenue October 2024 3.99 % 300,000 300,000 1515 Broadway March 2025 3.93 % 892,457 900,000 Series J Preferred Units (4) April 2051 3.75 % 4,000 4,000 885 Third Avenue (5) 6.26 % 267,650 267,650 11 Madison Avenue (6) — 1,400,000 388-390 Greenwich Street (7) — 1,004,000 500 West Putnam Avenue (8) — 22,376 Total fixed rate debt $ 3,563,685 $ 5,816,010 Floating Rate Debt: FHLB Facility December 2016 0.77 % $ 24,000 $ 45,750 719 Seventh Avenue February 2018 3.54 % 32,823 — 183, 187 Broadway & 5-7 Dey Street May 2018 3.19 % 58,000 40,000 Master Repurchase Agreement July 2018 3.01 % 134,642 253,424 1080 Amsterdam November 2018 4.24 % 3,525 3,525 220 East 42nd Street October 2020 2.09 % 275,000 275,000 One Vanderbilt Avenue (9) September 2021 4.03 % — — 600 Lexington Avenue — 112,795 388-390 Greenwich Street (7) — 446,000 248-252 Bedford Avenue (10) — 29,000 Total floating rate debt $ 527,990 $ 1,205,494 Total fixed rate and floating rate debt $ 4,091,675 $ 7,021,504 Mortgages reclassed to liabilities related to assets held for sale (3)(7)(10) (66,779 ) (29,000 ) Total mortgages and other loans payable $ 4,024,896 $ 6,992,504 Deferred financing costs, net of amortization (70,741 ) (110,584 ) Total mortgages and other loans payable, net $ 3,954,155 $ 6,881,920 (1) Effective weighted average interest rate for the quarter ended September 30, 2016 , taking into account interest rate hedges in effect during the period. (2) We own a 51.0% controlling interest in the consolidated joint venture that is the borrower on this loan. (3) In October 2016, we closed on the sale of an interest in 400 East 57th Street. At September 30, 2016, this property was classified as a held for sale property and the related mortgage, net of deferred financing costs, net of amortization of $2.1 million , was included in liabilities related to assets held for sale. (4) In connection with the acquisition of a commercial real estate property, the Operating Partnership issued $4.0 million , 3.75% Series J Preferred Units of limited partnership interest, or the Series J Preferred Units, with a mandatory liquidation preference of $1,000 per unit. The Series J Preferred Units are accounted for as debt because they 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 provided for in the related agreement. (5) In February 2016, we closed on the sale of 885 Third Avenue. The sale did not meet the criteria for sale accounting and as a result the property remains on our consolidated balance sheet until the criteria is met. The maturity date of the mortgage on the property, which was assumed by the buyer, is July 2017. (6) In August 2016, we closed on the sale of a 40.0% interest on 11 Madison Avenue. This property is now classified within unconsolidated joint ventures. (7) In June 2016, we closed on the sale of 388-390 Greenwich Street. At March 31, 2016, this property was classified as a held for sale property and the related mortgage, net of deferred financing costs, net of amortization of $24.5 million , was included in liabilities related to assets held for sale. (8) In January 2016, the mortgage was repaid. (9) In September 2016, we closed on a $1.5 billion construction facility in connection with the development of One Vanderbilt Avenue. This facility bears interest at 350 basis points over 30-day LIBOR, with reductions based on meeting certain conditions, and has an initial five -year term with two one -year extension options. Advances under the loan are subject to incurred costs, funded equity, loan to value thresholds, and entering into construction contracts. (10) The property at 248-252 Bedford Avenue in Brooklyn, New York was sold in February 2016. At December 31, 2015 this property was held for sale and the related mortgage, net of deferred financing, net of amortization costs of $0.9 million , was included in liabilities related to assets held for sale.

Corporate Indebtedness (Tables)

Corporate Indebtedness (Tables)	9 Months Ended
	Sep. 30, 2016
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 September 30, 2016 and December 31, 2015 , respectively, by scheduled maturity date (dollars in thousands): Issuance September 30, September 30, December 31, 2015 Accreted Balance Coupon Rate (1) Effective Rate Term (in Years) Maturity Date October 12, 2010 (2) $ 345,000 $ 330,754 $ 321,130 3.00 % 3.00 % 7 October 2017 August 5, 2011 (3) 250,000 249,862 249,810 5.00 % 5.00 % 7 August 2018 March 16, 2010 (3) 250,000 250,000 250,000 7.75 % 7.75 % 10 March 2020 November 15, 2012 (3) 200,000 200,000 200,000 4.50 % 4.50 % 10 December 2022 December 17, 2015 (3) 100,000 100,000 100,000 4.27 % 4.27 % 10 December 2025 March 26, 2007 (4) — — 10,008 March 31, 2006 (5) — — 255,296 $ 1,145,000 $ 1,130,616 $ 1,386,244 Deferred financing costs, net (6,163 ) (7,280 ) $ 1,145,000 $ 1,124,453 $ 1,378,964 (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 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 12.5697 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 became exchangeable commencing January 1, 2016 and remained exchangeable through March 31, 2016. The notes are guaranteed by ROP. On the issuance date, $78.3 million of the debt balance was recorded in equity. As of September 30, 2016 , $14.2 million remained to be amortized into the debt balance. (3) Issued by the Company, the Operating Partnership and ROP, as co-obligors. (4) Balance was repaid in September 2016. (5) Issued by ROP, balance was repaid in March 2016.
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 September 30, 2016 , including as-of-right extension options and put options, were as follows (in thousands): Scheduled Amortization Principal Revolving Credit Facility Unsecured Term Loan Trust Preferred Securities Senior Unsecured Notes Total Joint Venture Debt Remaining 2016 $ 12,694 $ 101,936 $ — $ — $ — $ — $ 114,630 $ 38,253 2017 53,467 930,329 — — — 345,000 1,328,796 534,720 2018 56,320 244,990 — — — 250,000 551,310 41,933 2019 62,048 — — 1,183,000 — — 1,245,048 554,686 2020 44,162 679,531 — — — 250,000 973,693 30,298 Thereafter 124,818 1,781,380 — — 100,000 300,000 2,306,198 1,494,287 $ 353,509 $ 3,738,166 $ — $ 1,183,000 $ 100,000 $ 1,145,000 $ 6,519,675 $ 2,694,177
Schedule of consolidated interest expense, excluding capitalized interest	Consolidated interest expense, excluding capitalized interest, was comprised of the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Interest expense before capitalized interest $ 78,715 $ 92,244 $ 276,437 $ 261,343 Interest capitalized (6,084 ) (7,327 ) (18,135 ) (23,496 ) Interest income (66 ) (776 ) (1,976 ) (2,153 ) Interest expense, net $ 72,565 $ 84,141 $ 256,326 $ 235,694

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2016
Related Party Transactions [Abstract]
Schedule of amounts due from/to related parties	Amounts due from related parties at September 30, 2016 and December 31, 2015 consisted of the following (in thousands): September 30, 2016 December 31, 2015 Due from joint ventures $ 1,727 $ 1,334 Other 13,113 9,316 Related party receivables $ 14,840 $ 10,650

Noncontrolling Interests on t43

Noncontrolling Interests on the Company's Consolidated Financial Statements (Tables)	9 Months Ended
	Sep. 30, 2016
Noncontrolling Interest [Abstract]
Schedule of Noncontrolling Interest	Below is the rollforward analysis of the activity relating to the noncontrolling interests in the Operating Partnership as of September 30, 2016 and December 31, 2015 (in thousands): September 30, 2016 December 31, 2015 Balance at beginning of period $ 424,206 $ 469,524 Distributions (9,245 ) (9,710 ) Issuance of common units 75,352 30,506 Redemption of common units (12,746 ) (55,697 ) Net income 8,171 10,565 Accumulated other comprehensive income allocation (257 ) (67 ) Fair value adjustment 4,959 (20,915 ) Balance at end of period $ 490,440 $ 424,206
Schedule of Preferred Unit Activity	Below is the rollforward analysis of the activity relating to the preferred units in the Operating Partnership as of September 30, 2016 and December 31, 2015 (in thousands): September 30, 2016 December 31, 2015 Balance at beginning of period $ 282,516 $ 71,115 Issuance of preferred units 22,793 211,601 Redemption of preferred units (2,999 ) (200 ) Balance at end of period $ 302,310 $ 282,516

Stockholders' Equity of the C44

Stockholders' Equity of the Company (Tables)	9 Months Ended
	Sep. 30, 2016
Stockholders' Equity Note [Abstract]
Schedule of Earnings Per Share	SL Green's earnings per share for the three and nine months ended September 30, 2016 and 2015 are computed as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Numerator 2016 2015 2016 2015 Basic Earnings: Income attributable to SL Green common stockholders $ 34,252 $ 163,658 $ 190,930 $ 167,829 Effect of Dilutive Securities: Redemption of units to common shares 1,663 6,467 8,171 6,634 Diluted Earnings: Income attributable to SL Green common stockholders $ 35,915 $ 170,125 $ 199,101 $ 174,463 Three Months Ended September 30, Nine Months Ended September 30, Denominator 2016 2015 2016 2015 Basic Shares: Weighted average common stock outstanding 100,233 99,621 100,140 99,205 Effect of Dilutive Securities: Operating Partnership units redeemable for common shares 4,497 3,901 4,272 3,924 Stock-based compensation plans 413 407 349 480 Diluted weighted average common stock outstanding 105,143 103,929 104,761 103,609

Partners' Capital of the Oper45

Partners' Capital of the Operating Partnership (Tables)	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Schedule of calculation of numerator and denominator in earnings per unit	The Operating Partnership's earnings per unit for the three and nine months ended September 30, 2016 and 2015 , respectively are computed as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Numerator 2016 2015 2016 2015 Basic and Diluted Earnings: Net income attributable to SLGOP common unitholders $ 35,915 $ 170,125 $ 199,101 $ 174,463 Three Months Ended September 30, Nine Months Ended September 30, Denominator 2016 2015 2016 2015 Basic units: Weighted average common units outstanding 104,730 103,522 104,412 103,129 Effect of Dilutive Securities: Stock-based compensation plans 413 407 349 480 Diluted weighted average common units outstanding 105,143 103,929 104,761 103,609

Share-based Compensation (Table

Share-based Compensation (Tables)	9 Months Ended
	Sep. 30, 2016
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 nine months ended September 30, 2016 and the year ended December 31, 2015 . September 30, 2016 December 31, 2015 Dividend yield 2.30 % 1.97 % Expected life of option 4.2 years 3.6 years Risk-free interest rate 1.08 % 1.43 % Expected stock price volatility 29.08 % 32.34 %
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 September 30, 2016 and December 31, 2015 , and changes during the nine months ended September 30, 2016 and year ended December 31, 2015 are as follows: September 30, 2016 December 31, 2015 Options Outstanding Weighted Average Exercise Price Options Outstanding Weighted Average Exercise Price Balance at beginning of period $ 1,595,007 $ 95.52 $ 1,462,726 $ 87.98 Granted 109,500 99.65 389,836 112.54 Exercised (157,361 ) 77.90 (217,438 ) 74.69 Lapsed or cancelled (48,117 ) 110.81 (40,117 ) 98.61 Balance at end of period $ 1,499,029 $ 97.18 $ 1,595,007 $ 95.52 Options exercisable at end of period 794,797 $ 90.29 589,055 $ 89.85 Weighted average fair value of options granted during the period $ 2,258,336 $ 9,522,613
Summary of restricted stock and charges during the period	A summary of the Company's restricted stock as of September 30, 2016 and December 31, 2015 and charges during the nine months ended September 30, 2016 and the year ended December 31, 2015 , are as follows: September 30, 2016 December 31, 2015 Balance at beginning of period 3,137,881 3,000,979 Granted 14,550 143,053 Cancelled (34,600 ) (6,151 ) Balance at end of period 3,117,831 3,137,881 Vested during the period 83,822 87,081 Compensation expense recorded $ 5,275,799 $ 7,540,747 Weighted average fair value of restricted stock granted during the period $ 1,613,846 $ 16,061,201

Accumulated Other Comprehensi47

Accumulated Other Comprehensive Loss (Tables)	9 Months Ended
	Sep. 30, 2016
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 September 30, 2016 (in thousands): Net unrealized (loss) gain on derivative instruments ( 1 ) SL Green’s share of joint venture net unrealized (loss) gain on derivative instruments ( 2 ) Unrealized gain (loss) on marketable securities Total Balance at December 31, 2015 $ (10,160 ) $ (592 ) $ 2,003 $ (8,749 ) Other comprehensive loss before reclassifications (7,810 ) (7,409 ) (869 ) (16,088 ) Amounts reclassified from accumulated other comprehensive income 7,862 2,901 — 10,763 Balance at September 30, 2016 $ (10,108 ) $ (5,100 ) $ 1,134 $ (14,074 ) (1) Amount reclassified from accumulated other comprehensive income (loss) is included in interest expense in the respective consolidated statements of operations. As of September 30, 2016 and December 31, 2015 , 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 $8.1 million and $9.7 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 operations.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2016
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 September 30, 2016 and December 31, 2015 (in thousands): September 30, 2016 Total Level 1 Level 2 Level 3 Assets: Marketable securities $ 60,352 $ 23,213 $ 37,139 $ — Interest rate cap and swap agreements (included in other assets) $ 4 $ — $ 4 $ — Liabilities: Interest rate cap and swap agreements (included in accrued interest payable and other liabilities) $ 2,127 $ — $ 2,127 $ — Interest rate cap and swap agreements (included in liabilities related to assets held for sale) $ — $ — $ — $ — December 31, 2015 Total Level 1 Level 2 Level 3 Assets: Marketable securities $ 45,138 $ 4,704 $ 40,434 $ — Interest rate cap and swap agreements (included in other assets) $ 204 $ — $ 204 $ — Liabilities: Interest rate cap and swap agreements (included in accrued interest payable and other liabilities) $ 10,776 $ — $ 10,776 $ —
Fair Value, by Balance Sheet Grouping	The following table provides the carrying value and fair value of these financial instruments as of September 30, 2016 and December 31, 2015 (in thousands): September 30, 2016 December 31, 2015 Carrying Value (1) Fair Value Carrying Value (1) Fair Value Debt and preferred equity investments $ 1,453,234 (2) $ 1,670,020 (2) Fixed rate debt $ 5,494,301 $ 5,922,120 $ 7,232,254 $ 7,591,388 Variable rate debt 1,010,990 1,014,458 3,202,494 3,179,186 $ 6,505,291 $ 6,936,578 $ 10,434,748 $ 10,770,574 (1) Amounts exclude net deferred financing costs. (2) At September 30, 2016 , debt and preferred equity investments had an estimated fair value ranging between $1.5 billion and $1.6 billion . At December 31, 2015, debt and preferred equity investments had an estimated fair value ranging between $1.7 billion and $1.8 billion .

