SL Green Operating Partnership 10-Q 6 Nov 20 2020 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Nov. 04, 2020
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	1-13199
Entity Registrant Name	SL GREEN REALTY CORP
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	13-3956775
Entity Address, Address Line One	420 Lexington Avenue
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10170
City Area Code	212
Local Phone Number	594-2700
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		72,569,561
Entity Central Index Key	0001040971
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false
Common Stock
Document Information [Line Items]
Trading Symbol	SLG
Title of 12(b) Security	Common Stock, $0.01 par value
Security Exchange Name	NYSE
Preferred Stock
Document Information [Line Items]
Trading Symbol	SLG.PRI
Title of 12(b) Security	6.500% Series I Cumulative Redeemable Preferred Stock, $0.01 par value
Security Exchange Name	NYSE
SL Green Operating Partnership
Document Information [Line Items]
Entity File Number	33-167793-02
Entity Registrant Name	SL GREEN OPERATING PARTNERSHIP, L.P.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	13-3960938
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		1,025,366
Entity Central Index Key	0001492869
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Commercial real estate properties, at cost:
Land and land interests		$ 1,639,118	$ 1,751,544
Building and improvements		5,483,155	5,154,990
Building leasehold and improvements		1,442,251	1,433,793
Right of use asset - financing leases		75,711	47,445
Right of use asset - operating leases		381,255	396,795
Total commercial real estate properties, at cost		9,021,490	8,784,567
Less: accumulated depreciation		(2,260,247)	(2,060,560)
Total commercial real estate properties, net		6,761,243	6,724,007
Assets held for sale		0	391,664
Cash and cash equivalents		221,404	166,070
Restricted cash		83,045	75,360
Investments in marketable securities		27,734	29,887
Tenant and other receivables		72,806	43,968
Related party receivables		31,936	21,121
Deferred rents receivable		304,673	283,011
Debt and preferred equity investments, net of discounts and deferred origination fees of $12,031 and $14,562 and allowances of $19,010 and $1,750 in 2020 and 2019, respectively		1,153,363	1,580,306
Investments in unconsolidated joint ventures		2,946,673	2,912,842
Deferred costs, net		206,289	205,283
Other assets		514,873	332,801
Total assets	[1]	12,324,039	12,766,320
Liabilities
Mortgages and other loans payable, net		2,391,744	2,183,253
Revolving credit facility, net		184,840	234,013
Unsecured term loans, net		1,494,793	1,494,024
Unsecured notes, net		1,247,795	1,496,847
Accrued interest payable		23,438	22,148
Other liabilities		306,077	177,080
Accounts payable and accrued expenses		152,983	166,905
Deferred revenue		117,615	114,052
Lease liability - financing leases		174,983	44,448
Lease liability - operating leases		358,419	381,671
Dividend and distributions payable		25,486	79,282
Security deposits		56,212	62,252
Liabilities related to assets held for sale		0	0
Junior subordinated deferrable interest debentures held by trusts that issued trust preferred securities		100,000	100,000
Total liabilities	[1]	6,634,385	6,555,975
Commitments and contingencies
Noncontrolling interests in Operating Partnership		353,480	409,862
Preferred units		202,169	283,285
Equity
Series I Preferred Stock, $0.01 par value, $25.00 liquidation preference, 9,200 issued and outstanding at both September 30, 2020 and December 31, 2019		221,932	221,932
Common stock, $0.01 par value, 160,000 shares authorized and 74,095 and 80,257 issued and outstanding at September 30, 2020 and December 31, 2019, respectively (including 1,055 and 1,055 shares held in treasury at September 30, 2020 and December 31, 2019, respectively)		741	803
Additional paid-in-capital		3,998,516	4,286,395
Treasury stock at cost		(124,049)	(124,049)
Accumulated other comprehensive loss		(76,200)	(28,485)
Retained earnings		1,035,172	1,084,719
Total SL Green stockholders' equity		5,056,112	5,441,315
Noncontrolling interests in other partnerships		77,893	75,883
Total equity		5,134,005	5,517,198
SL Green stockholders equity:
Total liabilities and equity/capital		12,324,039	12,766,320
Variable Interest Entity, Primary Beneficiary
Commercial real estate properties, at cost:
Land and land interests		375,900	205,200
Building and improvements		1,400,000	481,900
Building leasehold and improvements		2,000	2,000
Right of use asset - financing leases		61,700	61,700
Less: accumulated depreciation		(296,300)	(17,600)
Other assets		322,800	169,500
Liabilities
Mortgages and other loans payable, net		510,700	457,100
Accrued interest payable		1,100	1,200
Other liabilities		48,900	43,700
Lease liability - financing leases		58,400	57,700
SL Green Operating Partnership
Commercial real estate properties, at cost:
Land and land interests		1,639,118	1,751,544
Building and improvements		5,483,155	5,154,990
Building leasehold and improvements		1,442,251	1,433,793
Right of use asset - financing leases		75,711	47,445
Right of use asset - operating leases		381,255	396,795
Total commercial real estate properties, at cost		9,021,490	8,784,567
Less: accumulated depreciation		(2,260,247)	(2,060,560)
Total commercial real estate properties, net		6,761,243	6,724,007
Assets held for sale		0	391,664
Cash and cash equivalents		221,404	166,070
Restricted cash		83,045	75,360
Investments in marketable securities		27,734	29,887
Tenant and other receivables		72,806	43,968
Related party receivables		31,936	21,121
Deferred rents receivable		304,673	283,011
Debt and preferred equity investments, net of discounts and deferred origination fees of $12,031 and $14,562 and allowances of $19,010 and $1,750 in 2020 and 2019, respectively		1,153,363	1,580,306
Investments in unconsolidated joint ventures		2,946,673	2,912,842
Deferred costs, net		206,289	205,283
Other assets		514,873	332,801
Total assets	[2]	12,324,039	12,766,320
Liabilities
Mortgages and other loans payable, net		2,391,744	2,183,253
Revolving credit facility, net		184,840	234,013
Unsecured term loans, net		1,494,793	1,494,024
Unsecured notes, net		1,247,795	1,496,847
Accrued interest payable		23,438	22,148
Other liabilities		306,077	177,080
Accounts payable and accrued expenses		152,983	166,905
Deferred revenue		117,615	114,052
Lease liability - financing leases		174,983	44,448
Lease liability - operating leases		358,419	381,671
Dividend and distributions payable		25,486	79,282
Security deposits		56,212	62,252
Liabilities related to assets held for sale		0	0
Junior subordinated deferrable interest debentures held by trusts that issued trust preferred securities		100,000	100,000
Total liabilities	[2]	6,634,385	6,555,975
Commitments and contingencies
Limited partner interests in SLGOP (4,027 and 4,196 limited partner common units outstanding at September 30, 2020 and December 31, 2019, respectively)		353,480	409,862
Preferred units		202,169	283,285
Equity
Accumulated other comprehensive loss		(76,200)	(28,485)
SL Green stockholders equity:
Series I Preferred Units, $25.00 liquidation preference, 9,200 issued and outstanding at both September 30, 2020 and December 31, 2019		221,932	221,932
SL Green partners' capital (771 and 834 general partner common units and 72,269 and 78,368 limited partner common units outstanding at September 30, 2020 and December 31, 2019, respectively)		4,910,380	5,247,868
Total SLGOP partners' capital		5,056,112	5,441,315
Noncontrolling interests in other partnerships		77,893	75,883
Total capital		5,134,005	5,517,198
Total liabilities and equity/capital		12,324,039	12,766,320
SL Green Operating Partnership | Variable Interest Entity, Primary Beneficiary
Commercial real estate properties, at cost:
Land and land interests		375,900	205,200
Building and improvements		1,400,000	481,900
Building leasehold and improvements		2,000	2,000
Right of use asset - financing leases		61,700	61,700
Less: accumulated depreciation		(296,300)	(17,600)
Other assets		322,800	169,500
Liabilities
Mortgages and other loans payable, net		510,700	457,100
Accrued interest payable		1,100	1,200
Other liabilities		48,900	43,700
Lease liability - financing leases		$ 58,400	$ 57,700
[1]	The Company's consolidated balance sheets include assets and liabilities of consolidated variable interest entities ("VIEs"). See Note 2. The consolidated balance sheets include the following amounts related to our consolidated VIEs, excluding the Operating Partnership: $375.9 million and $205.2 million of land, $1.4 billion and $481.9 million of building and improvements, $2.0 million and $2.0 million of building and leasehold improvements, $61.7 million and $61.7 million of right of use assets, $296.3 million and $17.6 million of accumulated depreciation, $322.8 million and $169.5 million of other assets included in other line items, $510.7 million and $457.1 million of real estate debt, net, $1.1 million and $1.2 million of accrued interest payable, $58.4 million and 57.7 million of lease liabilities, and $48.9 million and $43.7 million of other liabilities included in other line items as of September 30, 2020 and December 31, 2019, respectively.
[2]	The Operating Partnership's consolidated balance sheets include assets and liabilities of consolidated variable interest entities ("VIEs"). See Note 2. The consolidated balance sheets include the following amounts related to our consolidated VIEs, excluding the Operating Partnership: 375.9 million and $205.2 million of land, $1.4 billion and $481.9 million of building and improvements, $2.0 million and $2.0 million of building and leasehold improvements, $61.7 million and $61.7 million of right of use assets, $296.3 million and $17.6 million of accumulated depreciation, $322.8 million and $169.5 million of other assets included in other line items, $510.7 million and $457.1 million of real estate debt, net, $1.1 million and $1.2 million of accrued interest payable, $58.4 million and $57.7 million of lease liabilities, and $48.9 million and $43.7 million of other liabilities included in other line items as of September 30, 2020 and December 31, 2019, respectively.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Debt and preferred equity investments, discount and deferred origination fees	$ 12,031	$ 14,562
Allowance for loan and lease losses, real estate	$ 19,010	$ 1,750
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)	74,095,000	80,257,000
Common stock, shares outstanding (in shares)	74,095,000	80,257,000
Treasury stock, shares (in shares)	1,055,000	1,055,000
Land and land interests	$ 1,639,118	$ 1,751,544
Building and improvements	5,483,155	5,154,990
Building leasehold and improvements	1,442,251	1,433,793
Right of use asset - financing leases	75,711	47,445
Accumulated depreciation	2,260,247	2,060,560
Other assets	514,873	332,801
Mortgages and other loans payable, net	2,391,744	2,183,253
Accrued interest payable	23,438	22,148
Lease liability - financing leases	174,983	44,448
Other liabilities	$ 306,077	$ 177,080
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
Debt and preferred equity investments, discount and deferred origination fees	$ 12,031	$ 14,562
Allowance for loan and lease losses, real estate	$ 19,010	$ 1,750
Limited partner interests in Operating Partnership, limited partner common units outstanding (shares)	4,027,000	4,196,000
SL Green partner's capital, general partner common units outstanding (shares)	771,000	834,000
SL Green partners' capital, limited partner common units outstanding (shares)	72,269,000	78,368,000
Land and land interests	$ 1,639,118	$ 1,751,544
Building and improvements	5,483,155	5,154,990
Building leasehold and improvements	1,442,251	1,433,793
Right of use asset - financing leases	75,711	47,445
Accumulated depreciation	2,260,247	2,060,560
Other assets	514,873	332,801
Mortgages and other loans payable, net	2,391,744	2,183,253
Accrued interest payable	23,438	22,148
Lease liability - financing leases	174,983	44,448
Other liabilities	$ 306,077	$ 177,080
SL Green Operating Partnership | Series I Preferred Stock
Preferred units, liquidation preference (in dollars per share)	$ 25	$ 25
Preferred units, shares issued (in shares)	9,200,000	9,200,000
Preferred units, shares outstanding (in shares)	9,200,000	9,200,000
Consolidated VIEs
Land and land interests	$ 375,900	$ 205,200
Building and improvements	1,400,000	481,900
Building leasehold and improvements	2,000	2,000
Right of use asset - financing leases	61,700	61,700
Accumulated depreciation	296,300	17,600
Other assets	322,800	169,500
Mortgages and other loans payable, net	510,700	457,100
Accrued interest payable	1,100	1,200
Lease liability - financing leases	58,400	57,700
Other liabilities	48,900	43,700
Consolidated VIEs | SL Green Operating Partnership
Land and land interests	375,900	205,200
Building and improvements	1,400,000	481,900
Building leasehold and improvements	2,000	2,000
Right of use asset - financing leases	61,700	61,700
Accumulated depreciation	296,300	17,600
Other assets	322,800	169,500
Mortgages and other loans payable, net	510,700	457,100
Accrued interest payable	1,100	1,200
Lease liability - financing leases	58,400	57,700
Other liabilities	$ 48,900	$ 43,700

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues
Rental revenue, net	$ 195,515	$ 248,028	$ 614,032	$ 733,105
Investment income	22,988	51,518	101,464	153,167
Other income	31,341	14,088	102,350	44,641
Total revenues	249,844	313,634	817,846	930,913
Expenses
Operating expenses, including related party expenses of $2,801 and $9,289 in 2020 and $5,460 and $13,575 in 2019	45,910	59,847	140,673	175,862
Real estate taxes	43,522	49,626	131,805	143,008
Operating lease rent	6,973	8,295	22,171	24,891
Interest expense, net of interest income	23,536	48,112	91,100	145,797
Amortization of deferred financing costs	3,151	3,112	8,312	8,566
Depreciation and amortization	92,516	70,464	256,736	208,268
Loan loss and other investment reserves, net of recoveries	8,957	0	27,018	0
Transaction related costs	45	44	483	360
Marketing, general and administrative	23,602	23,841	66,682	75,300
Total expenses	248,212	263,341	744,980	782,052
Equity in net loss from unconsolidated joint ventures	(432)	(9,864)	(15,445)	(22,644)
Equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate	0	0	0	76,181
Purchase price and other fair value adjustments	0	3,799	0	69,389
Gain on sale of real estate, net	26,104	3,541	163,624	2,492
Depreciable real estate reserves and impairment	(6,627)	(7,047)	(6,627)	(7,047)
Net income	20,677	40,722	214,418	267,232
Net (income) loss attributable to noncontrolling interests:
Noncontrolling interests in the Operating Partnership	(802)	(1,719)	(10,073)	(12,306)
Noncontrolling interests in other partnerships	(414)	624	(1,145)	2,524
Preferred units distributions	(1,864)	(2,732)	(6,883)	(8,185)
Net income (loss) attributable to SL Green/SLGOP	17,597	36,895	196,317	249,265
Perpetual preferred stock dividends	(3,738)	(3,738)	(11,213)	(11,213)
Net income attributable to SL Green common stockholders	$ 13,859	$ 33,157	$ 185,104	$ 238,052
Basic earnings per share (usd per share)	$ 0.19	$ 0.40	$ 2.44	$ 2.87
Diluted earnings per share (usd per share)	$ 0.19	$ 0.40	$ 2.44	$ 2.87
Basic weighted average common shares outstanding (in shares)	73,020	82,292	75,521	82,855
Diluted weighted average common shares and common share equivalents outstanding (in shares)	77,491	86,714	80,085	87,309
Operating expenses, paid to related parties	$ 2,801	$ 5,460	$ 9,289	$ 13,575
SL Green Operating Partnership
Revenues
Rental revenue, net	195,515	248,028	614,032	733,105
Investment income	22,988	51,518	101,464	153,167
Other income	31,341	14,088	102,350	44,641
Total revenues	249,844	313,634	817,846	930,913
Expenses
Operating expenses, including related party expenses of $2,801 and $9,289 in 2020 and $5,460 and $13,575 in 2019	45,910	59,847	140,673	175,862
Real estate taxes	43,522	49,626	131,805	143,008
Operating lease rent	6,973	8,295	22,171	24,891
Interest expense, net of interest income	23,536	48,112	91,100	145,797
Amortization of deferred financing costs	3,151	3,112	8,312	8,566
Depreciation and amortization	92,516	70,464	256,736	208,268
Loan loss and other investment reserves, net of recoveries	8,957	0	27,018	0
Transaction related costs	45	44	483	360
Marketing, general and administrative	23,602	23,841	66,682	75,300
Total expenses	248,212	263,341	744,980	782,052
Equity in net loss from unconsolidated joint ventures	(432)	(9,864)	(15,445)	(22,644)
Equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate	0	0	0	76,181
Purchase price and other fair value adjustments	0	3,799	0	69,389
Gain on sale of real estate, net	26,104	3,541	163,624	2,492
Depreciable real estate reserves and impairment	(6,627)	(7,047)	(6,627)	(7,047)
Net income	20,677	40,722	214,418	267,232
Net (income) loss attributable to noncontrolling interests:
Noncontrolling interests in other partnerships	(414)	624	(1,145)	2,524
Preferred units distributions	(1,864)	(2,732)	(6,883)	(8,185)
Net income (loss) attributable to SL Green/SLGOP	18,399	38,614	206,390	261,571
Perpetual preferred unit distributions	(3,738)	(3,738)	(11,213)	(11,213)
Net income attributable to SLGOP common unitholders	$ 14,661	$ 34,876	$ 195,177	$ 250,358
Basic earnings per unit (usd per share)	$ 0.19	$ 0.40	$ 2.44	$ 2.87
Diluted earnings per unit (usd per share)	$ 0.19	$ 0.40	$ 2.44	$ 2.87
Basic weighted average common units outstanding (in shares)	77,049	86,550	79,644	87,138
Diluted weighted average common units and common unit equivalents outstanding (in shares)	77,491	86,714	80,085	87,309
Operating expenses, paid to related parties	$ 2,801	$ 5,460	$ 9,289	$ 13,575

Consolidated Statements of Op_2

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Operating expenses, paid to related parties	$ 2,801	$ 5,460	$ 9,289	$ 13,575
SL Green Operating Partnership
Operating expenses, paid to related parties	$ 2,801	$ 5,460	$ 9,289	$ 13,575

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net income	$ 20,677	$ 40,722	$ 214,418	$ 267,232
Other comprehensive income (loss):
Increase (decrease) in unrealized value of derivative instruments, including SL Green's share of joint venture derivative instruments	6,099	(12,574)	(48,227)	(59,680)
Increase (decrease) in unrealized value of marketable securities	389	230	(2,152)	1,571
Other comprehensive income (loss)	6,488	(12,344)	(50,379)	(58,109)
Comprehensive income	27,165	28,378	164,039	209,123
Net income attributable to noncontrolling interests and preferred units distributions	(3,080)	(3,827)	(18,101)	(17,967)
Net (income) loss attributable to noncontrolling interests	(414)	624	(1,145)	2,524
Other comprehensive (income) loss attributable to noncontrolling interests	(317)	607	2,664	2,869
Comprehensive income attributable to SL Green/SLGOP	23,768	25,158	148,602	194,025
SL Green Operating Partnership
Net income	20,677	40,722	214,418	267,232
Other comprehensive income (loss):
Increase (decrease) in unrealized value of derivative instruments, including SL Green's share of joint venture derivative instruments	6,099	(12,574)	(48,227)	(59,680)
Increase (decrease) in unrealized value of marketable securities	389	230	(2,152)	1,571
Other comprehensive income (loss)	6,488	(12,344)	(50,379)	(58,109)
Comprehensive income	27,165	28,378	164,039	209,123
Net (income) loss attributable to noncontrolling interests	(414)	624	(1,145)	2,524
Other comprehensive (income) loss attributable to noncontrolling interests	(317)	607	2,664	2,869
Comprehensive income attributable to SL Green/SLGOP	$ 26,434	$ 29,609	$ 165,558	$ 214,516

Consolidated Statement of Equit

Consolidated Statement of Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In-Capital	Treasury Stock	Accumulated Other Comprehensive Loss	Retained Earnings	Noncontrolling Interests	Series I Preferred StockPreferred Stock	Cumulative Effect, Period Of Adoption, Adjustment	Cumulative Effect, Period Of Adoption, AdjustmentRetained Earnings	Cumulative Effect, Period Of Adoption, Adjusted Balance	Cumulative Effect, Period Of Adoption, Adjusted BalanceCommon Stock	Cumulative Effect, Period Of Adoption, Adjusted BalanceAdditional Paid-In-Capital	Cumulative Effect, Period Of Adoption, Adjusted BalanceTreasury Stock	Cumulative Effect, Period Of Adoption, Adjusted BalanceAccumulated Other Comprehensive Loss	Cumulative Effect, Period Of Adoption, Adjusted BalanceRetained Earnings	Cumulative Effect, Period Of Adoption, Adjusted BalanceNoncontrolling Interests	Cumulative Effect, Period Of Adoption, Adjusted BalanceSeries I Preferred StockPreferred Stock
Beginning Balance at Dec. 31, 2018	$ 5,947,855	$ 847	$ 4,508,685	$ (124,049)	$ 15,108	$ 1,278,998	$ 46,334	$ 221,932
Beginning Balance (in shares) at Dec. 31, 2018		83,684
Increase (Decrease) in Stockholders' Equity
Net income (loss)	210,470					212,370	(1,900)
Acquisition of subsidiary interest from noncontrolling interest	(25,791)		(515)				(25,276)
Other comprehensive loss	(43,503)				(43,503)
Preferred dividends	(7,475)					(7,475)
DRSPP proceeds (in shares)		3
DRSPP proceeds	263		263
Conversion of units of the Operating Partnership to common stock (in shares)		5
Conversion of units in the Operating Partnership for common stock	446		446
Reallocation of noncontrolling interest in the Operating Partnership	(14,028)					(14,028)
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings (in shares)		(17)
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	10,533		10,533
Repurchases of common stock (in shares)		(1,265)
Repurchases of common stock	(109,313)	$ (12)	(68,203)			(41,098)
Contributions to consolidated joint venture interests	50,692						50,692
Cash distributions to noncontrolling interests	(271)						(271)
Cash distributions declared (per common share, none of which represented a return of capital for federal income tax purposes)	(140,377)					(140,377)
Ending Balance at Jun. 30, 2019	5,879,501	$ 835	4,451,209	(124,049)	(28,395)	1,288,390	69,579	221,932
Ending Balance (in shares) at Jun. 30, 2019		82,410
Beginning Balance at Dec. 31, 2018	5,947,855	$ 847	4,508,685	(124,049)	15,108	1,278,998	46,334	221,932
Beginning Balance (in shares) at Dec. 31, 2018		83,684
Increase (Decrease) in Stockholders' Equity
Preferred dividends	(11,213)
Ending Balance at Sep. 30, 2019	5,763,300	$ 826	4,407,667	(124,049)	(40,132)	1,225,904	71,152	221,932
Ending Balance (in shares) at Sep. 30, 2019		81,515
Beginning Balance at Dec. 31, 2018	5,947,855	$ 847	4,508,685	(124,049)	15,108	1,278,998	46,334	221,932
Beginning Balance (in shares) at Dec. 31, 2018		83,684
Ending Balance at Dec. 31, 2019	5,517,198	$ 803	4,286,395	(124,049)	(28,485)	1,084,719	75,883	221,932			$ 5,478,014	$ 803	$ 4,286,395	$ (124,049)	$ (28,485)	$ 1,045,535	$ 75,883	$ 221,932
Ending Balance (Accounting Standards Update 2016-13) at Dec. 31, 2019									$ (39,184)	$ (39,184)
Ending Balance (in shares) at Dec. 31, 2019		79,202										79,202
Beginning Balance at Jun. 30, 2019	5,879,501	$ 835	4,451,209	(124,049)	(28,395)	1,288,390	69,579	221,932
Beginning Balance (in shares) at Jun. 30, 2019		82,410
Increase (Decrease) in Stockholders' Equity
Net income (loss)	36,271					36,895	(624)
Acquisition of subsidiary interest from noncontrolling interest	(54)		(54)
Other comprehensive loss	(11,737)				(11,737)
Preferred dividends	(3,738)					(3,738)
DRSPP proceeds (in shares)
DRSPP proceeds	39		39
Conversion of units in the Operating Partnership for common stock	25		25
Reallocation of noncontrolling interest in the Operating Partnership	(1,481)					(1,481)
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings (in shares)		21
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	5,948		5,948
Repurchases of common stock (in shares)		(916)
Repurchases of common stock	(74,531)	$ (9)	(49,500)			(25,022)
Contributions to consolidated joint venture interests	2,404						2,404
Cash distributions to noncontrolling interests	(207)						(207)
Cash distributions declared (per common share, none of which represented a return of capital for federal income tax purposes)	(69,140)					(69,140)
Ending Balance at Sep. 30, 2019	$ 5,763,300	$ 826	4,407,667	(124,049)	(40,132)	1,225,904	71,152	221,932
Ending Balance (in shares) at Sep. 30, 2019		81,515
Increase (Decrease) in Stockholders' Equity
Cash distribution declared, per common share (in dollars per share)	$ 0.85
Beginning Balance at Dec. 31, 2019	$ 5,517,198	$ 803	4,286,395	(124,049)	(28,485)	1,084,719	75,883	221,932			5,478,014	$ 803	4,286,395	(124,049)	(28,485)	1,045,535	75,883	221,932
Beginning Balance (in shares) at Dec. 31, 2019		79,202										79,202
Increase (Decrease) in Stockholders' Equity
Net income (loss)	179,451					178,720	731
Acquisition of subsidiary interest from noncontrolling interest	(1,536)		(3,123)				1,587
Other comprehensive loss	(53,886)				(53,886)
Preferred dividends	(7,475)					(7,475)
DRSPP proceeds (in shares)		6
DRSPP proceeds	364		364
Conversion of units of the Operating Partnership to common stock (in shares)		101
Conversion of units in the Operating Partnership for common stock	8,744	$ 1	8,743
Reallocation of noncontrolling interest in the Operating Partnership	31,144					31,144
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings (in shares)		(33)
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	13,493		13,493
Repurchases of common stock (in shares)		(5,601)
Repurchases of common stock	(360,868)	$ (56)	(283,981)			(76,831)
Contributions to consolidated joint venture interests	8,185						8,185
Cash distributions to noncontrolling interests	(596)						(596)
Cash distributions declared (per common share, none of which represented a return of capital for federal income tax purposes)	(89,272)					(89,272)
Ending Balance at Jun. 30, 2020	5,205,762	$ 748	4,021,891	(124,049)	(82,371)	1,081,821	85,790	221,932
Ending Balance (in shares) at Jun. 30, 2020		73,675
Beginning Balance at Dec. 31, 2019	5,517,198	$ 803	4,286,395	(124,049)	(28,485)	1,084,719	75,883	221,932			$ 5,478,014	$ 803	$ 4,286,395	$ (124,049)	$ (28,485)	$ 1,045,535	$ 75,883	$ 221,932
Beginning Balance (Accounting Standards Update 2016-13) at Dec. 31, 2019									$ (39,184)	$ (39,184)
Beginning Balance (in shares) at Dec. 31, 2019		79,202										79,202
Increase (Decrease) in Stockholders' Equity
Preferred dividends	(11,213)
Ending Balance at Sep. 30, 2020	5,134,005	$ 741	3,998,516	(124,049)	(76,200)	1,035,172	77,893	221,932
Ending Balance (in shares) at Sep. 30, 2020		73,040
Beginning Balance at Jun. 30, 2020	5,205,762	$ 748	4,021,891	(124,049)	(82,371)	1,081,821	85,790	221,932
Beginning Balance (in shares) at Jun. 30, 2020		73,675
Increase (Decrease) in Stockholders' Equity
Net income (loss)	18,011					17,597	414
Acquisition of subsidiary interest from noncontrolling interest	0		0				0
Other comprehensive loss	6,171				6,171
Preferred dividends	(3,738)					(3,738)
DRSPP proceeds (in shares)		4
DRSPP proceeds	202		202
Conversion of units of the Operating Partnership to common stock (in shares)		0
Conversion of units in the Operating Partnership for common stock	0	$ 0	0
Reallocation of noncontrolling interest in the Operating Partnership	4,109					4,109
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings (in shares)		3
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	7,543	$ 0	7,543
Repurchases of common stock (in shares)		(642)
Repurchases of common stock	(31,127)	$ (7)	(31,120)			0
Contributions to consolidated joint venture interests	4,219						4,219
Cash distributions to noncontrolling interests	(12,530)						(12,530)
Cash distributions declared (per common share, none of which represented a return of capital for federal income tax purposes)	(64,617)					(64,617)
Ending Balance at Sep. 30, 2020	$ 5,134,005	$ 741	$ 3,998,516	$ (124,049)	$ (76,200)	$ 1,035,172	$ 77,893	$ 221,932
Ending Balance (in shares) at Sep. 30, 2020		73,040
Increase (Decrease) in Stockholders' Equity
Cash distribution declared, per common share (in dollars per share)	$ 0.885

Consolidated Statement of Equ_2

Consolidated Statement of Equity (Parenthetical) - $ / shares	3 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Jun. 30, 2019
Statement of Stockholders' Equity [Abstract]
Cash distribution declared, per common share (in dollars per share)	$ 0.885	$ 1.180	$ 0.85	$ 1.70