Financial Instruments_ Deriva49

Financial Instruments: Derivatives and Hedging (Tables)	9 Months Ended
	Sep. 30, 2016
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 value at inception and fair value of our consolidated derivative financial instruments at September 30, 2016 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 Value Strike Rate Effective Date Expiration Date Balance Sheet Location Fair Value Interest Rate Swap $ 200,000 0.938 % October 2014 December 2017 Other Liabilities $ (551 ) Interest Rate Swap 150,000 0.940 % October 2014 December 2017 Other Liabilities (417 ) Interest Rate Swap 150,000 0.940 % October 2014 December 2017 Other Liabilities (417 ) Interest Rate Cap 117,392 6.000 % October 2014 October 2016 Other Liabilities — Interest Rate Swap 14,409 0.500 % January 2015 January 2017 Other Assets 4 Interest Rate Swap 8,018 0.852 % February 2015 February 2017 Other Liabilities (7 ) Interest Rate Cap 137,500 4.000 % September 2015 September 2017 Other Assets — Interest Rate Cap 1,450,000 4.750 % May 2016 May 2017 Other Assets — Interest Rate Swap 200,000 1.131 % July 2016 July 2023 Other Liabilities (361 ) Interest Rate Swap 100,000 1.161 % July 2016 July 2023 Other Liabilities (374 ) Interest Rate Cap 23,199 4.500 % October 2016 October 2017 Other Assets — Total $ (2,123 )
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 operations for the three months ended September 30, 2016 and 2015 , respectively (in thousands): Amount of Gain Location of (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income Amount of Loss Location of (Loss) or Gain Recognized in Income on Derivative Amount of (Loss) Gain Three Months Ended September 30, Three Months Ended September 30, Three Months Ended September 30, Derivative 2016 2015 2016 2015 2016 2015 Interest Rate Swaps/Caps $ (7 ) $ (6,921 ) Interest expense $ 1,442 $ 2,737 Interest expense $ — $ (31 ) Share of unconsolidated joint ventures' derivative instruments (222 ) (1,526 ) Equity in net income from unconsolidated joint ventures 547 287 Equity in net income from unconsolidated joint ventures 830 (21 ) $ (229 ) $ (8,447 ) $ 1,989 $ 3,024 $ 830 $ (52 ) 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 operations for the nine months ended September 30, 2016 and 2015 , respectively (in thousands): Amount of Gain Location of (Loss) Reclassified from Accumulated Other Comprehensive Loss into Income Amount of Loss Location of (Loss) or Gain Recognized in Income on Derivative Amount of Loss Nine Months Ended September 30, Nine Months Ended September 30, Nine Months Ended September 30, Derivative 2016 2015 2016 2015 2016 2015 Interest Rate Swaps/Caps $ (8,112 ) $ (15,537 ) Interest expense $ 8,073 $ 8,221 Interest expense $ (38 ) $ (455 ) Share of unconsolidated joint ventures' derivative instruments (5,992 ) (2,486 ) Equity in net income from unconsolidated joint ventures 1,465 949 Equity in net income from unconsolidated joint ventures (206 ) (21 ) $ (14,104 ) $ (18,023 ) $ 9,538 $ 9,170 $ (244 ) $ (476 )

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	The following is a schedule of future minimum lease payments under capital leases and non-cancellable operating leases with initial terms in excess of one year as of September 30, 2016 (in thousands): Capital lease Non-cancellable operating leases Remaining 2016 $ 585 $ 7,835 2017 2,387 31,374 2018 2,387 31,455 2019 2,411 31,716 2020 2,620 32,086 Thereafter 825,483 983,213 Total minimum lease payments $ 835,873 $ 1,117,679 Amount representing interest (793,922 ) Capital lease obligations $ 41,951
Schedule of Future Minimum Lease Payments for Capital Leases	The following is a schedule of future minimum lease payments under capital leases and non-cancellable operating leases with initial terms in excess of one year as of September 30, 2016 (in thousands): Capital lease Non-cancellable operating leases Remaining 2016 $ 585 $ 7,835 2017 2,387 31,374 2018 2,387 31,455 2019 2,411 31,716 2020 2,620 32,086 Thereafter 825,483 983,213 Total minimum lease payments $ 835,873 $ 1,117,679 Amount representing interest (793,922 ) Capital lease obligations $ 41,951

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Schedule of selected results of operations and selected asset information	Selected consolidated results of operations for the three and nine months ended September 30, 2016 and 2015 , and selected asset information as of September 30, 2016 and December 31, 2015 , regarding our operating segments are as follows (in thousands): Real Estate Segment Debt and Preferred Equity Segment Total Company Total revenues Three months ended: September 30, 2016 $ 335,652 $ 81,029 $ 416,681 September 30, 2015 375,623 56,443 432,066 Nine months ended: September 30, 2016 1,300,082 189,657 1,489,739 September 30, 2015 1,085,870 151,569 1,237,439 (Loss) Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain on sale of real estate, depreciable real estate reserves net of recoveries, and loss on sale of investment in marketable securities Three months ended: September 30, 2016 $ (33,613 ) $ 76,334 $ 42,721 September 30, 2015 (29,577 ) 50,571 20,994 Nine months ended: September 30, 2016 (190,633 ) 171,706 (18,927 ) September 30, 2015 (96,333 ) 129,605 33,272 Total assets As of: September 30, 2016 $ 13,992,319 $ 1,798,623 $ 15,790,942 December 31, 2015 17,814,787 1,912,859 19,727,646
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 three and nine months ended September 30, 2016 , and 2015 (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 Income (Loss) from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain on sale of real estate, depreciable real estate reserves net of recoveries, and loss on sale of investment in marketable securities $ 42,721 $ 20,994 $ (18,927 ) $ 33,272 Equity in net gain on sale of interest in unconsolidated joint venture/real estate 225 15,281 43,588 16,050 Gain on sale of real estate, net 397 159,704 210,750 159,704 Depreciable real estate reserves — (19,226 ) (10,387 ) (19,226 ) Loss on sale of investment in marketable securities — — (83 ) — Income from continuing operations 43,343 176,753 224,941 189,800 Net income from discontinued operations — — — 427 Gain on sale of discontinued operations — — — 12,983 Net income $ 43,343 $ 176,753 $ 224,941 $ 203,210

Organization and Basis of Pre52

Organization and Basis of Presentation (Details) - SL Green Operating Partnership	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
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)	4.29%	3.61%
Service Corporation
Organization
Economic interest in variable interest entity (as a percent)	95.00%

Organization and Basis of Pre53

Organization and Basis of Presentation (Schedule of Commercial Office Properties)(Details) $ in Billions	9 Months Ended
	Sep. 30, 2016USD ($)ft²buildingshares
Real estate properties
Number of Properties | building	109
Approximate Square Feet unaudited (sqft)	32,918,879
Weighted Average Occupancy unaudited (as a percent)	90.30%
Debt and preferred equity investments including investments held by unconsolidated joint ventures | $	$ 1.8
Debt and preferred equity investments and other financing receivables included in other balance sheet items | $	$ 0.3
Number of shares to be received on redemption of one unit of limited partnership interests (shares) | shares	1
Commercial properties
Real estate properties
Number of Properties | building	88
Approximate Square Feet unaudited (sqft)	29,199,010
Weighted Average Occupancy unaudited (as a percent)	91.40%
Residential
Real estate properties
Number of Properties | building	21
Approximate Square Feet unaudited (sqft)	3,719,869
Weighted Average Occupancy unaudited (as a percent)	81.40%
Managed office properties
Real estate properties
Approximate Square Feet unaudited (sqft)	336,000
Consolidated properties
Real estate properties
Number of Properties | building	69
Approximate Square Feet unaudited (sqft)	21,621,251
Consolidated properties | Commercial properties
Real estate properties
Number of Properties | building	65
Approximate Square Feet unaudited (sqft)	20,858,664
Consolidated properties | Residential
Real estate properties
Number of Properties | building	4
Approximate Square Feet unaudited (sqft)	762,587
Unconsolidated properties
Real estate properties
Number of Properties | building	40
Approximate Square Feet unaudited (sqft)	11,297,628
Unconsolidated properties | Commercial properties
Real estate properties
Number of Properties | building	23
Approximate Square Feet unaudited (sqft)	8,340,346
Unconsolidated properties | Residential
Real estate properties
Number of Properties | building	17
Approximate Square Feet unaudited (sqft)	2,957,282
Manhattan
Real estate properties
Number of Properties | building	58
Approximate Square Feet unaudited (sqft)	24,392,210
Weighted Average Occupancy unaudited (as a percent)	93.20%
Manhattan | Office
Real estate properties
Number of Properties | building	31
Approximate Square Feet unaudited (sqft)	22,612,745
Weighted Average Occupancy unaudited (as a percent)	95.40%
Manhattan | Retail
Real estate properties
Number of Properties | building	19
Approximate Square Feet unaudited (sqft)	766,063
Weighted Average Occupancy unaudited (as a percent)	87.60%
Manhattan | Development/Redevelopment
Real estate properties
Number of Properties | building	6
Approximate Square Feet unaudited (sqft)	809,946
Weighted Average Occupancy unaudited (as a percent)	35.50%
Manhattan | Fee Interest
Real estate properties
Number of Properties | building	2
Approximate Square Feet unaudited (sqft)	203,456
Weighted Average Occupancy unaudited (as a percent)	86.80%
Manhattan | Residential
Real estate properties
Number of Properties | building	21
Approximate Square Feet unaudited (sqft)	3,719,869
Weighted Average Occupancy unaudited (as a percent)	81.40%
Manhattan | Consolidated properties
Real estate properties
Number of Properties | building	38
Approximate Square Feet unaudited (sqft)	16,691,864
Manhattan | Consolidated properties | Office
Real estate properties
Number of Properties | building	24
Approximate Square Feet unaudited (sqft)	16,054,606
Manhattan | Consolidated properties | Retail
Real estate properties
Number of Properties | building	10
Approximate Square Feet unaudited (sqft)	418,093
Manhattan | Consolidated properties | Development/Redevelopment
Real estate properties
Number of Properties | building	3
Approximate Square Feet unaudited (sqft)	42,635
Manhattan | Consolidated properties | Fee Interest
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft)	176,530
Manhattan | Consolidated properties | Residential
Real estate properties
Number of Properties | building	4
Approximate Square Feet unaudited (sqft)	762,587
Manhattan | Consolidated properties | Dual property type, retail portion
Real estate properties
Approximate Square Feet unaudited (sqft)	270,132
Manhattan | Consolidated properties | Dual property type, residential portion
Real estate properties
Approximate Square Feet unaudited (sqft)	222,855
Manhattan | Unconsolidated properties
Real estate properties
Number of Properties | building	20
Approximate Square Feet unaudited (sqft)	7,700,346
Manhattan | Unconsolidated properties | Office
Real estate properties
Number of Properties | building	7
Approximate Square Feet unaudited (sqft)	6,558,139
Manhattan | Unconsolidated properties | Retail
Real estate properties
Number of Properties | building	9
Approximate Square Feet unaudited (sqft)	347,970
Manhattan | Unconsolidated properties | Development/Redevelopment
Real estate properties
Number of Properties | building	3
Approximate Square Feet unaudited (sqft)	767,311
Manhattan | Unconsolidated properties | Fee Interest
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft)	26,926
Manhattan | Unconsolidated properties | Residential
Real estate properties
Number of Properties | building	17
Approximate Square Feet unaudited (sqft)	2,957,282
Suburban
Real estate properties
Number of Properties | building	30
Approximate Square Feet unaudited (sqft)	4,806,800
Weighted Average Occupancy unaudited (as a percent)	82.20%
Suburban | Office
Real estate properties
Number of Properties | building	27
Approximate Square Feet unaudited (sqft)	4,753,800
Weighted Average Occupancy unaudited (as a percent)	82.00%
Suburban | Retail
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft)	52,000
Weighted Average Occupancy unaudited (as a percent)	100.00%
Suburban | Development/Redevelopment
Real estate properties
Number of Properties | building	2
Approximate Square Feet unaudited (sqft)	1,000
Weighted Average Occupancy unaudited (as a percent)	100.00%
Suburban | Residential
Real estate properties
Number of Properties | building	0
Approximate Square Feet unaudited (sqft)	0
Weighted Average Occupancy unaudited (as a percent)	0.00%
Suburban | Consolidated properties
Real estate properties
Number of Properties | building	27
Approximate Square Feet unaudited (sqft)	4,166,800
Suburban | Consolidated properties | Office
Real estate properties
Number of Properties | building	25
Approximate Square Feet unaudited (sqft)	4,113,800
Suburban | Consolidated properties | Retail
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft)	52,000
Suburban | Consolidated properties | Development/Redevelopment
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft)	1,000
Suburban | Consolidated properties | Residential
Real estate properties
Number of Properties | building	0
Approximate Square Feet unaudited (sqft)	0
Suburban | Unconsolidated properties
Real estate properties
Number of Properties | building	3
Approximate Square Feet unaudited (sqft)	640,000
Suburban | Unconsolidated properties | Office
Real estate properties
Number of Properties | building	2
Approximate Square Feet unaudited (sqft)	640,000
Suburban | Unconsolidated properties | Retail
Real estate properties
Number of Properties | building	0
Approximate Square Feet unaudited (sqft)	0
Suburban | Unconsolidated properties | Development/Redevelopment
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft)	0
Suburban | Unconsolidated properties | Residential
Real estate properties
Number of Properties | building	0
Approximate Square Feet unaudited (sqft)	0

Significant Accounting Polici54

Significant Accounting Policies (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Principles of Consolidation
Commercial real estate properties	$ 10,418,719	$ 14,620,896
Mortgages and other loans payable, net	3,954,155	6,881,920
Consolidated VIEs
Principles of Consolidation
Commercial real estate properties	1,600,000	200,700
Mortgages and other loans payable, net	$ 605,800	$ 101,100

Significant Accounting Polici55

Significant Accounting Policies (Investments in Commercial Real Estate Properties)(Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Investment in Commercial Real Estate Properties
Rental revenue from amortization of acquired leases	$ (200,000)	$ 10,200,000	$ 191,400,000	$ 32,900,000
Reduction in interest expense from amortization of above-market rate mortgages	700,000	$ 600,000	2,000,000	$ 1,700,000
Identified intangible assets (included in other assets):
Gross amount	624,557,000		624,557,000		$ 939,518,000
Accumulated amortization	(397,148,000)		(397,148,000)		(403,747,000)
Net	227,409,000		227,409,000		535,771,000
Identified intangible liabilities (included in deferred revenue):
Gross amount	648,583,000		648,583,000		866,561,000
Accumulated amortization	(455,568,000)		(455,568,000)		(486,928,000)
Net	193,015,000		193,015,000		379,633,000
Net intangible assets reclassed to assets held for sale	300,000		300,000		200,000
Net intangible liabilities reclassed to liabilities relates to assets held for sale	800,000		$ 800,000		$ 100,000
Minimum | Above-market leases
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets (in years)			1 year
Minimum | Below-market leases
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets (in years)			1 year
Minimum | In-place leases
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets (in years)			1 year
Maximum | Above-market leases
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets (in years)			14 years
Maximum | Below-market leases
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets (in years)			14 years
Maximum | In-place leases
Investment in Commercial Real Estate Properties
Estimated useful life of other intangible assets (in years)			14 years
Building | Minimum
Investment in Commercial Real Estate Properties
Estimated useful life (in years)			3 years
Building | Maximum
Investment in Commercial Real Estate Properties
Estimated useful life (in years)			40 years
388-390 Greenwich Street
Investment in Commercial Real Estate Properties
Rental revenue from amortization of acquired leases	$ 0		$ 172,400,000

Significant Accounting Polici56

Significant Accounting Policies (Investment in Marketable Securities)(Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Investment in Marketable Securities
Marketable securities	$ 60,352		$ 60,352		$ 45,138
Cost basis	36,100		36,100		38,700
Proceeds from sale of marketable securities	1,700	$ 100	6,900	$ 400
Fair Value
Investment in Marketable Securities
Marketable securities	60,352		60,352		45,138
Equity marketable securities
Investment in Marketable Securities
Marketable securities	23,213		23,213		4,704
Commercial mortgage-backed securities
Investment in Marketable Securities
Marketable securities	$ 37,139		$ 37,139		$ 40,434

Significant Accounting Polici57

Significant Accounting Policies (Revenue Recognition/Income Taxes)(Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accounting Policies [Abstract]
Days past due for income recognition on debt and preferred equity investments to be suspended			90 days
Income taxes
Federal, state and local tax provision	$ 0.9	$ 1.1	$ 1.9	$ 2.5

Significant Accounting Polici58

Significant Accounting Policies (Concentrations of Credit Risk/Accounting Standards Updates)(Details) $ in Millions	9 Months Ended
	Sep. 30, 2016USD ($)Tenant	Dec. 31, 2015USD ($)
Concentration of Credit Risk
Deferred debt issuance costs | $	$ 101.5	$ 130.3
Annualized rent | Customer concentration
Concentration of Credit Risk
Number of tenants (tenants) | Tenant	2
Maximum percentage of annualized rent for any one tenant not individually disclosed (percent) (more than)	5.00%
Annualized rent | 1515 Broadway | Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	9.70%
Annualized rent | 919 Third Avenue | Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	7.90%
Annualized rent | 1185 Avenue of the Americas | Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	7.50%
Annualized rent | 420 Lexington Avenue | Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	6.60%
Annualized rent | 1 Madison Ave | Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	5.70%
Annualized rent | 485 Lexington Avenue | Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	5.10%
Tenant 1 | Annualized rent | Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	7.80%
Tenant 2 | Annualized rent | Customer concentration
Concentration of Credit Risk
Percentage of concentration (percent)	6.80%

Property Acquisitions (Details)

Property Acquisitions (Details) - USD ($) $ in Thousands	1 Months Ended					3 Months Ended		9 Months Ended
	Mar. 31, 2016	Aug. 31, 2015	Jul. 31, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Recognized Identifiable Assets Acquired and Liabilities Assumed
Impact to rental revenue for amortization of aggregate below-market leases						$ 281,482	$ 318,465	$ 1,043,898	$ 926,020
Impact to depreciation expense						$ 112,665	$ 146,185	717,015	$ 454,087
183 Broadway
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land	$ 26,640
Building and building leasehold	2,960
Above market lease value	0
Acquired in-place leases	0
Other assets, net of other liabilities	0
Assets acquired	29,600
Mark-to-market assumed debt	0
Below market lease value	0
Derivatives	0
Liabilities assumed	0
Purchase price	29,600
Net consideration funded by us at closing, excluding consideration financed by debt	29,600
Equity and/or debt investment held	0
Debt assumed	$ 0
183, 187 Broadway & 5-7 Dey Street
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land		$ 20,266
Building and building leasehold		42,468
Above market lease value		17
Acquired in-place leases		3,621
Other assets, net of other liabilities		0
Assets acquired		66,372
Mark-to-market assumed debt		0
Below market lease value		(3,226)
Derivatives		0
Liabilities assumed		(3,226)
Purchase price		63,146
Net consideration funded by us at closing, excluding consideration financed by debt		0
Equity and/or debt investment held		0
Debt assumed		0
183, 187 Broadway & 5-7 Dey Street | As Previously Reported
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land		22,100
Building and building leasehold		41,000
110 Greene Street
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land			$ 45,120
Building and building leasehold			215,470
Above market lease value			0
Acquired in-place leases			8,967
Other assets, net of other liabilities			0
Assets acquired			269,557
Mark-to-market assumed debt			0
Below market lease value			(14,557)
Derivatives			0
Liabilities assumed			(14,557)
Purchase price			255,000
Net consideration funded by us at closing, excluding consideration financed by debt			0
Equity and/or debt investment held			0
Debt assumed			0
110 Greene Street | As Previously Reported
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land			89,300
Building and building leasehold			$ 165,800
Upper East Side Residential
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land				$ 48,152
Building and building leasehold				0
Above market lease value				0
Acquired in-place leases				1,922
Other assets, net of other liabilities				0
Assets acquired				50,074
Mark-to-market assumed debt				0
Below market lease value				0
Derivatives				0
Liabilities assumed				0
Purchase price				50,074
Net consideration funded by us at closing, excluding consideration financed by debt				0
Equity and/or debt investment held				0
Debt assumed				0
Upper East Side Residential | As Previously Reported
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land				17,500
Building and building leasehold				$ 32,500
11 Madison Avenue
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land		675,776
Building and building leasehold		1,553,602
Above market lease value		19,764
Acquired in-place leases		366,949
Other assets, net of other liabilities		0
Assets acquired		2,616,091
Mark-to-market assumed debt		0
Below market lease value		(187,732)
Derivatives		0
Liabilities assumed		(187,732)
Purchase price		2,428,359
Net consideration funded by us at closing, excluding consideration financed by debt		0
Equity and/or debt investment held		0
Debt assumed		0
11 Madison Avenue | As Previously Reported
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land		849,900
Building and building leasehold		$ 1,600,000
1640 Flatbush Avenue
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land					$ 6,226
Building and building leasehold					501
Above market lease value					0
Acquired in-place leases					146
Other assets, net of other liabilities					0
Assets acquired					6,873
Mark-to-market assumed debt					0
Below market lease value					(73)
Derivatives					0
Liabilities assumed					(73)
Purchase price					6,800
Net consideration funded by us at closing, excluding consideration financed by debt					0
Equity and/or debt investment held					0
Debt assumed					0
1640 Flatbush Avenue | As Previously Reported
Recognized Identifiable Assets Acquired and Liabilities Assumed
Land					6,100
Building and building leasehold					$ 700
Upper East Side Residential, 11 Madison Avenue and 1640 Flatbush Avenue
Recognized Identifiable Assets Acquired and Liabilities Assumed
Impact to rental revenue for amortization of aggregate below-market leases								8,000
Impact to depreciation expense								$ 17,900

Properties Held for Sale and 60

Properties Held for Sale and Property Dispositions (Properties Held for Sale) (Details) - 400 East 57th Street	1 Months Ended	3 Months Ended
	Oct. 31, 2016	Sep. 30, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage prior to disposal		90.00%
Subsequent Event
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage in disposed asset	49.00%

Properties Held for Sale and 61

Properties Held for Sale and Property Dispositions (Property Dispositions) (Details) $ in Thousands	1 Months Ended						3 Months Ended		9 Months Ended
	Aug. 31, 2016USD ($)ft²	Jul. 31, 2016USD ($)ft²	Jun. 30, 2016USD ($)ft²	May 31, 2016USD ($)a	Feb. 29, 2016USD ($)ft²	Dec. 31, 2015USD ($)	Sep. 30, 2016USD ($)ft²	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)ft²	Sep. 30, 2015USD ($)
Properties Sold [Abstract]
Approximate Square Feet (sqft/acres) | ft²							32,918,879		32,918,879
Gain on Sale							$ 0	$ 0	$ 0	$ 12,983
Employee compensation award									1,100
Investments in unconsolidated joint ventures						$ 1,203,858	1,860,912		1,860,912
Revenues
Rental revenue										236
Escalation and reimbursement revenues										(127)
Total revenues										109
Operating expenses										(631)
Real estate taxes										250
Transaction related costs										(49)
Depreciable real estate reserves										109
Interest expense, net of interest income										3
Total expenses										(318)
Net income from discontinued operations							0	$ 0	0	$ 427
248-252 Bedford Avenue
Properties Sold [Abstract]
Approximate Square Feet (sqft/acres) | ft²					66,611
Sales Price					$ 55,000
Gain on Sale					15,300
Employee compensation award					$ 1,300
885 Third Avenue
Properties Sold [Abstract]
Approximate Square Feet (sqft/acres) | ft²					607,000
Sales Price					$ 453,000
Gain on Sale					$ 0	$ (6,600)
7 International Drive
Properties Sold [Abstract]
Approximate Square Feet (sqft/acres) | a				31
Sales Price				$ 20,000
Gain on Sale				$ (6,900)
388 Greenwich
Properties Sold [Abstract]
Approximate Square Feet (sqft/acres) | ft²			2,635,000
Sales Price			$ 2,002,300
Gain on Sale			206,500
Employee compensation award			$ 1,600
500 West Putnam Avenue
Properties Sold [Abstract]
Approximate Square Feet (sqft/acres) | ft²		121,500
Sales Price		$ 41,000
Gain on Sale		$ (10,400)
11 Madison Avenue
Properties Sold [Abstract]
Approximate Square Feet (sqft/acres) | ft²	2,314,000
Sales Price	$ 2,600,000
Gain on Sale	$ 0
Revenues
Ownership percentage in disposed asset	40.00%
885 Third Avenue
Properties Sold [Abstract]
Investments in unconsolidated joint ventures							$ 135,000		$ 135,000
Investment in unconsolidated joint venture, interest percentage							5.75%		5.75%

Debt and Preferred Equity Inv62

Debt and Preferred Equity Investments (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Apr. 30, 2016	Dec. 31, 2015	Sep. 30, 2014	Jul. 31, 2014
Debt investment
Increase in debt and preferred equity investments (net of discounts), including investments classified as held-for-sale	$ 590,400	$ 464,900
Decrease in debt and preferred equity investments (net of discounts), including investments classified as held-for-sale	$ 807,200	$ 372,100
Aggregate weighted average current yield (as a percent)	9.29%
Debt Investments Held [Abstract]
Carrying Value, Net of Discounts and Deferred Origination Fees	$ 1,453,234			$ 1,670,020
Debt investment
Debt Investments Held [Abstract]
Future Funding Obligations	216,097
Senior Financing	4,340,809
Carrying Value, Net of Discounts and Deferred Origination Fees	1,405,389			1,627,844
Mezzanine Loan, June 2017
Debt Investments Held [Abstract]
Amount participated out	41,300
Mezzanine Loan, November 2023
Debt Investments Held [Abstract]
Amount participated out	5,000
Mezzanine Loan, June 2024
Debt Investments Held [Abstract]
Amount participated out	12,000
Mezzanine Loan Repaid in April 2016
Debt Investments Held [Abstract]
Carrying Value, Net of Discounts and Deferred Origination Fees						$ 50,000
Purchase option, percentage of underlying asset			20.00%
Mortgage/Mezzanine Loan, January 2017
Debt Investments Held [Abstract]
Amount participated out	36,300
Mezzanine Loan, June 2017
Debt Investments Held [Abstract]
Amount participated out	14,500
Mezzanine Loan, December 2017
Debt Investments Held [Abstract]
Amount participated out	14,600
Mezzanine Loan, December 2017
Debt Investments Held [Abstract]
Amount participated out	14,100
Mortgage/Mezzanine Loan, December 2017
Debt Investments Held [Abstract]
Amount participated out	5,100
Total fixed rate
Debt Investments Held [Abstract]
Future Funding Obligations	5,000
Senior Financing	1,925,044
Carrying Value, Net of Discounts and Deferred Origination Fees	336,134			511,389
Total fixed rate | Junior Mortgage Participation/Mezzanine Loan, March 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	1,109,000
Carrying Value, Net of Discounts and Deferred Origination Fees	189,250			104,661
Total fixed rate | Mezzanine Loan, June 2017
Debt Investments Held [Abstract]
Future Funding Obligations	5,000
Senior Financing	502,100
Carrying Value, Net of Discounts and Deferred Origination Fees	61,059			41,115
Total fixed rate | Mortgage Loan, February 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	26,297			26,262
Loan acquired					$ 26,400
Discount amount					200
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	414			513
Total fixed rate | Mezzanine Loan, September 2021
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	15,000
Carrying Value, Net of Discounts and Deferred Origination Fees	3,500			3,500
Total fixed rate | Mezzanine Loan, November 2023
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	88,944
Carrying Value, Net of Discounts and Deferred Origination Fees	12,691			19,936
Total fixed rate | Mezzanine Loan, June 2024
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	115,000
Carrying Value, Net of Discounts and Deferred Origination Fees	12,923			24,916
Total fixed rate | Mezzanine Loan, January 2025
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	95,000
Carrying Value, Net of Discounts and Deferred Origination Fees	30,000			30,000
Total fixed rate | Mezzanine Loan Repaid in July 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	0			72,102
Total fixed rate | Mezzanine Loan Repaid in April 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	0			49,691
Total fixed rate | Junior Mortgage Participation Loan Repaid in March 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	0			49,000
Total fixed rate | Loan Collateralized by Defeasance Securities Repaid in March 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	0			23,510
Total fixed rate | Loan Collateralized by Defeasance Securities Repaid in March 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	0			66,183
Total fixed rate | Junior Mortgage Participation, Related To Mortgage Loan, February 2019
Debt Investments Held [Abstract]
Loan acquired					5,700
Discount amount					$ 5,700
Total floating rate
Debt Investments Held [Abstract]
Future Funding Obligations	211,097
Senior Financing	2,415,765
Carrying Value, Net of Discounts and Deferred Origination Fees	1,069,255			1,116,455
Total floating rate | Mezzanine Loan, November 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	360,000
Carrying Value, Net of Discounts and Deferred Origination Fees	99,945			99,530
Total floating rate | Mezzanine Loan, December 2016
Debt Investments Held [Abstract]
Future Funding Obligations	7,939
Senior Financing	144,008
Carrying Value, Net of Discounts and Deferred Origination Fees	53,405			49,751
Total floating rate | Mezzanine Loan, December 2016
Debt Investments Held [Abstract]
Future Funding Obligations	281
Senior Financing	39,201
Carrying Value, Net of Discounts and Deferred Origination Fees	11,024			13,731
Total floating rate | Mortgage/Mezzanine Loan, January 2017
Debt Investments Held [Abstract]
Future Funding Obligations	40,086
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	140,920			134,264
Total floating rate | Mezzanine Loan, January 2017
Debt Investments Held [Abstract]
Future Funding Obligations	1,127
Senior Financing	118,949
Carrying Value, Net of Discounts and Deferred Origination Fees	28,834			28,551
Total floating rate | Mezzanine Loan, June 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	40,000
Carrying Value, Net of Discounts and Deferred Origination Fees	15,290			68,977
Total floating rate | Mortgage/Mezzanine Loan, June 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	32,763			0
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	22,939			22,877
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	16,946			16,901
Total floating rate | Mortgage/Mezzanine Loan, October 2017
Debt Investments Held [Abstract]
Future Funding Obligations	4,038
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	19,834			19,282
Total floating rate | Mezzanine Loan, November 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	60,000
Carrying Value, Net of Discounts and Deferred Origination Fees	14,944			14,904
Total floating rate | Mezzanine Loan, December 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	85,000
Carrying Value, Net of Discounts and Deferred Origination Fees	15,075			29,505
Total floating rate | Mezzanine Loan, December 2017
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	65,000
Carrying Value, Net of Discounts and Deferred Origination Fees	14,598			28,563
Total floating rate | Mortgage/Mezzanine Loan, December 2017
Debt Investments Held [Abstract]
Future Funding Obligations	795
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	15,024			14,942
Total floating rate | Junior Participation Loan, April 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	40,000
Carrying Value, Net of Discounts and Deferred Origination Fees	19,896			19,846
Total floating rate | Mezzanine Loan, April 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	175,000
Carrying Value, Net of Discounts and Deferred Origination Fees	34,814			34,725
Total floating rate | Mortgage/Mezzanine Loan, August 2018
Debt Investments Held [Abstract]
Future Funding Obligations	523
Senior Financing	24,818
Carrying Value, Net of Discounts and Deferred Origination Fees	10,846			31,210
Total floating rate | Mortgage Loan, August 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	19,815			0
Total floating rate | Mezzanine Loan, August 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	65,000
Carrying Value, Net of Discounts and Deferred Origination Fees	14,862			0
Total floating rate | Mezzanine Loan, September 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	14,599			0
Total floating rate | Mezzanine Loan, October 2018
Debt Investments Held [Abstract]
Future Funding Obligations	2,325
Senior Financing	45,025
Carrying Value, Net of Discounts and Deferred Origination Fees	34,411			0
Total floating rate | Mezzanine Loan, December 2018
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	33,000
Carrying Value, Net of Discounts and Deferred Origination Fees	26,831			26,777
Total floating rate | Mezzanine Loan, December 2018
Debt Investments Held [Abstract]
Future Funding Obligations	4,097
Senior Financing	156,383
Carrying Value, Net of Discounts and Deferred Origination Fees	55,264			52,774
Total floating rate | Mezzanine Loan, December 2018
Debt Investments Held [Abstract]
Future Funding Obligations	18,883
Senior Financing	246,758
Carrying Value, Net of Discounts and Deferred Origination Fees	59,917			49,625
Total floating rate | Mezzanine Loan, January 2019
Debt Investments Held [Abstract]
Future Funding Obligations	6,383
Senior Financing	16,383
Carrying Value, Net of Discounts and Deferred Origination Fees	5,387			0
Total floating rate | Mezzanine Loan, March 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	38,000
Carrying Value, Net of Discounts and Deferred Origination Fees	21,880			21,845
Total floating rate | Mezzanine Loan, April 2019
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	265,000
Carrying Value, Net of Discounts and Deferred Origination Fees	24,677			0
Total floating rate | Mortgage/Jr Mortgage Participate Loan, August 2019
Debt Investments Held [Abstract]
Future Funding Obligations	34,500
Senior Financing	180,740
Carrying Value, Net of Discounts and Deferred Origination Fees	64,549			0
Total floating rate | Mezzanine Loan, September 2019
Debt Investments Held [Abstract]
Future Funding Obligations	2,500
Senior Financing	187,500
Carrying Value, Net of Discounts and Deferred Origination Fees	37,307			0
Total floating rate | Mortgage/Mezzanine Loan, September 2019
Debt Investments Held [Abstract]
Future Funding Obligations	87,620
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	107,060			0
Total floating rate | Jr Mortgage Participation/Mezzanine Loan, July 2021
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	30,000
Carrying Value, Net of Discounts and Deferred Origination Fees	15,599			0
Total floating rate | Mortgage/Mezzanine Loan Repaid in September 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	0			94,901
Total floating rate | Jr Mortgage Participation/Mezzanine Loan Repaid in July 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	0			20,510
Total floating rate | Mezzanine Loan Repaid in June 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	0			22,625
Total floating rate | Mezzanine Loan Repaid in May 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	0			74,700
Total floating rate | Mezzanine Loan Contributed for a Joint Venture Interest
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	0			66,398
Total floating rate | Jr Mortgage Participation/Mezzanine Loan Repaid in March 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	0			18,395
Total floating rate | Mezzanine Loan Repaid in February 2016
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value, Net of Discounts and Deferred Origination Fees	$ 0			$ 40,346