Consolidated Statements of Capi

Consolidated Statements of Capital (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended		9 Months Ended	12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2020	Dec. 31, 2019
Increase (Decrease) in Partner's Capital
Acquisition of subsidiary interest from noncontrolling interest	$ 0		$ (54)		$ (1,536)	$ (25,791)
DRSPP proceeds	202		39		364	263
Conversion of common units	0		25		8,744	446
Reallocation of noncontrolling interests in the operating partnership	4,109		(1,481)		31,144	(14,028)
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	7,543		5,948		13,493	10,533
Repurchases of common stock	(31,127)		(74,531)		(360,868)	(109,313)
Contribution to consolidated joint venture interests	4,219		2,404		8,185	50,692
Cash distributions to noncontrolling interests	$ (12,530)		$ (207)		$ (596)	$ (271)
Cash distribution declared, per common share (in dollars per share)	$ 0.885	$ 1.180	$ 0.85	$ 1.70
Common Stock
Increase (Decrease) in Partner's Capital
DRSPP proceeds (in shares)	4				6	3
Conversion of common units	$ 0				$ 1
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings (in shares)	3		21		(33)	(17)
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	$ 0
Repurchases of common stock (in shares)	(642)		(916)		(5,601)	(1,265)
Repurchases of common stock	$ (7)		$ (9)		$ (56)	$ (12)
Noncontrolling Interests
Increase (Decrease) in Partner's Capital
Acquisition of subsidiary interest from noncontrolling interest	0				1,587	(25,276)
Contribution to consolidated joint venture interests	4,219		2,404		8,185	50,692
Cash distributions to noncontrolling interests	(12,530)		(207)		(596)	(271)
SL Green Operating Partnership
Increase (Decrease) in Partner's Capital
Beginning Balance	5,205,762		5,879,501		5,517,198	5,947,855	$ 5,517,198	$ 5,947,855
Net income (loss)	18,011		36,271		179,451	210,470
Acquisition of subsidiary interest from noncontrolling interest	0		(54)		(1,536)	(25,791)
Other comprehensive income	6,171		(11,737)		(53,886)	(43,503)
Preferred distributions	(3,738)		(3,738)		(7,475)	(7,475)
DRSPP proceeds	202		39		364	263
Conversion of common units	0		25		8,744	446
Reallocation of noncontrolling interests in the operating partnership	4,109		(1,481)		31,144	(14,028)
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	7,543		5,948		13,493	10,533
Repurchases of common stock	(31,127)		(74,531)		(360,868)	(109,313)
Contribution to consolidated joint venture interests	4,219		2,404		8,185	50,692
Cash distributions to noncontrolling interests	$ (12,530)		$ (207)		(596)	(271)
Cash distribution declared, per common share (in dollars per share)	$ 0.885	$ 1.180	$ 0.85	$ 1.70
Cash distributions declared (per common unit, none of which represented a return of capital for federal income tax purposes)	$ (64,617)		$ (69,140)		(89,272)	(140,377)
Ending Balance	5,134,005	$ 5,205,762	5,763,300	$ 5,879,501	5,205,762	5,879,501	5,134,005	5,517,198
SL Green Operating Partnership | Common Stock | Partners' Interest
Increase (Decrease) in Partner's Capital
Beginning Balance	$ 4,980,411		$ 5,616,385		$ 5,247,868	$ 5,664,481	$ 5,247,868	$ 5,664,481
Beginning Balance (units)	73,675		82,410		79,202	83,684	79,202	83,684
Net income (loss)	$ 17,597		$ 36,895		$ 178,720	$ 212,370
Acquisition of subsidiary interest from noncontrolling interest	0		(54)		(3,123)	(515)
Preferred distributions	$ (3,738)		$ (3,738)		$ (7,475)	$ (7,475)
DRSPP proceeds (in shares)	4		0		6	3
DRSPP proceeds	$ 202		$ 39		$ 364	$ 263
Conversion of common units (in shares)	0		0		101	5
Conversion of common units	$ 0		$ 25		$ 8,744	$ 446
Reallocation of noncontrolling interests in the operating partnership	$ 4,109		$ (1,481)		$ 31,144	$ (14,028)
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings (in shares)	3		21		(33)	(17)
Deferred compensation plan and stock awards, net of forfeitures and tax withholdings	$ 7,543		$ 5,948		$ 13,493	$ 10,533
Repurchases of common stock (in shares)	(642)		(916)		(5,601)	(1,265)
Repurchases of common stock	$ (31,127)		$ (74,531)		$ (360,868)	$ (109,313)
Cash distributions declared (per common unit, none of which represented a return of capital for federal income tax purposes)	(64,617)		(69,140)		(89,272)	(140,377)
Ending Balance	$ 4,910,380	$ 4,980,411	$ 5,510,348	$ 5,616,385	$ 4,980,411	$ 5,616,385	$ 4,910,380	$ 5,247,868
Ending Balance (units)	73,040	73,675	81,515	82,410	73,675	82,410	73,040	79,202
SL Green Operating Partnership | Accumulated Other Comprehensive Loss
Increase (Decrease) in Partner's Capital
Beginning Balance	$ (82,371)		$ (28,395)		$ (28,485)	$ 15,108	$ (28,485)	$ 15,108
Other comprehensive income	6,171		(11,737)		(53,886)	(43,503)
Ending Balance	(76,200)	$ (82,371)	(40,132)	$ (28,395)	(82,371)	(28,395)	(76,200)	(28,485)
SL Green Operating Partnership | Noncontrolling Interests
Increase (Decrease) in Partner's Capital
Beginning Balance	85,790		69,579		75,883	46,334	75,883	46,334
Net income (loss)	414		(624)		731	(1,900)
Acquisition of subsidiary interest from noncontrolling interest	0				1,587	(25,276)
Contribution to consolidated joint venture interests	4,219		2,404		8,185	50,692
Cash distributions to noncontrolling interests	(12,530)		(207)		(596)	(271)
Ending Balance	77,893	85,790	71,152	69,579	85,790	69,579	77,893	75,883
Series I Preferred Stock | SL Green Operating Partnership | Preferred Units
Increase (Decrease) in Partner's Capital
Beginning Balance	221,932		221,932		221,932	221,932	221,932	221,932
Ending Balance	$ 221,932	$ 221,932	$ 221,932	$ 221,932	221,932	$ 221,932	221,932	221,932
Cumulative Effect, Period Of Adoption, Adjusted Balance | SL Green Operating Partnership
Increase (Decrease) in Partner's Capital
Beginning Balance					5,478,014		5,478,014
Ending Balance								5,478,014
Cumulative Effect, Period Of Adoption, Adjusted Balance | SL Green Operating Partnership | Common Stock | Partners' Interest
Increase (Decrease) in Partner's Capital
Beginning Balance					$ 5,208,684		$ 5,208,684
Beginning Balance (units)					79,202		79,202
Ending Balance								$ 5,208,684
Ending Balance (units)								79,202
Cumulative Effect, Period Of Adoption, Adjusted Balance | SL Green Operating Partnership | Accumulated Other Comprehensive Loss
Increase (Decrease) in Partner's Capital
Beginning Balance					$ (28,485)		$ (28,485)
Ending Balance								$ (28,485)
Cumulative Effect, Period Of Adoption, Adjusted Balance | SL Green Operating Partnership | Noncontrolling Interests
Increase (Decrease) in Partner's Capital
Beginning Balance					75,883		75,883
Ending Balance								75,883
Cumulative Effect, Period Of Adoption, Adjusted Balance | Series I Preferred Stock | SL Green Operating Partnership | Preferred Units
Increase (Decrease) in Partner's Capital
Beginning Balance					221,932		221,932
Ending Balance								221,932
Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment | SL Green Operating Partnership
Increase (Decrease) in Partner's Capital
Beginning Balance					(39,184)		(39,184)
Ending Balance								(39,184)
Accounting Standards Update 2016-13 | Cumulative Effect, Period Of Adoption, Adjustment | SL Green Operating Partnership | Common Stock | Partners' Interest
Increase (Decrease) in Partner's Capital
Beginning Balance					$ (39,184)		$ (39,184)
Ending Balance								$ (39,184)

Consolidated Statements of Ca_2

Consolidated Statements of Capital (Parenthetical) - $ / shares	3 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Sep. 30, 2019	Jun. 30, 2019
Cash distribution declared, per common share (in dollars per share)	$ 0.885	$ 1.180	$ 0.85	$ 1.70
SL Green Operating Partnership
Cash distribution declared, per common share (in dollars per share)	$ 0.885	$ 1.180	$ 0.85	$ 1.70

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating Activities
Net income	$ 214,418	$ 267,232
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	265,048	216,834
Equity in net loss from unconsolidated joint ventures	15,445	22,644
Distributions of cumulative earnings from unconsolidated joint ventures	576	648
Equity in net gain on sale of interest in unconsolidated joint venture interest/real estate	0	(76,181)
Purchase price and other fair value adjustments	0	(69,389)
Depreciable real estate reserves and impairment	6,627	7,047
Gain on sale of real estate, net	(163,624)	(2,492)
Loan loss reserves and other investment reserves, net of recoveries	27,018	0
Deferred rents receivable	(3,459)	(10,005)
Non-cash lease expense	9,735	10,255
Other non-cash adjustments	14,874	(11,766)
Changes in operating assets and liabilities:
Tenant and other receivables	(43,069)	(7,564)
Related party receivables	4,195	8,921
Deferred lease costs	(12,472)	(38,542)
Other assets	(55,301)	(47,139)
Accounts payable, accrued expenses, other liabilities and security deposits	43,256	18,737
Deferred revenue	13,206	18,255
Change in lease liability - operating leases	(8,530)	(8,062)
Net cash provided by operating activities	327,943	299,433
Investing Activities
Acquisitions of real estate property	(86,846)	(261,596)
Additions to land, buildings and improvements	(281,651)	(150,742)
Acquisition deposits and deferred purchase price	0	(228)
Investments in unconsolidated joint ventures	(39,724)	(114,050)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	104,300	62,576
Net proceeds from disposition of real estate/joint venture interest	333,037	138,948
Other investments	(3,921)	(2,491)
Origination of debt and preferred equity investments	(353,797)	(555,951)
Repayments or redemption of debt and preferred equity investments	703,625	642,634
Net cash provided by (used in) investing activities	375,023	(240,900)
Financing Activities
Proceeds from mortgages and other loans payable	1,128,775	699,072
Repayments of mortgages and other loans payable	(710,352)	(162,024)
Proceeds from revolving credit facility and senior unsecured notes	1,275,000	1,090,000
Repayments of revolving credit facility and senior unsecured notes	(1,575,000)	(1,255,000)
Proceeds from stock options exercised and DRSPP issuance	566	302
Repurchase of common stock	(381,992)	(175,005)
Redemption of preferred stock	(82,750)	(15,142)
Redemption of OP units	(18,913)	(15,918)
Distributions to noncontrolling interests in other partnerships	(13,126)	(478)
Contributions from noncontrolling interests in other partnerships	12,404	4,873
Acquisition of subsidiary interest from noncontrolling interest	(1,536)	(25,791)
Distributions to noncontrolling interests in the Operating Partnership	(8,857)	(10,993)
Dividends paid on common and preferred stock	(224,147)	(230,804)
Tax withholdings related to restricted share awards	(4,752)	(3,126)
Deferred loan costs	(34,687)	(21,068)
Principal payments of on financing lease liabilities	(580)	0
Net cash used in financing activities	(639,947)	(121,102)
Net increase (decrease) in cash, cash equivalents, and restricted cash	63,019	(62,569)
Cash, cash equivalents, and restricted cash at beginning of year	241,430	279,113
Cash, cash equivalents, and restricted cash at end of period	304,449	216,544
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Conversion of units in the Operating Partnership	8,744	471
Exchange of preferred equity investment for real estate or equity in joint venture	119,497	0
Issuance of preferred units relating to a real estate acquisition	0	1,000
Tenant improvements and capital expenditures payable	11,993	10,040
Fair value adjustment to noncontrolling interest in the Operating Partnership	35,253	15,509
Deconsolidation of a subsidiary	0	395
Reversal of assets held for sale	391,664	0
Seller financed purchases	100,000	0
Debt and preferred equity reserves	4,638	0
Transfer of assets related to assets held for sale	0	403,488
Removal of fully depreciated commercial real estate properties	7,906	6,602
Contribution to consolidated joint venture by noncontrolling interest	0	48,223
Share repurchase payable	10,003	8,839
Recognition of right of use assets and related lease liabilities	57,500	389,120
Total cash, cash equivalents, and restricted cash	304,449	216,544
SL Green Operating Partnership
Operating Activities
Net income	214,418	267,232
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	265,048	216,834
Equity in net loss from unconsolidated joint ventures	15,445	22,644
Distributions of cumulative earnings from unconsolidated joint ventures	576	648
Equity in net gain on sale of interest in unconsolidated joint venture interest/real estate	0	(76,181)
Purchase price and other fair value adjustments	0	(69,389)
Depreciable real estate reserves and impairment	6,627	7,047
Gain on sale of real estate, net	(163,624)	(2,492)
Loan loss reserves and other investment reserves, net of recoveries	27,018	0
Deferred rents receivable	(3,459)	(10,005)
Non-cash lease expense	9,735	10,255
Other non-cash adjustments	14,874	(11,766)
Changes in operating assets and liabilities:
Tenant and other receivables	(43,069)	(7,564)
Related party receivables	4,195	8,921
Deferred lease costs	(12,472)	(38,542)
Other assets	(55,301)	(47,139)
Accounts payable, accrued expenses, other liabilities and security deposits	43,256	18,737
Deferred revenue	13,206	18,255
Change in lease liability - operating leases	(8,530)	(8,062)
Net cash provided by operating activities	327,943	299,433
Investing Activities
Acquisitions of real estate property	(86,846)	(261,596)
Additions to land, buildings and improvements	(281,651)	(150,742)
Acquisition deposits and deferred purchase price	0	(228)
Investments in unconsolidated joint ventures	(39,724)	(114,050)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	104,300	62,576
Net proceeds from disposition of real estate/joint venture interest	333,037	138,948
Other investments	(3,921)	(2,491)
Origination of debt and preferred equity investments	(353,797)	(555,951)
Repayments or redemption of debt and preferred equity investments	703,625	642,634
Net cash provided by (used in) investing activities	375,023	(240,900)
Financing Activities
Proceeds from mortgages and other loans payable	1,128,775	699,072
Repayments of mortgages and other loans payable	(710,352)	(162,024)
Proceeds from revolving credit facility and senior unsecured notes	1,275,000	1,090,000
Repayments of revolving credit facility and senior unsecured notes	(1,575,000)	(1,255,000)
Proceeds from stock options exercised and DRSPP issuance	566	302
Repurchase of common stock	(381,992)	(175,005)
Redemption of preferred stock	(82,750)	(15,142)
Redemption of OP units	(18,913)	(15,918)
Distributions to noncontrolling interests in other partnerships	(13,126)	(478)
Contributions from noncontrolling interests in other partnerships	12,404	4,873
Acquisition of subsidiary interest from noncontrolling interest	(1,536)	(25,791)
Dividends paid on common and preferred stock	(233,004)	(241,797)
Tax withholdings related to restricted share awards	(4,752)	(3,126)
Deferred loan costs	(34,687)	(21,068)
Principal payments of on financing lease liabilities	(580)	0
Net cash used in financing activities	(639,947)	(121,102)
Net increase (decrease) in cash, cash equivalents, and restricted cash	63,019	(62,569)
Cash, cash equivalents, and restricted cash at beginning of year	241,430	279,113
Cash, cash equivalents, and restricted cash at end of period	304,449	216,544
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Conversion of units in the Operating Partnership	8,744	471
Exchange of preferred equity investment for real estate or equity in joint venture	119,497	0
Issuance of preferred units relating to a real estate acquisition	0	1,000
Tenant improvements and capital expenditures payable	11,993	10,040
Fair value adjustment to noncontrolling interest in the Operating Partnership	35,253	15,509
Deconsolidation of a subsidiary	0	395
Reversal of assets held for sale	391,664	0
Seller financed purchases	100,000	0
Debt and preferred equity reserves	4,638	0
Transfer of assets related to assets held for sale	0	403,488
Transfer of liabilities related to assets held for sale	0	0
Removal of fully depreciated commercial real estate properties	7,906	6,602
Contribution to consolidated joint venture by noncontrolling interest	0	48,223
Share repurchase payable	10,003	8,839
Recognition of right of use assets and related lease liabilities	57,500	389,120
Total cash, cash equivalents, and restricted cash	$ 304,449	$ 216,544

Partners' Capital of the Operat

Partners' Capital of the Operating Partnership	9 Months Ended
	Sep. 30, 2020
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, 2020, 73,040,291 shares of common stock and no shares of excess stock were issued and outstanding. Share Repurchase Program In August 2016, our Board of Directors approved a share repurchase program under which we can buy up to $1.0 billion of shares of our common stock. The Board of Directors has since authorized four separate $500.0 million increases to the size of the share repurchase program in the fourth quarter of 2017, second quarter of 2018, fourth quarter of 2018, and fourth quarter of 2019 bringing the total program size to $3.0 billion. At September 30, 2020, repurchases executed under the program were as follows: Period Shares repurchased Average price paid per share Cumulative number of shares repurchased as part of the repurchase plan or programs Year ended 2017 8,342,411 $101.64 8,342,411 Year ended 2018 9,744,911 $96.22 18,087,322 Year ended 2019 4,596,171 $83.62 22,683,493 Nine months ended September 30, 2020 (1) 6,243,165 $62.77 28,926,658 (1) Includes 216,101 shares of common stock repurchased by the Company in September 2020 that were settled in October 2020. 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. 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 ("DRSPP") In February 2018, 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 our common stock under the DRSPP. The DRSPP commenced on September 24, 2001. The following table summarizes SL Green common stock issued, and proceeds received from dividend reinvestments and/or stock purchases under the DRSPP for the three and nine months ended September 30, 2020 and 2019, respectively (dollars in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Shares of common stock issued 4,205 490 9,884 3,485 Dividend reinvestments/stock purchases under the DRSPP $ 202 $ 39 $ 566 $ 303 Earnings per Share We use the two-class method of computing earnings per share (“EPS”), which is an earnings allocation formula that determines EPS for common stock and any participating securities according to dividends declared (whether paid or unpaid). Under the two-class method, basic EPS is computed by dividing the income available to common stockholders by the weighted-average number of common stock shares outstanding for the period. Diluted EPS reflects the potential dilution that could occur from share equivalent activity. SL Green's earnings per share for the three and nine months ended September 30, 2020 and 2019 are computed as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Numerator 2020 2019 2020 2019 Basic Earnings: Income attributable to SL Green common stockholders $ 13,859 $ 33,157 $ 185,104 $ 238,052 Less: distributed earnings allocated to participating securities (333) (108) (777) (325) Less: undistributed earnings allocated to participating securities — — (141) (41) Net income attributable to SL Green common stockholders (numerator for basic earnings per share) $ 13,526 $ 33,049 $ 184,186 $ 237,686 Add back: dilutive effect of earnings allocated to participating securities 333 108 777 325 Add back: undistributed earnings allocated to participating securities — — 141 41 Add back: effect of dilutive securities (redemption of units to common shares) 802 1,719 10,073 12,306 Income attributable to SL Green common stockholders (numerator for diluted earnings per share) $ 14,661 $ 34,876 $ 195,177 $ 250,358 Three Months Ended September 30, Nine Months Ended September 30, Denominator 2020 2019 2020 2019 Basic Shares: Weighted average common stock outstanding 73,020 82,292 75,521 82,855 Effect of Dilutive Securities: Operating Partnership units redeemable for common shares 4,029 4,258 4,123 4,283 Stock-based compensation plans 442 164 441 171 Diluted weighted average common stock outstanding 77,491 86,714 80,085 87,309 The Company has excluded 2,131,606 and 1,779,212 common stock equivalents from the calculation of diluted shares outstanding for the three and nine months ended September 30, 2020, respectively, as they were anti-dilutive. The Company has excluded 1,317,803 and 1,266,296 common stock equivalents from the calculation of diluted shares outstanding for the three and nine months ended September 30, 2019, respectively, as they were anti-dilutive. The following tables set forth the changes in accumulated other comprehensive loss by component as of September 30, 2020 (in thousands): Net unrealized loss on derivative instruments ( 1 ) SL Green’s share of joint venture net unrealized loss on derivative instruments ( 2 ) Net unrealized gain (loss) on marketable securities Total Balance at December 31, 2019 $ (22,780) $ (7,982) $ 2,277 $ (28,485) Other comprehensive loss before reclassifications (50,038) (7,954) (2,047) (60,039) Amounts reclassified from accumulated other comprehensive loss 9,120 3,204 — 12,324 Balance at September 30, 2020 $ (63,698) $ (12,732) $ 230 $ (76,200) (1) Amount reclassified from accumulated other comprehensive loss is included in interest expense in the respective consolidated statements of operations. As of September 30, 2020 and December 31, 2019, the deferred net gains from these terminated hedges, which is included in accumulated other comprehensive loss relating to net unrealized (loss) gain on derivative instrument, was $(0.5) million and $(0.7) million, respectively. (2) Amount reclassified from accumulated other comprehensive loss is included in equity in net loss from unconsolidated joint ventures in the respective consolidated statements of operations.
SL Green Operating Partnership
Stockholders' Equity
Partners' Capital of the Operating Partnership	Partners' Capital of the Operating PartnershipThe Company is the sole managing general partner of the Operating Partnership and at September 30, 2020 owned 73,040,291 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, 2020, limited partners other than SL Green owned 5.23%, or 4,027,317 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, 2020 and 2019, respectively, are computed as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Numerator 2020 2019 2020 2019 Basic Earnings: Income attributable to SLGOP common unitholders $ 14,661 $ 34,876 $ 195,177 $ 250,358 Less: distributed earnings allocated to participating securities (333) (108) (777) (325) Less: undistributed earnings allocated to participating securities — — (141) (41) Net Income attributable to SLGOP common unitholders (numerator for basic earnings per unit) $ 14,328 $ 34,768 $ 194,259 $ 249,992 Add back: dilutive effect of earnings allocated to participating securities 333 108 777 325 Add back: undistributed earnings allocated to participating securities — — 141 41 Income attributable to SLGOP common unitholders (numerator for diluted earnings per unit) $ 14,661 $ 34,876 $ 195,177 $ 250,358 Three Months Ended September 30, Nine Months Ended September 30, Denominator 2020 2019 2020 2019 Basic units: Weighted average common units outstanding 77,049 86,550 79,644 87,138 Effect of Dilutive Securities: Stock-based compensation plans 442 164 441 171 Diluted weighted average common units outstanding 77,491 86,714 80,085 87,309 The Operating Partnership has excluded 2,131,606 and 1,779,212 common unit equivalents from the diluted units outstanding for the three and nine months ended September 30, 2020, respectively, as they were anti-dilutive. The Operating Partnership has excluded 1,317,803 and 1,266,296 common unit equivalents from the diluted units outstanding for the three and nine months ended September 30, 2019, respectively, as they were anti-dilutive.

Organization and Basis of Prese

Organization and Basis of Presentation	9 Months Ended
	Sep. 30, 2020
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, 2020, noncontrolling investors held, in the aggregate, a 5.23% 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." As of September 30, 2020, we owned the following interests in properties in the New York metropolitan area, primarily in midtown Manhattan. Our investments located outside of Manhattan are referred to 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 18 10,647,191 11 11,841,483 29 22,488,674 93.1 % Retail 4 44,189 8 289,050 12 333,239 94.0 % Development/Redevelopment 10 2,908,362 2 1,755,610 12 4,663,972 N/A Fee Interest — — 1 — 1 — — % 32 13,599,742 22 13,886,143 54 27,485,885 93.1 % Suburban Office 8 1,044,800 — — 8 1,044,800 85.0 % Retail 1 52,000 — — 1 52,000 100.0 % 9 1,096,800 — — 9 1,096,800 85.7 % Total commercial properties 41 14,696,542 22 13,886,143 63 28,582,685 92.7 % Residential: Manhattan Residential 1 82,250 8 1,663,774 9 1,746,024 78.8 % Total residential properties 1 82,250 8 1,663,774 9 1,746,024 78.8 % Total portfolio 42 14,778,792 30 15,549,917 72 30,328,709 91.9 % (1) The weighted average occupancy for commercial properties represents the total occupied square footage divided by the total square footage at acquisition. The weighted average occupancy for residential properties represents the total occupied units divided by the total available units. As of September 30, 2020, we also managed two office buildings owned by third parties encompassing approximately 2.1 million square feet (unaudited), and held debt and preferred equity investments with a book value of $1.15 billion, excluding $0.1 billion of debt and preferred equity investments and other financing receivables that are included in balance sheet line items other than the Debt and Preferred Equity Investments line item. 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, subject to the priority distributions with respect to preferred units and special provisions that apply to LTIP Units. 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, 2020 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, 2020. 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, 2019 of the Company and the Operating Partnership. The consolidated balance sheet at December 31, 2019 has been derived from the audited financial statements as of that date but does not include all the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. Subsequent Events Beginning in late 2019, a novel strain of Coronavirus (“COVID-19”) began to spread throughout the world, including the United States, ultimately being declared a pandemic by the World Health Organization. The pandemic has caused, and continues to cause, severe disruptions with wide ranging impacts to the global economy and everyday life. We expect that our business, results of operations, liquidity, cash flows, prospects, and our ability to achieve forward-looking targets and expectations could be materially and adversely affected for at least the duration of the COVID-19 pandemic and possibly longer. This has and may continue to cause significant volatility in the trading prices of our securities. The extent of the impact of the COVID-19 pandemic will depend on future developments, including the duration, severity and spread of the pandemic, health and safety actions taken to contain its spread and how quickly and to what extent normal economic and operating conditions can resume. Additionally, the COVID-19 pandemic could increase the magnitude of many of the other risks described in our latest Annual Report on Form 10-K and other SEC filings and may have other adverse effects on our operations that we are not currently able to predict. As of the date of this filing, we have collected gross tenant billings for the third quarter of 2020 of 92.7% overall, including 96.9% from office tenants and 70.2% from retail tenants. As of the date of this filing, we have collected gross tenant billings for the month of October 2020 of 93.0% overall, including 96.4% from office tenants and 72.6% from retail tenants. In October 2020, the Company, together with its partners, entered into a contract to sell interests in 410 Tenth Avenue for gross consideration of $952.5 million. We currently own 70.9% of the venture. As part of the sale, the venture is retaining a 5% interest through completion of the property's redevelopment. This transaction is expected to close in the fourth quarter of 2020, subject to satisfaction of various closing conditions. At September 30, 2020, we determined that the held for sale criteria was not met for this property as it was not probable that the sale of the asset would be completed within one year.

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2020
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 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. Investment in Commercial Real Estate Properties 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 3 years 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 1 year 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 1 year 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 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. The Company classifies those leases under which the Company is the lessee at lease commencement as finance or operating leases. Leases qualify as finance leases if the lease transfers ownership of the asset at the end of the lease term, the lease grants an option to purchase the asset that we are reasonably certain to exercise, the lease term is for a major part of the remaining economic life of the asset, or the present value of the lease payments exceeds substantially all of the fair value of the asset. Leases that do not qualify as finance leases are deemed to be operating leases. At lease commencement the Company records a lease liability which is measured as the present value of the lease payments and a right of use asset which is measured as the amount of the lease liability and any initial direct costs incurred. The Company applies a discount rate to determine the present value of the lease payments. If the rate implicit in the lease is known, the Company uses that rate. If the rate implicit in the lease is not known, the Company uses a discount rate reflective of the Company’s collateralized borrowing rate given the term of the lease. To determine the discount rate, the Company employs a third party specialist to develop an analysis based primarily on the observable borrowing rates of the Company, other REITs, and other corporate borrowers with long-term borrowings. On the consolidated statements of operations, operating leases are expensed through operating lease rent while financing leases are expensed through amortization and interest expense. On the consolidated balance sheet, financing leases include the amounts previously captioned "Properties under capital lease." When applicable, the Company combines the consideration for lease and non-lease components in the calculation of the value of the lease obligation and right-of-use asset. On a periodic basis, we assess whether there are any indications that the value of our real estate properties may be impaired or that their carrying value may not be recoverable. A property's value is considered impaired if management's estimate of the aggregate future cash flows (undiscounted) 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 fair value of the property as calculated in accordance with ASC 820. We also evaluate our real estate properties for impairment when a property has been classified as held for sale. Real estate assets held for sale are valued at the lower of their carrying value or fair value less costs to sell and depreciation expense is no longer recorded. We recognized $1.6 million and $4.5 million of rental revenue for the three and nine months ended September 30, 2020, respectively, and $1.2 million and $3.6 million of rental revenue for the three and nine months ended September 30, 2019, respectively, for the amortization of aggregate below-market leases in excess of above-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, 2020 and December 31, 2019 (in thousands): September 30, 2020 December 31, 2019 Identified intangible assets (included in other assets): Gross amount $ 224,221 $ 255,198 Accumulated amortization (208,135) (228,223) Net (1) $ 16,086 $ 26,975 Identified intangible liabilities (included in deferred revenue): Gross amount $ 273,240 $ 282,048 Accumulated amortization (255,879) (249,514) Net (1) $ 17,361 $ 32,534 (1) As of September 30, 2020 and December 31, 2019, no net intangible assets and no net intangible liabilities were reclassified to assets held for sale or liabilities related to assets held for sale. Fair Value Measurements See Note 16, "Fair Value Measurements." Investment in Marketable Securities At acquisition, we designate a security as held-to-maturity, available-for-sale, or trading. As of September 30, 2020, 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. The cost of marketable securities sold and the amount reclassified out of accumulated other comprehensive income into earnings is determined using the specific identification method. Any unrealized losses that are determined to be other-than-temporary are recognized in earnings up to their credit component. At September 30, 2020 and December 31, 2019, we held the following marketable securities (in thousands): September 30, 2020 December 31, 2019 Commercial mortgage-backed securities $ 27,734 $ 29,887 Total marketable securities available-for-sale $ 27,734 $ 29,887 The cost basis of the commercial mortgage-backed securities was $27.5 million at both September 30, 2020 and December 31, 2019. These securities mature at various times through 2035. We held no equity marketable securities as of September 30, 2020 and December 31, 2019. During the three and nine months ended September 30, 2020, we did not dispose of any marketable securities. During the three and nine months ended September 30, 2019, we did not dispose of any marketable securities. 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 each joint venture's projected discounted cash flows. We do not believe that the values of any of our equity investments were impaired at September 30, 2020. Deferred Lease Costs Deferred lease costs consist of incremental fees and direct costs that would not have been incurred if the lease had not been obtained and are amortized on a straight-line basis over the related lease term. Lease Classification Lease classification for leases under which the Company is the lessor is evaluated at lease commencement and leases not classified as sales-type leases or direct financing leases are classified as operating leases. Leases qualify as sales-type leases if the contract includes either transfer of ownership clauses, certain purchase options, a lease term representing a major part of the economic life of the asset, or the present value of the lease payments and residual guarantees provided by the lessee exceeds substantially all of the fair value of the asset. Additionally, leasing an asset so specialized that it is not deemed to have any value to the Company at the end of the lease term may also result in classification as a sales-type lease. Leases qualify as direct financing leases when the present value of the lease payments and residual value guarantees provided by the lessee and unrelated third parties exceeds substantially all of the fair value of the asset and collection of the payments is probable. Revenue Recognition Rental revenue for operating leases is recognized on a straight-line basis over the term of the lease. Rental revenue recognition commences when the leased space is available for use by the lessee. To determine whether the leased space is available for use by the lessee, 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 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. In addition to base rent, our tenants also generally will pay variable rent which represents their pro rata share of increases in real estate taxes and certain operating expenses for the building over a base year. In some leases, in lieu of paying additional rent based upon increases in certain 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. Rental revenue is recognized if collectability is probable. If collectability of substantially all of the lease payments is assessed as not probable, any difference between the rental revenue recognized to date and the lease payments that have been collected is recognized as a current-period adjustment to rental revenue. A subsequent change in the assessment of collectability to probable may result in a current-period adjustment to rental revenue for any difference between the rental revenue that would have been recognized if collectability had always been assessed as probable and the rental revenue recognized to date. We recognize lease concessions related to COVID-19 such as rent deferrals and abatements in accordance with the Lease Modification Q&A issued by the FASB in April 2020, which provides entities with the option to elect to account for lease concessions as though the enforceable rights and obligations existed in the original lease. This election is only available when total cash flows resulting from the modified lease are substantially similar to the cash flows in the original lease. When total cash flows resulting from the modified lease are not substantially similar to the cash flows in the original lease, we account for the concession agreement as a new lease. The Company provides its tenants with certain customary services for lease contracts such as common area maintenance and general security. We have elected to combine the non-lease components with the lease components of our operating lease agreements and account for them as a single lease component in accordance with ASC 842. Tenant and other receivables at September 30, 2020 and December 31, 2019 is shown net of $9.5 million and $2.6 million, respectively, of reserves for recognized receivables. The Company may also have claims to contractual lease payments that were not recorded to income in instances where their collection was not probable. We record a gain or loss on sale of real estate assets when we no longer hold a controlling financial interest in the entity holding the real estate, a contract exists with a third party and that third party has control of the assets acquired. Investment income on debt and preferred equity investments is accrued based on the contractual terms of the instruments and when 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 collectible. 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 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 cash flows 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 is resumed on any debt or preferred equity investment that is on non-accrual status when such investment becomes contractually current and performance is demonstrated to be resumed. 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 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. Debt and Preferred Equity Investments Debt and preferred equity investments are presented at the net amount expected to be collected. An allowance for loan losses is deducted from the amortized cost basis of the financial assets to present the net carrying value at the amount expected to be collected through the expected maturity date of such investments. The expense for loan loss and other investment reserves is the charge to earnings to adjust the allowance for loan losses to the appropriate level. The Company evaluates the amount expected to be collected based on current market and economic conditions, historical loss information, and reasonable and supportable forecasts. The Company's assumptions are derived from both internal data and external data which may include, among others, governmental economic projections for the New York City Metropolitan area, public data on recent transactions and filings for securitized debt instruments. This information is aggregated by asset class and adjusted for duration. Based on these inputs, loans are evaluated at the individual asset level. In certain instances, we may also use a probability-weighted model that considers the likelihood of multiple outcomes and the amount expected to be collected for each outcome. The evaluation of the possible credit deterioration associated with the performance and/or value of the underlying collateral property as well as the financial and operating capability of the borrower/sponsor requires significant judgment, which include both asset level and market assumptions over the relevant time period. In addition, quarterly, the Company assigns each loan a risk rating. Based on a 3-point scale, loans are rated “1” through “3,” from lower risk to higher risk, which ratings are defined as follows: 1 - Low Risk Assets - Low probability of loss, 2 - Watch List Assets - Higher potential for loss, 3 - High Risk Assets - Loss more likely than not. Loans with risk ratings of 2 or above are evaluated to determine whether the expected risk of loss is appropriately captured through the combination of our expectations of current conditions, historical loss information and supportable forecasts described above or whether risk characteristics specific to the loan warrant the use of a probability-weighted model. Financing investments that are classified as held for sale are carried at the expected amount to be collected 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 expected amount to be collected. Other financing receivables that are included in balance sheet line items other than the Debt and Preferred Equity Investments line are also measured at the net amount expected to the be collected. Accrued interest receivable amounts related to these debt and preferred equity investment and other financing receivables are recorded at the net amount expected to be collected within Other assets in the consolidated balance sheets. Write offs of accrued interest receivables are recognized as an expense for loan loss and other investment reserves. 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 its 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 its 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. We have elected, and may elect in the future, to treat certain of our 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 months ended September 30, 2020, we recorded no Federal, state and local tax provisions. During the nine months ended September 30, 2020, we recorded Federal, state and local tax provisions of $2.0 million. During the three and nine months ended September 30, 2019, we recorded a Federal, state benefit of $1.0 million and a provision of $0.5 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. 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 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 initial and ongoing evaluations of the credit quality 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 potential source of funds to offset the economic costs associated with lost revenue from that tenant and the costs associated with re-tenanting a space. The properties in our real estate portfolio are located in the New York metropolitan area. The tenants located in our buildings operate in various industries. Other than one tenant, ViacomCBS Inc., which accounts for 5.5% 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, 2020. For the three months ended September 30, 2020, the following properties contributed more than 5.0% of our annualized cash rent from office properties, including our share of annualized cash rent from joint venture office properties: Property Three months ended September 30, 2020 1185 Avenue of the Americas 8.4% 11 Madison Avenue 8.1% 420 Lexington Avenue 7.4% 1515 Broadway 6.3% 220 East 42nd Street 5.9% 280 Park Avenue 5.4% 485 Lexington Avenue 5.0% Reclassification Certain prior year balances have been reclassified to conform to our current year presentation. Accounting Standards Updates In August 2020, the FASB issued Accounting Standard Update, or "ASU", No. 2020-06 Debt - Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging - Contracts in Entity's Own Equity (Subtopic 815-40). ASU 2020-06 simplifies the accounting for convertible instruments by reducing the number of accounting models for convertible debt instruments and convertible preferred stock, removes certain settlement conditions that are required for equity contracts to qualify for the derivative scope exception and also simplifies the diluted earnings per share calculation in certain areas. ASU 2020-06 is effective for reporting periods beginning after December 15, 2021, with early adoption permitted. We are currently evaluating the impact of the adoption of ASU 2020-06 on our consolidated financial statements, but do not believe the adoption of this standard will have a material impact on our consolidated financial statements. In April 2020, the FASB staff issued a question and answer document (the “Lease Modification Q&A”) on the application of lease accounting guidance to lease concessions provided as a result of the COVID-19 pandemic. Under existing lease guidance, the entity would have to determine, on a lease by lease basis, if a lease concession was the result of a new arrangement reached with the tenant, which would be accounted for under the lease modification framework, or if a lease concession was under the enforceable rights and obligations that existed in the original lease, which would be accounted for outside the lease modification framework. The Lease Modification Q&A provides entities with the option to elect to account for lease concessions as though the enforceable rights and obligations existed in the original lease. This election is only available when total cash flows resulting from the modified lease are substantially similar to the cash flows in the original lease. The Lease Modification Q&A has no material impact on the Company’s consolidated financial statements as of and for the nine months ended September 30, 2020, however, its future impact to the Company is dependent upon the extent of lease concessions granted to tenants as a result of the COVID-19 pandemic in future periods and the elections made by the Company at the time of entering into such concessions. In March 2020, the FASB issued ASU No. 2020-04 Reference Rate Reform (Topic 848) Facilitation of the Effects of Reference Rate Reform on Financial Reporting. The amendments provide practical expedients for reference rate reform related activities that impact debt, leases, derivatives and other contracts. The guidance is optional and is effective between March 12, 2020 and December 31, 2022. The guidance may be elected over time as reference rate reform activities occur. During the first quarter of 2020, the Company has elected to apply the hedge accounting expedients related to probability and the assessments of effectiveness for future LIBOR-indexed cash flows to assume that the index upon which future hedged transactions will be based matches the index on the corresponding derivatives. Application of these expedients preserves the presentation of derivatives consistent with past presentation. The Company continues to evaluate the impact of the guidance and may apply other elections as applicable as additional changes in the market occur. In January 2020, the FASB issued ASU No. 2020-01, Investments - Equity Securities (Topic 321), Investments - Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815) Clarifying the Interactions between Topic 321, Topic 323, and Topic 815. The amendment most relevant to the Company is how to apply the fair value measurement alternative in Topic 321 when an investor must apply the fair value to an investment under the equity method in Topic 323. The amendment clarifies that an entity should consider observable transactions when considering the fair value of an investment. The guidance is effective for the Company for fiscal years beginning after December 15, 2020. Early adoption is permitted. The Company adopted this guidance on January 1, 2020 and it did not have a material impact on the Company’s consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-15, Intangibles - Goodwill and Other- Internal-Use Software (Topic 350-40), Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract. The amendments provide guidance on accounting for fees paid when the arrangement includes a software license and align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing costs to develop or obtain internal-use software. The Company adopted this guidance on January 1, 2020 and it did not have a material impact on the Company’s consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820), Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement. This amendment removed, modified and added the disclosure requirements under Topic 820. The changes are effective for the Company for fiscal years beginning after December 15, 2019. Early adoption is permitted for the removed or modified disclosures with adoption of the additional disclosures upon the effective date. The Company adopted this guidance on January 1, 2020 and it did not have a material impact on the Company’s consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments; in November 2018 issued ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments - Credit Losses, in April, May and November 2019, issued ASU No. 2019-04, 2