Debt and Preferred Equity Inv63

Debt and Preferred Equity Investments (Preferred Equity Investments)(Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Preferred equity investment
Aggregate weighted average current yield (as a percent)	9.29%
Carrying Value, Net of Discounts and Deferred Origination Fees	$ 1,453,234	$ 1,670,020
Preferred Equity, March 2018
Preferred equity investment
Future Funding Obligations	0
Senior Financing	71,486
Carrying Value, Net of Discounts and Deferred Origination Fees	9,978	9,967
Preferred Equity, November 2018
Preferred equity investment
Future Funding Obligations	0
Senior Financing	59,034
Carrying Value, Net of Discounts and Deferred Origination Fees	$ 37,867	32,209
Preferred equity investments
Preferred equity investment
Aggregate weighted average current yield (as a percent)	7.32%
Future Funding Obligations	$ 0
Senior Financing	130,520
Carrying Value, Net of Discounts and Deferred Origination Fees	$ 47,845	$ 42,176

Debt and Preferred Equity Inv64

Debt and Preferred Equity Investments (Narrative)(Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2016USD ($)segment	Dec. 31, 2015USD ($)segment
Preferred equity investment
Carrying Value, Net of Discounts and Deferred Origination Fees	$ 1,453,234,000	$ 1,670,020,000
Number of portfolio segments of financial receivables (segment) | segment	1	1
Additional amount of financing receivables included in other assets	$ 101,400,000	$ 121,500,000
Junior Mortgage Participation Acquired in September 2014
Preferred equity investment
Carrying Value, Net of Discounts and Deferred Origination Fees	$ 0	$ 0

Investments in Unconsolidated65

Investments in Unconsolidated Joint Ventures (Details) $ in Thousands	1 Months Ended	3 Months Ended	9 Months Ended
	Aug. 31, 2016ft²	Sep. 30, 2016USD ($)ft²unit	Sep. 30, 2016USD ($)ft²unitnote	Apr. 30, 2016	Dec. 31, 2015USD ($)	Jul. 31, 2014USD ($)
General information on each joint venture
Net equity investment in VIEs in which the entity is not primary beneficiary		$ 220,700	$ 220,700		$ 39,700
Approximate Square Feet (sqft) | ft²		32,918,879	32,918,879
Joint venture
General information on each joint venture
Equity method investment, assets		$ 10,478,811	$ 10,478,811		$ 6,984,186
Mezzanine Loan Repaid in April 2016
General information on each joint venture
Ownership Interest (as a percent)				20.00%
Mezzanine loan						$ 50,000
100 Park Avenue
General information on each joint venture
Ownership Interest (as a percent)		49.90%	49.90%
Economic Interest (as a percent)		49.90%	49.90%
Approximate Square Feet (sqft) | ft²		834,000	834,000
Acquisition Price		$ 95,800	$ 95,800
717 Fifth Avenue
General information on each joint venture
Ownership Interest (as a percent)		10.92%	10.92%
Economic Interest (as a percent)		10.92%	10.92%
Approximate Square Feet (sqft) | ft²		119,500	119,500
Acquisition Price		$ 251,900	$ 251,900
800 Third Avenue
General information on each joint venture
Ownership Interest (as a percent)		60.52%	60.52%
Economic Interest (as a percent)		60.52%	60.52%
Approximate Square Feet (sqft) | ft²		526,000	526,000
Acquisition Price		$ 285,000	$ 285,000
1745 Broadway
General information on each joint venture
Ownership Interest (as a percent)		56.88%	56.88%
Economic Interest (as a percent)		56.88%	56.88%
Approximate Square Feet (sqft) | ft²		674,000	674,000
Acquisition Price		$ 520,000	$ 520,000
Jericho Plaza
General information on each joint venture
Ownership Interest (as a percent)		11.67%	11.67%		77.78%
Economic Interest (as a percent)		11.67%	11.67%
Approximate Square Feet (sqft) | ft²		640,000	640,000
Acquisition Price		$ 210,000	$ 210,000
11 West 34th Street
General information on each joint venture
Ownership Interest (as a percent)		30.00%	30.00%
Economic Interest (as a percent)		30.00%	30.00%
Approximate Square Feet (sqft) | ft²		17,150	17,150
Acquisition Price		$ 10,800	$ 10,800
3 Columbus Circle
General information on each joint venture
Ownership Interest (as a percent)		48.90%	48.90%
Economic Interest (as a percent)		48.90%	48.90%
Approximate Square Feet (sqft) | ft²		741,500	741,500
Acquisition Price		$ 500,000	$ 500,000
280 Park Avenue
General information on each joint venture
Ownership Interest (as a percent)		50.00%	50.00%
Economic Interest (as a percent)		50.00%	50.00%
Approximate Square Feet (sqft) | ft²		1,219,158	1,219,158
Acquisition Price		$ 400,000	$ 400,000
1552-1560 Broadway
General information on each joint venture
Ownership Interest (as a percent)		50.00%	50.00%
Economic Interest (as a percent)		50.00%	50.00%
Approximate Square Feet (sqft) | ft²		35,897	35,897
Acquisition Price		$ 136,550	$ 136,550
724 Fifth Avenue
General information on each joint venture
Ownership Interest (as a percent)		50.00%	50.00%
Economic Interest (as a percent)		50.00%	50.00%
Approximate Square Feet (sqft) | ft²		65,040	65,040
Acquisition Price		$ 223,000	$ 223,000
10 East 53rd Street
General information on each joint venture
Ownership Interest (as a percent)		55.00%	55.00%
Economic Interest (as a percent)		55.00%	55.00%
Approximate Square Feet (sqft) | ft²		354,300	354,300
Acquisition Price		$ 252,500	$ 252,500
521 Fifth Avenue
General information on each joint venture
Ownership Interest (as a percent)		50.50%	50.50%
Economic Interest (as a percent)		50.50%	50.50%
Approximate Square Feet (sqft) | ft²		460,000	460,000
Acquisition Price		$ 315,000	$ 315,000
21 East 66th Street
General information on each joint venture
Ownership Interest (as a percent)		32.28%	32.28%
Economic Interest (as a percent)		32.28%	32.28%
Approximate Square Feet (sqft) | ft²		16,736	16,736
Acquisition Price		$ 75,000	$ 75,000
21 East 66th Street | Three Retail and Two Residential Units
General information on each joint venture
Ownership Interest (as a percent)		32.28%	32.28%
Number of Stores | unit		3	3
Number Of Residential Units | unit		2	2
21 East 66th Street | Three Residential Units
General information on each joint venture
Ownership Interest (as a percent)		16.14%	16.14%
Number Of Residential Units | unit		3	3
650 Fifth Avenue
General information on each joint venture
Ownership Interest (as a percent)		50.00%	50.00%
Economic Interest (as a percent)		50.00%	50.00%
Approximate Square Feet (sqft) | ft²		32,324	32,324
121 Greene Street
General information on each joint venture
Ownership Interest (as a percent)		50.00%	50.00%
Economic Interest (as a percent)		50.00%	50.00%
Approximate Square Feet (sqft) | ft²		7,131	7,131
Acquisition Price		$ 27,400	$ 27,400
175-225 Third Street Brooklyn, New York
General information on each joint venture
Ownership Interest (as a percent)		95.00%	95.00%
Economic Interest (as a percent)		95.00%	95.00%
Approximate Square Feet (sqft) | ft²		0	0
Acquisition Price		$ 74,600	$ 74,600
55 West 46th Street
General information on each joint venture
Ownership Interest (as a percent)		25.00%	25.00%
Economic Interest (as a percent)		25.00%	25.00%
Approximate Square Feet (sqft) | ft²		347,000	347,000
Acquisition Price		$ 295,000	$ 295,000
Stonehenge Portfolio
General information on each joint venture
Approximate Square Feet (sqft) | ft²		2,046,733	2,046,733
Acquisition Price		$ 36,668	$ 36,668
131-137 Spring Street
General information on each joint venture
Ownership Interest (as a percent)		20.00%	20.00%
Economic Interest (as a percent)		20.00%	20.00%
Approximate Square Feet (sqft) | ft²		68,342	68,342
Acquisition Price		$ 277,750	$ 277,750
76 11th Avenue
General information on each joint venture
Ownership Interest (as a percent)		33.33%	33.33%
Economic Interest (as a percent)		36.58%	36.58%
Approximate Square Feet (sqft) | ft²		764,000	764,000
Acquisition Price		$ 138,240	$ 138,240
Number of mezzanine notes secured by interests in the entity which owns 76 11th avenue | note			2
Exit fee, percentage owned			50.00%
605 West 42nd Street
General information on each joint venture
Ownership Interest (as a percent)		20.00%	20.00%
Economic Interest (as a percent)		20.00%	20.00%
Approximate Square Feet (sqft) | ft²		927,358	927,358
Acquisition Price		$ 759,000	$ 759,000
1552 Broadway
General information on each joint venture
Approximate Square Feet (sqft) | ft²		13,045	13,045
11 Madison Avenue
General information on each joint venture
Ownership Interest (as a percent)		60.00%	60.00%
Economic Interest (as a percent)		60.00%	60.00%
Approximate Square Feet (sqft) | ft²		2,314,000	2,314,000
Acquisition Price		$ 2,605,000	$ 2,605,000
Equity method investment, assets		2,700,000	2,700,000
Equity method investment, liabilities		1,500,000	1,500,000
Contingent consideration received at closing		$ 482,000	$ 482,000
333 East 22nd St
General information on each joint venture
Ownership Interest (as a percent)		33.33%	33.33%
Economic Interest (as a percent)		33.33%	33.33%
Approximate Square Feet (sqft) | ft²		26,926	26,926
Acquisition Price		$ 0	$ 0
Partners' Interest | 76 11th Avenue | Joint venture
General information on each joint venture
Exit fee, percentage owned			25.00%
Partners' Interest | 11 Madison Avenue | Joint venture
General information on each joint venture
Equity method investments, depreciation		$ 4,700	$ 4,700
11 Madison Avenue
General information on each joint venture
Approximate Square Feet (sqft) | ft²	2,314,000
Ownership percentage in disposed asset	40.00%

Investments in Unconsolidated66

Investments in Unconsolidated Joint Ventures (Acquisition, Development and Construction Arrangements/Sale of Joint Venture Interest or Property)(Details) - USD ($) $ in Thousands	1 Months Ended				3 Months Ended		9 Months Ended
	Sep. 30, 2016	May 31, 2016	Mar. 31, 2016	Feb. 29, 2016	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Acquisition, development and construction arrangements, carrying value	$ 169,794				$ 169,794		$ 169,794		$ 145,878
Gain on Sale					$ 0	$ 0	0	$ 12,983
Employee compensation award							$ 1,100
1 Jericho Plaza
Schedule of Equity Method Investments [Line Items]
Ownership Percentage			11.67%	66.11%					77.78%
Gross Asset Valuation				$ 95,200
Gain on Sale				$ 3,300
7 Renaissance Square
Schedule of Equity Method Investments [Line Items]
Ownership Percentage			50.00%
Gross Asset Valuation			$ 20,700
Gain on Sale			$ 4,200
EOP Denver
Schedule of Equity Method Investments [Line Items]
Ownership Percentage			4.79%
Gross Asset Valuation			$ 180,700
Gain on Sale			$ 2,800
33 Beekman
Schedule of Equity Method Investments [Line Items]
Ownership Percentage		45.90%
Gross Asset Valuation		$ 196,000
Gain on Sale		33,000
Promote recognized		$ 10,800
EOP Denver
Schedule of Equity Method Investments [Line Items]
Ownership Percentage	0.48%				0.48%		0.48%
Gross Asset Valuation	$ 180,700				$ 180,700		$ 180,700
Gain on Sale	300
Mezzanine loan and preferred equity due March 2017
Schedule of Equity Method Investments [Line Items]
Acquisition, development and construction arrangements, carrying value	100,000				100,000		100,000		$ 99,936
Mezzanine loan due July 2036
Schedule of Equity Method Investments [Line Items]
Acquisition, development and construction arrangements, carrying value	24,119				24,119		24,119		0
Mezzanine loan due February 2022
Schedule of Equity Method Investments [Line Items]
Acquisition, development and construction arrangements, carrying value	$ 45,675				$ 45,675		$ 45,675		$ 45,942

Investments in Unconsolidated67

Investments in Unconsolidated Joint Ventures (Mortgages and Other Loans Payable)(Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Total fixed rate debt	$ 3,563,685	$ 5,816,010
Total floating rate debt	527,990	1,205,494
Total fixed rate and floating rate debt	4,091,675	7,021,504
Deferred financing costs, net	$ (101,500)	(130,300)
1745 Broadway
Debt Instrument [Line Items]
Ownership Percentage	56.88%
521 Fifth Avenue
Debt Instrument [Line Items]
Ownership Percentage	50.50%
717 Fifth Avenue
Debt Instrument [Line Items]
Ownership Percentage	10.92%
21 East 66th Street
Debt Instrument [Line Items]
Ownership Percentage	32.28%
3 Columbus Circle
Debt Instrument [Line Items]
Ownership Percentage	48.90%
11 Madison Avenue
Debt Instrument [Line Items]
Total fixed rate debt	$ 0	1,400,000
Ownership Percentage	60.00%
800 Third Avenue
Debt Instrument [Line Items]
Ownership Percentage	60.52%
280 Park Avenue
Debt Instrument [Line Items]
Ownership Percentage	50.00%
175-225 Third Street Brooklyn, New York
Debt Instrument [Line Items]
Ownership Percentage	95.00%
10 East 53rd Street
Debt Instrument [Line Items]
Ownership Percentage	55.00%
724 Fifth Avenue
Debt Instrument [Line Items]
Ownership Percentage	50.00%
55 West 46th Street
Debt Instrument [Line Items]
Ownership Percentage	25.00%
605 West 42nd Street
Debt Instrument [Line Items]
Ownership Percentage	20.00%
650 Fifth Avenue
Debt Instrument [Line Items]
Ownership Percentage	50.00%
121 Greene Street
Debt Instrument [Line Items]
Ownership Percentage	50.00%
131-137 Spring Street
Debt Instrument [Line Items]
Ownership Percentage	20.00%
11 West 34th Street
Debt Instrument [Line Items]
Ownership Percentage	30.00%
100 Park Avenue
Debt Instrument [Line Items]
Ownership Percentage	49.90%
Joint venture
Debt Instrument [Line Items]
Total fixed rate debt	$ 3,468,583	2,645,131
Total floating rate debt	2,964,349	1,663,982
Total fixed rate and floating rate debt	6,432,932	4,309,113
Deferred financing costs, net	(100,426)	(42,565)
Total joint venture mortgages and other loans payable, net	6,332,506	4,266,548
Joint venture | 1745 Broadway
Debt Instrument [Line Items]
Total fixed rate debt	340,000	340,000
Joint venture | 521 Fifth Avenue
Debt Instrument [Line Items]
Total fixed rate debt	170,000	170,000
Joint venture | 717 Fifth Avenue | Mortgage loan
Debt Instrument [Line Items]
Committed amount	300,000
Joint venture | 717 Fifth Avenue | Mezzanine loans
Debt Instrument [Line Items]
Committed amount	355,300
Joint venture | 717 Fifth Avenue | Initial Maturity July 2022
Debt Instrument [Line Items]
Total fixed rate debt	300,000	300,000
Joint venture | 717 Fifth Avenue | Initial Maturity July 2022, 2
Debt Instrument [Line Items]
Total fixed rate debt	355,328	325,704
Joint venture | 21 East 66th Street
Debt Instrument [Line Items]
Total fixed rate debt	12,000	12,000
Total floating rate debt	1,746	1,805
Joint venture | 3 Columbus Circle
Debt Instrument [Line Items]
Total fixed rate debt	350,000	350,000
Joint venture | 11 Madison Avenue
Debt Instrument [Line Items]
Total fixed rate debt	1,400,000	0
Joint venture | 800 Third Avenue
Debt Instrument [Line Items]
Total fixed rate debt	177,000	20,910
Joint venture | Stonehenge Portfolio
Debt Instrument [Line Items]
Total fixed rate debt	364,255	430,627
Total floating rate debt	65,664	10,500
Joint venture | Stonehenge Portfolio | Initial Maturity April 2017
Debt Instrument [Line Items]
Total fixed rate debt	13,200
Joint venture | Stonehenge Portfolio | Initial Maturity November 2017
Debt Instrument [Line Items]
Total fixed rate debt	34,600
Joint venture | Stonehenge Portfolio | Initial Maturity August 2019
Debt Instrument [Line Items]
Total fixed rate debt	140,300
Joint venture | Stonehenge Portfolio | Initial Maturity June 2024
Debt Instrument [Line Items]
Total fixed rate debt	176,100
Joint venture | Stonehenge Portfolio | Initial Maturity June 2017
Debt Instrument [Line Items]
Total floating rate debt	55,300
Joint venture | Stonehenge Portfolio | Initial Maturity December 2017
Debt Instrument [Line Items]
Total floating rate debt	10,300
Joint venture | 280 Park Avenue
Debt Instrument [Line Items]
Total fixed rate debt	0	692,963
Total floating rate debt	900,000	30,000
Joint venture | 7 Renaissance Square
Debt Instrument [Line Items]
Total fixed rate debt	0	2,927
Joint venture | 175-225 Third Street Brooklyn, New York
Debt Instrument [Line Items]
Total floating rate debt	40,000	40,000
Joint venture | 10 East 53rd Street
Debt Instrument [Line Items]
Total floating rate debt	125,000	125,000
Joint venture | 724 Fifth Avenue
Debt Instrument [Line Items]
Total floating rate debt	275,000	275,000
Joint venture | 1552 Broadway
Debt Instrument [Line Items]
Total floating rate debt	185,410	190,409
Joint venture | 1552 Broadway | Mortgage loan
Debt Instrument [Line Items]
Committed amount	145,000
Unfunded amount	600
Joint venture | 1552 Broadway | Mezzanine loans
Debt Instrument [Line Items]
Committed amount	41,500
Unfunded amount	500
Joint venture | 55 West 46th Street
Debt Instrument [Line Items]
Total floating rate debt	151,536	150,000
Joint venture | 55 West 46th Street | Mortgage loan
Debt Instrument [Line Items]
Committed amount	190,000
Unfunded amount	38,500
Joint venture | Jericho Plaza
Debt Instrument [Line Items]
Total floating rate debt	$ 76,993	163,750
Ownership Percentage	11.67%
Term (in Years)	2 years
Face amount of loan	$ 100,000
Joint venture | 605 West 42nd Street
Debt Instrument [Line Items]
Total floating rate debt	539,000	0
Joint venture | 650 Fifth Avenue
Debt Instrument [Line Items]
Total floating rate debt	65,000	65,000
Joint venture | 650 Fifth Avenue | Mortgage loan
Debt Instrument [Line Items]
Committed amount	97,000
Unfunded amount	32,000
Joint venture | 121 Greene Street
Debt Instrument [Line Items]
Total floating rate debt	15,000	15,000
Joint venture | 131-137 Spring Street
Debt Instrument [Line Items]
Total floating rate debt	141,000	141,000
Joint venture | 11 West 34th Street
Debt Instrument [Line Items]
Total floating rate debt	23,000	23,000
Joint venture | 100 Park Avenue
Debt Instrument [Line Items]
Total floating rate debt	360,000	360,000
Joint venture | 33 Beekman
Debt Instrument [Line Items]
Total floating rate debt	$ 0	$ 73,518
Weighted Average | Joint venture | 1745 Broadway
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	5.68%
Weighted Average | Joint venture | 521 Fifth Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.73%
Weighted Average | Joint venture | 717 Fifth Avenue | Initial Maturity July 2022
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	4.45%
Weighted Average | Joint venture | 717 Fifth Avenue | Initial Maturity July 2022, 2
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	5.50%
Weighted Average | Joint venture | 21 East 66th Street
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.60%
Interest rate, floating rate debt (as a percent)	3.00%
Weighted Average | Joint venture | 3 Columbus Circle
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.61%
Weighted Average | Joint venture | 11 Madison Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.84%
Weighted Average | Joint venture | 800 Third Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.37%
Weighted Average | Joint venture | Stonehenge Portfolio
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	4.19%
Interest rate, floating rate debt (as a percent)	5.81%
Weighted Average | Joint venture | 280 Park Avenue
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	2.49%
Weighted Average | Joint venture | 175-225 Third Street Brooklyn, New York
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	4.50%
Weighted Average | Joint venture | 10 East 53rd Street
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	2.99%
Weighted Average | Joint venture | 724 Fifth Avenue
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	2.91%
Weighted Average | Joint venture | 1552 Broadway
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	4.71%
Weighted Average | Joint venture | 55 West 46th Street
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	2.79%
Weighted Average | Joint venture | Jericho Plaza
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	4.64%
Weighted Average | Joint venture | 605 West 42nd Street
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	2.85%
Weighted Average | Joint venture | 650 Fifth Avenue
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	4.17%
Weighted Average | Joint venture | 121 Greene Street
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	1.99%
Weighted Average | Joint venture | 131-137 Spring Street
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	2.04%
Weighted Average | Joint venture | 11 West 34th Street
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	1.94%
Weighted Average | Joint venture | 100 Park Avenue
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	2.24%

Investments in Unconsolidated68

Investments in Unconsolidated Joint Ventures (Schedules of Combined Financial Statements for the Unconsolidated Joint Ventures)(Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014
Assets
Commercial real estate property, net	$ 10,418,719		$ 10,418,719		$ 14,620,896
Cash and cash equivalents	405,896	$ 244,360	405,896	$ 244,360	255,399	$ 281,409
Tenant and other receivables, related party receivables, and deferred rents receivable, net of allowance	55,976		55,976		63,491
Other assets	620,838		620,838		850,939
Liabilities and members' equity
Mortgages and other loans payable, net	3,954,155		3,954,155		6,881,920
Deferred revenue/gain	237,548		237,548		399,102
Other liabilities	211,513		211,513		168,477
Company's investments in unconsolidated joint ventures	1,860,912		1,860,912		1,203,858
Combined statements of income for the unconsolidated joint ventures
Operating expenses	79,425	78,648	234,269	225,539
Ground rent	8,338	8,252	24,953	24,526
Real estate taxes	64,133	61,009	187,931	173,018
Interest expense, net of interest income	72,565	84,141	256,326	235,694
Amortization of deferred financing costs	4,815	7,160	20,180	19,727
Transaction related costs	2,593	5,829	5,987	10,039
Depreciation and amortization	112,665	146,185	717,015	454,087
Total expenses	369,992	414,699	1,520,635	1,214,769
Company's equity in net (loss) income from unconsolidated joint ventures	(3,968)	3,627	11,969	10,651
Joint venture
Investment in Unconsolidated Joint Ventures
Management fees, base revenue	2,000	1,900	4,500	6,800
Assets
Commercial real estate property, net	8,927,385		8,927,385		6,122,468
Cash and cash equivalents	320,318		320,318		258,564
Tenant and other receivables, related party receivables, and deferred rents receivable, net of allowance	227,937		227,937		208,802
Debt and preferred equity investments, net	332,506		332,506		145,878
Other assets	670,665		670,665		248,474
Total assets	10,478,811		10,478,811		6,984,186
Liabilities and members' equity
Mortgages and other loans payable, net	6,332,506		6,332,506		4,266,548
Deferred revenue/gain	367,873		367,873		209,095
Other liabilities	374,198		374,198		314,065
Members' equity	3,404,234		3,404,234		2,194,478
Total liabilities and members' equity	10,478,811		10,478,811		$ 6,984,186
Combined statements of income for the unconsolidated joint ventures
Total revenues	184,221	150,638	498,308	423,089
Operating expenses	34,727	27,647	89,147	79,478
Ground rent	3,744	4,677	10,670	9,841
Real estate taxes	30,814	23,494	79,356	65,205
Interest expense, net of interest income	51,789	51,430	147,876	147,152
Amortization of deferred financing costs	7,155	3,473	17,667	9,628
Transaction related costs	5,359	604	5,359	615
Depreciation and amortization	56,890	38,144	132,035	109,022
Total expenses	190,478	149,469	482,110	420,941
Loss on early extinguishment of debt	0	(248)	(1,606)	(1,081)
Net (loss) income before gain on sale	(6,257)	921	14,592	1,067
Company's equity in net (loss) income from unconsolidated joint ventures	$ (3,968)	$ 3,627	$ 11,969	$ 10,651

Deferred Costs (Details)

Deferred Costs (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred leasing	$ 450,192	$ 415,406
Less: accumulated amortization	(198,013)	(175,486)
Deferred costs, net	$ 252,179	$ 239,920