Property Acquisitions

Property Acquisitions	9 Months Ended
	Sep. 30, 2020
Business Combinations [Abstract]
Property Acquisitions	Property Acquisitions The following table summarizes the properties acquired during the nine months ended September 30, 2020: Property Acquisition Date Property Type Approximate Square Feet Gross Asset Valuation 762 Madison Avenue (1) January 2020 Fee Interest 6,109 $ 29.3 707 Eleventh Avenue January 2020 Fee Interest 159,720 90.0 126 Nassau Street (2) January 2020 Leasehold Interest 98,412 — (1) The Company acquired from our joint venture partner the remaining 10% interest in this property that the Company did not already own. (2) In January 2020, the Company entered into a 99-year ground lease of 126 Nassau Street. In August 2020, we entered into a partnership with Meritz Alternative Investment as part of the capitalization of this development project. See note 6, "Investments in Unconsolidated Joint Ventures."

Properties Held for Sale and Pr

Properties Held for Sale and Property Dispositions	9 Months Ended
	Sep. 30, 2020
Discontinued Operations and Disposal Groups [Abstract]
Properties Held for Sale and Property Dispositions	Properties Held for Sale and Property Dispositions Properties Held for Sale As of September 30, 2020, no properties were classified as held for sale. Property Dispositions The following table summarizes the properties sold during the nine months ended September 30, 2020: Property Disposition Date Property Type Approximate Square Feet Sales Price (1) (in millions) Gain (loss) (2) (in millions) 315 West 33rd Street - "The Olivia" March 2020 Fee Interest 492,987 $ 446.5 $ 72.3 609 Fifth Avenue Retail Condominium May 2020 Fee Interest 21,437 168.0 65.4 400 East 58th Street September 2020 Fee Interest 140,000 62.0 8.3 (1) Sales price represents the gross sales price for a property or the gross asset valuation for interests in a property. (2) The gains on sale for 315 West 33rd Street - "The Olivia" and 609 Fifth Avenue Retail Condominium are net of $6.0 million and $2.0 million, respectively, of employee compensation accrued in connection with the realization of these investment gains. Additionally, amounts do not include adjustments for expenses recorded in subsequent periods.

Debt and Preferred Equity Inves

Debt and Preferred Equity Investments	9 Months Ended
	Sep. 30, 2020
Investments, Debt and Equity Securities [Abstract]
Debt and Preferred Equity Investments	Debt and Preferred Equity Investments Below is a summary of the activity in our debt and preferred equity investments for the nine months ended September 30, 2020 and the twelve months ended December 31, 2019 (in thousands): September 30, 2020 December 31, 2019 Balance at beginning of year (1) $ 1,580,306 $ 2,099,393 Debt investment originations/accretion (2) 383,365 652,866 Preferred equity investment originations/accretion (2) 163,821 14,736 Redemptions/sales/syndications/equity ownership/amortization (3) (956,869) (1,190,689) Net change in loan loss reserves (17,260) 4,000 Balance at end of period (1) $ 1,153,363 $ 1,580,306 (1) Net of unamortized fees, discounts, and premiums. (2) Accretion includes amortization of fees and discounts and paid-in-kind investment income. (3) Certain participations in debt investments that were sold or syndicated, but did not meet the conditions for sale accounting, are included in other assets and other liabilities on the consolidated balance sheets. Below is a summary of our debt and preferred equity investments as of September 30, 2020 (dollars in thousands): Floating Rate Fixed Rate Total Carrying Value Senior Financing Maturity (1) Type Carrying Value Face Value Interest Rate Carrying Value Face Value Interest Rate Senior Mortgage Debt $ 62,683 $63,425 L + 2.00% - 3.50% $ 1,249 $1,250 3.00% $ 63,932 $ — 2020 - 2022 Junior Mortgage Debt 85,295 96,697 L + 6.00% - 7.25% 32,805 33,000 6.00% $ 118,100 542,241 2020 - 2023 Mezzanine Debt 278,726 283,336 L + 4.95% - 14.62% 436,040 447,265 2.90% - 9.30% $ 714,766 4,447,803 2020 - 2029 Preferred Equity — — — 256,565 259,431 6.50% - 11.00% $ 256,565 1,962,750 2022 - 2027 Balance at end of period $ 426,704 $ 443,458 — $ 726,659 $ 740,946 — $ 1,153,363 (1) Excludes available extension options to the extent they have not been exercised as of the date of this filing. The following table is a rollforward of our total allowance for loan losses for the nine months ended September 30, 2020 and the twelve months ended December 31, 2019 (in thousands): September 30, 2020 December 31, 2019 Balance at beginning of year $ 1,750 $ 5,750 Cumulative adjustment upon adoption of ASC 326 27,804 — Current period provision for loan loss 20,741 — Write-offs charged against the allowance (31,285) (4,000) Balance at end of period $ 19,010 $ 1,750 At September 30, 2020, all debt and preferred equity investments were performing in accordance with their respective terms, with the exception of two investments with a carrying value, net of reserves, of $25.3 million, as discussed in subnotes 6 and 7 of the Debt Investments table below. At December 31, 2019, all debt and preferred equity investments were performing in accordance with their respective terms. No other financing receivables were 90 days past due at September 30, 2020 and December 31, 2019 with the exception of a $27.7 million financing receivable which was put on nonaccrual in August 2018 as a result of interest default. As of September 30, 2020, management estimated the weighted average risk rating for our debt and preferred equity investments to be 1.4. We have determined that we have one portfolio segment of financing receivables at September 30, 2020 and December 31, 2019 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 representing loans to joint venture partners totaling $110.9 million and $131.1 million at September 30, 2020 and December 31, 2019, respectively, for which the Company recorded adjustments upon adoption of ASC 326 of $11.4 million and provisions for loan losses of $0.0 million and $6.3 million for the three and nine months ended September 30, 2020, respectively. Debt Investments As of September 30, 2020 and December 31, 2019, we held the following debt investments with an aggregate weighted average current yield of 6.26% at September 30, 2020 (dollars in thousands): Loan Type September 30, 2020 September 30, 2020 Senior September 30, 2020 Carrying Value (1) December 31, 2019 (1) Maturity (2) Fixed Rate Investments: Mortgage/Mezzanine Loan $ — $ 63,750 $ 56,242 $ 55,573 October 2020 (3) Junior Mortgage (4b) 10,000 67,000 32,805 — January 2021 Loan Type September 30, 2020 September 30, 2020 Senior September 30, 2020 Carrying Value (1) December 31, 2019 (1) Maturity (2) Mezzanine Loan — 15,000 3,500 3,500 September 2021 Mezzanine Loan — 280,000 40,458 38,734 August 2022 Mezzanine Loan (5) — 348,327 225,204 215,737 June 2023 Mezzanine Loan (4a)(6) — 115,000 13,265 12,950 June 2024 Mezzanine Loan — 95,000 30,000 30,000 January 2025 Mezzanine Loan — 1,712,750 55,250 55,250 June 2027 Mezzanine Loan — 85,000 20,000 20,000 December 2029 Mezzanine Loan — — — 24,952 Mezzanine Loan — — — 30,000 Mezzanine Loan — — — 12,714 Total fixed rate $ 10,000 $ 2,781,827 $ 476,724 $ 499,410 Floating Rate Investments: Junior Mortgage (7) $ — $ 40,000 $ 20,000 $ 20,000 April 2020 Mezzanine Loan — 275,000 49,919 49,809 April 2021 Junior Mortgage Participation/Mezzanine Loan — 60,000 15,724 15,698 July 2021 Mezzanine Loan 7,933 169,540 46,613 41,395 July 2021 Mezzanine Loan 5,329 54,204 23,753 15,743 July 2021 Mezzanine Loan (4c) — 1,115,000 126,486 222,775 March 2022 Mortgage/Mezzanine Loan 7,425 — 60,116 — May 2022 Mortgage/Mezzanine Loan 44,000 — 13,987 13,918 December 2022 Mortgage Loan (8) 35,303 375,241 63,899 — February 2023 Mezzanine Loan 55,033 59,232 18,587 69,839 May 2023 Mortgage/Mezzanine Loan — — — 35,386 Mortgage Loan — — — 19,971 Mortgage Loan — — — 106,473 Mezzanine Loan — — — 51,387 Mortgage/Mezzanine Loan — — — 96,570 Mortgage/Mezzanine Loan — — — 82,696 Total floating rate $ 155,023 $ 2,148,217 $ 439,084 $ 841,660 Allowance for loan loss $ — $ — $ (19,010) $ — Total $ 165,023 $ 4,930,044 $ 896,798 $ 1,341,070 (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) In October 2020, this loan was extended one year to October 2021. (4) Carrying value is net of the following amounts that were sold or syndicated, 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) $12.0 million, (b) $66.6 million and (c) $0.4 million. (5) This loan is on non-accrual at September 30, 2020. (6) This loan is in default and on non-accrual as of the date of this filing. The Company is in discussions with the borrower. (7) As of September 30, 2020 this loan was in default and on non-accrual. In October 2020, the Company accepted a purchase in lieu of repayment and marked the assets received and liabilities assumed to fair value. (8) This loan was sold on October 1, 2020. Preferred Equity Investments As of September 30, 2020 and December 31, 2019, we held the following preferred equity investments with an aggregate weighted average current yield of 9.98% at September 30, 2020 (dollars in thousands): Type September 30, 2020 September 30, 2020 Senior September 30, 2020 Carrying Value (1) December 31, 2019 Carrying Value (1) Mandatory Redemption (2) Preferred Equity $ — $ 1,712,750 $ 153,196 $ 98,065 June 2022 Preferred Equity — 250,000 103,369 — February 2027 Preferred Equity (3) — — — 142,921 Total Preferred Equity $ — $ 1,962,750 $ 256,565 $ 240,986 Allowance for loan loss $ — $ — $ — $ (1,750) Total $ — $ 1,962,750 $ 256,565 $ 239,236 (1) Carrying value is net of deferred origination fees. (2) Represents contractual maturity, excluding any unexercised extension options. (3) In June 2020, we, along with the common member in the investment, amended the partnership documents related to the investment to provide us with more rights over management of the underlying property. This resulted in the investment being accounted for using the equity method. See Note 6, "Investments in Unconsolidated Joint Ventures."

Investments in Unconsolidated J

Investments in Unconsolidated Joint Ventures	9 Months Ended
	Sep. 30, 2020
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, 2020, the book value of these investments was $2.9 billion, net of investments with negative book values totaling $85.8 million for which we have an implicit commitment to fund future capital needs. As of September 30, 2020 and December 31, 2019, 800 Third Avenue, 21 East 66th Street, 605 West 42nd 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 $136.3 million and $145.9 million as of September 30, 2020 and December 31, 2019, respectively. Our maximum loss is limited to the amount of our equity investment in these VIEs. See the "Principles of Consolidation" section of Note 2, "Significant Accounting Policies". 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, 2020: Property Partner Ownership (1) Economic (1) Unaudited Approximate Square Feet 100 Park Avenue Prudential Real Estate Investors 49.90% 49.90% 834,000 717 Fifth Avenue Wharton Properties/Private Investor 10.92% 10.92% 119,500 800 Third Avenue Private Investors 60.52% 60.52% 526,000 919 Third Avenue New York State Teacher's Retirement System 51.00% 51.00% 1,454,000 11 West 34th Street Private Investor/Wharton Properties 30.00% 30.00% 17,150 280 Park Avenue Vornado Realty Trust 50.00% 50.00% 1,219,158 1552-1560 Broadway (2) Wharton Properties 50.00% 50.00% 57,718 10 East 53rd Street Canadian Pension Plan Investment Board 55.00% 55.00% 354,300 21 East 66th Street (3) Private Investors 32.28% 32.28% 13,069 650 Fifth Avenue (4) Wharton Properties 50.00% 50.00% 69,214 121 Greene Street Wharton Properties 50.00% 50.00% 7,131 55 West 46th Street Prudential Real Estate Investors 25.00% 25.00% 347,000 Stonehenge Portfolio Various Various Various 1,439,016 605 West 42nd Street The Moinian Group 20.00% 20.00% 927,358 11 Madison Avenue PGIM Real Estate 60.00% 60.00% 2,314,000 333 East 22nd Street Private Investors 33.33% 33.33% 26,926 400 East 57th Street (5) BlackRock, Inc and Stonehenge Partners 51.00% 41.00% 290,482 Property Partner Ownership (1) Economic (1) Unaudited Approximate Square Feet One Vanderbilt National Pension Service of Korea/Hines Interest LP 71.01% 71.01% — Worldwide Plaza RXR Realty / New York REIT / Private Investor 24.35% 24.35% 2,048,725 1515 Broadway Allianz Real Estate of America 56.87% 56.87% 1,750,000 2 Herald Square Israeli Institutional Investor 51.00% 51.00% 369,000 115 Spring Street Private Investor 51.00% 51.00% 5,218 885 Third Avenue (6) Private Investor (6) 100.00% 625,300 126 Nassau Street (7) Meritz Alternative Investment Management 20.00% 20.00% 98,412 (1) Ownership interest and economic interest represent the Company's interests in the joint venture as of September 30, 2020. Changes in ownership or economic interests within the current year are disclosed in the notes below. (2) The acquisition 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. (3) We hold a 32.28% interest in three retail units and one residential unit at the property and a 16.14% interest in three residential units at the property. (4) The joint venture owns a long-term leasehold interest in the retail space at 650 Fifth Avenue. (5) In October 2016, we sold a 49% interest in this property. Our interest in the property was sold within a consolidated joint venture owned 90% by the Company and 10% by Stonehenge. The transaction resulted in the deconsolidation of the venture's remaining 51% interest in the property. Our joint venture with Stonehenge remains consolidated resulting in the combined 51% interest being shown within investments in unconsolidated joint ventures on our balance sheet. (6) We hold 100% of the preferred equity interest in the property and believe there is no value to the common equity. (7) In August 2020, the Company formed a joint venture, which then entered into a long-term sublease with the Company. As a result of this transaction, we recognized a gain of $17.7 million, which is included in Gain on sale of real estate, net, in our consolidated statements of operations. This gain was calculated in accordance with ASC 842, as the Company identified the lease and non-lease components included in the sublease agreement and allocated the consideration in the agreement to each lease and non-lease component based on each components’ standalone selling price, which was estimated utilizing a combination of the adjusted market assessment and residual approaches as provided for in ASC 606. Disposition of Joint Venture Interests or Properties We did not dispose of any investments in unconsolidated joint ventures during the nine months ended September 30, 2020: Joint Venture Mortgages and Other Loans Payable We generally finance our joint ventures with non-recourse debt. In certain cases we may provide guarantees or master leases for tenant space, which terminate upon the satisfaction of specified circumstances or repayment of the underlying loans. The mortgage notes and other loans payable collateralized by the respective joint venture properties and assignment of leases at September 30, 2020 and December 31, 2019, respectively, are as follows (dollars in thousands): Property Economic (1) Initial Maturity Final Maturity Date (2) Interest Rate (3) September 30, 2020 December 31, 2019 Fixed Rate Debt: 885 Third Avenue (4) 100.00 % April 2021 April 2021 3.35 % $ 272,000 $ — 717 Fifth Avenue (mortgage) 10.92 % July 2022 July 2022 4.45 % 300,000 300,000 717 Fifth Avenue (mezzanine) 10.92 % July 2022 July 2022 5.50 % 355,328 355,328 650 Fifth Avenue (mortgage) 50.00 % October 2022 October 2022 4.46 % 210,000 210,000 650 Fifth Avenue (mezzanine) 50.00 % October 2022 October 2022 5.45 % 65,000 65,000 21 East 66th Street 32.28 % April 2023 April 2028 3.60 % 12,000 12,000 919 Third Avenue 51.00 % June 2023 June 2023 5.12 % 500,000 500,000 1515 Broadway 56.87 % March 2025 March 2025 3.93 % 825,204 838,546 11 Madison Avenue 60.00 % September 2025 September 2025 3.84 % 1,400,000 1,400,000 800 Third Avenue 60.52 % February 2026 February 2026 3.37 % 177,000 177,000 400 East 57th Street 41.00 % November 2026 November 2026 3.00 % 97,024 97,735 Worldwide Plaza 24.35 % November 2027 November 2027 3.98 % 1,200,000 1,200,000 Stonehenge Portfolio (5) Various Various Various 3.50 % 195,899 196,112 Property Economic (1) Initial Maturity Final Maturity Date (2) Interest Rate (3) September 30, 2020 December 31, 2019 Total fixed rate debt $ 5,609,455 $ 5,351,721 Floating Rate Debt: 121 Greene Street 50.00 % November 2020 November 2021 L+ 1.50 % $ 15,000 $ 15,000 11 West 34th Street 30.00 % January 2021 January 2023 L+ 1.45 % 23,000 23,000 100 Park Avenue 49.90 % February 2021 February 2021 L+ 1.75 % 354,087 356,972 280 Park Avenue 50.00 % September 2021 September 2024 L+ 1.73 % 1,200,000 1,200,000 One Vanderbilt (6) 71.01 % September 2021 September 2023 L+ 2.50 % 1,094,873 732,928 1552 Broadway 50.00 % October 2021 October 2022 L+ 2.65 % 195,000 195,000 2 Herald Square 51.00 % November 2021 November 2023 L+ 1.45 % 214,500 190,000 55 West 46th Street (7) 25.00 % August 2022 August 2024 L+ 1.25 % 192,524 192,524 115 Spring Street 51.00 % September 2023 September 2023 L+ 3.40 % 65,550 65,550 126 Nassau Street (8) 20.00 % January 2024 July 2025 L+ 1.50 % 5,593 — 10 East 53rd Street 55.00 % February 2025 February 2025 L+ 1.35 % 220,000 170,000 605 West 42nd Street 20.00 % August 2027 August 2027 L+ 1.44 % 550,000 550,000 21 East 66th Street 32.28 % June 2033 June 2033 1 Year Treasury+ 2.75 % 688 712 Total floating rate debt $ 4,130,815 $ 3,691,686 Total joint venture mortgages and other loans payable $ 9,740,270 $ 9,043,407 Deferred financing costs, net (87,763) (91,538) Total joint venture mortgages and other loans payable, net $ 9,652,507 $ 8,951,869 (1) Economic interest represents the Company's interests in the joint venture as of September 30, 2020. Changes in ownership or economic interests, if any, within the current year are disclosed in the notes to the investment in unconsolidated joint ventures table above. (2) Reflects exercise of all available extension options. The ability to exercise extension options may be subject to certain tests based on the operating performance of the property. (3) Interest rates as of September 30, 2020, taking into account interest rate hedges in effect during the period. Floating rate debt is presented with the stated spread over the 30-day LIBOR, unless otherwise specified. (4) The Company holds 100% of the preferred equity interest in the property and believes that there is no value to the common equity. In August 2020, the servicer asserted certain loan defaults. The venture has determined that the servicer is misinterpreting the loan documents and is contesting the assertion. The servicer has taken no additional action on the loan. (5) Comprised of three mortgages totaling $132.4 million that mature in April 2028 and two mortgages totaling $63.5 million that mature in July 2029. (6) This loan is a $1.75 billion construction facility with reductions in interest cost based on meeting conditions, the first of which has been satisfied, and has an initial five-year term with two one-year extension options. Advances under the loan are subject to costs incurred. (7) This loan has a committed amount of $198.0 million, of which $5.5 million was unfunded as of September 30, 2020. (8) This loan is a $125.0 million construction facility. Advances under the loan are subject to costs incurred. We are entitled to receive fees for providing management, leasing, construction supervision and asset management services to certain of our joint ventures. We earned $2.2 million and $6.1 million from these services, net of our ownership share of the joint ventures, for the three and nine months ended September 30, 2020, respectively. We earned $2.4 million and $8.8 million from these services, net of our ownership share of the joint ventures, for the three and nine months ended September 30, 2019, 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, 2020 and December 31, 2019 are as follows (in thousands): September 30, 2020 December 31, 2019 Assets (1) Commercial real estate property, net $ 15,045,603 $ 14,349,628 Cash and restricted cash 326,488 336,189 Tenant and other receivables, related party receivables, and deferred rents receivable 404,138 371,065 Other assets 1,940,540 2,039,429 Total assets $ 17,716,769 $ 17,096,311 Liabilities and equity (1) Mortgages and other loans payable, net $ 9,652,507 $ 8,951,869 Deferred revenue 1,400,458 1,501,616 Lease liabilities 1,015,477 897,380 Other liabilities 294,972 308,304 Equity 5,353,355 5,437,142 Total liabilities and equity $ 17,716,769 $ 17,096,311 Company's investments in unconsolidated joint ventures $ 2,946,673 $ 2,912,842 (1) The combined assets, liabilities and equity for the unconsolidated joint ventures reflects the effect of step ups in basis on the retained, non-controlling interests in deconsolidated investments as a result of the adoption of ASC 610-20 in January 2018. In addition, at September 30, 2020, $166.8 million of net unamortized basis differences between the amount at which our investments are carried and our share of equity in net assets of the underlying property will be amortized through equity in net income (loss) from unconsolidated joint ventures over the remaining life of the underlying items having given rise to the differences. The combined statements of operations for the unconsolidated joint ventures, from acquisition date through the three and nine months ended September 30, 2020 and 2019, are as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Total revenues $ 292,929 $ 286,010 $ 846,967 $ 883,977 Operating expenses 44,650 50,759 131,578 153,397 Real estate taxes 56,459 53,321 161,566 159,544 Operating lease rent 6,385 6,713 18,947 18,848 Interest expense, net of interest income 79,723 92,601 245,685 282,917 Amortization of deferred financing costs 5,575 4,436 15,197 14,434 Depreciation and amortization 103,262 100,736 300,700 308,748 Total expenses 296,054 308,566 873,673 937,888 Loss on early extinguishment of debt — (1,031) — (1,031) Net loss before gain on sale (1) $ (3,125) $ (23,587) $ (26,706) $ (54,942) Company's equity in net loss from unconsolidated joint ventures (1) $ (432) $ (9,864) $ (15,445) $ (22,644) (1) The combined statements of operations and the Company's equity in net loss for the unconsolidated joint ventures reflects the effect of step ups in basis on the retained non-controlling interests in deconsolidated investments as a result of the adoption of ASC 610-20 in January 2018.