Mortgages and Other Loans Pay70

Mortgages and Other Loans Payable (Details)	Dec. 06, 2015USD ($)	Sep. 30, 2016USD ($)extenstion_option$ / shares	Aug. 31, 2016	Sep. 30, 2016USD ($)$ / shares	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Debt Instrument [Line Items]
Total fixed rate debt		$ 3,563,685,000		$ 3,563,685,000		$ 5,816,010,000
Total floating rate debt		527,990,000		527,990,000		1,205,494,000
Total fixed rate and floating rate debt		4,091,675,000		4,091,675,000		7,021,504,000
Mortgages reclassed to liabilities related to assets held for sale		(66,779,000)		(66,779,000)		(29,000,000)
Total mortgages and other loans payable		4,024,896,000		4,024,896,000		6,992,504,000
Deferred financing costs, net of amortization		(70,741,000)		(70,741,000)		(110,584,000)
Total mortgages and other loans payable, net		3,954,155,000		3,954,155,000		6,881,920,000
Deferred financing costs, net of amortization		101,500,000		101,500,000		130,300,000
Federal Home Loan Bank Advances outstanding		$ 229,000,000		$ 229,000,000
Federal Home Loan Bank, advances, weighted-average borrowing rate (as a percent)		0.90%		0.90%
Book value of collateral		$ 6,400,000,000		$ 6,400,000,000		10,800,000,000
Series J Preferred Units
Debt Instrument [Line Items]
Total fixed rate debt		4,000,000		4,000,000		4,000,000
Limited partnership interest		$ 4,000,000		$ 4,000,000
Preferred Units (as a percent)				3.75%
Preferred Units, liquidation preference (in dollars per unit) | $ / shares		$ 1,000		$ 1,000
Series J Preferred Units | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		3.75%		3.75%
FHLB Advance Maturing in January 2017
Debt Instrument [Line Items]
Total fixed rate debt		$ 105,000,000		$ 105,000,000		0
FHLB Advance Maturing in January 2017 | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		1.03%		1.03%
FHLB Advance Maturing in January 2017, 2
Debt Instrument [Line Items]
Total fixed rate debt		$ 100,000,000		$ 100,000,000		0
FHLB Advance Maturing in January 2017, 2 | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		0.80%		0.80%
Unsecured Loan
Debt Instrument [Line Items]
Total fixed rate debt		$ 16,000,000		$ 16,000,000		16,000,000
Unsecured Loan | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		4.81%		4.81%
FHLB Advance Maturing in December 2016
Debt Instrument [Line Items]
Total floating rate debt		$ 24,000,000		$ 24,000,000		45,750,000
FHLB Advance Maturing in December 2016 | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		0.77%		0.77%
Master Repurchase Agreement
Debt Instrument [Line Items]
Total floating rate debt		$ 134,642,000		$ 134,642,000		253,424,000
Maximum facility capacity		$ 300,000,000		$ 300,000,000
Basis Point Fee (as a percent)	0.25%
Threshold amount for basis point fee to be applicable (less than)	$ 150,000,000
Master Repurchase Agreement | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		3.01%		3.01%
Master Repurchase Agreement | Minimum | LIBOR
Debt Instrument [Line Items]
Credit facility, interest rate (as a percent)				2.25%
Master Repurchase Agreement | Maximum | LIBOR
Debt Instrument [Line Items]
Credit facility, interest rate (as a percent)				4.00%
Landmark Square
Debt Instrument [Line Items]
Total fixed rate debt		$ 78,236,000		$ 78,236,000		79,562,000
Landmark Square | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		4.00%		4.00%
485 Lexington Avenue
Debt Instrument [Line Items]
Total fixed rate debt		$ 450,000,000		$ 450,000,000		450,000,000
485 Lexington Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		5.61%		5.61%
762 Madison Avenue
Debt Instrument [Line Items]
Total fixed rate debt		$ 7,739,000		$ 7,739,000		7,872,000
762 Madison Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		3.86%		3.86%
One Madison Avenue
Debt Instrument [Line Items]
Total fixed rate debt		$ 524,814,000		$ 524,814,000		542,817,000
One Madison Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		5.91%		5.91%
100 Church Street
Debt Instrument [Line Items]
Total fixed rate debt		$ 222,390,000		$ 222,390,000		225,099,000
100 Church Street | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		4.68%		4.68%
919 Third Avenue
Debt Instrument [Line Items]
Total fixed rate debt		$ 500,000,000		$ 500,000,000		500,000,000
Interest in property (as a percent)		51.00%		51.00%
919 Third Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		5.12%		5.12%
400 East 57th Street
Debt Instrument [Line Items]
Total fixed rate debt		$ 66,779,000		$ 66,779,000		67,644,000
Deferred financing costs, net of amortization		$ 2,100,000		$ 2,100,000
400 East 57th Street | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		4.13%		4.13%
400 East 58th Street
Debt Instrument [Line Items]
Total fixed rate debt		$ 28,620,000		$ 28,620,000		28,990,000
400 East 58th Street | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		4.13%		4.13%
420 Lexington Avenue
Debt Instrument [Line Items]
Total fixed rate debt		$ 300,000,000		$ 300,000,000		300,000,000
420 Lexington Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		3.99%		3.99%
1515 Broadway
Debt Instrument [Line Items]
Total fixed rate debt		$ 892,457,000		$ 892,457,000		900,000,000
1515 Broadway | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		3.93%		3.93%
885 Third Avenue
Debt Instrument [Line Items]
Total fixed rate debt		$ 267,650,000		$ 267,650,000		267,650,000
885 Third Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		6.26%		6.26%
11 Madison Avenue
Debt Instrument [Line Items]
Total fixed rate debt		$ 0		$ 0		1,400,000,000
388-390 Greenwich Street
Debt Instrument [Line Items]
Total fixed rate debt		0		0		1,004,000,000
Total floating rate debt		0		0		446,000,000
Deferred financing costs, net of amortization					$ 24,500,000
500 West Putnam Avenue
Debt Instrument [Line Items]
Total fixed rate debt		0		0		22,376,000
719 Seventh Avenue
Debt Instrument [Line Items]
Total floating rate debt		$ 32,823,000		$ 32,823,000		0
719 Seventh Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		3.54%		3.54%
183, 187 Broadway & 5-7 Dey Street
Debt Instrument [Line Items]
Total floating rate debt		$ 58,000,000		$ 58,000,000		40,000,000
183, 187 Broadway & 5-7 Dey Street | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		3.19%		3.19%
1080 Amsterdam
Debt Instrument [Line Items]
Total floating rate debt		$ 3,525,000		$ 3,525,000		3,525,000
1080 Amsterdam | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		4.24%		4.24%
220 East 42nd Street
Debt Instrument [Line Items]
Total floating rate debt		$ 275,000,000		$ 275,000,000		275,000,000
220 East 42nd Street | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		2.09%		2.09%
One Vanderbilt
Debt Instrument [Line Items]
Total floating rate debt		$ 0		$ 0		0
One Vanderbilt | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		4.03%		4.03%
One Vanderbilt | Construction Loans
Debt Instrument [Line Items]
Term (in Years)		5 years
Number of extension options | extenstion_option		2
Period of extension options		1 year
Maximum facility capacity		$ 1,500,000,000		$ 1,500,000,000
One Vanderbilt | Construction Loans | LIBOR
Debt Instrument [Line Items]
Credit facility, interest rate (as a percent)		3.50%
600 Lexington Avenue
Debt Instrument [Line Items]
Total floating rate debt		$ 0		0		112,795,000
248-252 Bedford Avenue
Debt Instrument [Line Items]
Total floating rate debt		$ 0		$ 0		29,000,000
Deferred financing costs, net of amortization						$ 900,000
11 Madison Avenue
Debt Instrument [Line Items]
Ownership percentage in disposed asset			40.00%

Corporate Indebtedness (Details

Corporate Indebtedness (Details) - USD ($)	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Corporate Indebtedness
Outstanding under line of credit facility	$ 0	$ 985,055,000
Long-term debt, carrying value	6,519,675,000
Revolving credit facility
Corporate Indebtedness
Credit facility, maximum borrowing capacity	1,600,000,000
Maximum borrowing capacity, optional expansion	$ 3,000,000,000
Effective rate (as a percent)	1.73%
Facility fee (as a percent)	0.25%
Outstanding under line of credit facility	$ 0
Revolving credit facility | Minimum
Corporate Indebtedness
Facility fee (as a percent)	12.50%
Revolving credit facility | Maximum
Corporate Indebtedness
Facility fee (as a percent)	30.00%
Revolving credit facility | LIBOR
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.25%
Revolving credit facility | LIBOR | Minimum
Corporate Indebtedness
Interest rate added to base rate (as a percent)	0.875%
Revolving credit facility | LIBOR | Maximum
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.55%
Term loan
Corporate Indebtedness
Credit facility, maximum borrowing capacity	$ 1,183,000,000
Effective rate (as a percent)	2.25%
Long-term debt, carrying value	$ 1,183,000,000
Term loan | Line of Credit
Corporate Indebtedness
Long-term debt, carrying value	$ 1,200,000,000	929,500,000
Term loan | LIBOR
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.40%
Term loan | LIBOR | Minimum
Corporate Indebtedness
Interest rate added to base rate (as a percent)	0.95%
Term loan | LIBOR | Maximum
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.90%
2012 Credit Facility
Corporate Indebtedness
Letters of credit	$ 56,500,000
Ability to borrow under line of credit facility	1,500,000,000
Long-term debt, carrying value	0
2012 Credit Facility | Line of Credit
Corporate Indebtedness
Long-term debt, carrying value	$ (6,900,000)	$ 985,100,000

Corporate Indebtedness (Senior

Corporate Indebtedness (Senior Unsecured Notes)(Details)	9 Months Ended
	Sep. 30, 2016USD ($)	Dec. 31, 2015USD ($)	Oct. 06, 2010USD ($)$ / shares
Debt disclosures by scheduled maturity date
Accreted Balance	$ 2,303,657,000	$ 2,308,478,000
Deferred financing costs, net	(101,500,000)	(130,300,000)
Senior unsecured notes
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	1,145,000,000
Accreted Balance	1,130,616,000	1,386,244,000
Deferred financing costs, net	(6,163,000)	(7,280,000)
Accreted Balance, Net of Deferred Financing Costs	1,124,453,000	1,378,964,000
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
Accreted Balance	$ 330,754,000	321,130,000
Coupon Rate (as a percent)	3.00%
Effective rate (as a percent)	3.00%
Term (in Years)	7 years
Premium on sale price to calculate exchange price of notes (as a percent)			30.00%
Exchange price (in dollars per share) | $ / shares			$ 85.81
Adjusted exchange rate for the debentures (in shares)	12.5697
Principal amount of debentures, basis for conversion	$ 1,000
Amount of convertible debt recorded in equity			$ 78,300,000
Debt Instrument, Unamortized Discount	14,200,000
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
Accreted Balance	$ 249,862,000	249,810,000
Coupon Rate (as a percent)	5.00%
Effective rate (as a percent)	5.00%
Term (in Years)	7 years
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
Accreted Balance	$ 250,000,000	250,000,000
Coupon Rate (as a percent)	7.75%
Effective rate (as a percent)	7.75%
Term (in Years)	10 years
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
Accreted Balance	$ 200,000,000	200,000,000
Coupon Rate (as a percent)	4.50%
Effective rate (as a percent)	4.50%
Term (in Years)	10 years
Senior unsecured notes | 4.27% Senior unsecured notes maturing on December 17, 2025
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	$ 100,000,000
Accreted Balance	$ 100,000,000	100,000,000
Coupon Rate (as a percent)	4.27%
Effective rate (as a percent)	4.27%
Term (in Years)	10 years
Senior unsecured notes | 3.00% Senior unsecured notes maturing on March 30, 2027
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	$ 0
Accreted Balance	0	10,008,000
Senior unsecured notes | Senior Unsecured Notes repaid in March 2016
Debt disclosures by scheduled maturity date
Unpaid Principal Balance	0
Accreted Balance	$ 0	$ 255,296,000

Corporate Indebtedness (Junior

Corporate Indebtedness (Junior Subordinated Deferrable Interest Debentures and Principal Maturities)(Details) - USD ($)	1 Months Ended	9 Months Ended
	Jun. 30, 2005	Sep. 30, 2016
Scheduled Amortization and Principal Repayments
Remaining 2,016		$ 114,630,000
2,017		1,328,796,000
2,018		551,310,000
2,019		1,245,048,000
2,020		973,693,000
Thereafter		2,306,198,000
Total amortization of debt and principal repayments		6,519,675,000
Joint Venture Debt
Principal Repayments and Joint Venture Debt
Remaining 2,016		38,253,000
2,017		534,720,000
2,018		41,933,000
2,019		554,686,000
2,020		30,298,000
Thereafter		1,494,287,000
Total principal repayments		2,694,177,000
Trust Preferred Securities
Debt Instrument [Line Items]
Proceeds from Issuance of Debt	$ 100,000,000
Scheduled Amortization and Principal Repayments
Remaining 2,016		0
2,017		0
2,018		0
2,019		0
2,020		0
Thereafter		100,000,000
Total amortization of debt and principal repayments		100,000,000
Mortgages and other loans payable
Scheduled Amortization
Remaining 2,016		12,694,000
2,017		53,467,000
2,018		56,320,000
2,019		62,048,000
2,020		44,162,000
Thereafter		124,818,000
Total amortization of debt		353,509,000
Principal Repayments and Joint Venture Debt
Remaining 2,016		101,936,000
2,017		930,329,000
2,018		244,990,000
2,019		0
2,020		679,531,000
Thereafter		1,781,380,000
Total principal repayments		3,738,166,000
Revolving Credit Facility
Scheduled Amortization and Principal Repayments
Remaining 2,016		0
2,017		0
2,018		0
2,019		0
2,020		0
Thereafter		0
Total amortization of debt and principal repayments		0
Unsecured Term Loan
Scheduled Amortization and Principal Repayments
Remaining 2,016		0
2,017		0
2,018		0
2,019		1,183,000,000
2,020		0
Thereafter		0
Total amortization of debt and principal repayments		1,183,000,000
Senior Unsecured Notes
Scheduled Amortization and Principal Repayments
Remaining 2,016		0
2,017		345,000,000
2,018		250,000,000
2,019		0
2,020		250,000,000
Thereafter		300,000,000
Total amortization of debt and principal repayments		$ 1,145,000,000
LIBOR | Trust Preferred Securities
Debt Instrument [Line Items]
Interest rate added to base rate (as a percent)		1.25%
LIBOR | Unsecured Term Loan
Debt Instrument [Line Items]
Interest rate added to base rate (as a percent)		1.40%

Corporate Indebtedness (Schedul

Corporate Indebtedness (Schedule of Consolidated Interest Expense, Excluding Capitalized Interest)(Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Interest expense
Interest expense before capitalized interest	$ 78,715	$ 92,244	$ 276,437	$ 261,343
Interest capitalized	(6,084)	(7,327)	(18,135)	(23,496)
Interest income	(66)	(776)	(1,976)	(2,153)
Interest expense, net	$ 72,565	$ 84,141	$ 256,326	$ 235,694