Deferred Costs

Deferred Costs	9 Months Ended
	Sep. 30, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred Costs	Deferred Costs Deferred costs at September 30, 2020 and December 31, 2019 consisted of the following (in thousands): September 30, 2020 December 31, 2019 Deferred leasing costs $ 496,812 $ 466,136 Less: accumulated amortization (290,523) (260,853) Deferred costs, net $ 206,289 $ 205,283

Mortgages and Other Loans Payab

Mortgages and Other Loans Payable	9 Months Ended
	Sep. 30, 2020
Mortgages and Other Loans Payable
Mortgages and other loans payable	Mortgages and Other Loans Payable The mortgages and other loans payable collateralized by the respective properties and assignment of leases or debt investments at September 30, 2020 and December 31, 2019, respectively, were as follows (dollars in thousands): Property Initial Maturity Final Maturity Date (1) Interest Rate (2) September 30, 2020 December 31, 2019 Fixed Rate Debt: 100 Church Street July 2022 July 2022 4.68% $ 206,013 $ 209,296 420 Lexington Avenue October 2024 October 2040 3.99% 295,355 299,165 Landmark Square January 2027 January 2027 4.90% 100,000 100,000 485 Lexington Avenue February 2027 February 2027 4.25% 450,000 450,000 1080 Amsterdam (3) February 2027 February 2027 3.59% 34,773 35,123 762 Madison Avenue (4) — 771 315 West 33rd Street (5) — 250,000 400 East 58th Street 39,094 Total fixed rate debt $ 1,086,141 $ 1,383,449 Floating Rate Debt: 133 Greene Street (6) (6) L+ 2.00% $ 15,523 $ 15,523 106 Spring Street January 2021 January 2022 L+ 2.50% 38,025 38,025 FHLB Facility January 2021 January 2021 L+ 0.28% 10,000 — FHLB Facility January 2021 January 2021 L+ 0.23% 15,000 — FHLB Facility January 2021 January 2021 L+ 0.18% 35,000 — 609 Fifth Avenue March 2021 March 2024 L+ 2.40% 57,651 53,773 185 Broadway (7) November 2021 November 2023 L+ 2.85% 144,448 120,110 712 Madison Avenue December 2021 December 2022 L+ 1.85% 28,000 28,000 220 East 42nd Street June 2023 June 2025 L+ 2.75% 510,000 — 410 Tenth Avenue (8) August 2023 August 2025 L+ 2.25% 434,934 330,819 719 Seventh Avenue September 2023 September 2023 L+ 1.20% 50,000 50,000 2017 Master Repurchase Agreement (9) — 152,684 FHLB Facility — 10,000 FHLB Facility — 15,000 FHLB Facility — 14,500 Total floating rate debt $ 1,338,581 $ 828,434 Total mortgages and other loans payable $ 2,424,722 $ 2,211,883 Deferred financing costs, net of amortization (32,978) (28,630) Total mortgages and other loans payable, net $ 2,391,744 $ 2,183,253 (1) Reflects exercise of all available extension options. The ability to exercise extension options may be subject to certain tests based on the operating performance of the property. (2) Interest rate as of September 30, 2020, taking into account interest rate hedges in effect during the period. Floating rate debt is presented with the stated spread over the 30-day LIBOR, unless otherwise specified. (3) The loan is comprised of a $33.9 million mortgage loan and $0.9 million mezzanine loan with a fixed interest rate of 350 basis points and 700 basis points, respectively, for the first five years and is prepayable without penalty at the end of fifth year. (4) In January 2020, the Company closed on the acquisition of the remaining 10% interest in this property from our joint venture partner. As part of this transaction, the loan was repaid. (5) In March 2020, the loan was assumed by the buyer in connection with the sale of the property. (6) This loan matured in August 2020. The Company is in discussions with the lender on resolution. (7) This loan is a $225.0 million construction facility, with reductions in interest cost based on meeting certain conditions, and has an initial three-year term with two one-year extension options. Advances under the loan are subject to incurred costs and funded equity requirements. (8) This loan is a $600.0 million construction facility and has an initial three-year term with two one-year extension options. Advances under the loan are subject to incurred costs and funded equity requirements. (9) In June 2020, we exercised a one-year extension option which extended the maturity date to June 2021. At September 30, 2020, there was no outstanding balance on the $400 million facility. At September 30, 2020 and December 31, 2019, the gross book value of the properties and debt and preferred equity investments collateralizing the mortgages and other loans payable was approximately $3.2 billion and $3.3 billion, respectively. Federal Home Loan Bank of New York ("FHLB") Facility The Company's wholly-owned subsidiary, Ticonderoga Insurance Company, or Ticonderoga, a Vermont licensed captive insurance company, is a member of the Federal Home Loan Bank of New York, or FHLBNY. As a member, Ticonderoga may borrow funds from the FHLBNY in the form of secured advances that bear interest at a floating rate. Unless Congress or the Federal Home Finance Authority extends membership criteria, then on February 19, 2021 Ticonderoga’s membership in FHLB New York will terminate and all advances will need to be repaid by such date. As of September 30, 2020, Ticonderoga had a total of $60.0 million in outstanding secured advances with an average spread of 21 basis points over 30-day LIBOR. Master Repurchase Agreement The Company entered into a Master Repurchase Agreement, or MRA, known as the 2017 MRA, which provides us with the ability to sell certain mortgage investments with a simultaneous agreement to repurchase the same at a certain date or on demand. 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 collateralize the facility with additional assets from our portfolio of debt investments, our ability to satisfy margin calls with cash or cash equivalents and our access to additional liquidity. As of September 30, 2020, there have been no margin calls on the 2017 MRA. In April 2018, we increased the maximum facility capacity from $300.0 million to $400.0 million. The facility bears interest on a floating rate basis at a spread to 30-day LIBOR based on the pledged collateral and advance rate and is scheduled to mature in June 2021, with a one-year extension option. At September 30, 2020, the facility had no outstanding balance. 2017 Credit Facility In November 2017, we entered into an amendment to the credit facility, referred to as the 2017 credit facility, that was originally entered into by the Company in November 2012, or the 2012 credit facility. As of September 30, 2020, the 2017 credit facility consisted of a $1.5 billion revolving credit facility, a $1.3 billion term loan (or "Term Loan A"), and a $200.0 million term loan (or "Term Loan B") with maturity dates of March 31, 2022, March 31, 2023, and November 21, 2024, respectively. The revolving credit facility has two six-month, as-of-right extension options to March 31, 2023. We also have an option, subject to customary conditions, to increase the capacity of the credit facility to $4.5 billion at any time prior to the maturity dates for the revolving credit facility and term loans without the consent of existing lenders, by obtaining additional commitments from our existing lenders or other financial institutions. As of September 30, 2020, the 2017 credit facility bore interest at a spread over 30-day LIBOR ranging from (i) 82.5 basis points to 155 basis points for loans under the revolving credit facility, (ii) 90 basis points to 175 basis points for loans under Term Loan A, and (iii) 85 basis points to 165 basis points for loans under Term Loan B, in each case based on the credit rating assigned to the senior unsecured long term indebtedness of the Company. In instances where there are either only two ratings available or where there are more than two and the difference between them is one rating category, the applicable rating shall be the highest rating. In instances where there are more than two ratings and the difference between the highest and the lowest is two or more rating categories, then the applicable rating used is the average of the highest two, rounded down if the average is not a recognized category. At September 30, 2020, the applicable spread was 100 basis points for the revolving credit facility, 110 basis points for Term Loan A, and 100 basis points for Term Loan B. 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 the Company. As of September 30, 2020, the facility fee was 20 basis points. As of September 30, 2020, we had $26.0 million of outstanding letters of credit, $190.0 million drawn under the revolving credit facility and $1.5 billion outstanding under the term loan facilities, with total undrawn capacity of $1.3 billion under the 2017 credit facility. At September 30, 2020 and December 31, 2019, the revolving credit facility had a carrying value of $184.8 million and $234.0 million, respectively, net of deferred financing costs. At September 30, 2020 and December 31, 2019, the term loan facilities had a carrying value of $1.5 billion and $1.5 billion, respectively, net of deferred financing costs. The Company and the Operating Partnership are borrowers jointly and severally obligated under the 2017 credit facility. The 2017 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, 2020 and December 31, 2019, respectively, by scheduled maturity date (dollars in thousands): Issuance September 30, September 30, December 31, Interest Rate (1) Initial Term Maturity Date August 7, 2018 (2) (3) $ 350,000 $ 350,000 $ 350,000 1.52 % 3 August 2021 October 5, 2017 (2) 500,000 499,775 499,695 3.25 % 5 October 2022 November 15, 2012 (4) 300,000 302,352 303,142 4.50 % 10 December 2022 December 17, 2015 (5) 100,000 100,000 100,000 4.27 % 10 December 2025 March 16, 2010 (6) — — 250,000 $ 1,250,000 $ 1,252,127 $ 1,502,837 Deferred financing costs, net (4,332) (5,990) $ 1,250,000 $ 1,247,795 $ 1,496,847 (1) Interest rate as of September 30, 2020, taking into account interest rate hedges in effect during the period. (2) Issued by the Operating Partnership with the Company as the guarantor. (3) The notes are subject to redemption at the Company's option, in whole but not in part, at a redemption price equal to 100% of the principal amount of the notes, plus unpaid accrued interest thereon to the redemption date. In April 2020, the Company entered into $350.0 million of fixed rate interest swaps at a rate of 0.54375% through August 2021. (4) In October 2017, the Company and the Operating Partnership as co-obligors issued an additional $100.0 million of 4.50% senior unsecured notes due December 2022. The notes were priced at 105.334% of par. (5) Issued by the Company and the Operating Partnership as co-obligors. (6) In March 2020, the notes were repaid. Restrictive Covenants The terms of the 2017 credit facility 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, 2020 and December 31, 2019, 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 a floating rate of 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, the 2017 credit facility, trust preferred securities, senior unsecured notes and our share of joint venture debt as of September 30, 2020, including as-of-right extension options, were as follows (in thousands): Scheduled Mortgages and Other Loans Payable Revolving Unsecured Term Loans Trust Senior Total Joint Remaining 2020 $ 2,635 $ 15,523 $ — $ — $ — $ — $ 18,158 $ 10,867 2021 10,766 270,474 — — — 350,000 631,240 1,444,277 2022 8,779 255,435 — — — 800,000 1,064,214 268,952 2023 6,608 994,934 190,000 1,300,000 — — 2,491,542 311,436 2024 5,294 272,749 — 200,000 — — 478,043 618,140 Thereafter 1,779 579,746 — — 100,000 100,000 781,525 1,935,202 $ 35,861 $ 2,388,861 $ 190,000 $ 1,500,000 $ 100,000 $ 1,250,000 $ 5,464,722 $ 4,588,874 Consolidated interest expense, excluding capitalized interest, was comprised of the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Interest expense before capitalized interest $ 42,595 $ 63,607 $ 144,345 $ 185,163 Interest on financing leases 2,198 813 6,010 2,425 Interest capitalized (20,677) (15,700) (57,528) (38,228) Interest income (580) (608) (1,727) (3,563) Interest expense, net $ 23,536 $ 48,112 $ 91,100 $ 145,797

Corporate Indebtedness

Corporate Indebtedness	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Corporate Indebtedness	Mortgages and Other Loans Payable The mortgages and other loans payable collateralized by the respective properties and assignment of leases or debt investments at September 30, 2020 and December 31, 2019, respectively, were as follows (dollars in thousands): Property Initial Maturity Final Maturity Date (1) Interest Rate (2) September 30, 2020 December 31, 2019 Fixed Rate Debt: 100 Church Street July 2022 July 2022 4.68% $ 206,013 $ 209,296 420 Lexington Avenue October 2024 October 2040 3.99% 295,355 299,165 Landmark Square January 2027 January 2027 4.90% 100,000 100,000 485 Lexington Avenue February 2027 February 2027 4.25% 450,000 450,000 1080 Amsterdam (3) February 2027 February 2027 3.59% 34,773 35,123 762 Madison Avenue (4) — 771 315 West 33rd Street (5) — 250,000 400 East 58th Street 39,094 Total fixed rate debt $ 1,086,141 $ 1,383,449 Floating Rate Debt: 133 Greene Street (6) (6) L+ 2.00% $ 15,523 $ 15,523 106 Spring Street January 2021 January 2022 L+ 2.50% 38,025 38,025 FHLB Facility January 2021 January 2021 L+ 0.28% 10,000 — FHLB Facility January 2021 January 2021 L+ 0.23% 15,000 — FHLB Facility January 2021 January 2021 L+ 0.18% 35,000 — 609 Fifth Avenue March 2021 March 2024 L+ 2.40% 57,651 53,773 185 Broadway (7) November 2021 November 2023 L+ 2.85% 144,448 120,110 712 Madison Avenue December 2021 December 2022 L+ 1.85% 28,000 28,000 220 East 42nd Street June 2023 June 2025 L+ 2.75% 510,000 — 410 Tenth Avenue (8) August 2023 August 2025 L+ 2.25% 434,934 330,819 719 Seventh Avenue September 2023 September 2023 L+ 1.20% 50,000 50,000 2017 Master Repurchase Agreement (9) — 152,684 FHLB Facility — 10,000 FHLB Facility — 15,000 FHLB Facility — 14,500 Total floating rate debt $ 1,338,581 $ 828,434 Total mortgages and other loans payable $ 2,424,722 $ 2,211,883 Deferred financing costs, net of amortization (32,978) (28,630) Total mortgages and other loans payable, net $ 2,391,744 $ 2,183,253 (1) Reflects exercise of all available extension options. The ability to exercise extension options may be subject to certain tests based on the operating performance of the property. (2) Interest rate as of September 30, 2020, taking into account interest rate hedges in effect during the period. Floating rate debt is presented with the stated spread over the 30-day LIBOR, unless otherwise specified. (3) The loan is comprised of a $33.9 million mortgage loan and $0.9 million mezzanine loan with a fixed interest rate of 350 basis points and 700 basis points, respectively, for the first five years and is prepayable without penalty at the end of fifth year. (4) In January 2020, the Company closed on the acquisition of the remaining 10% interest in this property from our joint venture partner. As part of this transaction, the loan was repaid. (5) In March 2020, the loan was assumed by the buyer in connection with the sale of the property. (6) This loan matured in August 2020. The Company is in discussions with the lender on resolution. (7) This loan is a $225.0 million construction facility, with reductions in interest cost based on meeting certain conditions, and has an initial three-year term with two one-year extension options. Advances under the loan are subject to incurred costs and funded equity requirements. (8) This loan is a $600.0 million construction facility and has an initial three-year term with two one-year extension options. Advances under the loan are subject to incurred costs and funded equity requirements. (9) In June 2020, we exercised a one-year extension option which extended the maturity date to June 2021. At September 30, 2020, there was no outstanding balance on the $400 million facility. At September 30, 2020 and December 31, 2019, the gross book value of the properties and debt and preferred equity investments collateralizing the mortgages and other loans payable was approximately $3.2 billion and $3.3 billion, respectively. Federal Home Loan Bank of New York ("FHLB") Facility The Company's wholly-owned subsidiary, Ticonderoga Insurance Company, or Ticonderoga, a Vermont licensed captive insurance company, is a member of the Federal Home Loan Bank of New York, or FHLBNY. As a member, Ticonderoga may borrow funds from the FHLBNY in the form of secured advances that bear interest at a floating rate. Unless Congress or the Federal Home Finance Authority extends membership criteria, then on February 19, 2021 Ticonderoga’s membership in FHLB New York will terminate and all advances will need to be repaid by such date. As of September 30, 2020, Ticonderoga had a total of $60.0 million in outstanding secured advances with an average spread of 21 basis points over 30-day LIBOR. Master Repurchase Agreement The Company entered into a Master Repurchase Agreement, or MRA, known as the 2017 MRA, which provides us with the ability to sell certain mortgage investments with a simultaneous agreement to repurchase the same at a certain date or on demand. 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 collateralize the facility with additional assets from our portfolio of debt investments, our ability to satisfy margin calls with cash or cash equivalents and our access to additional liquidity. As of September 30, 2020, there have been no margin calls on the 2017 MRA. In April 2018, we increased the maximum facility capacity from $300.0 million to $400.0 million. The facility bears interest on a floating rate basis at a spread to 30-day LIBOR based on the pledged collateral and advance rate and is scheduled to mature in June 2021, with a one-year extension option. At September 30, 2020, the facility had no outstanding balance. 2017 Credit Facility In November 2017, we entered into an amendment to the credit facility, referred to as the 2017 credit facility, that was originally entered into by the Company in November 2012, or the 2012 credit facility. As of September 30, 2020, the 2017 credit facility consisted of a $1.5 billion revolving credit facility, a $1.3 billion term loan (or "Term Loan A"), and a $200.0 million term loan (or "Term Loan B") with maturity dates of March 31, 2022, March 31, 2023, and November 21, 2024, respectively. The revolving credit facility has two six-month, as-of-right extension options to March 31, 2023. We also have an option, subject to customary conditions, to increase the capacity of the credit facility to $4.5 billion at any time prior to the maturity dates for the revolving credit facility and term loans without the consent of existing lenders, by obtaining additional commitments from our existing lenders or other financial institutions. As of September 30, 2020, the 2017 credit facility bore interest at a spread over 30-day LIBOR ranging from (i) 82.5 basis points to 155 basis points for loans under the revolving credit facility, (ii) 90 basis points to 175 basis points for loans under Term Loan A, and (iii) 85 basis points to 165 basis points for loans under Term Loan B, in each case based on the credit rating assigned to the senior unsecured long term indebtedness of the Company. In instances where there are either only two ratings available or where there are more than two and the difference between them is one rating category, the applicable rating shall be the highest rating. In instances where there are more than two ratings and the difference between the highest and the lowest is two or more rating categories, then the applicable rating used is the average of the highest two, rounded down if the average is not a recognized category. At September 30, 2020, the applicable spread was 100 basis points for the revolving credit facility, 110 basis points for Term Loan A, and 100 basis points for Term Loan B. 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 the Company. As of September 30, 2020, the facility fee was 20 basis points. As of September 30, 2020, we had $26.0 million of outstanding letters of credit, $190.0 million drawn under the revolving credit facility and $1.5 billion outstanding under the term loan facilities, with total undrawn capacity of $1.3 billion under the 2017 credit facility. At September 30, 2020 and December 31, 2019, the revolving credit facility had a carrying value of $184.8 million and $234.0 million, respectively, net of deferred financing costs. At September 30, 2020 and December 31, 2019, the term loan facilities had a carrying value of $1.5 billion and $1.5 billion, respectively, net of deferred financing costs. The Company and the Operating Partnership are borrowers jointly and severally obligated under the 2017 credit facility. The 2017 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, 2020 and December 31, 2019, respectively, by scheduled maturity date (dollars in thousands): Issuance September 30, September 30, December 31, Interest Rate (1) Initial Term Maturity Date August 7, 2018 (2) (3) $ 350,000 $ 350,000 $ 350,000 1.52 % 3 August 2021 October 5, 2017 (2) 500,000 499,775 499,695 3.25 % 5 October 2022 November 15, 2012 (4) 300,000 302,352 303,142 4.50 % 10 December 2022 December 17, 2015 (5) 100,000 100,000 100,000 4.27 % 10 December 2025 March 16, 2010 (6) — — 250,000 $ 1,250,000 $ 1,252,127 $ 1,502,837 Deferred financing costs, net (4,332) (5,990) $ 1,250,000 $ 1,247,795 $ 1,496,847 (1) Interest rate as of September 30, 2020, taking into account interest rate hedges in effect during the period. (2) Issued by the Operating Partnership with the Company as the guarantor. (3) The notes are subject to redemption at the Company's option, in whole but not in part, at a redemption price equal to 100% of the principal amount of the notes, plus unpaid accrued interest thereon to the redemption date. In April 2020, the Company entered into $350.0 million of fixed rate interest swaps at a rate of 0.54375% through August 2021. (4) In October 2017, the Company and the Operating Partnership as co-obligors issued an additional $100.0 million of 4.50% senior unsecured notes due December 2022. The notes were priced at 105.334% of par. (5) Issued by the Company and the Operating Partnership as co-obligors. (6) In March 2020, the notes were repaid. Restrictive Covenants The terms of the 2017 credit facility 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, 2020 and December 31, 2019, 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 a floating rate of 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, the 2017 credit facility, trust preferred securities, senior unsecured notes and our share of joint venture debt as of September 30, 2020, including as-of-right extension options, were as follows (in thousands): Scheduled Mortgages and Other Loans Payable Revolving Unsecured Term Loans Trust Senior Total Joint Remaining 2020 $ 2,635 $ 15,523 $ — $ — $ — $ — $ 18,158 $ 10,867 2021 10,766 270,474 — — — 350,000 631,240 1,444,277 2022 8,779 255,435 — — — 800,000 1,064,214 268,952 2023 6,608 994,934 190,000 1,300,000 — — 2,491,542 311,436 2024 5,294 272,749 — 200,000 — — 478,043 618,140 Thereafter 1,779 579,746 — — 100,000 100,000 781,525 1,935,202 $ 35,861 $ 2,388,861 $ 190,000 $ 1,500,000 $ 100,000 $ 1,250,000 $ 5,464,722 $ 4,588,874 Consolidated interest expense, excluding capitalized interest, was comprised of the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Interest expense before capitalized interest $ 42,595 $ 63,607 $ 144,345 $ 185,163 Interest on financing leases 2,198 813 6,010 2,425 Interest capitalized (20,677) (15,700) (57,528) (38,228) Interest income (580) (608) (1,727) (3,563) Interest expense, net $ 23,536 $ 48,112 $ 91,100 $ 145,797

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2020
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, who serves as a member and as the chairman emeritus of our 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 the profit participation, which is included in other income on the consolidated statements of operations, was $0.1 million and $1.1 million for the three and nine months ended September 30, 2020, respectively, and $0.9 million and $2.7 million for the three and nine months ended September 30, 2019, respectively. We also recorded expenses, inclusive of capitalized expenses, of $3.0 million and $9.7 million for the three and nine months ended September 30, 2020, respectively, for these services (excluding services provided directly to tenants), and $5.6 million and $14.1 million for the three and nine months ended September 30, 2019, 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 $0.4 million for the three and nine months ended September 30, 2020, respectively, and $0.2 million and $0.5 million for the three and nine months ended September 30, 2019, respectively. One Vanderbilt Investment In December 2016, we entered into agreements with entities owned and controlled by our Chairman and CEO, Marc Holliday, and our President, Andrew Mathias, pursuant to which they agreed to make an investment in our One Vanderbilt project at the appraised fair market value for the interests acquired. This investment entitles these entities to receive approximately 1.50% - 1.80% and 1.00% - 1.20%, respectively, of any profits realized by the Company from its One Vanderbilt project in excess of the Company’s capital contributions. The entities have no right to any return of capital. Accordingly, subject to previously disclosed repurchase rights, these interests will have no value and will not entitle these entities to any amounts (other than limited distributions to cover tax liabilities incurred) unless and until the Company has received distributions from the One Vanderbilt project in excess of the Company’s aggregate investment in the project. In the event that the Company does not realize a profit on its investment in the project (or would not realize a profit based on the value at the time the interests are repurchased), the entities owned and controlled by Messrs. Holliday and Mathias will lose the entire amount of their investment. The entities owned and controlled by Messrs. Holliday and Mathias paid $1.4 million and $1.0 million, respectively, which equal the fair market value of the interests acquired as of the date the investment agreements were entered into as determined by an independent third party appraisal that we obtained. Other We are entitled to receive fees for providing management, leasing, construction supervision and asset management services to certain of our joint ventures as further described in Note 6, "Investments in Unconsolidated Joint Ventures." Amounts due from joint ventures and related parties at September 30, 2020 and December 31, 2019 consisted of the following (in thousands): September 30, 2020 December 31, 2019 Due from joint ventures $ 24,912 $ 9,352 Other 7,024 11,769 Related party receivables $ 31,936 $ 21,121

Noncontrolling Interests on the

Noncontrolling Interests on the Company's Consolidated Financial Statements	9 Months Ended
	Sep. 30, 2020
Noncontrolling Interest [Abstract]
Noncontrolling Interests on the Company's Consolidated Financial Statements	Noncontrolling Interests on the Company's Consolidated Financial Statements Noncontrolling interests represent the common and preferred units of limited partnership interest in the Operating Partnership not held by the Company as well as third party equity interests in our other consolidated subsidiaries. Noncontrolling interests in the Operating Partnership are shown in the mezzanine equity while the noncontrolling interests in our other consolidated subsidiaries are shown in the equity section of the Company’s consolidated financial statements. Common Units of Limited Partnership Interest in the Operating Partnership As of September 30, 2020 and December 31, 2019, the noncontrolling interest unit holders owned 5.23%, or 4,027,317 units, and 5.03%, or 4,195,875 units, of the Operating Partnership, respectively. As of September 30, 2020, 4,027,317 shares of our 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 our common stock at the end of the reporting period. Below is a summary of the activity relating to the noncontrolling interests in the Operating Partnership for the nine months ended September 30, 2020 and the twelve months ended December 31, 2019 (in thousands): September 30, 2020 December 31, 2019 Balance at beginning of period $ 409,862 $ 387,805 Distributions (8,857) (14,729) Issuance of common units 7,976 19,403 Redemption and conversion of common units (27,657) (27,962) Net income 10,073 13,301 Accumulated other comprehensive loss allocation (2,664) (2,276) Fair value adjustment (35,253) 34,320 Balance at end of period $ 353,480 $ 409,862 Preferred Units of Limited Partnership Interest in the Operating Partnership Below is a summary of the preferred units of limited partnership interest in the Operating Partnership as of September 30, 2020: Issuance Number of Units Authorized Number of Units Issued Number of Units Outstanding Annual Dividend Per Unit (1) Liquidation Preference Per Unit (2) Conversion Price Per Unit (3) Date of Issuance 3.50% Series A (4) 109,161 109,161 109,161 $ 35.0000 $ 1,000.00 $ — August 2015 7.00% Series F 60 60 60 $ 70.0000 $ 1,000.00 $ 29.12 January 2007 4.50% Series G (5) 1,902,000 1,902,000 863,972 $ 1.1250 $ 25.00 $ 88.50 January 2012 3.50% Series K 700,000 563,954 341,677 $ 0.8750 $ 25.00 $ 134.67 August 2014 4.00% Series L 500,000 378,634 372,634 $ 1.0000 $ 25.00 — August 2014 3.75% Series M 1,600,000 1,600,000 96,357 $ 0.9375 $ 25.00 — February 2015 4.00% Series P 200,000 200,000 200,000 $ 1.0000 $ 25.00 — July 2015 3.50% Series Q 268,000 268,000 268,000 $ 0.8750 $ 25.00 $ 148.95 July 2015 3.50% Series R 400,000 400,000 400,000 $ 0.8750 $ 25.00 $ 154.89 August 2015 4.00% Series S 1,077,280 1,077,280 1,077,280 $ 1.0000 $ 25.00 — August 2015 3.50% Series V 40,000 40,000 40,000 $ 0.8750 $ 25.00 — May 2019 Series W (6) 1 1 1 (6) (6) — January 2020 (1) Dividends are cumulative, subject to certain provisions. (2) Units are redeemable at any time at par for cash at the option of the unitholder unless otherwise specified. (3) If applicable, 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) the amount shown in the table. (4) Issued through a consolidated subsidiary. The units are convertible on a one-for-one basis, into the Series B Preferred Units of limited partnership interest, or the Subsidiary Series B Preferred Units. The Subsidiary 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 Subsidiary Series B Preferred Unit. As of September 30, 2020, no Subsidiary Series B Preferred Units have been issued. (5) Common units of limited partnership interest in the Operating Partnership issued in a conversion may be redeemed in exchange for our 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. (6) The Series W preferred unit was issued in January 2020 in exchange for the then-outstanding Series O preferred unit. The holder of the Series W preferred unit is entitled to quarterly dividends in an amount calculated as (i) 1,350 multiplied by (ii) the current distribution per common unit of limited partnership in SL Green Operating Partnership. The holder has the right to require the Operating Partnership to repurchase the Series W unit for cash, or convert the Series W unit for Class B units, in each case at a price that is determined based on the closing price of the Company's common stock at the time such right is exercised. The unit's liquidation preference is the fair market value of the unit plus accrued distributions at the time of a liquidation event. Below is a summary of the activity relating to the preferred units in the Operating Partnership for the nine months ended September 30, 2020 and the twelve months ended December 31, 2019 (in thousands): September 30, 2020 December 31, 2019 Balance at beginning of period $ 283,285 $ 300,427 Issuance of preferred units — 1,000 Redemption of preferred units (82,750) (18,142) Accrued dividends on preferred units 1,634 — Balance at end of period $ 202,169 $ 283,285

Stockholders' Equity of the Com

Stockholders' Equity of the Company	9 Months Ended
	Sep. 30, 2020
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, 2020, 73,040,291 shares of common stock and no shares of excess stock were issued and outstanding. Share Repurchase Program In August 2016, our Board of Directors approved a share repurchase program under which we can buy up to $1.0 billion of shares of our common stock. The Board of Directors has since authorized four separate $500.0 million increases to the size of the share repurchase program in the fourth quarter of 2017, second quarter of 2018, fourth quarter of 2018, and fourth quarter of 2019 bringing the total program size to $3.0 billion. At September 30, 2020, repurchases executed under the program were as follows: Period Shares repurchased Average price paid per share Cumulative number of shares repurchased as part of the repurchase plan or programs Year ended 2017 8,342,411 $101.64 8,342,411 Year ended 2018 9,744,911 $96.22 18,087,322 Year ended 2019 4,596,171 $83.62 22,683,493 Nine months ended September 30, 2020 (1) 6,243,165 $62.77 28,926,658 (1) Includes 216,101 shares of common stock repurchased by the Company in September 2020 that were settled in October 2020. 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. 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 ("DRSPP") In February 2018, 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 our common stock under the DRSPP. The DRSPP commenced on September 24, 2001. The following table summarizes SL Green common stock issued, and proceeds received from dividend reinvestments and/or stock purchases under the DRSPP for the three and nine months ended September 30, 2020 and 2019, respectively (dollars in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Shares of common stock issued 4,205 490 9,884 3,485 Dividend reinvestments/stock purchases under the DRSPP $ 202 $ 39 $ 566 $ 303 Earnings per Share We use the two-class method of computing earnings per share (“EPS”), which is an earnings allocation formula that determines EPS for common stock and any participating securities according to dividends declared (whether paid or unpaid). Under the two-class method, basic EPS is computed by dividing the income available to common stockholders by the weighted-average number of common stock shares outstanding for the period. Diluted EPS reflects the potential dilution that could occur from share equivalent activity. SL Green's earnings per share for the three and nine months ended September 30, 2020 and 2019 are computed as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Numerator 2020 2019 2020 2019 Basic Earnings: Income attributable to SL Green common stockholders $ 13,859 $ 33,157 $ 185,104 $ 238,052 Less: distributed earnings allocated to participating securities (333) (108) (777) (325) Less: undistributed earnings allocated to participating securities — — (141) (41) Net income attributable to SL Green common stockholders (numerator for basic earnings per share) $ 13,526 $ 33,049 $ 184,186 $ 237,686 Add back: dilutive effect of earnings allocated to participating securities 333 108 777 325 Add back: undistributed earnings allocated to participating securities — — 141 41 Add back: effect of dilutive securities (redemption of units to common shares) 802 1,719 10,073 12,306 Income attributable to SL Green common stockholders (numerator for diluted earnings per share) $ 14,661 $ 34,876 $ 195,177 $ 250,358 Three Months Ended September 30, Nine Months Ended September 30, Denominator 2020 2019 2020 2019 Basic Shares: Weighted average common stock outstanding 73,020 82,292 75,521 82,855 Effect of Dilutive Securities: Operating Partnership units redeemable for common shares 4,029 4,258 4,123 4,283 Stock-based compensation plans 442 164 441 171 Diluted weighted average common stock outstanding 77,491 86,714 80,085 87,309 The Company has excluded 2,131,606 and 1,779,212 common stock equivalents from the calculation of diluted shares outstanding for the three and nine months ended September 30, 2020, respectively, as they were anti-dilutive. The Company has excluded 1,317,803 and 1,266,296 common stock equivalents from the calculation of diluted shares outstanding for the three and nine months ended September 30, 2019, respectively, as they were anti-dilutive. The following tables set forth the changes in accumulated other comprehensive loss by component as of September 30, 2020 (in thousands): Net unrealized loss on derivative instruments ( 1 ) SL Green’s share of joint venture net unrealized loss on derivative instruments ( 2 ) Net unrealized gain (loss) on marketable securities Total Balance at December 31, 2019 $ (22,780) $ (7,982) $ 2,277 $ (28,485) Other comprehensive loss before reclassifications (50,038) (7,954) (2,047) (60,039) Amounts reclassified from accumulated other comprehensive loss 9,120 3,204 — 12,324 Balance at September 30, 2020 $ (63,698) $ (12,732) $ 230 $ (76,200) (1) Amount reclassified from accumulated other comprehensive loss is included in interest expense in the respective consolidated statements of operations. As of September 30, 2020 and December 31, 2019, the deferred net gains from these terminated hedges, which is included in accumulated other comprehensive loss relating to net unrealized (loss) gain on derivative instrument, was $(0.5) million and $(0.7) million, respectively. (2) Amount reclassified from accumulated other comprehensive loss is included in equity in net loss from unconsolidated joint ventures in the respective consolidated statements of operations.