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Amounts due from/to related parties
Due from joint ventures	$ 1,727		$ 1,727		$ 1,334
Other	13,113		13,113		9,316
Related party receivables	14,840		14,840		$ 10,650
Alliance Building Services
Related Party Transactions
Profit participation from related party	800	$ 900	2,600	$ 2,900
Payments made for services	5,300	5,700	16,100	14,300
Entity with Stephen L Green ownership interest
Related Party Transactions
Property management fees from related party	$ 100	$ 100	$ 300	$ 400

Noncontrolling Interests on t76

Noncontrolling Interests on the Company's Consolidated Financial Statements (Details)	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 31, 2012$ / sharesshares	Sep. 30, 2016USD ($)shares$ / shares	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)shares$ / shares	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)unit	Mar. 31, 2016shares	Aug. 31, 2015shares	Jul. 31, 2015shares	Jun. 30, 2015shares	Feb. 28, 2015shares	Aug. 31, 2014shares
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Balance at beginning of period | $				$ 424,206,000
Net income | $		$ 1,663,000	$ 6,467,000	8,171,000	$ 6,634,000
Accumulated other comprehensive income allocation | $		118,000	(191,000)	(257,000)	(349,000)
Balance at end of period | $		$ 490,440,000		$ 490,440,000		$ 424,206,000
Number of company common stock issued on conversion of Series B preferred units				6.71348
SL Green Operating Partnership
Organization
Noncontrolling interest in the operating partnership (as a percent)		4.29%		4.29%		3.61%
Number of units of operating partnership owned by the noncontrolling interest unit holders (shares)		4,495,410		4,495,410		3,745,766
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares) | shares		4,495,410		4,495,410
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Balance at beginning of period | $				$ 424,206,000	469,524,000	$ 469,524,000
Distributions | $				(9,245,000)		(9,710,000)
Issuance of common units | $				75,352,000		30,506,000
Redemption of common units | $				(12,746,000)		(55,697,000)
Net income | $				8,171,000		10,565,000
Accumulated other comprehensive income allocation | $		$ 118,000	$ (191,000)	(257,000)	$ (349,000)	(67,000)
Fair value adjustment | $				4,959,000		(20,915,000)
Balance at end of period | $		$ 490,440,000		$ 490,440,000		$ 424,206,000
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) | 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)				$ 1.125
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) | shares		60		60
Mandatory liquidation preference (in dollars per share) | $		$ 1,000		$ 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) | shares												563,954
Dividend rate preferred units (as a percent)				3.50%
Liquidation preference of preferred units (in dollars per share)		$ 25		$ 25
Annual dividends on preferred units (in dollars per share)				0.875
Operating partnership common stock value use for conversion of preferred units (in dollars per share)		$ 134.67		$ 134.67
Preferred Units, shares authorized | shares		700,000		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) | shares												378,634
Dividend rate preferred units (as a percent)				4.00%
Liquidation preference of preferred units (in dollars per share)		$ 25		$ 25
Annual dividends on preferred units (in dollars per share)				$ 1
Preferred Units, shares authorized | shares		500,000		500,000
SL Green Operating Partnership | Series M Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares											1,600,000
Dividend rate preferred units (as a percent)				3.75%
Liquidation preference of preferred units (in dollars per share)		$ 25		$ 25
Annual dividends on preferred units (in dollars per share)				$ 0.9375
Preferred Units, shares authorized | shares		1,600,000		1,600,000
SL Green Operating Partnership | Series N Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares										552,303
Dividend rate preferred units (as a percent)				3.00%
Liquidation preference of preferred units (in dollars per share)		$ 25		$ 25
Annual dividends on preferred units (in dollars per share)				$ 0.75
Preferred Units, shares authorized | shares		552,303		552,303
SL Green Operating Partnership | Series O Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Dividend rate preferred units (as a percent)				6.25%
Preferred Units, shares authorized | shares		1		1
SL Green Operating Partnership | Series P Preferred Units
Organization
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares) | shares		200,000		200,000
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares									200,000
Dividend rate preferred units (as a percent)				4.00%
Liquidation preference of preferred units (in dollars per share)		$ 25		$ 25
Annual dividends on preferred units (in dollars per share)				$ 1
SL Green Operating Partnership | Series Q Preferred Units
Organization
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares) | shares		268,000		268,000
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares									268,000
Dividend rate preferred units (as a percent)				3.50%
Liquidation preference of preferred units (in dollars per share)		$ 25		$ 25
Annual dividends on preferred units (in dollars per share)				0.875
Operating partnership common stock value use for conversion of preferred units (in dollars per share)		$ 148.95		$ 148.95
SL Green Operating Partnership | Series R Preferred Units
Organization
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares) | shares		400,000		400,000
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares								400,000
Dividend rate preferred units (as a percent)				3.50%
Liquidation preference of preferred units (in dollars per share)		$ 25		$ 25
Annual dividends on preferred units (in dollars per share)				0.875
Operating partnership common stock value use for conversion of preferred units (in dollars per share)		$ 154.89		$ 154.89
SL Green Operating Partnership | Series S Preferred Units
Organization
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares) | shares		1,077,280		1,077,280
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares								1,077,280
Dividend rate preferred units (as a percent)				4.00%
Liquidation preference of preferred units (in dollars per share)		$ 25		$ 25
Annual dividends on preferred units (in dollars per share)				$ 1
SL Green Operating Partnership | Series T Preferred Units
Organization
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares) | shares		230,000		230,000
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares							230,000
Dividend rate preferred units (as a percent)				2.75%
Liquidation preference of preferred units (in dollars per share)		$ 25		$ 25
Annual dividends on preferred units (in dollars per share)				0.6875
Operating partnership common stock value use for conversion of preferred units (in dollars per share)		$ 119.02		$ 119.02
SL Green Operating Partnership | Series U Preferred Units
Organization
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares) | shares		680,000		680,000
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares							680,000
Dividend rate preferred units (as a percent)				4.50%
Liquidation preference of preferred units (in dollars per share)		$ 25		$ 25
Annual dividends on preferred units (in dollars per share)				1.125
SL Green Operating Partnership | Series U Preferred Units | Minimum
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Annual dividends on preferred units (in dollars per share)				$ 0.75
SL Green Operating Partnership | Series A Preferred Units
Organization
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares) | shares		109,161		109,161
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares								109,161
Dividend rate preferred units (as a percent)				3.50%
Liquidation preference of preferred units (in dollars per share)		$ 1,000		$ 1,000
Annual dividends on preferred units (in dollars per share)				$ 35
SL Green Operating Partnership | Series B Preferred Units
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Number of preferred units issued (in shares) | shares		0		0

Noncontrolling Interests on t77

Noncontrolling Interests on the Company's Consolidated Financial Statements (Common Unit Activity) (Details) - SL Green Operating Partnership - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Rollforward Analysis of Preferred Unit Activity
Issuance of preferred units	$ 75,352	$ 30,506
Redemption of preferred units	(12,746)	(55,697)
Preferred Units
Rollforward Analysis of Preferred Unit Activity
Balance at beginning of period	282,516	71,115
Issuance of preferred units	22,793	211,601
Redemption of preferred units	(2,999)	(200)
Balance at end of period	$ 302,310	$ 282,516

Stockholders' Equity of the C78

Stockholders' Equity of the Company (Details) - $ / shares	Sep. 30, 2016	Dec. 31, 2015
Stockholders' Equity Note [Abstract]
Authorized capital stock (shares)	260,000,000
Authorized shares, par value (in dollars per share)	$ 0.01
Common stock, shares authorized (in shares)	160,000,000	160,000,000
Common stock, par value (in dollars per share)	$ 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)	100,264,253
Excess shares issued (shares)	0

Stockholders' Equity of the C79

Stockholders' Equity of the Company (At-the-Market Equity Offering Program and Perpetual Preferred Stock)(Details) - USD ($)	1 Months Ended	9 Months Ended		12 Months Ended
	Aug. 31, 2012	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Mar. 31, 2015	Feb. 28, 2015
Stockholders' Equity
Proceeds from sale of common stock		$ 0	$ 124,794,000
Common stock, shares authorized (in shares)		160,000,000		160,000,000
New At-the-Market Equity offering programs
Stockholders' Equity
Aggregate value of the shares of common stock to be sold (up to)					$ 300,000,000
Contributions - net proceeds from common stock offering (in shares)				91,180
Proceeds from sale of common stock				$ 12,000,000
Series I Preferred Stock
Stockholders' Equity
Preferred stock, shares outstanding (in shares)		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
Perpetual Preferred stock, annual dividends per share (in dollars per share)		$ 1.625
Contributions of net proceeds from sale of preferred stock	$ 221,900,000
Dividend Reinvestment and Stock Purchase Plan (DRIP)
Stockholders' Equity
Common stock, shares authorized (in shares)						3,500,000

Stockholders' Equity of the C80

Stockholders' Equity of the Company (Earnings per Share)(Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Basic Earnings:
Income attributable to SL Green common stockholders	$ 34,252	$ 163,658	$ 190,930	$ 167,829
Diluted Earnings:
Income attributable to SL Green common stockholders	$ 35,915	$ 170,125	$ 199,101	$ 174,463
Basic Shares:
Weighted average common shares outstanding (shares)	100,233,000	99,621,000	100,140,000	99,205,000
Effect of Dilutive Securities:
Operating Partnership units redeemable for common shares (shares)	4,497,000	3,901,000	4,272,000	3,924,000
Stock-based compensation plans (shares)	413,000	407,000	349,000	480,000
Diluted weighted average common stock outstanding (shares)	105,143,000	103,929,000	104,761,000	103,609,000
Common stock shares excluded from the diluted shares outstanding (shares)	673,298	263,236	753,344	231,970
Common Stock
Effect of Dilutive Securities:
Redemption of units to common shares	$ 1,663	$ 6,467	$ 8,171	$ 6,634

Partners' Capital of the Oper81

Partners' Capital of the Operating Partnership (Details)	Sep. 30, 2016shares	Dec. 31, 2015unitshares
Common Stock
Stockholders' Equity
Units outstanding (units)	100,264,000	99,976,000
SL Green Operating Partnership
Stockholders' Equity
Noncontrolling interest in the operating partnership (as a percent)	4.29%	3.61%
Number of units of operating partnership owned by the noncontrolling interest unit holders (units)	4,495,410	3,745,766
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)	100,264,253

Partners' Capital of the Oper82

Partners' Capital of the Operating Partnership (EPS) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Stockholders' Equity
Weighted average common shares outstanding (shares)	100,233,000	99,621,000	100,140,000	99,205,000
Common stock shares excluded from the diluted shares outstanding (shares)	673,298	263,236	753,344	231,970
SL Green Operating Partnership
Stockholders' Equity
Net income attributable to SLGOP common unitholders	$ 35,915	$ 170,125	$ 199,101	$ 174,463
Weighted average common shares outstanding (shares)	104,730,000	103,522,000	104,412,000	103,129,000
Stock-based compensation plans (shares)	413,000	407,000	349,000	480,000
Diluted weighted average common units outstanding (shares)	105,143,000	103,929,000	104,761,000	103,609,000
Common stock shares excluded from the diluted shares outstanding (shares)	673,298	753,344	263,236	231,970

Share-based Compensation (Addit

Share-based Compensation (Additional Information) (Details)

1 Months Ended

3 Months Ended

9 Months Ended

12 Months Ended

Jan. 31, 2015USD ($)

Aug. 31, 2014shares

Aug. 31, 2011USD ($)

Sep. 30, 2016USD ($)unit / sharesfungible_unitshares

Sep. 30, 2015USD ($)

Sep. 30, 2016USD ($)unit / sharesfungible_unit$ / sharesshares

Sep. 30, 2015USD ($)

Dec. 31, 2015USD ($)shares

Dec. 31, 2014shares

Sep. 30, 2014shares

Jun. 30, 2014shares

Dec. 11, 2013

Dec. 31, 2012shares

Dec. 17, 2012

Dec. 31, 2011shares

Dec. 31, 2010shares

Dec. 31, 2009USD ($)

Jan. 01, 2008shares

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Capitalized to assets associated with compensation expense related to our long-term compensation plans, restricted stock and stock options

$ 1,500,000

$ 1,500,000

$ 4,400,000

$ 4,900,000

Stock options

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Period of commencement of option vesting, from date of grant (in years)

1 year

Exercise price of options granted, low end of the range (in dollars per share) | $ / shares

$ 20.67

Exercise price of options granted, high end of the range (in dollars per share) | $ / shares

$ 137.18

Remaining weighted average contractual life of the options outstanding (in years)

3 years 4 months 24 days

Remaining average contractual life of the options exercisable (in years)

2 years 8 months 12 days

Total unrecognized compensation cost related to unvested stock awards

9,800,000

$ 9,800,000

Weighted average period for recognition of compensation cost related to unvested stock awards (in years)

1 year 4 months 24 days

Weighted average fair value of options granted during the period

$ 2,258,336

$ 9,522,613

Stock options | Minimum

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Award expiration period (in years)

5 years

Options vesting period (in years)

1 year

Stock options | Maximum

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Award expiration period (in years)

10 years

Options vesting period (in years)

5 years

Restricted Stock Awards

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation expense

$ 5,275,799

7,540,747

Total unrecognized compensation cost related to unvested stock awards

$ 13,600,000

$ 13,600,000

Weighted average period for recognition of compensation cost related to unvested stock awards (in years)

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

$ 7,600,000

7,400,000

Weighted average fair value of options granted during the period

$ 1,613,846

$ 16,061,201

Awards granted (in shares) | shares

14,550

143,053

Awards outstanding (in shares) | shares

3,117,831

3,117,831

3,137,881

3,000,979

LTIP units

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Weighted average fair value of options granted during the period

$ 28,100,000

$ 25,400,000

Performance Shares

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Total unrecognized compensation cost related to unvested stock awards

$ 6,000,000

$ 6,000,000

Weighted average period for recognition of compensation cost related to unvested stock awards (in years)

1 year 2 months 12 days

Share-based Compensation

$ 2,300,000

2,700,000

$ 15,100,000

19,000,000

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) | fungible_unit

27,030,000

27,030,000

Fungible units per share (in fungible units per share) | unit / shares

3.74

3.74

Shares that may be issued if equal to fungible units (shares) (less than) | shares

27,030,000

27,030,000

Fungible units | fungible_unit

10,300,000

10,300,000

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

$ 2,500,000

1,900,000

$ 6,400,000

5,800,000

Stock options, stock appreciation rights and other awards

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Fungible units per share (in fungible units per share) | unit / shares

0.73

0.73

Award expiration period (in years)

5 years

All other awards

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Fungible units per share (in fungible units per share) | unit / shares

1

1

Award expiration period (in years)

10 years

2010 Notional Unit Long-Term Compensation Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Capitalized to assets associated with compensation expense related to our long-term compensation plans, restricted stock and stock options

$ 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) | shares

327,416

327,416

385,583

Percentage of LTIP Units earned, vested (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