Share-based Compensation

Share-based Compensation	9 Months Ended
	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
Share-based Compensation	Share-based CompensationWe have share-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. 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) 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 our 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, 2020, 3.4 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. Stock Options and Class O LTIP Units Options are granted with an exercise price at the fair market value of the Company's common stock on the date of grant and, subject to employment, generally expire five years or ten years from the date of grant, are not transferable other than on death, and generally vest in one year to five years commencing one year from the date of grant. We have also granted Class O LTIP Units, which are a class of LTIP Units in the Operating Partnership structured to provide economics similar to those of stock options. Class O LTIP Units, once vested, may be converted, at the election of the holder, into a number of common units of the Operating Partnership per Class O LTIP Unit determined by the increase in value of a share of the Company’s common stock at the time of conversion over a participation threshold, which equals the fair market value of a share of the Company’s common stock at the time of grant. Class O LTIP Units are entitled to distributions, subject to vesting, equal per unit to 10% of the per unit distributions paid with respect to the common units of the Operating Partnership. The fair value of each stock option or LTIP Unit granted is estimated on the date of grant using the Black-Scholes option pricing model based on historical information. There were no options granted during the nine months ended September 30, 2020 or the year ended December 31, 2019. A summary of the status of the Company's stock options as of September 30, 2020 and December 31, 2019, and changes during the nine months ended September 30, 2020 and year ended December 31, 2019 are as follows: September 30, 2020 December 31, 2019 Options Outstanding Weighted Average Options Outstanding Weighted Average Balance at beginning of period 1,037,068 $ 102.36 1,137,017 $ 103.54 Granted — — — — Exercised — — — — Lapsed or canceled (53,700) 111.18 (99,949) 115.81 Balance at end of period 983,368 $ 101.88 1,037,068 $ 102.36 Options exercisable at end of period 982,368 $ 101.88 914,929 $ 101.69 The remaining weighted average contractual life of the options outstanding was 2.0 years and the remaining average contractual life of the options exercisable was 2.0 years. During the three and nine months ended September 30, 2020, we recognized compensation expense for these options of $0.00 million and $0.03 million, respectively. During the three and nine months ended September 30, 2019, we recognized compensation expense for these options of $0.6 million and $1.8 million, respectively. As of September 30, 2020, there was $0.01 million of total unrecognized compensation cost related to unvested stock options, which is expected to be recognized over a weighted average period of 0.5 years. Restricted Shares Shares are granted to certain employees, including our executives, and vesting occurs 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, 2020 and December 31, 2019 and charges during the nine months ended September 30, 2020 and the year ended December 31, 2019, are as follows: September 30, 2020 December 31, 2019 Balance at beginning of period 3,566,466 3,452,016 Granted 9,220 126,350 Canceled (26,043) (11,900) Balance at end of period 3,549,643 3,566,466 Vested during the period 132,652 113,259 Compensation expense recorded $ 8,528,991 $ 12,892,249 Total fair value of restricted stock granted during the period $ 734,315 $ 11,131,181 The fair value of restricted stock that vested during the nine months ended September 30, 2020 and the year ended December 31, 2019 was $12.5 million and $12.1 million, respectively. As of September 30, 2020, there was $11.0 million of total unrecognized compensation cost related to restricted stock, which is expected to be recognized over a weighted average period of 1.5 years. We granted LTIP Units, which include bonus, time-based and performance-based awards, with a fair value of $33.7 million and $58.3 million as of September 30, 2020 and December 31, 2019, 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 our 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, 2020, there was $41.8 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 2.0 years. During the three and nine months ended September 30, 2020, we recorded compensation expense related to bonus, time-based and performance based awards of $6.4 million and $20.4 million, respectively. During the three and nine months ended September 30, 2019, we recorded compensation expense related to bonus, time-based and performance based awards of $3.0 million and $14.0 million, respectively. For the three and nine months ended September 30, 2020, $0.6 million and $1.7 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, 2019, $0.5 million and $1.4 million, respectively, was capitalized to assets associated with compensation expense related to our long-term compensation plans, restricted stock and stock options. 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 our 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, 2020, 18,167 phantom stock units and 8,285 shares of common stock were issued to our board of directors. We recorded compensation expense of $0.2 million and $2.1 million during the three and nine months ended September 30, 2020, respectively, related to the Deferred Compensation Plan. We recorded compensation expense of $0.2 million and $2.2 million during the three and nine months ended September 30, 2019, respectively, related to the Deferred Compensation Plan. As of September 30, 2020, there were 138,189 phantom stock units outstanding pursuant to our Non-Employee Director's Deferral Program. Employee Stock Purchase Plan

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Accumulated Other Comprehensive Loss	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, 2020, 73,040,291 shares of common stock and no shares of excess stock were issued and outstanding. Share Repurchase Program In August 2016, our Board of Directors approved a share repurchase program under which we can buy up to $1.0 billion of shares of our common stock. The Board of Directors has since authorized four separate $500.0 million increases to the size of the share repurchase program in the fourth quarter of 2017, second quarter of 2018, fourth quarter of 2018, and fourth quarter of 2019 bringing the total program size to $3.0 billion. At September 30, 2020, repurchases executed under the program were as follows: Period Shares repurchased Average price paid per share Cumulative number of shares repurchased as part of the repurchase plan or programs Year ended 2017 8,342,411 $101.64 8,342,411 Year ended 2018 9,744,911 $96.22 18,087,322 Year ended 2019 4,596,171 $83.62 22,683,493 Nine months ended September 30, 2020 (1) 6,243,165 $62.77 28,926,658 (1) Includes 216,101 shares of common stock repurchased by the Company in September 2020 that were settled in October 2020. 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. 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 ("DRSPP") In February 2018, 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 our common stock under the DRSPP. The DRSPP commenced on September 24, 2001. The following table summarizes SL Green common stock issued, and proceeds received from dividend reinvestments and/or stock purchases under the DRSPP for the three and nine months ended September 30, 2020 and 2019, respectively (dollars in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Shares of common stock issued 4,205 490 9,884 3,485 Dividend reinvestments/stock purchases under the DRSPP $ 202 $ 39 $ 566 $ 303 Earnings per Share We use the two-class method of computing earnings per share (“EPS”), which is an earnings allocation formula that determines EPS for common stock and any participating securities according to dividends declared (whether paid or unpaid). Under the two-class method, basic EPS is computed by dividing the income available to common stockholders by the weighted-average number of common stock shares outstanding for the period. Diluted EPS reflects the potential dilution that could occur from share equivalent activity. SL Green's earnings per share for the three and nine months ended September 30, 2020 and 2019 are computed as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Numerator 2020 2019 2020 2019 Basic Earnings: Income attributable to SL Green common stockholders $ 13,859 $ 33,157 $ 185,104 $ 238,052 Less: distributed earnings allocated to participating securities (333) (108) (777) (325) Less: undistributed earnings allocated to participating securities — — (141) (41) Net income attributable to SL Green common stockholders (numerator for basic earnings per share) $ 13,526 $ 33,049 $ 184,186 $ 237,686 Add back: dilutive effect of earnings allocated to participating securities 333 108 777 325 Add back: undistributed earnings allocated to participating securities — — 141 41 Add back: effect of dilutive securities (redemption of units to common shares) 802 1,719 10,073 12,306 Income attributable to SL Green common stockholders (numerator for diluted earnings per share) $ 14,661 $ 34,876 $ 195,177 $ 250,358 Three Months Ended September 30, Nine Months Ended September 30, Denominator 2020 2019 2020 2019 Basic Shares: Weighted average common stock outstanding 73,020 82,292 75,521 82,855 Effect of Dilutive Securities: Operating Partnership units redeemable for common shares 4,029 4,258 4,123 4,283 Stock-based compensation plans 442 164 441 171 Diluted weighted average common stock outstanding 77,491 86,714 80,085 87,309 The Company has excluded 2,131,606 and 1,779,212 common stock equivalents from the calculation of diluted shares outstanding for the three and nine months ended September 30, 2020, respectively, as they were anti-dilutive. The Company has excluded 1,317,803 and 1,266,296 common stock equivalents from the calculation of diluted shares outstanding for the three and nine months ended September 30, 2019, respectively, as they were anti-dilutive. The following tables set forth the changes in accumulated other comprehensive loss by component as of September 30, 2020 (in thousands): Net unrealized loss on derivative instruments ( 1 ) SL Green’s share of joint venture net unrealized loss on derivative instruments ( 2 ) Net unrealized gain (loss) on marketable securities Total Balance at December 31, 2019 $ (22,780) $ (7,982) $ 2,277 $ (28,485) Other comprehensive loss before reclassifications (50,038) (7,954) (2,047) (60,039) Amounts reclassified from accumulated other comprehensive loss 9,120 3,204 — 12,324 Balance at September 30, 2020 $ (63,698) $ (12,732) $ 230 $ (76,200) (1) Amount reclassified from accumulated other comprehensive loss is included in interest expense in the respective consolidated statements of operations. As of September 30, 2020 and December 31, 2019, the deferred net gains from these terminated hedges, which is included in accumulated other comprehensive loss relating to net unrealized (loss) gain on derivative instrument, was $(0.5) million and $(0.7) million, respectively. (2) Amount reclassified from accumulated other comprehensive loss is included in equity in net loss from unconsolidated joint ventures in the respective consolidated statements of operations.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2020
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, 2020 and December 31, 2019 (in thousands): September 30, 2020 Total Level 1 Level 2 Level 3 Assets: Marketable securities $ 27,734 $ — $ 27,734 $ — Interest rate cap and swap agreements (included in other assets) $ 39 $ — $ 39 $ — Liabilities: Interest rate cap and swap agreements (included in other liabilities) $ 67,680 $ — $ 67,680 $ — December 31, 2019 Total Level 1 Level 2 Level 3 Assets: Marketable securities $ 29,887 $ — $ 29,887 $ — Interest rate cap and swap agreements (included in other assets) $ 4,419 $ — $ 4,419 $ — Liabilities: Interest rate cap and swap agreements (included in other liabilities) $ 29,110 $ — $ 29,110 $ — We evaluate real estate investments and debt and preferred equity investments, including intangibles, for potential impairment primarily utilizing cash flow projections that apply, among other things, estimated revenue and expense growth rates, discount rates and capitalization rates, as well as sales comparison approach, which utilizes comparable sales, listings and sales contracts. All of which are classified as Level 3 inputs. Marketable securities classified as Level 1 are derived from quoted prices in active markets. The valuation technique used to measure the fair value of 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 instrument 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, 2020 and December 31, 2019 (in thousands): September 30, 2020 December 31, 2019 Carrying Value (1) Fair Value Carrying Value (1) Fair Value Debt and preferred equity investments $ 1,153,363 (2) $ 1,580,306 (2) Fixed rate debt $ 3,338,268 $ 3,427,731 $ 3,536,286 $ 3,642,770 Variable rate debt 2,128,581 2,112,589 2,018,434 2,018,714 $ 5,466,849 $ 5,540,320 $ 5,554,720 $ 5,661,484 (1) Amounts exclude net deferred financing costs. (2) At September 30, 2020, debt and preferred equity investments had an estimated fair value ranging between $1.04 billion and $1.15 billion. At December 31, 2019, debt and preferred equity investments had an estimated fair value ranging between $1.58 billion and $1.74 billion. Disclosure about fair value of financial instruments was based on pertinent information available to us as of September 30, 2020 and December 31, 2019. 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, 2020
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 sheet 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 (loss) until the hedged item is 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, 2020 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 (dollars in thousands). Notional Strike Effective Expiration Balance Sheet Location Fair Interest Rate Swap $ 100,000 1.928 % December 2017 November 2020 Other Liabilities $ (295) Interest Rate Swap 100,000 1.934 % December 2017 November 2020 Other Liabilities (296) Interest Rate Cap 111,869 3.500 % December 2019 December 2020 Other Assets — Interest Rate Cap 85,000 4.000 % March 2019 March 2021 Other Assets — Interest Rate Swap 350,000 0.544 % April 2020 August 2021 Other Liabilities (978) Interest Rate Cap 510,000 3.000 % June 2020 December 2021 Other Assets 1 Interest Rate Swap 200,000 1.131 % July 2016 July 2023 Other Liabilities (5,599) Interest Rate Swap 100,000 1.161 % July 2016 July 2023 Other Liabilities (2,883) Interest Rate Cap 600,000 4.000 % August 2020 September 2023 Other Assets 38 Interest Rate Swap 150,000 2.696 % January 2019 January 2024 Other Liabilities (12,430) Interest Rate Swap 150,000 2.721 % January 2019 January 2026 Other Liabilities (19,286) Interest Rate Swap 200,000 2.740 % January 2019 January 2026 Other Liabilities (25,913) $ (67,641) No gains or losses on the changes in the fair values were included in interest expense in the consolidated statements of operations during the three months ended September 30, 2020 or 2019. No gains or losses on the changes in the fair values were included in interest expense in the consolidated statements of operations during the nine months ended September 30, 2020 or 2019. The Company has agreements with each of its derivative counterparties that contain a provision where if the Company defaults on any of its indebtedness, then the Company could also be declared in default on its derivative obligations. As of September 30, 2020, 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 $68.9 million. As of September 30, 2020, 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 $70.2 million at September 30, 2020. Gains and losses on terminated hedges are included in accumulated other comprehensive income (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 $17.7 million of the current balance held in accumulated other comprehensive loss will be reclassified into interest expense and $7.4 million of the portion related to our share of joint venture accumulated other comprehensive loss will be reclassified into equity in net loss 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, 2020 and 2019, respectively (in thousands): Amount of Loss Location of Loss Reclassified from Accumulated Other Comprehensive Loss into Income Amount of Loss Reclassified from Three Months Ended September 30, Three Months Ended September 30, Derivative 2020 2019 2020 2019 Interest Rate Swaps/Caps $ (318) $ (10,169) Interest expense $ (5,162) $ (105) Share of unconsolidated joint ventures' derivative instruments (199) (2,437) Equity in net loss from unconsolidated joint ventures (1,454) (192) $ (517) $ (12,606) $ (6,616) $ (297) 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, 2020 and 2019, respectively (in thousands): Amount of Loss Location of (Loss) Gain Reclassified from Accumulated Other Comprehensive Loss into Income Amount of (Loss) Gain Reclassified from Nine Months Ended September 30, Nine Months Ended September 30, Derivative 2020 2019 2020 2019 Interest Rate Swaps/Caps $ (52,808) $ (43,008) Interest expense $ (9,610) $ 886 Share of unconsolidated joint ventures' derivative instruments (8,375) (11,963) Equity in net loss from unconsolidated joint ventures (3,347) 713 $ (61,183) $ (54,971) $ (12,957) $ 1,599

Rental Income

Rental Income	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Rental Income	Rental Income The Operating Partnership is the lessor and the sublessor to tenants under operating and sales-type leases. The minimum rental amounts due under the leases are generally subject to scheduled fixed increases or adjustments. The leases generally also require that the tenants reimburse us for increases in certain operating costs and real estate taxes above their base year costs. The components of operating lease revenues were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Fixed lease payments $ 171,866 $ 214,282 $ 538,601 $ 641,007 Variable lease payments 21,979 32,581 70,892 88,539 Total lease payments $ 193,845 $ 246,863 $ 609,493 $ 729,546 Amortization of acquired above and below-market leases 1,670 1,165 4,539 3,559 Total rental revenue $ 195,515 $ 248,028 $ 614,032 $ 733,105 The components of sales-type lease revenues were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Loss recognized at commencement, net (1) $ (5,973) $ — $ (5,973) $ — Interest income (2) 484 — 484 — Total loss recognized on sales-type leases $ (5,489) $ — $ (5,489) $ — (1) These amounts are included in gain on sale of real estate, net and depreciable real estate reserves and impairment in our consolidated statements of operations. (2) These amounts are included in other income in our consolidated statements of operations.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings As of September 30, 2020, 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 Our management believes that the properties are in compliance in all material respects with applicable Federal, state and local ordinances and regulations regarding environmental issues. Management is not aware of any environmental liability that it believes would have a materially adverse impact on our financial position, results of operations or cash flows. Management is unaware of any instances in which it would incur significant environmental cost if any of our properties were sold. Ground Lease Arrangements We are a tenant under ground leases for certain properties. These leases have expirations from 2022 to 2119, or 2043 to 2119 as fully extended. Certain leases offer extension options which we assess against relevant economic factors to determine whether we are reasonably certain of exercising or not exercising the option. Lease payments associated with renewal periods that we are reasonably certain will be exercised, if any, are included in the measurement of the corresponding lease liability and right of use asset. Certain of our ground leases are subject to rent resets, generally based on a percentage of the then fair market value, a fixed amount, or a percentage of the preceding rent at specified future dates. Rent resets will be recognized in the periods in which they are incurred. The table below summarizes our current ground lease arrangements as of September 30, 2020: Property (1) Year of Current Expiration Year of Final Expiration (2) 1185 Avenue of the Americas 2043 2043 625 Madison Avenue 2022 2054 420 Lexington Avenue 2050 2080 711 Third Avenue (3) 2033 2083 461 Fifth Avenue (4) 2027 2084 1055 Washington Blvd, Stamford, Connecticut 2090 2090 1080 Amsterdam Avenue (5) 2111 2111 30 East 40th Street (5) 2114 2114 126 Nassau Street (4)(6) 2119 2119 Other Various Various (1) All leases are classified as operating leases unless otherwise specified. (2) Reflects exercise of all available renewal options. (3) The Company owns 50% of the fee interest. (4) The Company has an option to purchase the ground lease for a fixed price on a specific date. The lease is classified as a financing lease. (5) A portion of the lease is classified as a financing lease. (6) In August 2020, the Company entered into a long-term sublease with an unconsolidated joint venture as part of the capitalization of the 126 Nassau Street development project. See Note 6, "Investments in Unconsolidated Joint Ventures." The following is a schedule of future minimum lease payments as evaluated in accordance with ASC 842 for our financing leases and operating leases with initial terms in excess of one year as of September 30, 2020 (in thousands): Financing leases Operating leases (1) Remaining 2020 $ 1,974 $ 7,363 2021 34,885 29,452 2022 5,881 27,148 2023 5,927 24,844 2024 5,999 24,863 2025 6,266 24,962 Thereafter 1,018,013 618,326 Total minimum lease payments $ 1,078,945 $ 756,958 Amount representing interest (903,962) Amount discounted using incremental borrowing rate (398,539) Lease liabilities $ 174,983 $ 358,419 (1) As of September 30, 2020, the total future minimum payments to be received under non-cancelable subleases is $1.7 billion. The following table provides lease cost information for the Company's operating and financing leases for the three and nine months ended September 30, 2020 and 2019 (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Operating Lease Costs Operating lease costs before capitalized operating lease costs $ 7,751 $ 8,315 $ 24,486 $ 24,918 Operating lease costs capitalized (778) (20) (2,315) (27) Operating lease costs, net (1) 6,973 8,295 22,171 24,891 Financing Lease Costs Interest on financing leases before capitalized interest 2,198 813 6,010 2,425 Interest on financing leases capitalized (588) — (2,378) — Interest on financing leases, net (2) 1,610 813 3,632 2,425 Amortization of right-of-use assets (3) 304 304 914 914 Financing lease costs, net 1,914 1,117 4,546 3,339 (1) This amount is included in operating lease rent in our consolidated statements of operations. (2) These amounts are included in interest expense, net of interest income in our consolidated statements of operations. (3) These amounts are included in depreciation and amortization in our consolidated statements of operations.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Segment Information	Segment Information The Company has two reportable segments, real estate and debt and preferred equity investments. We evaluate real estate performance and allocate resources based on earnings contributions. 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, insurance, 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, 2020 and 2019, and selected asset information as of September 30, 2020 and December 31, 2019, 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, 2020 $ 226,856 $ 22,988 $ 249,844 September 30, 2019 262,115 51,519 313,634 Nine months ended: September 30, 2020 $ 716,382 $ 101,464 817,846 September 30, 2019 777,745 153,168 930,913 Net income Three months ended: September 30, 2020 $ 10,097 $ 10,580 $ 20,677 September 30, 2019 6,133 34,589 40,722 Nine months ended: September 30, 2020 $ 161,388 $ 53,030 214,418 September 30, 2019 168,639 98,593 267,232 Total assets As of: September 30, 2020 $ 11,079,252 $ 1,244,787 $ 12,324,039 December 31, 2019 11,063,155 1,703,165 12,766,320 Interest costs for the debt and preferred equity segment include actual costs incurred for borrowings on the 2017 MRA and the FHLB Facility. Interest is imputed on the investments that do not collateralize the 2017 MRA and the FHLB Facility using our weighted average 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 because the use of personnel and resources is dependent on transaction volume between the two segments and varies period over period. In addition, we base performance on the individual segments prior to allocating marketing, general and administrative expenses. For the three and nine months ended September 30, 2020, marketing, general and administrative expenses totaled $23.6 million and $66.7 million, respectively. For the three and nine months ended September 30, 2019, marketing, general and administrative expenses totaled $23.8 million and $75.3 million, respectively. All other expenses, except interest, relate entirely to the real estate assets. There were no transactions between the above two segments.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2020
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.
Investment in Commercial Real Estate Properties	Investment in Commercial Real Estate Properties 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 3 years 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 1 year 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 1 year 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 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. The Company classifies those leases under which the Company is the lessee at lease commencement as finance or operating leases. Leases qualify as finance leases if the lease transfers ownership of the asset at the end of the lease term, the lease grants an option to purchase the asset that we are reasonably certain to exercise, the lease term is for a major part of the remaining economic life of the asset, or the present value of the lease payments exceeds substantially all of the fair value of the asset. Leases that do not qualify as finance leases are deemed to be operating leases. At lease commencement the Company records a lease liability which is measured as the present value of the lease payments and a right of use asset which is measured as the amount of the lease liability and any initial direct costs incurred. The Company applies a discount rate to determine the present value of the lease payments. If the rate implicit in the lease is known, the Company uses that rate. If the rate implicit in the lease is not known, the Company uses a discount rate reflective of the Company’s collateralized borrowing rate given the term of the lease. To determine the discount rate, the Company employs a third party specialist to develop an analysis based primarily on the observable borrowing rates of the Company, other REITs, and other corporate borrowers with long-term borrowings. On the consolidated statements of operations, operating leases are expensed through operating lease rent while financing leases are expensed through amortization and interest expense. On the consolidated balance sheet, financing leases include the amounts previously captioned "Properties under capital lease." When applicable, the Company combines the consideration for lease and non-lease components in the calculation of the value of the lease obligation and right-of-use asset. On a periodic basis, we assess whether there are any indications that the value of our real estate properties may be impaired or that their carrying value may not be recoverable. A property's value is considered impaired if management's estimate of the aggregate future cash flows (undiscounted) 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 fair value of the property as calculated in accordance with ASC 820. We also evaluate our real estate properties for impairment when a property has been classified as held for sale. Real estate assets held for sale are valued at the lower of their carrying value or fair value less costs to sell and depreciation expense is no longer recorded.
Investment in Marketable Securities	Investment in Marketable Securities At acquisition, we designate a security as held-to-maturity, available-for-sale, or trading. As of September 30, 2020, 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. The cost of marketable securities sold and the amount reclassified out of accumulated other comprehensive income into earnings is determined using the specific identification method. Any unrealized losses that are determined to be other-than-temporary are recognized in earnings up to their credit component.
Investments in Unconsolidated Joint Ventures	Investments in Unconsolidated Joint VenturesWe 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 each joint venture's projected discounted cash flows.
Deferred Lease Costs and Lease Classification	Deferred Lease Costs Deferred lease costs consist of incremental fees and direct costs that would not have been incurred if the lease had not been obtained and are amortized on a straight-line basis over the related lease term. Lease Classification Lease classification for leases under which the Company is the lessor is evaluated at lease commencement and leases not classified as sales-type leases or direct financing leases are classified as operating leases. Leases qualify as sales-type leases if the contract includes either transfer of ownership clauses, certain purchase options, a lease term representing a major part of the economic life of the asset, or the present value of the lease payments and residual guarantees provided by the lessee exceeds substantially all of the fair value of the asset. Additionally, leasing an asset so specialized that it is not deemed to have any value to the Company at the end of the lease term may also result in classification as a sales-type lease. Leases qualify as direct financing leases when the present value of the lease payments and residual value guarantees provided by the lessee and unrelated third parties exceeds substantially all of the fair value of the asset and collection of the payments is probable.
Revenue Recognition	Revenue Recognition Rental revenue for operating leases is recognized on a straight-line basis over the term of the lease. Rental revenue recognition commences when the leased space is available for use by the lessee. To determine whether the leased space is available for use by the lessee, 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 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. In addition to base rent, our tenants also generally will pay variable rent which represents their pro rata share of increases in real estate taxes and certain operating expenses for the building over a base year. In some leases, in lieu of paying additional rent based upon increases in certain 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. Rental revenue is recognized if collectability is probable. If collectability of substantially all of the lease payments is assessed as not probable, any difference between the rental revenue recognized to date and the lease payments that have been collected is recognized as a current-period adjustment to rental revenue. A subsequent change in the assessment of collectability to probable may result in a current-period adjustment to rental revenue for any difference between the rental revenue that would have been recognized if collectability had always been assessed as probable and the rental revenue recognized to date. We recognize lease concessions related to COVID-19 such as rent deferrals and abatements in accordance with the Lease Modification Q&A issued by the FASB in April 2020, which provides entities with the option to elect to account for lease concessions as though the enforceable rights and obligations existed in the original lease. This election is only available when total cash flows resulting from the modified lease are substantially similar to the cash flows in the original lease. When total cash flows resulting from the modified lease are not substantially similar to the cash flows in the original lease, we account for the concession agreement as a new lease. The Company provides its tenants with certain customary services for lease contracts such as common area maintenance and general security. We have elected to combine the non-lease components with the lease components of our operating lease agreements and account for them as a single lease component in accordance with ASC 842. Tenant and other receivables at September 30, 2020 and December 31, 2019 is shown net of $9.5 million and $2.6 million, respectively, of reserves for recognized receivables. The Company may also have claims to contractual lease payments that were not recorded to income in instances where their collection was not probable. We record a gain or loss on sale of real estate assets when we no longer hold a controlling financial interest in the entity holding the real estate, a contract exists with a third party and that third party has control of the assets acquired. Investment income on debt and preferred equity investments is accrued based on the contractual terms of the instruments and when 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 collectible. 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 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 cash flows 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 is resumed on any debt or preferred equity investment that is on non-accrual status when such investment becomes contractually current and performance is demonstrated to be resumed. 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 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.
Debt and Preferred Equity Investments	Debt and Preferred Equity Investments Debt and preferred equity investments are presented at the net amount expected to be collected. An allowance for loan losses is deducted from the amortized cost basis of the financial assets to present the net carrying value at the amount expected to be collected through the expected maturity date of such investments. The expense for loan loss and other investment reserves is the charge to earnings to adjust the allowance for loan losses to the appropriate level. The Company evaluates the amount expected to be collected based on current market and economic conditions, historical loss information, and reasonable and supportable forecasts. The Company's assumptions are derived from both internal data and external data which may include, among others, governmental economic projections for the New York City Metropolitan area, public data on recent transactions and filings for securitized debt instruments. This information is aggregated by asset class and adjusted for duration. Based on these inputs, loans are evaluated at the individual asset level. In certain instances, we may also use a probability-weighted model that considers the likelihood of multiple outcomes and the amount expected to be collected for each outcome. The evaluation of the possible credit deterioration associated with the performance and/or value of the underlying collateral property as well as the financial and operating capability of the borrower/sponsor requires significant judgment, which include both asset level and market assumptions over the relevant time period. In addition, quarterly, the Company assigns each loan a risk rating. Based on a 3-point scale, loans are rated “1” through “3,” from lower risk to higher risk, which ratings are defined as follows: 1 - Low Risk Assets - Low probability of loss, 2 - Watch List Assets - Higher potential for loss, 3 - High Risk Assets - Loss more likely than not. Loans with risk ratings of 2 or above are evaluated to determine whether the expected risk of loss is appropriately captured through the combination of our expectations of current conditions, historical loss information and supportable forecasts described above or whether risk characteristics specific to the loan warrant the use of a probability-weighted model. Financing investments that are classified as held for sale are carried at the expected amount to be collected 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 expected amount to be collected. Other financing receivables that are included in balance sheet line items other than the Debt and Preferred Equity Investments line are also measured at the net amount expected to the be collected. Accrued interest receivable amounts related to these debt and preferred equity investment and other financing receivables are recorded at the net amount expected to be collected within Other assets in the consolidated balance sheets. Write offs of accrued interest receivables are recognized as an expense for loan loss and other investment reserves.
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 its 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 its 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. We have elected, and may elect in the future, to treat certain of our 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 months ended September 30, 2020, we recorded no Federal, state and local tax provisions. During the nine months ended September 30, 2020, we recorded Federal, state and local tax provisions of $2.0 million. During the three and nine months ended September 30, 2019, we recorded a Federal, state benefit of $1.0 million and a provision of $0.5 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.
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 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."
Reclassification	Reclassification Certain prior year balances have been reclassified to conform to our current year presentation.
Accounting Standards Updates	Accounting Standards Updates In August 2020, the FASB issued Accounting Standard Update, or "ASU", No. 2020-06 Debt - Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging - Contracts in Entity's Own Equity (Subtopic 815-40). ASU 2020-06 simplifies the accounting for convertible instruments by reducing the number of accounting models for convertible debt instruments and convertible preferred stock, removes certain settlement conditions that are required for equity contracts to qualify for the derivative scope exception and also simplifies the diluted earnings per share calculation in certain areas. ASU 2020-06 is effective for reporting periods beginning after December 15, 2021, with early adoption permitted. We are currently evaluating the impact of the adoption of ASU 2020-06 on our consolidated financial statements, but do not believe the adoption of this standard will have a material impact on our consolidated financial statements. In April 2020, the FASB staff issued a question and answer document (the “Lease Modification Q&A”) on the application of lease accounting guidance to lease concessions provided as a result of the COVID-19 pandemic. Under existing lease guidance, the entity would have to determine, on a lease by lease basis, if a lease concession was the result of a new arrangement reached with the tenant, which would be accounted for under the lease modification framework, or if a lease concession was under the enforceable rights and obligations that existed in the original lease, which would be accounted for outside the lease modification framework. The Lease Modification Q&A provides entities with the option to elect to account for lease concessions as though the enforceable rights and obligations existed in the original lease. This election is only available when total cash flows resulting from the modified lease are substantially similar to the cash flows in the original lease. The Lease Modification Q&A has no material impact on the Company’s consolidated financial statements as of and for the nine months ended September 30, 2020, however, its future impact to the Company is dependent upon the extent of lease concessions granted to tenants as a result of the COVID-19 pandemic in future periods and the elections made by the Company at the time of entering into such concessions. In March 2020, the FASB issued ASU No. 2020-04 Reference Rate Reform (Topic 848) Facilitation of the Effects of Reference Rate Reform on Financial Reporting. The amendments provide practical expedients for reference rate reform related activities that impact debt, leases, derivatives and other contracts. The guidance is optional and is effective between March 12, 2020 and December 31, 2022. The guidance may be elected over time as reference rate reform activities occur. During the first quarter of 2020, the Company has elected to apply the hedge accounting expedients related to probability and the assessments of effectiveness for future LIBOR-indexed cash flows to assume that the index upon which future hedged transactions will be based matches the index on the corresponding derivatives. Application of these expedients preserves the presentation of derivatives consistent with past presentation. The Company continues to evaluate the impact of the guidance and may apply other elections as applicable as additional changes in the market occur. In January 2020, the FASB issued ASU No. 2020-01, Investments - Equity Securities (Topic 321), Investments - Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815) Clarifying the Interactions between Topic 321, Topic 323, and Topic 815. The amendment most relevant to the Company is how to apply the fair value measurement alternative in Topic 321 when an investor must apply the fair value to an investment under the equity method in Topic 323. The amendment clarifies that an entity should consider observable transactions when considering the fair value of an investment. The guidance is effective for the Company for fiscal years beginning after December 15, 2020. Early adoption is permitted. The Company adopted this guidance on January 1, 2020 and it did not have a material impact on the Company’s consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-15, Intangibles - Goodwill and Other- Internal-Use Software (Topic 350-40), Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract. The amendments provide guidance on accounting for fees paid when the arrangement includes a software license and align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing costs to develop or obtain internal-use software. The Company adopted this guidance on January 1, 2020 and it did not have a material impact on the Company’s consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820), Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement. This amendment removed, modified and added the disclosure requirements under Topic 820. The changes are effective for the Company for fiscal years beginning after December 15, 2019. Early adoption is permitted for the removed or modified disclosures with adoption of the additional disclosures upon the effective date. The Company adopted this guidance on January 1, 2020 and it did not have a material impact on the Company’s consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments; in November 2018 issued ASU No. 2018-19, Codification Improvements to Topic 326, Financial Instruments - Credit Losses, in April, May and November 2019, issued ASU No. 2019-04, 2019-05 and 2019-11, which provide codification improvements and targeted transition relief; and in 2020 issued ASU 2020-02 Financial Instruments-Credit Losses (Topic 326) and Leases (Topic 842), which updates SEC guidance in those Topics. The guidance changes how entities will measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. The guidance replaces the current ‘incurred loss’ model with an ‘expected loss’ approach. The Company’s DPE portfolio and financing lease assets are subject to this guidance. ASU No. 2018-19 excludes operating lease receivables from the scope of this guidance. The Company adopted this guidance on January 1, 2020 and recorded a $39.2 million cumulative adjustment to retained earnings upon adoption.
Fair Value Measurements	Fair Value MeasurementsWe 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 evaluate real estate investments and debt and preferred equity investments, including intangibles, for potential impairment primarily utilizing cash flow projections that apply, among other things, estimated revenue and expense growth rates, discount rates and capitalization rates, as well as sales comparison approach, which utilizes comparable sales, listings and sales contracts. All of which are classified as Level 3 inputs. Marketable securities classified as Level 1 are derived from quoted prices in active markets. The valuation technique used to measure the fair value of 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.

Organization and Basis of Pre_2

Organization and Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of commercial office properties	As of September 30, 2020, we owned the following interests in properties in the New York metropolitan area, primarily in midtown Manhattan. Our investments located outside of Manhattan are referred to 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 18 10,647,191 11 11,841,483 29 22,488,674 93.1 % Retail 4 44,189 8 289,050 12 333,239 94.0 % Development/Redevelopment 10 2,908,362 2 1,755,610 12 4,663,972 N/A Fee Interest — — 1 — 1 — — % 32 13,599,742 22 13,886,143 54 27,485,885 93.1 % Suburban Office 8 1,044,800 — — 8 1,044,800 85.0 % Retail 1 52,000 — — 1 52,000 100.0 % 9 1,096,800 — — 9 1,096,800 85.7 % Total commercial properties 41 14,696,542 22 13,886,143 63 28,582,685 92.7 % Residential: Manhattan Residential 1 82,250 8 1,663,774 9 1,746,024 78.8 % Total residential properties 1 82,250 8 1,663,774 9 1,746,024 78.8 % Total portfolio 42 14,778,792 30 15,549,917 72 30,328,709 91.9 % (1) The weighted average occupancy for commercial properties represents the total occupied square footage divided by the total square footage at acquisition. The weighted average occupancy for residential properties represents the total occupied units divided by the total available units.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2020
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, 2020 and December 31, 2019 (in thousands): September 30, 2020 December 31, 2019 Identified intangible assets (included in other assets): Gross amount $ 224,221 $ 255,198 Accumulated amortization (208,135) (228,223) Net (1) $ 16,086 $ 26,975 Identified intangible liabilities (included in deferred revenue): Gross amount $ 273,240 $ 282,048 Accumulated amortization (255,879) (249,514) Net (1) $ 17,361 $ 32,534 (1) As of September 30, 2020 and December 31, 2019, no net intangible assets and no net intangible liabilities were reclassified to assets held for sale or liabilities related to assets held for sale.
Schedule of marketable securities	At September 30, 2020 and December 31, 2019, we held the following marketable securities (in thousands): September 30, 2020 December 31, 2019 Commercial mortgage-backed securities $ 27,734 $ 29,887 Total marketable securities available-for-sale $ 27,734 $ 29,887
Schedules of Concentration of Risk, by Risk Factor	For the three months ended September 30, 2020, the following properties contributed more than 5.0% of our annualized cash rent from office properties, including our share of annualized cash rent from joint venture office properties: Property Three months ended September 30, 2020 1185 Avenue of the Americas 8.4% 11 Madison Avenue 8.1% 420 Lexington Avenue 7.4% 1515 Broadway 6.3% 220 East 42nd Street 5.9% 280 Park Avenue 5.4% 485 Lexington Avenue 5.0%

Property Acquisitions (Tables)

Property Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2020
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition	The following table summarizes the properties acquired during the nine months ended September 30, 2020: Property Acquisition Date Property Type Approximate Square Feet Gross Asset Valuation 762 Madison Avenue (1) January 2020 Fee Interest 6,109 $ 29.3 707 Eleventh Avenue January 2020 Fee Interest 159,720 90.0 126 Nassau Street (2) January 2020 Leasehold Interest 98,412 — (1) The Company acquired from our joint venture partner the remaining 10% interest in this property that the Company did not already own. (2) In January 2020, the Company entered into a 99-year ground lease of 126 Nassau Street. In August 2020, we entered into a partnership with Meritz Alternative Investment as part of the capitalization of this development project. See note 6, "Investments in Unconsolidated Joint Ventures."

Properties Held for Sale and _2

Properties Held for Sale and Property Dispositions (Tables)	9 Months Ended
	Sep. 30, 2020
Discontinued Operations and Disposal Groups [Abstract]
Summary Of Properties Sold	The following table summarizes the properties sold during the nine months ended September 30, 2020: Property Disposition Date Property Type Approximate Square Feet Sales Price (1) (in millions) Gain (loss) (2) (in millions) 315 West 33rd Street - "The Olivia" March 2020 Fee Interest 492,987 $ 446.5 $ 72.3 609 Fifth Avenue Retail Condominium May 2020 Fee Interest 21,437 168.0 65.4 400 East 58th Street September 2020 Fee Interest 140,000 62.0 8.3 (1) Sales price represents the gross sales price for a property or the gross asset valuation for interests in a property. (2) The gains on sale for 315 West 33rd Street - "The Olivia" and 609 Fifth Avenue Retail Condominium are net of $6.0 million and $2.0 million, respectively, of employee compensation accrued in connection with the realization of these investment gains. Additionally, amounts do not include adjustments for expenses recorded in subsequent periods.

Debt and Preferred Equity Inv_2

Debt and Preferred Equity Investments (Tables)	9 Months Ended
	Sep. 30, 2020
Investments, Debt and Equity Securities [Abstract]
Schedule of debt and preferred equity book balance roll forward	Below is a summary of the activity in our debt and preferred equity investments for the nine months ended September 30, 2020 and the twelve months ended December 31, 2019 (in thousands): September 30, 2020 December 31, 2019 Balance at beginning of year (1) $ 1,580,306 $ 2,099,393 Debt investment originations/accretion (2) 383,365 652,866 Preferred equity investment originations/accretion (2) 163,821 14,736 Redemptions/sales/syndications/equity ownership/amortization (3) (956,869) (1,190,689) Net change in loan loss reserves (17,260) 4,000 Balance at end of period (1) $ 1,153,363 $ 1,580,306 (1) Net of unamortized fees, discounts, and premiums. (2) Accretion includes amortization of fees and discounts and paid-in-kind investment income. (3) Certain participations in debt investments that were sold or syndicated, but did not meet the conditions for sale accounting, are included in other assets and other liabilities on the consolidated balance sheets.
Schedule of Debt	Below is a summary of our debt and preferred equity investments as of September 30, 2020 (dollars in thousands): Floating Rate Fixed Rate Total Carrying Value Senior Financing Maturity (1) Type Carrying Value Face Value Interest Rate Carrying Value Face Value Interest Rate Senior Mortgage Debt $ 62,683 $63,425 L + 2.00% - 3.50% $ 1,249 $1,250 3.00% $ 63,932 $ — 2020 - 2022 Junior Mortgage Debt 85,295 96,697 L + 6.00% - 7.25% 32,805 33,000 6.00% $ 118,100 542,241 2020 - 2023 Mezzanine Debt 278,726 283,336 L + 4.95% - 14.62% 436,040 447,265 2.90% - 9.30% $ 714,766 4,447,803 2020 - 2029 Preferred Equity — — — 256,565 259,431 6.50% - 11.00% $ 256,565 1,962,750 2022 - 2027 Balance at end of period $ 426,704 $ 443,458 — $ 726,659 $ 740,946 — $ 1,153,363 (1) Excludes available extension options to the extent they have not been exercised as of the date of this filing.
Allowance for Credit Losses on Financing Receivables	The following table is a rollforward of our total allowance for loan losses for the nine months ended September 30, 2020 and the twelve months ended December 31, 2019 (in thousands): September 30, 2020 December 31, 2019 Balance at beginning of year $ 1,750 $ 5,750 Cumulative adjustment upon adoption of ASC 326 27,804 — Current period provision for loan loss 20,741 — Write-offs charged against the allowance (31,285) (4,000) Balance at end of period $ 19,010 $ 1,750
Summary of debt investments	As of September 30, 2020 and December 31, 2019, we held the following debt investments with an aggregate weighted average current yield of 6.26% at September 30, 2020 (dollars in thousands): Loan Type September 30, 2020 September 30, 2020 Senior September 30, 2020 Carrying Value (1) December 31, 2019 (1) Maturity (2) Fixed Rate Investments: Mortgage/Mezzanine Loan $ — $ 63,750 $ 56,242 $ 55,573 October 2020 (3) Junior Mortgage (4b) 10,000 67,000 32,805 — January 2021 Loan Type September 30, 2020 September 30, 2020 Senior September 30, 2020 Carrying Value (1) December 31, 2019 (1) Maturity (2) Mezzanine Loan — 15,000 3,500 3,500 September 2021 Mezzanine Loan — 280,000 40,458 38,734 August 2022 Mezzanine Loan (5) — 348,327 225,204 215,737 June 2023 Mezzanine Loan (4a)(6) — 115,000 13,265 12,950 June 2024 Mezzanine Loan — 95,000 30,000 30,000 January 2025 Mezzanine Loan — 1,712,750 55,250 55,250 June 2027 Mezzanine Loan — 85,000 20,000 20,000 December 2029 Mezzanine Loan — — — 24,952 Mezzanine Loan — — — 30,000 Mezzanine Loan — — — 12,714 Total fixed rate $ 10,000 $ 2,781,827 $ 476,724 $ 499,410 Floating Rate Investments: Junior Mortgage (7) $ — $ 40,000 $ 20,000 $ 20,000 April 2020 Mezzanine Loan — 275,000 49,919 49,809 April 2021 Junior Mortgage Participation/Mezzanine Loan — 60,000 15,724 15,698 July 2021 Mezzanine Loan 7,933 169,540 46,613 41,395 July 2021 Mezzanine Loan 5,329 54,204 23,753 15,743 July 2021 Mezzanine Loan (4c) — 1,115,000 126,486 222,775 March 2022 Mortgage/Mezzanine Loan 7,425 — 60,116 — May 2022 Mortgage/Mezzanine Loan 44,000 — 13,987 13,918 December 2022 Mortgage Loan (8) 35,303 375,241 63,899 — February 2023 Mezzanine Loan 55,033 59,232 18,587 69,839 May 2023 Mortgage/Mezzanine Loan — — — 35,386 Mortgage Loan — — — 19,971 Mortgage Loan — — — 106,473 Mezzanine Loan — — — 51,387 Mortgage/Mezzanine Loan — — — 96,570 Mortgage/Mezzanine Loan — — — 82,696 Total floating rate $ 155,023 $ 2,148,217 $ 439,084 $ 841,660 Allowance for loan loss $ — $ — $ (19,010) $ — Total $ 165,023 $ 4,930,044 $ 896,798 $ 1,341,070 (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) In October 2020, this loan was extended one year to October 2021. (4) Carrying value is net of the following amounts that were sold or syndicated, 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) $12.0 million, (b) $66.6 million and (c) $0.4 million. (5) This loan is on non-accrual at September 30, 2020. (6) This loan is in default and on non-accrual as of the date of this filing. The Company is in discussions with the borrower. (7) As of September 30, 2020 this loan was in default and on non-accrual. In October 2020, the Company accepted a purchase in lieu of repayment and marked the assets received and liabilities assumed to fair value. (8) This loan was sold on October 1, 2020.
Summary of preferred equity investments	As of September 30, 2020 and December 31, 2019, we held the following preferred equity investments with an aggregate weighted average current yield of 9.98% at September 30, 2020 (dollars in thousands): Type September 30, 2020 September 30, 2020 Senior September 30, 2020 Carrying Value (1) December 31, 2019 Carrying Value (1) Mandatory Redemption (2) Preferred Equity $ — $ 1,712,750 $ 153,196 $ 98,065 June 2022 Preferred Equity — 250,000 103,369 — February 2027 Preferred Equity (3) — — — 142,921 Total Preferred Equity $ — $ 1,962,750 $ 256,565 $ 240,986 Allowance for loan loss $ — $ — $ — $ (1,750) Total $ — $ 1,962,750 $ 256,565 $ 239,236 (1) Carrying value is net of deferred origination fees. (2) Represents contractual maturity, excluding any unexercised extension options. (3) In June 2020, we, along with the common member in the investment, amended the partnership documents related to the investment to provide us with more rights over management of the underlying property. This resulted in the investment being accounted for using the equity method. See Note 6, "Investments in Unconsolidated Joint Ventures."

Investments in Unconsolidated_2

Investments in Unconsolidated Joint Ventures (Tables)	9 Months Ended
	Sep. 30, 2020
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, 2020: Property Partner Ownership (1) Economic (1) Unaudited Approximate Square Feet 100 Park Avenue Prudential Real Estate Investors 49.90% 49.90% 834,000 717 Fifth Avenue Wharton Properties/Private Investor 10.92% 10.92% 119,500 800 Third Avenue Private Investors 60.52% 60.52% 526,000 919 Third Avenue New York State Teacher's Retirement System 51.00% 51.00% 1,454,000 11 West 34th Street Private Investor/Wharton Properties 30.00% 30.00% 17,150 280 Park Avenue Vornado Realty Trust 50.00% 50.00% 1,219,158 1552-1560 Broadway (2) Wharton Properties 50.00% 50.00% 57,718 10 East 53rd Street Canadian Pension Plan Investment Board 55.00% 55.00% 354,300 21 East 66th Street (3) Private Investors 32.28% 32.28% 13,069 650 Fifth Avenue (4) Wharton Properties 50.00% 50.00% 69,214 121 Greene Street Wharton Properties 50.00% 50.00% 7,131 55 West 46th Street Prudential Real Estate Investors 25.00% 25.00% 347,000 Stonehenge Portfolio Various Various Various 1,439,016 605 West 42nd Street The Moinian Group 20.00% 20.00% 927,358 11 Madison Avenue PGIM Real Estate 60.00% 60.00% 2,314,000 333 East 22nd Street Private Investors 33.33% 33.33% 26,926 400 East 57th Street (5) BlackRock, Inc and Stonehenge Partners 51.00% 41.00% 290,482 Property Partner Ownership (1) Economic (1) Unaudited Approximate Square Feet One Vanderbilt National Pension Service of Korea/Hines Interest LP 71.01% 71.01% — Worldwide Plaza RXR Realty / New York REIT / Private Investor 24.35% 24.35% 2,048,725 1515 Broadway Allianz Real Estate of America 56.87% 56.87% 1,750,000 2 Herald Square Israeli Institutional Investor 51.00% 51.00% 369,000 115 Spring Street Private Investor 51.00% 51.00% 5,218 885 Third Avenue (6) Private Investor (6) 100.00% 625,300 126 Nassau Street (7) Meritz Alternative Investment Management 20.00% 20.00% 98,412 (1) Ownership interest and economic interest represent the Company's interests in the joint venture as of September 30, 2020. Changes in ownership or economic interests within the current year are disclosed in the notes below. (2) The acquisition 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. (3) We hold a 32.28% interest in three retail units and one residential unit at the property and a 16.14% interest in three residential units at the property. (4) The joint venture owns a long-term leasehold interest in the retail space at 650 Fifth Avenue. (5) In October 2016, we sold a 49% interest in this property. Our interest in the property was sold within a consolidated joint venture owned 90% by the Company and 10% by Stonehenge. The transaction resulted in the deconsolidation of the venture's remaining 51% interest in the property. Our joint venture with Stonehenge remains consolidated resulting in the combined 51% interest being shown within investments in unconsolidated joint ventures on our balance sheet. (6) We hold 100% of the preferred equity interest in the property and believe there is no value to the common equity. (7) In August 2020, the Company formed a joint venture, which then entered into a long-term sublease with the Company. As a result of this transaction, we recognized a gain of $17.7 million, which is included in Gain on sale of real estate, net, in our consolidated statements of operations. This gain was calculated in accordance with ASC 842, as the Company identified the lease and non-lease components included in the sublease agreement and allocated the consideration in the agreement to each lease and non-lease component based on each components’ standalone selling price, which was estimated utilizing a combination of the adjusted market assessment and residual approaches as provided for in ASC 606.
Schedule of first mortgage notes payable collateralized by the respective joint venture properties and assignment of leases	The mortgage notes and other loans payable collateralized by the respective joint venture properties and assignment of leases at September 30, 2020 and December 31, 2019, respectively, are as follows (dollars in thousands): Property Economic (1) Initial Maturity Final Maturity Date (2) Interest Rate (3) September 30, 2020 December 31, 2019 Fixed Rate Debt: 885 Third Avenue (4) 100.00 % April 2021 April 2021 3.35 % $ 272,000 $ — 717 Fifth Avenue (mortgage) 10.92 % July 2022 July 2022 4.45 % 300,000 300,000 717 Fifth Avenue (mezzanine) 10.92 % July 2022 July 2022 5.50 % 355,328 355,328 650 Fifth Avenue (mortgage) 50.00 % October 2022 October 2022 4.46 % 210,000 210,000 650 Fifth Avenue (mezzanine) 50.00 % October 2022 October 2022 5.45 % 65,000 65,000 21 East 66th Street 32.28 % April 2023 April 2028 3.60 % 12,000 12,000 919 Third Avenue 51.00 % June 2023 June 2023 5.12 % 500,000 500,000 1515 Broadway 56.87 % March 2025 March 2025 3.93 % 825,204 838,546 11 Madison Avenue 60.00 % September 2025 September 2025 3.84 % 1,400,000 1,400,000 800 Third Avenue 60.52 % February 2026 February 2026 3.37 % 177,000 177,000 400 East 57th Street 41.00 % November 2026 November 2026 3.00 % 97,024 97,735 Worldwide Plaza 24.35 % November 2027 November 2027 3.98 % 1,200,000 1,200,000 Stonehenge Portfolio (5) Various Various Various 3.50 % 195,899 196,112 Property Economic (1) Initial Maturity Final Maturity Date (2) Interest Rate (3) September 30, 2020 December 31, 2019 Total fixed rate debt $ 5,609,455 $ 5,351,721 Floating Rate Debt: 121 Greene Street 50.00 % November 2020 November 2021 L+ 1.50 % $ 15,000 $ 15,000 11 West 34th Street 30.00 % January 2021 January 2023 L+ 1.45 % 23,000 23,000 100 Park Avenue 49.90 % February 2021 February 2021 L+ 1.75 % 354,087 356,972 280 Park Avenue 50.00 % September 2021 September 2024 L+ 1.73 % 1,200,000 1,200,000 One Vanderbilt (6) 71.01 % September 2021 September 2023 L+ 2.50 % 1,094,873 732,928 1552 Broadway 50.00 % October 2021 October 2022 L+ 2.65 % 195,000 195,000 2 Herald Square 51.00 % November 2021 November 2023 L+ 1.45 % 214,500 190,000 55 West 46th Street (7) 25.00 % August 2022 August 2024 L+ 1.25 % 192,524 192,524 115 Spring Street 51.00 % September 2023 September 2023 L+ 3.40 % 65,550 65,550 126 Nassau Street (8) 20.00 % January 2024 July 2025 L+ 1.50 % 5,593 — 10 East 53rd Street 55.00 % February 2025 February 2025 L+ 1.35 % 220,000 170,000 605 West 42nd Street 20.00 % August 2027 August 2027 L+ 1.44 % 550,000 550,000 21 East 66th Street 32.28 % June 2033 June 2033 1 Year Treasury+ 2.75 % 688 712 Total floating rate debt $ 4,130,815 $ 3,691,686 Total joint venture mortgages and other loans payable $ 9,740,270 $ 9,043,407 Deferred financing costs, net (87,763) (91,538) Total joint venture mortgages and other loans payable, net $ 9,652,507 $ 8,951,869 (1) Economic interest represents the Company's interests in the joint venture as of September 30, 2020. Changes in ownership or economic interests, if any, within the current year are disclosed in the notes to the investment in unconsolidated joint ventures table above. (2) Reflects exercise of all available extension options. The ability to exercise extension options may be subject to certain tests based on the operating performance of the property. (3) Interest rates as of September 30, 2020, taking into account interest rate hedges in effect during the period. Floating rate debt is presented with the stated spread over the 30-day LIBOR, unless otherwise specified. (4) The Company holds 100% of the preferred equity interest in the property and believes that there is no value to the common equity. In August 2020, the servicer asserted certain loan defaults. The venture has determined that the servicer is misinterpreting the loan documents and is contesting the assertion. The servicer has taken no additional action on the loan. (5) Comprised of three mortgages totaling $132.4 million that mature in April 2028 and two mortgages totaling $63.5 million that mature in July 2029. (6) This loan is a $1.75 billion construction facility with reductions in interest cost based on meeting conditions, the first of which has been satisfied, and has an initial five-year term with two one-year extension options. Advances under the loan are subject to costs incurred. (7) This loan has a committed amount of $198.0 million, of which $5.5 million was unfunded as of September 30, 2020. (8) This loan is a $125.0 million construction facility. Advances under the loan are subject to costs incurred.
Schedule of combined balance sheets for the unconsolidated joint ventures	The combined balance sheets for the unconsolidated joint ventures, at September 30, 2020 and December 31, 2019 are as follows (in thousands): September 30, 2020 December 31, 2019 Assets (1) Commercial real estate property, net $ 15,045,603 $ 14,349,628 Cash and restricted cash 326,488 336,189 Tenant and other receivables, related party receivables, and deferred rents receivable 404,138 371,065 Other assets 1,940,540 2,039,429 Total assets $ 17,716,769 $ 17,096,311 Liabilities and equity (1) Mortgages and other loans payable, net $ 9,652,507 $ 8,951,869 Deferred revenue 1,400,458 1,501,616 Lease liabilities 1,015,477 897,380 Other liabilities 294,972 308,304 Equity 5,353,355 5,437,142 Total liabilities and equity $ 17,716,769 $ 17,096,311 Company's investments in unconsolidated joint ventures $ 2,946,673 $ 2,912,842 (1) The combined assets, liabilities and equity for the unconsolidated joint ventures reflects the effect of step ups in basis on the retained, non-controlling interests in deconsolidated investments as a result of the adoption of ASC 610-20 in January 2018. In addition, at September 30, 2020, $166.8 million of net unamortized basis differences between the amount at which our investments are carried and our share of equity in net assets of the underlying property will be amortized through equity in net income (loss) from unconsolidated joint ventures over the remaining life of the underlying items having given rise to the differences.
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, 2020 and 2019, are as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Total revenues $ 292,929 $ 286,010 $ 846,967 $ 883,977 Operating expenses 44,650 50,759 131,578 153,397 Real estate taxes 56,459 53,321 161,566 159,544 Operating lease rent 6,385 6,713 18,947 18,848 Interest expense, net of interest income 79,723 92,601 245,685 282,917 Amortization of deferred financing costs 5,575 4,436 15,197 14,434 Depreciation and amortization 103,262 100,736 300,700 308,748 Total expenses 296,054 308,566 873,673 937,888 Loss on early extinguishment of debt — (1,031) — (1,031) Net loss before gain on sale (1) $ (3,125) $ (23,587) $ (26,706) $ (54,942) Company's equity in net loss from unconsolidated joint ventures (1) $ (432) $ (9,864) $ (15,445) $ (22,644) (1) The combined statements of operations and the Company's equity in net loss for the unconsolidated joint ventures reflects the effect of step ups in basis on the retained non-controlling interests in deconsolidated investments as a result of the adoption of ASC 610-20 in January 2018.

Deferred Costs (Tables)

Deferred Costs (Tables)	9 Months Ended
	Sep. 30, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of components of deferred costs	Deferred costs at September 30, 2020 and December 31, 2019 consisted of the following (in thousands): September 30, 2020 December 31, 2019 Deferred leasing costs $ 496,812 $ 466,136 Less: accumulated amortization (290,523) (260,853) Deferred costs, net $ 206,289 $ 205,283

Mortgages and Other Loans Pay_2

Mortgages and Other Loans Payable (Tables)	9 Months Ended
	Sep. 30, 2020
Mortgages and Other Loans Payable
Schedule of first mortgages and other loans payable collateralized by the respective properties and assignment of leases	The mortgages and other loans payable collateralized by the respective properties and assignment of leases or debt investments at September 30, 2020 and December 31, 2019, respectively, were as follows (dollars in thousands): Property Initial Maturity Final Maturity Date (1) Interest Rate (2) September 30, 2020 December 31, 2019 Fixed Rate Debt: 100 Church Street July 2022 July 2022 4.68% $ 206,013 $ 209,296 420 Lexington Avenue October 2024 October 2040 3.99% 295,355 299,165 Landmark Square January 2027 January 2027 4.90% 100,000 100,000 485 Lexington Avenue February 2027 February 2027 4.25% 450,000 450,000 1080 Amsterdam (3) February 2027 February 2027 3.59% 34,773 35,123 762 Madison Avenue (4) — 771 315 West 33rd Street (5) — 250,000 400 East 58th Street 39,094 Total fixed rate debt $ 1,086,141 $ 1,383,449 Floating Rate Debt: 133 Greene Street (6) (6) L+ 2.00% $ 15,523 $ 15,523 106 Spring Street January 2021 January 2022 L+ 2.50% 38,025 38,025 FHLB Facility January 2021 January 2021 L+ 0.28% 10,000 — FHLB Facility January 2021 January 2021 L+ 0.23% 15,000 — FHLB Facility January 2021 January 2021 L+ 0.18% 35,000 — 609 Fifth Avenue March 2021 March 2024 L+ 2.40% 57,651 53,773 185 Broadway (7) November 2021 November 2023 L+ 2.85% 144,448 120,110 712 Madison Avenue December 2021 December 2022 L+ 1.85% 28,000 28,000 220 East 42nd Street June 2023 June 2025 L+ 2.75% 510,000 — 410 Tenth Avenue (8) August 2023 August 2025 L+ 2.25% 434,934 330,819 719 Seventh Avenue September 2023 September 2023 L+ 1.20% 50,000 50,000 2017 Master Repurchase Agreement (9) — 152,684 FHLB Facility — 10,000 FHLB Facility — 15,000 FHLB Facility — 14,500 Total floating rate debt $ 1,338,581 $ 828,434 Total mortgages and other loans payable $ 2,424,722 $ 2,211,883 Deferred financing costs, net of amortization (32,978) (28,630) Total mortgages and other loans payable, net $ 2,391,744 $ 2,183,253 (1) Reflects exercise of all available extension options. The ability to exercise extension options may be subject to certain tests based on the operating performance of the property. (2) Interest rate as of September 30, 2020, taking into account interest rate hedges in effect during the period. Floating rate debt is presented with the stated spread over the 30-day LIBOR, unless otherwise specified. (3) The loan is comprised of a $33.9 million mortgage loan and $0.9 million mezzanine loan with a fixed interest rate of 350 basis points and 700 basis points, respectively, for the first five years and is prepayable without penalty at the end of fifth year. (4) In January 2020, the Company closed on the acquisition of the remaining 10% interest in this property from our joint venture partner. As part of this transaction, the loan was repaid. (5) In March 2020, the loan was assumed by the buyer in connection with the sale of the property. (6) This loan matured in August 2020. The Company is in discussions with the lender on resolution. (7) This loan is a $225.0 million construction facility, with reductions in interest cost based on meeting certain conditions, and has an initial three-year term with two one-year extension options. Advances under the loan are subject to incurred costs and funded equity requirements. (8) This loan is a $600.0 million construction facility and has an initial three-year term with two one-year extension options. Advances under the loan are subject to incurred costs and funded equity requirements. (9) In June 2020, we exercised a one-year extension option which extended the maturity date to June 2021. At September 30, 2020, there was no outstanding balance on the $400 million facility.