2011 Outperformance Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation expense

$ 0

600,000

$ 0

4,500,000

Capitalized to assets associated with compensation expense related to our long-term compensation plans, restricted stock and stock options

26,700,000

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) | 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% (in years)

3 years

Cumulative return to stockholders (percent)

25.00%

Return to stockholders

$ 85,000,000

Performance period (in years)

3 years

2011 Outperformance Plan | Earned anytime after beginning of the second year

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Percentage of units vested

33.33%

2011 Outperformance Plan | Earned anytime after beginning of the third year

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Percentage of units vested

66.67%

2011 Outperformance Plan | Vested on August 31, 2014

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Percentage of units vested

50.00%

2011 Outperformance Plan | Vesting on August 31, 2015

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Percentage of units vested

50.00%

2014 Outperformance Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation expense

1,800,000

1,500,000

6,600,000

4,400,000

Capitalized to assets associated with compensation expense related to our long-term compensation plans, restricted stock and stock options

27,900,000

LTIP units earned (in shares) | shares

610,000

Performance period (in years)

3 years

Award period (in years)

3 years

Percentage of LTIP units that may be earned based on the Company's absolute total return to stockholders

66.67%

Percentage of LTIP units that may be earned based on relative total return to stockholders compared to constituents of the MSCI REIT index

33.33%

2014 Outperformance Plan | Vesting on August 31, 2017

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Percentage of units vested

50.00%

2014 Outperformance Plan | Vesting on August 31, 2018

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Percentage of units vested

50.00%

Deferred Stock Compensation Plan for Directors

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation expense

$ 100,000

$ 100,000

$ 1,900,000

$ 1,800,000

Maximum percentage of the annual retainer fee, chairman fees and meeting fees that may be deferred by non-employee directors (percent)

100.00%

100.00%

Awards granted (in shares) | shares

8,136

Shares issued (in shares) | shares

9,014

Awards outstanding (in shares) | shares

88,902

88,902

Employee Stock Purchase Plan

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Shares of common stock available for issuance (shares) | shares

500,000

Duration of each offering period starting the first day of each calendar quarter (in months)

3 months

Purchase price as a percentage of market value of the common stock (percent)

85.00%

85.00%

Shares of common stock issued (shares) | shares

93,288

93,288

Share-based Compensation (Detai

Share-based Compensation (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2016USD ($)$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares
Stock options
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Dividend yield (as a percent)	2.30%	1.97%
Expected life of option (in years)	4 years 2 months 12 days	3 years 7 months 6 days
Risk-free interest rate (as a percent)	1.08%	1.43%
Expected stock price volatility (as a percent)	29.08%	32.34%
Options Outstanding
Balance at beginning of period (in shares)	1,595,007	1,462,726
Granted (in shares)	109,500	389,836
Exercised (in shares)	(157,361)	(217,438)
Lapsed or cancelled (in shares)	(48,117)	(40,117)
Balance at end of period (in shares)	1,499,029	1,595,007
Options exercisable at end of period (in shares)	794,797	589,055
Weighted average fair value of options granted during the period | $	$ 2,258,336	$ 9,522,613
Weighted Average Exercise Price
Balance at beginning of year (in dollars per share) | $ / shares	$ 95.52	$ 87.98
Granted (in dollars per share) | $ / shares	99.65	112.54
Exercised (in dollars per share) | $ / shares	77.90	74.69
Lapsed or cancelled (in dollars per share) | $ / shares	110.81	98.61
Balance at end of period (in dollars per share) | $ / shares	97.18	95.52
Options exercisable at end of period (in dollars per share) | $ / shares	$ 90.29	$ 89.85
Restricted Stock Awards
Options Outstanding
Weighted average fair value of options granted during the period | $	$ 1,613,846	$ 16,061,201
Summary of restricted stock
Balance at beginning of year (in shares)	3,137,881	3,000,979
Granted (in shares)	14,550	143,053
Cancelled (in shares)	(34,600)	(6,151)
Balance at end of period (in shares)	3,117,831	3,137,881
Vested during the period (in shares)	83,822	87,081
Compensation expense recorded | $	$ 5,275,799	$ 7,540,747

Accumulated Other Comprehensi85

Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	$ (8,749)
Ending Balance	(14,074)
SL Green Realty Corp
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	(8,749)
Other comprehensive loss before reclassifications	(16,088)
Amounts reclassified from accumulated other comprehensive income	10,763
Ending Balance	(14,074)
Deferred net losses from terminated hedges	8,100	$ 9,700
SL Green Realty Corp | Net unrealized (loss) gain on derivative instruments
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	(10,160)
Other comprehensive loss before reclassifications	(7,810)
Amounts reclassified from accumulated other comprehensive income	7,862
Ending Balance	(10,108)
SL Green Realty Corp | Unrealized gain (loss) on marketable securities
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	2,003
Other comprehensive loss before reclassifications	(869)
Amounts reclassified from accumulated other comprehensive income	0
Ending Balance	1,134
SL Green Realty Corp | Joint venture | Net unrealized (loss) gain on derivative instruments
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	(592)
Other comprehensive loss before reclassifications	(7,409)
Amounts reclassified from accumulated other comprehensive income	2,901
Ending Balance	$ (5,100)

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair Value of Financial Instruments
Marketable securities	$ 60,352	$ 45,138
Interest rate cap and swap agreements (included in other assets)	4	204
Debt and preferred equity investments	1,453,234	1,670,020
Accrued Interest Payable And Other Liabilities
Fair Value of Financial Instruments
Interest rate cap and swap agreements	2,127	10,776
Liabilities Held for Sale
Fair Value of Financial Instruments
Interest rate cap and swap agreements	0
Carrying Value
Fair Value of Financial Instruments
Debt and preferred equity investments	1,453,234
Fixed rate debt	5,494,301	7,232,254
Variable rate debt	1,010,990	3,202,494
Total	6,505,291	10,434,748
Fair Value
Fair Value of Financial Instruments
Marketable securities	60,352	45,138
Total	6,936,578	10,770,574
Estimated fair value of debt and preferred equity investments, low end of range	1,500,000	1,700,000
Estimated fair value of debt and preferred equity investments, high end of range	1,600,000	1,800,000
Level 1
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in other assets)	0	0
Level 1 | Accrued Interest Payable And Other Liabilities
Fair Value of Financial Instruments
Interest rate cap and swap agreements	0	0
Level 1 | Liabilities Held for Sale
Fair Value of Financial Instruments
Interest rate cap and swap agreements	0
Level 2
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in other assets)	4	204
Level 2 | Accrued Interest Payable And Other Liabilities
Fair Value of Financial Instruments
Interest rate cap and swap agreements	2,127	10,776
Level 2 | Liabilities Held for Sale
Fair Value of Financial Instruments
Interest rate cap and swap agreements	0
Level 3
Fair Value of Financial Instruments
Marketable securities	0	0
Interest rate cap and swap agreements (included in other assets)	0	0
Level 3 | Accrued Interest Payable And Other Liabilities
Fair Value of Financial Instruments
Interest rate cap and swap agreements	0	0
Level 3 | Liabilities Held for Sale
Fair Value of Financial Instruments
Interest rate cap and swap agreements	0
Level 3 | Fair Value
Fair Value of Financial Instruments
Fixed rate debt	5,922,120	7,591,388
Variable rate debt	1,014,458	3,179,186
Equity marketable securities
Fair Value of Financial Instruments
Marketable securities	23,213	4,704
Equity marketable securities | Level 1
Fair Value of Financial Instruments
Marketable securities	23,213	4,704
Commercial mortgage-backed securities
Fair Value of Financial Instruments
Marketable securities	37,139	40,434
Commercial mortgage-backed securities | Level 2
Fair Value of Financial Instruments
Marketable securities	$ 37,139	$ 40,434

Financial Instruments_ Deriva87

Financial Instruments: Derivatives and Hedging (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Financial Instruments: Derivatives and Hedging
Fair Value	$ 4		$ 4		$ 204
Derivative, Fair Value, Net	(2,123)		(2,123)
Gain (loss) from changes in fair value	(100)	$ 100	500	$ 100
Fair value of derivatives in a net liability position	2,200		2,200
Aggregate termination value	2,100		2,100
Estimated current balance held in accumulated other comprehensive loss to be reclassified into earnings within the next 12 months			4,900
Share of joint venture of accumulated other comprehensive loss reclassified into equity in net income from unconsolidated joint ventures within the next 12 months			1,700
Amount of Gain Recognized in Other Comprehensive Loss (Effective Portion)	(229)	(8,447)	(14,104)	(18,023)
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	1,989	3,024	9,538	9,170
Amount of Loss Recognized into Income (Ineffective Portion)	830	(52)	(244)	(476)
Joint venture
Financial Instruments: Derivatives and Hedging
Amount of Gain Recognized in Other Comprehensive Loss (Effective Portion)	(222)	(1,526)	(5,992)	(2,486)
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	547	287	1,465	949
Amount of Loss Recognized into Income (Ineffective Portion)	830	(21)	(206)	(21)
Interest Rate Swap Expiring in December 2017
Financial Instruments: Derivatives and Hedging
Notional Value	$ 200,000		$ 200,000
Strike Rate (as a percent)	0.9375%		0.9375%
Fair Value	$ (551)		$ (551)
Interest Rate Swap Expiring in December 2017
Financial Instruments: Derivatives and Hedging
Notional Value	$ 150,000		$ 150,000
Strike Rate (as a percent)	0.94%		0.94%
Fair Value	$ (417)		$ (417)
Interest Rate Swap Expiring in December 2017
Financial Instruments: Derivatives and Hedging
Notional Value	$ 150,000		$ 150,000
Strike Rate (as a percent)	0.94%		0.94%
Fair Value	$ (417)		$ (417)
Interest Rate Cap Expiring October 2016
Financial Instruments: Derivatives and Hedging
Notional Value	$ 117,392		$ 117,392
Strike Rate (as a percent)	6.00%		6.00%
Fair Value	$ 0		$ 0
Interest Rate Swap Expiring in January 2017
Financial Instruments: Derivatives and Hedging
Notional Value	$ 14,409		$ 14,409
Strike Rate (as a percent)	0.50%		0.50%
Fair Value	$ 4		$ 4
Interest Rate Swap Expiring in February 2017
Financial Instruments: Derivatives and Hedging
Notional Value	$ 8,018		$ 8,018
Strike Rate (as a percent)	0.852%		0.852%
Fair Value	$ (7)		$ (7)
Interest Rate Cap Expiring in September 2017
Financial Instruments: Derivatives and Hedging
Notional Value	$ 137,500		$ 137,500
Strike Rate (as a percent)	4.00%		4.00%
Fair Value	$ 0		$ 0
Interest Rate Cap Expiring in May 2017
Financial Instruments: Derivatives and Hedging
Notional Value	$ 1,450,000		$ 1,450,000
Strike Rate (as a percent)	4.75%		4.75%
Fair Value	$ 0		$ 0
Interest Rate Swap Expiring in July 2023
Financial Instruments: Derivatives and Hedging
Notional Value	$ 200,000		$ 200,000
Strike Rate (as a percent)	1.131%		1.131%
Fair Value	$ (361)		$ (361)
Interest Rate Swap Expiring in July 2023
Financial Instruments: Derivatives and Hedging
Notional Value	$ 100,000		$ 100,000
Strike Rate (as a percent)	1.161%		1.161%
Fair Value	$ (374)		$ (374)
Interest Rate Cap Expiring in October 2017
Financial Instruments: Derivatives and Hedging
Notional Value	$ 23,199		$ 23,199
Strike Rate (as a percent)	4.50%		4.50%
Fair Value	$ 0		$ 0
Interest Rate Swaps/Caps
Financial Instruments: Derivatives and Hedging
Amount of Gain Recognized in Other Comprehensive Loss (Effective Portion)	(7)	(6,921)	(8,112)	(15,537)
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	1,442	2,737	8,073	8,221
Amount of Loss Recognized into Income (Ineffective Portion)	$ 0	$ (31)	$ (38)	$ (455)

Commitments and Contingencies88

Commitments and Contingencies (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2016USD ($)
Commitments and Contingencies Disclosure [Abstract]
Initial term of non cancellable operating leases, minimum (in years)	1 year
Capital lease
Remaining 2,016	$ 585
2,017	2,387
2,018	2,387
2,019	2,411
2,020	2,620
Thereafter	825,483
Total minimum lease payments	835,873
Amount representing interest	(793,922)
Capital lease obligations	41,951
Non-cancellable operating leases
Remaining 2,016	7,835
2,017	31,374
2,018	31,455
2,019	31,716
2,020	32,086
Thereafter	983,213
Total minimum lease payments	$ 1,117,679

Segment Information (Details)

Segment Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)segment	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Segment information
Number of reportable segments (segment) | segment			2
Total revenues	$ 416,681	$ 432,066	$ 1,489,739	$ 1,237,439
(Loss) Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain on sale of real estate, depreciable real estate reserves net of recoveries, and loss on sale of investment in marketable securities	42,721	20,994	(18,927)	33,272
Total assets	15,790,942		15,790,942		$ 19,727,646
Marketing, general and administrative	25,458	23,475	73,974	72,139
Operating Segments | Real Estate Segment
Segment information
Total revenues	335,652	375,623	1,300,082	1,085,870
(Loss) Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain on sale of real estate, depreciable real estate reserves net of recoveries, and loss on sale of investment in marketable securities	(33,613)	(29,577)	(190,633)	(96,333)
Total assets	13,992,319		13,992,319		17,814,787
Operating Segments | Debt and Preferred Equity Segment
Segment information
Total revenues	81,029	56,443	189,657	151,569
(Loss) Income from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain on sale of real estate, depreciable real estate reserves net of recoveries, and loss on sale of investment in marketable securities	76,334	$ 50,571	171,706	$ 129,605
Total assets	$ 1,798,623		$ 1,798,623		$ 1,912,859

Segment Information (Schedule o

Segment Information (Schedule of Reconciliation of Income from Continuing Operations to Net Income Attributable to SL Green Common Stockholders)(Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Reconciliation of income from continuing operations to net income attributable to SL Green common stockholders
Income (Loss) from continuing operations before equity in net gain on sale of interest in unconsolidated joint venture/real estate, gain on sale of real estate, depreciable real estate reserves net of recoveries, and loss on sale of investment in marketable securities	$ 42,721	$ 20,994	$ (18,927)	$ 33,272
Equity in net gain on sale of interest in unconsolidated joint venture/real estate	225	15,281	43,588	16,050
Gain on sale of real estate, net	397	159,704	210,750	159,704
Depreciable real estate reserves	0	(19,226)	(10,387)	(19,226)
Loss on sale of investment in marketable securities	0	0	(83)	0
Income from continuing operations	43,343	176,753	224,941	189,800
Net income from discontinued operations	0	0	0	427
Gain on sale of discontinued operations	0	0	0	12,983
Net income	$ 43,343	$ 176,753	$ 224,941	$ 203,210