Corporate Indebtedness (Tables)

Corporate Indebtedness (Tables)	9 Months Ended
	Sep. 30, 2020
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, 2020 and December 31, 2019, respectively, by scheduled maturity date (dollars in thousands): Issuance September 30, September 30, December 31, Interest Rate (1) Initial Term Maturity Date August 7, 2018 (2) (3) $ 350,000 $ 350,000 $ 350,000 1.52 % 3 August 2021 October 5, 2017 (2) 500,000 499,775 499,695 3.25 % 5 October 2022 November 15, 2012 (4) 300,000 302,352 303,142 4.50 % 10 December 2022 December 17, 2015 (5) 100,000 100,000 100,000 4.27 % 10 December 2025 March 16, 2010 (6) — — 250,000 $ 1,250,000 $ 1,252,127 $ 1,502,837 Deferred financing costs, net (4,332) (5,990) $ 1,250,000 $ 1,247,795 $ 1,496,847 (1) Interest rate as of September 30, 2020, taking into account interest rate hedges in effect during the period. (2) Issued by the Operating Partnership with the Company as the guarantor. (3) The notes are subject to redemption at the Company's option, in whole but not in part, at a redemption price equal to 100% of the principal amount of the notes, plus unpaid accrued interest thereon to the redemption date. In April 2020, the Company entered into $350.0 million of fixed rate interest swaps at a rate of 0.54375% through August 2021. (4) In October 2017, the Company and the Operating Partnership as co-obligors issued an additional $100.0 million of 4.50% senior unsecured notes due December 2022. The notes were priced at 105.334% of par. (5) Issued by the Company and the Operating Partnership as co-obligors. (6) In March 2020, the notes were repaid.
Schedule of combined aggregate principal maturities	Combined aggregate principal maturities of mortgages and other loans payable, the 2017 credit facility, trust preferred securities, senior unsecured notes and our share of joint venture debt as of September 30, 2020, including as-of-right extension options, were as follows (in thousands): Scheduled Mortgages and Other Loans Payable Revolving Unsecured Term Loans Trust Senior Total Joint Remaining 2020 $ 2,635 $ 15,523 $ — $ — $ — $ — $ 18,158 $ 10,867 2021 10,766 270,474 — — — 350,000 631,240 1,444,277 2022 8,779 255,435 — — — 800,000 1,064,214 268,952 2023 6,608 994,934 190,000 1,300,000 — — 2,491,542 311,436 2024 5,294 272,749 — 200,000 — — 478,043 618,140 Thereafter 1,779 579,746 — — 100,000 100,000 781,525 1,935,202 $ 35,861 $ 2,388,861 $ 190,000 $ 1,500,000 $ 100,000 $ 1,250,000 $ 5,464,722 $ 4,588,874
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, 2020 2019 2020 2019 Interest expense before capitalized interest $ 42,595 $ 63,607 $ 144,345 $ 185,163 Interest on financing leases 2,198 813 6,010 2,425 Interest capitalized (20,677) (15,700) (57,528) (38,228) Interest income (580) (608) (1,727) (3,563) Interest expense, net $ 23,536 $ 48,112 $ 91,100 $ 145,797

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2020
Related Party Transactions [Abstract]
Schedule of amounts due from/to related parties	Amounts due from joint ventures and related parties at September 30, 2020 and December 31, 2019 consisted of the following (in thousands): September 30, 2020 December 31, 2019 Due from joint ventures $ 24,912 $ 9,352 Other 7,024 11,769 Related party receivables $ 31,936 $ 21,121

Noncontrolling Interests on t_2

Noncontrolling Interests on the Company's Consolidated Financial Statements (Tables)	9 Months Ended
	Sep. 30, 2020
Noncontrolling Interest [Abstract]
Schedule of Noncontrolling Interest	Below is a summary of the activity relating to the noncontrolling interests in the Operating Partnership for the nine months ended September 30, 2020 and the twelve months ended December 31, 2019 (in thousands): September 30, 2020 December 31, 2019 Balance at beginning of period $ 409,862 $ 387,805 Distributions (8,857) (14,729) Issuance of common units 7,976 19,403 Redemption and conversion of common units (27,657) (27,962) Net income 10,073 13,301 Accumulated other comprehensive loss allocation (2,664) (2,276) Fair value adjustment (35,253) 34,320 Balance at end of period $ 353,480 $ 409,862
Schedule of Preferred Unit Activity	Below is a summary of the preferred units of limited partnership interest in the Operating Partnership as of September 30, 2020: Issuance Number of Units Authorized Number of Units Issued Number of Units Outstanding Annual Dividend Per Unit (1) Liquidation Preference Per Unit (2) Conversion Price Per Unit (3) Date of Issuance 3.50% Series A (4) 109,161 109,161 109,161 $ 35.0000 $ 1,000.00 $ — August 2015 7.00% Series F 60 60 60 $ 70.0000 $ 1,000.00 $ 29.12 January 2007 4.50% Series G (5) 1,902,000 1,902,000 863,972 $ 1.1250 $ 25.00 $ 88.50 January 2012 3.50% Series K 700,000 563,954 341,677 $ 0.8750 $ 25.00 $ 134.67 August 2014 4.00% Series L 500,000 378,634 372,634 $ 1.0000 $ 25.00 — August 2014 3.75% Series M 1,600,000 1,600,000 96,357 $ 0.9375 $ 25.00 — February 2015 4.00% Series P 200,000 200,000 200,000 $ 1.0000 $ 25.00 — July 2015 3.50% Series Q 268,000 268,000 268,000 $ 0.8750 $ 25.00 $ 148.95 July 2015 3.50% Series R 400,000 400,000 400,000 $ 0.8750 $ 25.00 $ 154.89 August 2015 4.00% Series S 1,077,280 1,077,280 1,077,280 $ 1.0000 $ 25.00 — August 2015 3.50% Series V 40,000 40,000 40,000 $ 0.8750 $ 25.00 — May 2019 Series W (6) 1 1 1 (6) (6) — January 2020 (1) Dividends are cumulative, subject to certain provisions. (2) Units are redeemable at any time at par for cash at the option of the unitholder unless otherwise specified. (3) If applicable, 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) the amount shown in the table. (4) Issued through a consolidated subsidiary. The units are convertible on a one-for-one basis, into the Series B Preferred Units of limited partnership interest, or the Subsidiary Series B Preferred Units. The Subsidiary 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 Subsidiary Series B Preferred Unit. As of September 30, 2020, no Subsidiary Series B Preferred Units have been issued. (5) Common units of limited partnership interest in the Operating Partnership issued in a conversion may be redeemed in exchange for our 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. (6) The Series W preferred unit was issued in January 2020 in exchange for the then-outstanding Series O preferred unit. The holder of the Series W preferred unit is entitled to quarterly dividends in an amount calculated as (i) 1,350 multiplied by (ii) the current distribution per common unit of limited partnership in SL Green Operating Partnership. The holder has the right to require the Operating Partnership to repurchase the Series W unit for cash, or convert the Series W unit for Class B units, in each case at a price that is determined based on the closing price of the Company's common stock at the time such right is exercised. The unit's liquidation preference is the fair market value of the unit plus accrued distributions at the time of a liquidation event. Below is a summary of the activity relating to the preferred units in the Operating Partnership for the nine months ended September 30, 2020 and the twelve months ended December 31, 2019 (in thousands): September 30, 2020 December 31, 2019 Balance at beginning of period $ 283,285 $ 300,427 Issuance of preferred units — 1,000 Redemption of preferred units (82,750) (18,142) Accrued dividends on preferred units 1,634 — Balance at end of period $ 202,169 $ 283,285

Stockholders' Equity of the C_2

Stockholders' Equity of the Company (Tables)	9 Months Ended
	Sep. 30, 2020
Stockholders' Equity Note [Abstract]
Class of Treasury Stock	At September 30, 2020, repurchases executed under the program were as follows: Period Shares repurchased Average price paid per share Cumulative number of shares repurchased as part of the repurchase plan or programs Year ended 2017 8,342,411 $101.64 8,342,411 Year ended 2018 9,744,911 $96.22 18,087,322 Year ended 2019 4,596,171 $83.62 22,683,493 Nine months ended September 30, 2020 (1) 6,243,165 $62.77 28,926,658 (1) Includes 216,101 shares of common stock repurchased by the Company in September 2020 that were settled in October 2020.
Schedule of Common Stock Issued and Proceeds Received Dividend Reinvestments	The following table summarizes SL Green common stock issued, and proceeds received from dividend reinvestments and/or stock purchases under the DRSPP for the three and nine months ended September 30, 2020 and 2019, respectively (dollars in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Shares of common stock issued 4,205 490 9,884 3,485 Dividend reinvestments/stock purchases under the DRSPP $ 202 $ 39 $ 566 $ 303
Schedule of Earnings Per Share	SL Green's earnings per share for the three and nine months ended September 30, 2020 and 2019 are computed as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Numerator 2020 2019 2020 2019 Basic Earnings: Income attributable to SL Green common stockholders $ 13,859 $ 33,157 $ 185,104 $ 238,052 Less: distributed earnings allocated to participating securities (333) (108) (777) (325) Less: undistributed earnings allocated to participating securities — — (141) (41) Net income attributable to SL Green common stockholders (numerator for basic earnings per share) $ 13,526 $ 33,049 $ 184,186 $ 237,686 Add back: dilutive effect of earnings allocated to participating securities 333 108 777 325 Add back: undistributed earnings allocated to participating securities — — 141 41 Add back: effect of dilutive securities (redemption of units to common shares) 802 1,719 10,073 12,306 Income attributable to SL Green common stockholders (numerator for diluted earnings per share) $ 14,661 $ 34,876 $ 195,177 $ 250,358 Three Months Ended September 30, Nine Months Ended September 30, Denominator 2020 2019 2020 2019 Basic Shares: Weighted average common stock outstanding 73,020 82,292 75,521 82,855 Effect of Dilutive Securities: Operating Partnership units redeemable for common shares 4,029 4,258 4,123 4,283 Stock-based compensation plans 442 164 441 171 Diluted weighted average common stock outstanding 77,491 86,714 80,085 87,309

Partners' Capital of the Oper_2

Partners' Capital of the Operating Partnership (Tables)	9 Months Ended
	Sep. 30, 2020
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, 2020 and 2019, respectively, are computed as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Numerator 2020 2019 2020 2019 Basic Earnings: Income attributable to SLGOP common unitholders $ 14,661 $ 34,876 $ 195,177 $ 250,358 Less: distributed earnings allocated to participating securities (333) (108) (777) (325) Less: undistributed earnings allocated to participating securities — — (141) (41) Net Income attributable to SLGOP common unitholders (numerator for basic earnings per unit) $ 14,328 $ 34,768 $ 194,259 $ 249,992 Add back: dilutive effect of earnings allocated to participating securities 333 108 777 325 Add back: undistributed earnings allocated to participating securities — — 141 41 Income attributable to SLGOP common unitholders (numerator for diluted earnings per unit) $ 14,661 $ 34,876 $ 195,177 $ 250,358 Three Months Ended September 30, Nine Months Ended September 30, Denominator 2020 2019 2020 2019 Basic units: Weighted average common units outstanding 77,049 86,550 79,644 87,138 Effect of Dilutive Securities: Stock-based compensation plans 442 164 441 171 Diluted weighted average common units outstanding 77,491 86,714 80,085 87,309

Share-based Compensation (Table

Share-based Compensation (Tables)	9 Months Ended
	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
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, 2020 and December 31, 2019, and changes during the nine months ended September 30, 2020 and year ended December 31, 2019 are as follows: September 30, 2020 December 31, 2019 Options Outstanding Weighted Average Options Outstanding Weighted Average Balance at beginning of period 1,037,068 $ 102.36 1,137,017 $ 103.54 Granted — — — — Exercised — — — — Lapsed or canceled (53,700) 111.18 (99,949) 115.81 Balance at end of period 983,368 $ 101.88 1,037,068 $ 102.36 Options exercisable at end of period 982,368 $ 101.88 914,929 $ 101.69
Summary of restricted stock and charges during the period	A summary of the Company's restricted stock as of September 30, 2020 and December 31, 2019 and charges during the nine months ended September 30, 2020 and the year ended December 31, 2019, are as follows: September 30, 2020 December 31, 2019 Balance at beginning of period 3,566,466 3,452,016 Granted 9,220 126,350 Canceled (26,043) (11,900) Balance at end of period 3,549,643 3,566,466 Vested during the period 132,652 113,259 Compensation expense recorded $ 8,528,991 $ 12,892,249 Total fair value of restricted stock granted during the period $ 734,315 $ 11,131,181

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Schedule of accumulated other comprehensive income (loss)	The following tables set forth the changes in accumulated other comprehensive loss by component as of September 30, 2020 (in thousands): Net unrealized loss on derivative instruments ( 1 ) SL Green’s share of joint venture net unrealized loss on derivative instruments ( 2 ) Net unrealized gain (loss) on marketable securities Total Balance at December 31, 2019 $ (22,780) $ (7,982) $ 2,277 $ (28,485) Other comprehensive loss before reclassifications (50,038) (7,954) (2,047) (60,039) Amounts reclassified from accumulated other comprehensive loss 9,120 3,204 — 12,324 Balance at September 30, 2020 $ (63,698) $ (12,732) $ 230 $ (76,200) (1) Amount reclassified from accumulated other comprehensive loss is included in interest expense in the respective consolidated statements of operations. As of September 30, 2020 and December 31, 2019, the deferred net gains from these terminated hedges, which is included in accumulated other comprehensive loss relating to net unrealized (loss) gain on derivative instrument, was $(0.5) million and $(0.7) million, respectively. (2) Amount reclassified from accumulated other comprehensive loss is included in equity in net loss from unconsolidated joint ventures in the respective consolidated statements of operations.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2020
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, 2020 and December 31, 2019 (in thousands): September 30, 2020 Total Level 1 Level 2 Level 3 Assets: Marketable securities $ 27,734 $ — $ 27,734 $ — Interest rate cap and swap agreements (included in other assets) $ 39 $ — $ 39 $ — Liabilities: Interest rate cap and swap agreements (included in other liabilities) $ 67,680 $ — $ 67,680 $ — December 31, 2019 Total Level 1 Level 2 Level 3 Assets: Marketable securities $ 29,887 $ — $ 29,887 $ — Interest rate cap and swap agreements (included in other assets) $ 4,419 $ — $ 4,419 $ — Liabilities: Interest rate cap and swap agreements (included in other liabilities) $ 29,110 $ — $ 29,110 $ —
Fair value, by balance sheet grouping	The following table provides the carrying value and fair value of these financial instruments as of September 30, 2020 and December 31, 2019 (in thousands): September 30, 2020 December 31, 2019 Carrying Value (1) Fair Value Carrying Value (1) Fair Value Debt and preferred equity investments $ 1,153,363 (2) $ 1,580,306 (2) Fixed rate debt $ 3,338,268 $ 3,427,731 $ 3,536,286 $ 3,642,770 Variable rate debt 2,128,581 2,112,589 2,018,434 2,018,714 $ 5,466,849 $ 5,540,320 $ 5,554,720 $ 5,661,484 (1) Amounts exclude net deferred financing costs. (2) At September 30, 2020, debt and preferred equity investments had an estimated fair value ranging between $1.04 billion and $1.15 billion. At December 31, 2019, debt and preferred equity investments had an estimated fair value ranging between $1.58 billion and $1.74 billion.

Financial Instruments_ Deriva_2

Financial Instruments: Derivatives and Hedging (Tables)	9 Months Ended
	Sep. 30, 2020
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, 2020 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 (dollars in thousands). Notional Strike Effective Expiration Balance Sheet Location Fair Interest Rate Swap $ 100,000 1.928 % December 2017 November 2020 Other Liabilities $ (295) Interest Rate Swap 100,000 1.934 % December 2017 November 2020 Other Liabilities (296) Interest Rate Cap 111,869 3.500 % December 2019 December 2020 Other Assets — Interest Rate Cap 85,000 4.000 % March 2019 March 2021 Other Assets — Interest Rate Swap 350,000 0.544 % April 2020 August 2021 Other Liabilities (978) Interest Rate Cap 510,000 3.000 % June 2020 December 2021 Other Assets 1 Interest Rate Swap 200,000 1.131 % July 2016 July 2023 Other Liabilities (5,599) Interest Rate Swap 100,000 1.161 % July 2016 July 2023 Other Liabilities (2,883) Interest Rate Cap 600,000 4.000 % August 2020 September 2023 Other Assets 38 Interest Rate Swap 150,000 2.696 % January 2019 January 2024 Other Liabilities (12,430) Interest Rate Swap 150,000 2.721 % January 2019 January 2026 Other Liabilities (19,286) Interest Rate Swap 200,000 2.740 % January 2019 January 2026 Other Liabilities (25,913) $ (67,641)
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, 2020 and 2019, respectively (in thousands): Amount of Loss Location of Loss Reclassified from Accumulated Other Comprehensive Loss into Income Amount of Loss Reclassified from Three Months Ended September 30, Three Months Ended September 30, Derivative 2020 2019 2020 2019 Interest Rate Swaps/Caps $ (318) $ (10,169) Interest expense $ (5,162) $ (105) Share of unconsolidated joint ventures' derivative instruments (199) (2,437) Equity in net loss from unconsolidated joint ventures (1,454) (192) $ (517) $ (12,606) $ (6,616) $ (297) 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, 2020 and 2019, respectively (in thousands): Amount of Loss Location of (Loss) Gain Reclassified from Accumulated Other Comprehensive Loss into Income Amount of (Loss) Gain Reclassified from Nine Months Ended September 30, Nine Months Ended September 30, Derivative 2020 2019 2020 2019 Interest Rate Swaps/Caps $ (52,808) $ (43,008) Interest expense $ (9,610) $ 886 Share of unconsolidated joint ventures' derivative instruments (8,375) (11,963) Equity in net loss from unconsolidated joint ventures (3,347) 713 $ (61,183) $ (54,971) $ (12,957) $ 1,599

Rental Income (Tables)

Rental Income (Tables)	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Operating Lease, Lease Income	The components of operating lease revenues were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Fixed lease payments $ 171,866 $ 214,282 $ 538,601 $ 641,007 Variable lease payments 21,979 32,581 70,892 88,539 Total lease payments $ 193,845 $ 246,863 $ 609,493 $ 729,546 Amortization of acquired above and below-market leases 1,670 1,165 4,539 3,559 Total rental revenue $ 195,515 $ 248,028 $ 614,032 $ 733,105
Sales-type Lease, Lease Income	The components of sales-type lease revenues were as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Loss recognized at commencement, net (1) $ (5,973) $ — $ (5,973) $ — Interest income (2) 484 — 484 — Total loss recognized on sales-type leases $ (5,489) $ — $ (5,489) $ — (1) These amounts are included in gain on sale of real estate, net and depreciable real estate reserves and impairment in our consolidated statements of operations. (2) These amounts are included in other income in our consolidated statements of operations.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Schedule of ground lease arrangements	The table below summarizes our current ground lease arrangements as of September 30, 2020: Property (1) Year of Current Expiration Year of Final Expiration (2) 1185 Avenue of the Americas 2043 2043 625 Madison Avenue 2022 2054 420 Lexington Avenue 2050 2080 711 Third Avenue (3) 2033 2083 461 Fifth Avenue (4) 2027 2084 1055 Washington Blvd, Stamford, Connecticut 2090 2090 1080 Amsterdam Avenue (5) 2111 2111 30 East 40th Street (5) 2114 2114 126 Nassau Street (4)(6) 2119 2119 Other Various Various (1) All leases are classified as operating leases unless otherwise specified. (2) Reflects exercise of all available renewal options. (3) The Company owns 50% of the fee interest. (4) The Company has an option to purchase the ground lease for a fixed price on a specific date. The lease is classified as a financing lease. (5) A portion of the lease is classified as a financing lease. (6) In August 2020, the Company entered into a long-term sublease with an unconsolidated joint venture as part of the capitalization of the 126 Nassau Street development project. See Note 6, "Investments in Unconsolidated Joint Ventures."
Finance lease, liability, maturity	The following is a schedule of future minimum lease payments as evaluated in accordance with ASC 842 for our financing leases and operating leases with initial terms in excess of one year as of September 30, 2020 (in thousands): Financing leases Operating leases (1) Remaining 2020 $ 1,974 $ 7,363 2021 34,885 29,452 2022 5,881 27,148 2023 5,927 24,844 2024 5,999 24,863 2025 6,266 24,962 Thereafter 1,018,013 618,326 Total minimum lease payments $ 1,078,945 $ 756,958 Amount representing interest (903,962) Amount discounted using incremental borrowing rate (398,539) Lease liabilities $ 174,983 $ 358,419 (1) As of September 30, 2020, the total future minimum payments to be received under non-cancelable subleases is $1.7 billion.
Schedule of future minimum rental payments for operating leases	The following is a schedule of future minimum lease payments as evaluated in accordance with ASC 842 for our financing leases and operating leases with initial terms in excess of one year as of September 30, 2020 (in thousands): Financing leases Operating leases (1) Remaining 2020 $ 1,974 $ 7,363 2021 34,885 29,452 2022 5,881 27,148 2023 5,927 24,844 2024 5,999 24,863 2025 6,266 24,962 Thereafter 1,018,013 618,326 Total minimum lease payments $ 1,078,945 $ 756,958 Amount representing interest (903,962) Amount discounted using incremental borrowing rate (398,539) Lease liabilities $ 174,983 $ 358,419 (1) As of September 30, 2020, the total future minimum payments to be received under non-cancelable subleases is $1.7 billion.
Lease, cost	The following table provides lease cost information for the Company's operating and financing leases for the three and nine months ended September 30, 2020 and 2019 (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Operating Lease Costs Operating lease costs before capitalized operating lease costs $ 7,751 $ 8,315 $ 24,486 $ 24,918 Operating lease costs capitalized (778) (20) (2,315) (27) Operating lease costs, net (1) 6,973 8,295 22,171 24,891 Financing Lease Costs Interest on financing leases before capitalized interest 2,198 813 6,010 2,425 Interest on financing leases capitalized (588) — (2,378) — Interest on financing leases, net (2) 1,610 813 3,632 2,425 Amortization of right-of-use assets (3) 304 304 914 914 Financing lease costs, net 1,914 1,117 4,546 3,339 (1) This amount is included in operating lease rent in our consolidated statements of operations. (2) These amounts are included in interest expense, net of interest income in our consolidated statements of operations. (3) These amounts are included in depreciation and amortization in our consolidated statements of operations.

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2020
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, 2020 and 2019, and selected asset information as of September 30, 2020 and December 31, 2019, 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, 2020 $ 226,856 $ 22,988 $ 249,844 September 30, 2019 262,115 51,519 313,634 Nine months ended: September 30, 2020 $ 716,382 $ 101,464 817,846 September 30, 2019 777,745 153,168 930,913 Net income Three months ended: September 30, 2020 $ 10,097 $ 10,580 $ 20,677 September 30, 2019 6,133 34,589 40,722 Nine months ended: September 30, 2020 $ 161,388 $ 53,030 214,418 September 30, 2019 168,639 98,593 267,232 Total assets As of: September 30, 2020 $ 11,079,252 $ 1,244,787 $ 12,324,039 December 31, 2019 11,063,155 1,703,165 12,766,320

Organization and Basis of Pre_3

Organization and Basis of Presentation - Additional Information (Details)	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Service Corporation
Organization
Percentage of ownership in SL Green Management LLC owned by operating partnership (percent)	95.00%
Operating Partnership | SL Green Operating Partnership
Organization
Noncontrolling interest in the operating partnership (as a percent)	5.23%	5.03%
SL Green Management | SL Green Management LLC
Organization
Percentage of ownership in SL Green Management LLC owned by operating partnership (percent)	100.00%

Organization and Basis of Pre_4

Organization and Basis of Presentation - Schedule of Commercial Office Properties (Details) $ in Millions	9 Months Ended
	Sep. 30, 2020USD ($)ft²buildingshares
Real estate properties
Number of Properties | building	72
Approximate Square Feet unaudited (sqft) | ft²	30,328,709
Weighted Average Occupancy unaudited (as a percent)	91.90%
Debt and preferred equity investments including investments held by unconsolidated joint ventures | $	$ 1,150
Debt and preferred equity investments and other financing receivables included in other balance sheet items | $	$ 100
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	63
Approximate Square Feet unaudited (sqft) | ft²	28,582,685
Weighted Average Occupancy unaudited (as a percent)	92.70%
Residential
Real estate properties
Number of Properties | building	9
Approximate Square Feet unaudited (sqft) | ft²	1,746,024
Weighted Average Occupancy unaudited (as a percent)	78.80%
Managed office properties
Real estate properties
Number of Properties | building	2
Approximate Square Feet unaudited (sqft) | ft²	2,100,000
Consolidated properties
Real estate properties
Number of Properties | building	42
Approximate Square Feet unaudited (sqft) | ft²	14,778,792
Consolidated properties | Commercial properties
Real estate properties
Number of Properties | building	41
Approximate Square Feet unaudited (sqft) | ft²	14,696,542
Consolidated properties | Residential
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft) | ft²	82,250
Unconsolidated properties
Real estate properties
Number of Properties | building	30
Approximate Square Feet unaudited (sqft) | ft²	15,549,917
Unconsolidated properties | Commercial properties
Real estate properties
Number of Properties | building	22
Approximate Square Feet unaudited (sqft) | ft²	13,886,143
Unconsolidated properties | Residential
Real estate properties
Number of Properties | building	8
Approximate Square Feet unaudited (sqft) | ft²	1,663,774
Manhattan
Real estate properties
Number of Properties | building	54
Approximate Square Feet unaudited (sqft) | ft²	27,485,885
Weighted Average Occupancy unaudited (as a percent)	93.10%
Manhattan | Office
Real estate properties
Number of Properties | building	29
Approximate Square Feet unaudited (sqft) | ft²	22,488,674
Weighted Average Occupancy unaudited (as a percent)	93.10%
Manhattan | Retail
Real estate properties
Number of Properties | building	12
Approximate Square Feet unaudited (sqft) | ft²	333,239
Weighted Average Occupancy unaudited (as a percent)	94.00%
Manhattan | Development/Redevelopment
Real estate properties
Number of Properties | building	12
Approximate Square Feet unaudited (sqft) | ft²	4,663,972
Manhattan | Fee Interest
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft) | ft²	0
Weighted Average Occupancy unaudited (as a percent)	0.00%
Manhattan | Residential
Real estate properties
Number of Properties | building	9
Approximate Square Feet unaudited (sqft) | ft²	1,746,024
Weighted Average Occupancy unaudited (as a percent)	78.80%
Manhattan | Consolidated properties
Real estate properties
Number of Properties | building	32
Approximate Square Feet unaudited (sqft) | ft²	13,599,742
Manhattan | Consolidated properties | Office
Real estate properties
Number of Properties | building	18
Approximate Square Feet unaudited (sqft) | ft²	10,647,191
Manhattan | Consolidated properties | Retail
Real estate properties
Number of Properties | building	4
Approximate Square Feet unaudited (sqft) | ft²	44,189
Manhattan | Consolidated properties | Development/Redevelopment
Real estate properties
Number of Properties | building	10
Approximate Square Feet unaudited (sqft) | ft²	2,908,362
Manhattan | Consolidated properties | Fee Interest
Real estate properties
Number of Properties | building	0
Approximate Square Feet unaudited (sqft) | ft²	0
Manhattan | Consolidated properties | Residential
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft) | ft²	82,250
Manhattan | Unconsolidated properties
Real estate properties
Number of Properties | building	22
Approximate Square Feet unaudited (sqft) | ft²	13,886,143
Manhattan | Unconsolidated properties | Office
Real estate properties
Number of Properties | building	11
Approximate Square Feet unaudited (sqft) | ft²	11,841,483
Manhattan | Unconsolidated properties | Retail
Real estate properties
Number of Properties | building	8
Approximate Square Feet unaudited (sqft) | ft²	289,050
Manhattan | Unconsolidated properties | Development/Redevelopment
Real estate properties
Number of Properties | building	2
Approximate Square Feet unaudited (sqft) | ft²	1,755,610
Manhattan | Unconsolidated properties | Fee Interest
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft) | ft²	0
Manhattan | Unconsolidated properties | Residential
Real estate properties
Number of Properties | building	8
Approximate Square Feet unaudited (sqft) | ft²	1,663,774
Suburban
Real estate properties
Number of Properties | building	9
Approximate Square Feet unaudited (sqft) | ft²	1,096,800
Weighted Average Occupancy unaudited (as a percent)	85.70%
Suburban | Office
Real estate properties
Number of Properties | building	8
Approximate Square Feet unaudited (sqft) | ft²	1,044,800
Weighted Average Occupancy unaudited (as a percent)	85.00%
Suburban | Retail
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft) | ft²	52,000
Weighted Average Occupancy unaudited (as a percent)	100.00%
Suburban | Consolidated properties
Real estate properties
Number of Properties | building	9
Approximate Square Feet unaudited (sqft) | ft²	1,096,800
Suburban | Consolidated properties | Office
Real estate properties
Number of Properties | building	8
Approximate Square Feet unaudited (sqft) | ft²	1,044,800
Suburban | Consolidated properties | Retail
Real estate properties
Number of Properties | building	1
Approximate Square Feet unaudited (sqft) | ft²	52,000
Suburban | Unconsolidated properties
Real estate properties
Number of Properties | building	0
Approximate Square Feet unaudited (sqft) | ft²	0
Suburban | Unconsolidated properties | Office
Real estate properties
Number of Properties | building	0
Approximate Square Feet unaudited (sqft) | ft²	0
Suburban | Unconsolidated properties | Retail
Real estate properties
Number of Properties | building	0
Approximate Square Feet unaudited (sqft) | ft²	0

Organization and Basis of Pre_5

Organization and Basis of Presentation - Subsequent Events (Details) - Subsequent Event - USD ($) $ in Millions	Nov. 04, 2020	Oct. 31, 2020
410 Tenth Avenue
Subsequent Event [Line Items]
Gross asset valuation		$ 952.5
Ownership Interest		70.90%
Ownership percentage retained by investee		5.00%
Third Quarter 2020
Subsequent Event [Line Items]
Gross tenant billings collected, percent	92.70%
Third Quarter 2020 | Office
Subsequent Event [Line Items]
Gross tenant billings collected, percent	96.90%
Third Quarter 2020 | Retail
Subsequent Event [Line Items]
Gross tenant billings collected, percent	70.20%
October 2020 Period
Subsequent Event [Line Items]
Gross tenant billings collected, percent	93.00%
October 2020 Period | Office
Subsequent Event [Line Items]
Gross tenant billings collected, percent	96.40%
October 2020 Period | Retail
Subsequent Event [Line Items]
Gross tenant billings collected, percent	72.60%

Significant Accounting Polici_4

Significant Accounting Policies - Investments in Commercial Real Estate Properties (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Investment in Commercial Real Estate Properties
Rental revenue from amortization of acquired leases	$ 1,600,000	$ 1,200,000	$ 4,500,000	$ 3,600,000
Identified intangible assets (included in other assets):
Gross amount	224,221,000		224,221,000		$ 255,198,000
Accumulated amortization	(208,135,000)		(208,135,000)		(228,223,000)
Net	16,086,000		16,086,000		26,975,000
Identified intangible liabilities (included in deferred revenue):
Gross amount	273,240,000		273,240,000		282,048,000
Accumulated amortization	(255,879,000)		(255,879,000)		(249,514,000)
Net	$ 17,361,000		$ 17,361,000		32,534,000
Net intangible assets reclassified to assets held for sale					0
Net intangible liabilities reclassified to liabilities relates to assets held for sale					$ 0
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

Significant Accounting Polici_5

Significant Accounting Policies - Investment in Marketable Securities (Details) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Investment in Marketable Securities
Marketable securities	$ 27,734,000	$ 29,887,000
Equity marketable securities	27,734,000	29,887,000
Fair Value
Investment in Marketable Securities
Marketable securities	27,734,000	29,887,000
Equity marketable securities
Investment in Marketable Securities
Equity marketable securities	0	0
Commercial mortgage-backed securities
Investment in Marketable Securities
Marketable securities	27,734,000	29,887,000
Cost basis of commercial mortgage-backed securities	$ 27,500,000	$ 27,500,000

Significant Accounting Polici_6

Significant Accounting Policies - Revenue Recognition/Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Income taxes
Reserves for recognized receivables	$ 9.5		$ 9.5		$ 2.6
Federal, state and local tax provision (benefit)	$ 0	$ (1)	$ 2	$ 0.5

Significant Accounting Polici_7

Significant Accounting Policies - Concentrations of Credit Risk/Accounting Standards Updates (Details) - Annualized rent - Customer concentration	9 Months Ended
	Sep. 30, 2020Tenant
Concentration of Credit Risk
Number of tenants (tenants)	1
Maximum percentage of annualized rent for any one tenant not individually disclosed (percent) (more than)	5.00%
1185 Avenue of the Americas
Concentration of Credit Risk
Percentage of concentration (percent)	8.40%
11 Madison Avenue
Concentration of Credit Risk
Percentage of concentration (percent)	8.10%
420 Lexington Avenue
Concentration of Credit Risk
Percentage of concentration (percent)	7.40%
1515 Broadway
Concentration of Credit Risk
Percentage of concentration (percent)	6.30%
220 East 42nd Street
Concentration of Credit Risk
Percentage of concentration (percent)	5.90%
280 Park Avenue
Concentration of Credit Risk
Percentage of concentration (percent)	5.40%
485 Lexington Avenue
Concentration of Credit Risk
Percentage of concentration (percent)	5.00%
Tenant 1
Concentration of Credit Risk
Percentage of concentration (percent)	5.50%

Significant Accounting Polici_8

Significant Accounting Policies - Accounting Standards Update (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jan. 01, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	$ 1,035,172		$ 1,084,719
Cumulative Effect, Period Of Adoption, Adjustment | Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings		$ 39,200

Property Acquisitions (Details)

Property Acquisitions (Details) $ in Millions	1 Months Ended
	Jan. 31, 2020USD ($)ft²	Sep. 30, 2020ft²
Property Acquisitions
Approximate Square Feet		30,328,709
762 Madison Avenue
Property Acquisitions
Approximate Square Feet	6,109
Gross Asset Valuation (in millions) | $	$ 29.3
Interest acquired	10.00%
707 Eleventh Avenue
Property Acquisitions
Approximate Square Feet	159,720
Gross Asset Valuation (in millions) | $	$ 90
126-132 Nassau Street
Property Acquisitions
Approximate Square Feet	98,412
Gross Asset Valuation (in millions) | $	$ 0
Ground leases, term of contract	99 years

Properties Held for Sale and _3

Properties Held for Sale and Property Dispositions (Details) $ in Millions	1 Months Ended
	Sep. 30, 2020USD ($)ft²	May 31, 2020USD ($)ft²	Mar. 31, 2020USD ($)ft²
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Square Feet | ft²	30,328,709
315 West 33rd Street
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Square Feet | ft²			492,987
Sales Price			$ 446.5
Gain (loss)			$ 72.3
Accrued employee compensation in connection with realization of investment	$ 6
609 Fifth Avenue
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Square Feet | ft²		21,437
Sales Price		$ 168
Gain (loss)		$ 65.4
Accrued employee compensation in connection with realization of investment	$ 2
400 East 58th Street
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Approximate Square Feet | ft²	140,000
Sales Price	$ 62
Gain (loss)	$ 8.3

Debt and Preferred Equity Inv_3

Debt and Preferred Equity Investments - Rollforward of Net Book Balance (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Balance at beginning of period	$ 1,580,306	$ 2,099,393
Redemptions/Sales/Syndications/Equity Ownership/Amortization	(956,869)	(1,190,689)
Net change in loan loss reserves	(17,260)	4,000
Balance at end of period	1,153,363	1,580,306
Debt Investments in Mortgage Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Originations/Accretion	383,365	652,866
Preferred equity investments
SEC Schedule, 12-29, Real Estate Companies, Investment in Movement in Mortgage Loans on Real Estate [Roll Forward]
Originations/Accretion	$ 163,821	$ 14,736

Debt and Preferred Equity Inv_4

Debt and Preferred Equity Investments - Debt and Preferred Equity Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Carrying Value	$ 1,153,363	$ 1,580,306
Senior Financing
Total floating rate
Debt Instrument [Line Items]
Carrying Value	426,704
Face Value	443,458
Total fixed rate
Debt Instrument [Line Items]
Carrying Value	726,659
Face Value	740,946
Senior Mortgage Debt
Debt Instrument [Line Items]
Carrying Value	63,932
Senior Financing	0
Senior Mortgage Debt | Total floating rate
Debt Instrument [Line Items]
Carrying Value	62,683
Face Value	63,425
Senior Mortgage Debt | Total fixed rate
Debt Instrument [Line Items]
Carrying Value	1,249
Face Value	$ 1,250
Interest rate	3.00%
Junior Mortgage Debt
Debt Instrument [Line Items]
Carrying Value	$ 118,100
Senior Financing	542,241
Junior Mortgage Debt | Total floating rate
Debt Instrument [Line Items]
Carrying Value	85,295
Face Value	96,697
Junior Mortgage Debt | Total fixed rate
Debt Instrument [Line Items]
Carrying Value	32,805
Face Value	$ 33,000
Interest rate	6.00%
Mezzanine Debt
Debt Instrument [Line Items]
Carrying Value	$ 714,766
Senior Financing	4,447,803
Mezzanine Debt | Total floating rate
Debt Instrument [Line Items]
Carrying Value	278,726
Face Value	283,336
Mezzanine Debt | Total fixed rate
Debt Instrument [Line Items]
Carrying Value	436,040
Face Value	447,265
Preferred Equity
Debt Instrument [Line Items]
Carrying Value	256,565
Senior Financing	1,962,750
Preferred Equity | Total floating rate
Debt Instrument [Line Items]
Carrying Value	0
Face Value	0
Preferred Equity | Total fixed rate
Debt Instrument [Line Items]
Carrying Value	256,565
Face Value	$ 259,431
Minimum | Mezzanine Debt | Total fixed rate
Debt Instrument [Line Items]
Interest rate	2.90%
Minimum | Preferred Equity | Total fixed rate
Debt Instrument [Line Items]
Interest rate	6.50%
Maximum | Mezzanine Debt | Total fixed rate
Debt Instrument [Line Items]
Interest rate	9.30%
Maximum | Preferred Equity | Total fixed rate
Debt Instrument [Line Items]
Interest rate	11.00%
LIBOR | Minimum | Senior Mortgage Debt | Total floating rate
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%
LIBOR | Minimum | Junior Mortgage Debt | Total floating rate
Debt Instrument [Line Items]
Basis spread on variable rate	6.00%
LIBOR | Minimum | Mezzanine Debt | Total floating rate
Debt Instrument [Line Items]
Basis spread on variable rate	4.95%
LIBOR | Maximum | Senior Mortgage Debt | Total floating rate
Debt Instrument [Line Items]
Basis spread on variable rate	3.50%
LIBOR | Maximum | Junior Mortgage Debt | Total floating rate
Debt Instrument [Line Items]
Basis spread on variable rate	7.25%
LIBOR | Maximum | Mezzanine Debt | Total floating rate
Debt Instrument [Line Items]
Basis spread on variable rate	14.62%

Debt and Preferred Equity Inv_5

Debt and Preferred Equity Investments - Rollforward of Total Allowance for Loan Loss Reserves (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Loan loss reserve activity
Balance at beginning of year	$ 1,750	$ 5,750
Current period provision for loan loss	20,741	0
Write-offs charged against the allowance	(31,285)	(4,000)
Balance at end of period	19,010	1,750
Cumulative adjustment upon adoption of ASC 326
Loan loss reserve activity
Balance at beginning of year	$ 27,804	0
Balance at end of period		$ 27,804

Debt and Preferred Equity Inv_6

Debt and Preferred Equity Investments - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Aggregate weighted average current yield (as a percent)	6.26%
Debt Investments Held [Abstract]
Carrying Value	$ 1,153,363	$ 1,580,306
Mezzanine Loan With Initial Maturity Date Of January 2021
Debt Investments Held [Abstract]
Amount participated out	66,600
Mezzanine Loan with an Initial Maturity Date of June 2024
Debt Investments Held [Abstract]
Amount participated out	12,000
Mezzanine Loan Due March 2022
Debt Investments Held [Abstract]
Amount participated out	400
Debt Investments in Mortgage Loans
Debt Investments Held [Abstract]
Future Funding Obligations	165,023
Senior Financing	4,930,044
Allowance for loan loss	(19,010)	0
Carrying Value	896,798	1,341,070
Total fixed rate
Debt Investments Held [Abstract]
Future Funding Obligations	10,000
Senior Financing	2,781,827
Carrying Value	476,724	499,410
Total fixed rate | Mortgage And Mezzanine Loan With An Initial Maturity Date Of October 2020
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	63,750
Carrying Value	56,242	55,573
Total fixed rate | Mezzanine Loan With Initial Maturity Date Of January 2021
Debt Investments Held [Abstract]
Future Funding Obligations	10,000
Senior Financing	67,000
Carrying Value	32,805	0
Total fixed rate | Mezzanine Loan, September 2021
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	15,000
Carrying Value	3,500	3,500
Total fixed rate | Mezzanine Loan With An Initial Maturity Of August 2022
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	280,000
Carrying Value	40,458	38,734
Total fixed rate | Mezzanine Loan With Maturity June 2023
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	348,327
Carrying Value	225,204	215,737
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of June 2024
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	115,000
Carrying Value	13,265	12,950
Total fixed rate | Mezzanine Loan, with an Initial Maturity Date of January 2025
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	95,000
Carrying Value	30,000	30,000
Total fixed rate | Mezzanine Loan with an Initial Maturity Date of June 2027
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	1,712,750
Carrying Value	55,250	55,250
Total fixed rate | Mezzanine Loan With Initial Maturity Date Of December 2029
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	85,000
Carrying Value	20,000	20,000
Total fixed rate | Mezzanine Loan Repaid In 2020, 1
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	24,952
Total fixed rate | Mezzanine Loan Repaid In 2020, 2
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	30,000
Total fixed rate | Mezzanine Loan Repaid In 2020, 3
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	12,714
Total floating rate
Debt Investments Held [Abstract]
Future Funding Obligations	155,023
Senior Financing	2,148,217
Carrying Value	439,084	841,660
Total floating rate | Mezzanine Loan Repaid In 2020, 1
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	51,387
Total floating rate | Junior Mortgage Loan With An Initial Maturity April 2020
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	40,000
Carrying Value	20,000	20,000
Total floating rate | Mezzanine Loan With An Initial Maturity Due April 2021
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	275,000
Carrying Value	49,919	49,809
Total floating rate | Jr Mortgage Participation/Mezzanine Loan with an Initial Maturity of July 2021
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	60,000
Carrying Value	15,724	15,698
Total floating rate | Mezzanine Loan With An Initial Maturity Due July 2021
Debt Investments Held [Abstract]
Future Funding Obligations	7,933
Senior Financing	169,540
Carrying Value	46,613	41,395
Total floating rate | Mezzanine Loan Due July 2021, 2
Debt Investments Held [Abstract]
Future Funding Obligations	5,329
Senior Financing	54,204
Carrying Value	23,753	15,743
Total floating rate | Mezzanine Loan Due March 2022
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	1,115,000
Carrying Value	126,486	222,775
Total floating rate | Mortgage/Mezzanine Loan Due May 2022
Debt Investments Held [Abstract]
Future Funding Obligations	7,425
Senior Financing	0
Carrying Value	60,116	0
Total floating rate | Mezzanine Loan Due December 2022
Debt Investments Held [Abstract]
Future Funding Obligations	44,000
Senior Financing	0
Carrying Value	13,987	13,918
Total floating rate | Mortgage Loan Due February 2023
Debt Investments Held [Abstract]
Future Funding Obligations	35,303
Senior Financing	375,241
Carrying Value	63,899	0
Total floating rate | Mezzanine Loan Due May 2023
Debt Investments Held [Abstract]
Future Funding Obligations	55,033
Senior Financing	59,232
Carrying Value	18,587	69,839
Total floating rate | Mortgage/Mezzanine Loan Repaid In 2020, 1
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	35,386
Total floating rate | Mortgage Loan Repaid In 2020, 1
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	19,971
Total floating rate | Mortgage Loan Repaid In 2020, 2
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	106,473
Total floating rate | Mortgage/Mezzanine Loan Repaid In 2020, 2
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	0	96,570
Total floating rate | Mortgage/Mezzanine Loan Repaid In 2020, 3
Debt Investments Held [Abstract]
Future Funding Obligations	0
Senior Financing	0
Carrying Value	$ 0	$ 82,696

Debt and Preferred Equity Inv_7

Debt and Preferred Equity Investments - Preferred Equity Investments (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Preferred equity investment
Aggregate weighted average current yield (as a percent)	6.26%
Carrying Value	$ 1,153,363	$ 1,580,306
Preferred Equity, June 2022
Preferred equity investment
Future Funding Obligations	0
Senior Financing	1,712,750
Carrying Value	153,196	98,065
Preferred Equity, February 2027
Preferred equity investment
Future Funding Obligations	0
Senior Financing	250,000
Carrying Value	103,369	0
Preferred Equity, April 2021
Preferred equity investment
Future Funding Obligations	0
Senior Financing	0
Carrying Value	$ 0	142,921
Preferred equity investments
Preferred equity investment
Aggregate weighted average current yield (as a percent)	9.98%
Future Funding Obligations	$ 0
Senior Financing	1,962,750
Carrying Value	256,565	240,986
Allowance for loan loss	0	(1,750)
Total after allowance for loan loss	$ 256,565	$ 239,236

Debt and Preferred Equity Inv_8

Debt and Preferred Equity Investments - Narrative (Details)	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2020USD ($)	Sep. 30, 2020USD ($)segment	Dec. 31, 2019USD ($)segment	Jan. 01, 2020USD ($)	Dec. 31, 2018USD ($)
Preferred equity investment
Carrying Value	$ 1,153,363,000	$ 1,153,363,000	$ 1,580,306,000
Recorded investment, nonaccrual status	$ 27,700,000	$ 27,700,000
Weighted average risk rating	1.4	1.4
Number of portfolio segments of financial receivables (segment) | segment		1	1
Additional amount of financing receivables included in other assets	$ 110,900,000	$ 110,900,000	$ 131,100,000
Provision for loan losses	0	6,300,000
Allowance for loan and lease losses, real estate	19,010,000	19,010,000	1,750,000		$ 5,750,000
Financing Receivables, Equal to Greater than 90 Days Past Due
Preferred equity investment
Recorded investment, past due	0	0	0
Cumulative Effect, Period Of Adoption, Adjustment
Preferred equity investment
Additional amount of financing receivables included in other assets				$ 11,400,000
Allowance for loan and lease losses, real estate			27,804,000		$ 0
Total floating rate
Preferred equity investment
Carrying Value	439,084,000	439,084,000	$ 841,660,000
Total floating rate | Mortgage/Mezzanine Loan Due March 2020
Preferred equity investment
Carrying Value	$ 25,300,000	$ 25,300,000

Investments in Unconsolidated_3

Investments in Unconsolidated Joint Ventures - Additional Information (Details) $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Aug. 31, 2020USD ($)	Oct. 31, 2016	Sep. 30, 2020USD ($)ft²unit	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)ft²unit	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)
General information on each joint venture
Equity method investments | $			$ 2,946,673		$ 2,946,673		$ 2,912,842
Net equity investment in VIEs in which the entity is not primary beneficiary | $			$ 136,300		$ 136,300		145,900
Unaudited Approximate Square Feet (sqft)			30,328,709		30,328,709
Purchase price and other fair value adjustments | $			$ 0	$ 3,799	$ 0	$ 69,389
Gain on sale of real estate, net | $			$ 26,104	$ 3,541	$ 163,624	$ 2,492
1552-1560 Broadway
General information on each joint venture
Unaudited Approximate Square Feet (sqft)			13,045		13,045
Stonehenge Portfolio
General information on each joint venture
Ownership Interest		90.00%
East 400 Street 57
General information on each joint venture
Ownership Interest		51.00%
126 Nassau Street
General information on each joint venture
Gain on sale of real estate, net | $	$ 17,700
East 400 Street 57
General information on each joint venture
Ownership percentage in disposed asset		49.00%
21 East 66th Street | Three Retail and Two Residential Units
General information on each joint venture
Ownership Interest			32.28%		32.28%
Number of stores | unit			3		3
Number of residential units | unit			1		1
21 East 66th Street | Three Residential Units
General information on each joint venture
Ownership Interest			16.14%		16.14%
Number of residential units | unit			3		3
Joint venture
General information on each joint venture
Equity method investments | $			$ 2,946,673		$ 2,946,673		$ 2,912,842
Equity method investments with negative book value | $			$ 85,800		$ 85,800
Joint venture | 100 Park Avenue
General information on each joint venture
Ownership Interest			49.90%		49.90%
Economic Interest (as a percent)			49.90%		49.90%
Unaudited Approximate Square Feet (sqft)			834,000		834,000
Joint venture | 717 Fifth Avenue
General information on each joint venture
Ownership Interest			10.92%		10.92%
Economic Interest (as a percent)			10.92%		10.92%
Unaudited Approximate Square Feet (sqft)			119,500		119,500
Joint venture | 800 Third Avenue
General information on each joint venture
Ownership Interest			60.52%		60.52%
Economic Interest (as a percent)			60.52%		60.52%
Unaudited Approximate Square Feet (sqft)			526,000		526,000
Interest rate, fixed rate debt (as a percent)			3.37%		3.37%
Joint venture | 919 Third Avenue
General information on each joint venture
Ownership Interest			51.00%		51.00%
Economic Interest (as a percent)			51.00%		51.00%
Unaudited Approximate Square Feet (sqft)			1,454,000		1,454,000
Interest rate, fixed rate debt (as a percent)			5.12%		5.12%
Joint venture | 11 West 34th Street
General information on each joint venture
Ownership Interest			30.00%		30.00%
Economic Interest (as a percent)			30.00%		30.00%
Unaudited Approximate Square Feet (sqft)			17,150		17,150
Joint venture | 280 Park Avenue
General information on each joint venture
Ownership Interest			50.00%		50.00%
Economic Interest (as a percent)			50.00%		50.00%
Unaudited Approximate Square Feet (sqft)			1,219,158		1,219,158
Joint venture | 1552-1560 Broadway
General information on each joint venture
Ownership Interest			50.00%		50.00%
Economic Interest (as a percent)			50.00%		50.00%
Unaudited Approximate Square Feet (sqft)			57,718		57,718
Joint venture | 10 East 53rd Street
General information on each joint venture
Ownership Interest			55.00%		55.00%
Economic Interest (as a percent)			55.00%		55.00%
Unaudited Approximate Square Feet (sqft)			354,300		354,300
Joint venture | 21 East 66th Street
General information on each joint venture
Ownership Interest			32.28%		32.28%
Economic Interest (as a percent)			32.28%		32.28%
Unaudited Approximate Square Feet (sqft)			13,069		13,069
Interest rate, fixed rate debt (as a percent)			3.60%		3.60%
Joint venture | 650 Fifth Avenue
General information on each joint venture
Ownership Interest			50.00%		50.00%
Economic Interest (as a percent)			50.00%		50.00%
Unaudited Approximate Square Feet (sqft)			69,214		69,214
Joint venture | 121 Greene Street
General information on each joint venture
Ownership Interest			50.00%		50.00%
Economic Interest (as a percent)			50.00%		50.00%
Unaudited Approximate Square Feet (sqft)			7,131		7,131
Joint venture | 55 West 46th Street
General information on each joint venture
Ownership Interest			25.00%		25.00%
Economic Interest (as a percent)			25.00%		25.00%
Unaudited Approximate Square Feet (sqft)			347,000		347,000
Joint venture | Stonehenge Portfolio
General information on each joint venture
Ownership Interest		10.00%
Unaudited Approximate Square Feet (sqft)			1,439,016		1,439,016
Interest rate, fixed rate debt (as a percent)			3.50%		3.50%
Joint venture | 605 West 42nd Street
General information on each joint venture
Ownership Interest			20.00%		20.00%
Economic Interest (as a percent)			20.00%		20.00%
Unaudited Approximate Square Feet (sqft)			927,358		927,358
Joint venture | 11 Madison Avenue
General information on each joint venture
Ownership Interest			60.00%		60.00%
Economic Interest (as a percent)			60.00%		60.00%
Unaudited Approximate Square Feet (sqft)			2,314,000		2,314,000
Interest rate, fixed rate debt (as a percent)			3.84%		3.84%
Joint venture | 333 East 22nd St
General information on each joint venture
Ownership Interest			33.33%		33.33%
Economic Interest (as a percent)			33.33%		33.33%
Unaudited Approximate Square Feet (sqft)			26,926		26,926
Joint venture | East 400 Street 57
General information on each joint venture
Ownership Interest			51.00%		51.00%
Economic Interest (as a percent)			41.00%		41.00%
Unaudited Approximate Square Feet (sqft)			290,482		290,482
Interest rate, fixed rate debt (as a percent)			3.00%		3.00%
Joint venture | One Vanderbilt
General information on each joint venture
Ownership Interest			71.01%		71.01%
Economic Interest (as a percent)			71.01%		71.01%
Unaudited Approximate Square Feet (sqft)			0		0
Joint venture | Worldwide Plaza
General information on each joint venture
Ownership Interest			24.35%		24.35%
Economic Interest (as a percent)			24.35%		24.35%
Unaudited Approximate Square Feet (sqft)			2,048,725		2,048,725
Interest rate, fixed rate debt (as a percent)			3.98%		3.98%
Joint venture | 1515 Broadway
General information on each joint venture
Ownership Interest			56.87%		56.87%
Economic Interest (as a percent)			56.87%		56.87%
Unaudited Approximate Square Feet (sqft)			1,750,000		1,750,000
Interest rate, fixed rate debt (as a percent)			3.93%		3.93%
Joint venture | 2 Herald Square
General information on each joint venture
Ownership Interest			51.00%		51.00%
Economic Interest (as a percent)			51.00%		51.00%
Unaudited Approximate Square Feet (sqft)			369,000		369,000
Joint venture | 115 Spring Street
General information on each joint venture
Ownership Interest			51.00%		51.00%
Economic Interest (as a percent)			51.00%		51.00%
Unaudited Approximate Square Feet (sqft)			5,218		5,218
Joint venture | 885 Third Avenue
General information on each joint venture
Economic Interest (as a percent)			100.00%		100.00%
Unaudited Approximate Square Feet (sqft)			625,300		625,300
Interest rate, fixed rate debt (as a percent)			3.35%		3.35%
Joint venture | 126 Nassau Street
General information on each joint venture
Ownership Interest			20.00%		20.00%
Economic Interest (as a percent)			20.00%		20.00%
Unaudited Approximate Square Feet (sqft)			98,412		98,412

Investments in Unconsolidated_4

Investments in Unconsolidated Joint Ventures - Acquisition, Development and Construction Arrangements/Sale of Joint Venture Interest or Property (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Oct. 31, 2016
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 2,946,673		$ 2,946,673		$ 2,912,842
Equity in net (loss) gain on sale of interest in unconsolidated joint venture/real estate	$ 0	$ 0	$ 0	$ 76,181
Stonehenge Portfolio
Schedule of Equity Method Investments [Line Items]
Ownership Interest						90.00%

Investments in Unconsolidated_5

Investments in Unconsolidated Joint Ventures - Mortgages and Other Loans Payable (Details)	9 Months Ended
	Sep. 30, 2020USD ($)extension	Dec. 31, 2019USD ($)	Aug. 31, 2019USD ($)
Debt Instrument [Line Items]
Total fixed rate debt	$ 1,086,141,000	$ 1,383,449,000
Total floating rate debt	1,338,581,000	828,434,000
Joint venture
Debt Instrument [Line Items]
Total fixed rate debt	5,609,455,000	5,351,721,000
Total floating rate debt	4,130,815,000	3,691,686,000
Total fixed rate and floating rate debt	9,740,270,000	9,043,407,000
Deferred financing costs, net	(87,763,000)	(91,538,000)
Total joint venture mortgages and other loans payable, net	$ 9,652,507,000	8,951,869,000
Joint venture | 885 Third Avenue
Debt Instrument [Line Items]
Economic Interest (as a percent)	100.00%
Interest rate, fixed rate debt (as a percent)	3.35%
Total fixed rate debt	$ 272,000,000	0
Joint venture | 717 Fifth Avenue
Debt Instrument [Line Items]
Economic Interest (as a percent)	10.92%
Joint venture | 717 Fifth Avenue | Mortgage loan
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	4.45%
Total fixed rate debt	$ 300,000,000	300,000,000
Joint venture | 717 Fifth Avenue | Mezzanine loans
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	5.50%
Total fixed rate debt	$ 355,328,000	355,328,000
Joint venture | 650 Fifth Avenue
Debt Instrument [Line Items]
Economic Interest (as a percent)	50.00%
Joint venture | 650 Fifth Avenue | Mortgage loan
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	4.46%
Total fixed rate debt	$ 210,000,000	210,000,000
Joint venture | 650 Fifth Avenue | Mezzanine loans
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	5.45%
Total fixed rate debt	$ 65,000,000	65,000,000
Joint venture | 21 East 66th Street
Debt Instrument [Line Items]
Economic Interest (as a percent)	32.28%
Interest rate, fixed rate debt (as a percent)	3.60%
Interest rate, floating rate debt (as a percent)	2.75%
Total fixed rate debt	$ 12,000,000	12,000,000
Total floating rate debt	$ 688,000	712,000
Joint venture | 919 Third Avenue
Debt Instrument [Line Items]
Economic Interest (as a percent)	51.00%
Interest rate, fixed rate debt (as a percent)	5.12%
Total fixed rate debt	$ 500,000,000	500,000,000
Joint venture | 1515 Broadway
Debt Instrument [Line Items]
Economic Interest (as a percent)	56.87%
Interest rate, fixed rate debt (as a percent)	3.93%
Total fixed rate debt	$ 825,204,000	838,546,000
Joint venture | 11 Madison Avenue
Debt Instrument [Line Items]
Economic Interest (as a percent)	60.00%
Interest rate, fixed rate debt (as a percent)	3.84%
Total fixed rate debt	$ 1,400,000,000	1,400,000,000
Joint venture | 800 Third Avenue
Debt Instrument [Line Items]
Economic Interest (as a percent)	60.52%
Interest rate, fixed rate debt (as a percent)	3.37%
Total fixed rate debt	$ 177,000,000	177,000,000
Joint venture | East 400 Street 57
Debt Instrument [Line Items]
Economic Interest (as a percent)	41.00%
Interest rate, fixed rate debt (as a percent)	3.00%
Total fixed rate debt	$ 97,024,000	97,735,000
Joint venture | Worldwide Plaza
Debt Instrument [Line Items]
Economic Interest (as a percent)	24.35%
Interest rate, fixed rate debt (as a percent)	3.98%
Total fixed rate debt	$ 1,200,000,000	1,200,000,000
Joint venture | Stonehenge Portfolio
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.50%
Total fixed rate debt	$ 195,899,000	196,112,000
Joint venture | 1552 Broadway
Debt Instrument [Line Items]
Economic Interest (as a percent)	50.00%
Interest rate, floating rate debt (as a percent)	2.65%
Total floating rate debt	$ 195,000,000	195,000,000
Period of extension options	1 year
Joint venture | 121 Greene Street
Debt Instrument [Line Items]
Economic Interest (as a percent)	50.00%
Interest rate, floating rate debt (as a percent)	1.50%
Total floating rate debt	$ 15,000,000	15,000,000
Joint venture | 11 West 34th Street
Debt Instrument [Line Items]
Economic Interest (as a percent)	30.00%
Interest rate, floating rate debt (as a percent)	1.45%
Total floating rate debt	$ 23,000,000	23,000,000
Joint venture | 100 Park Avenue
Debt Instrument [Line Items]
Economic Interest (as a percent)	49.90%
Interest rate, floating rate debt (as a percent)	1.75%
Total floating rate debt	$ 354,087,000	356,972,000
Joint venture | 280 Park Avenue
Debt Instrument [Line Items]
Economic Interest (as a percent)	50.00%
Interest rate, floating rate debt (as a percent)	1.73%
Total floating rate debt	$ 1,200,000,000	1,200,000,000
Joint venture | One Vanderbilt
Debt Instrument [Line Items]
Economic Interest (as a percent)	71.01%
Interest rate, floating rate debt (as a percent)	2.50%
Total floating rate debt	$ 1,094,873,000	732,928,000
Joint venture | One Vanderbilt | Construction Loans
Debt Instrument [Line Items]
Maximum facility capacity	$ 1,750,000,000
Term (in Years)	5 years
Number of extension options | extension	2
Period of extension options	1 year
Joint venture | 2 Herald Square
Debt Instrument [Line Items]
Economic Interest (as a percent)	51.00%
Interest rate, floating rate debt (as a percent)	1.45%
Total floating rate debt	$ 214,500,000	190,000,000
Joint venture | 55 West 46th Street
Debt Instrument [Line Items]
Economic Interest (as a percent)	25.00%
Interest rate, floating rate debt (as a percent)	1.25%
Total floating rate debt	$ 192,524,000	192,524,000
Joint venture | 55 West 46th Street | Mortgage loan
Debt Instrument [Line Items]
Committed amount			$ 198,000,000
Unfunded Amount	$ 5,500,000
Joint venture | 115 Spring Street
Debt Instrument [Line Items]
Economic Interest (as a percent)	51.00%
Interest rate, floating rate debt (as a percent)	3.40%
Total floating rate debt	$ 65,550,000	65,550,000
Joint venture | 126 Nassau Street
Debt Instrument [Line Items]
Economic Interest (as a percent)	20.00%
Interest rate, floating rate debt (as a percent)	1.50%
Total floating rate debt	$ 5,593,000	0
Joint venture | 126 Nassau Street | Construction Loans
Debt Instrument [Line Items]
Maximum facility capacity	$ 125,000,000
Joint venture | 10 East 53rd Street
Debt Instrument [Line Items]
Economic Interest (as a percent)	55.00%
Interest rate, floating rate debt (as a percent)	1.35%
Total floating rate debt	$ 220,000,000	170,000,000
Joint venture | 605 West 42nd Street
Debt Instrument [Line Items]
Economic Interest (as a percent)	20.00%
Interest rate, floating rate debt (as a percent)	1.44%
Total floating rate debt	$ 550,000,000	$ 550,000,000
Secured Debt, Initial Maturity August 2019 | Joint venture | Stonehenge Portfolio
Debt Instrument [Line Items]
Total fixed rate debt	132,400,000
Secured Debt, Initial Maturity June 2024 | Joint venture | Stonehenge Portfolio
Debt Instrument [Line Items]
Total fixed rate debt	$ 63,500,000

Investments in Unconsolidated_6

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, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Assets
Commercial real estate property, net	$ 6,761,243		$ 6,761,243		$ 6,724,007
Cash and cash equivalents	221,404	$ 121,751	221,404	$ 121,751	166,070
Tenant and other receivables, related party receivables, and deferred rents receivable	72,806		72,806		43,968
Other assets	514,873		514,873		332,801
Liabilities and equity
Mortgages and other loans payable, net	2,391,744		2,391,744		2,183,253
Deferred revenue	117,615		117,615		114,052
Lease liabilities	358,419		358,419		381,671
Other liabilities	306,077		306,077		177,080
Company's investments in unconsolidated joint ventures	2,946,673		2,946,673		2,912,842
Investments difference between carrying amount and underlying equity	166,800		166,800
Combined statements of income for the unconsolidated joint ventures
Operating expenses	45,910	59,847	140,673	175,862
Real estate taxes	43,522	49,626	131,805	143,008
Operating lease rent	6,973	8,295	22,171	24,891
Interest expense, net of interest income	23,536	48,112	91,100	145,797
Amortization of deferred financing costs	3,151	3,112	8,312	8,566
Depreciation and amortization	92,516	70,464	256,736	208,268
Total expenses	248,212	263,341	744,980	782,052
Company's equity in net (loss) income from unconsolidated joint ventures	(432)	(9,864)	(15,445)	(22,644)
Joint venture
Assets
Commercial real estate property, net	15,045,603		15,045,603		14,349,628
Cash and cash equivalents	326,488		326,488		336,189
Tenant and other receivables, related party receivables, and deferred rents receivable	404,138		404,138		371,065
Other assets	1,940,540		1,940,540		2,039,429
Total assets	17,716,769		17,716,769		17,096,311
Liabilities and equity
Mortgages and other loans payable, net	9,652,507		9,652,507		8,951,869
Deferred revenue	1,400,458		1,400,458		1,501,616
Lease liabilities	1,015,477		1,015,477		897,380
Other liabilities	294,972		294,972		308,304
Equity	5,353,355		5,353,355		5,437,142
Total liabilities and equity	17,716,769		17,716,769		17,096,311
Company's investments in unconsolidated joint ventures	2,946,673		2,946,673		$ 2,912,842
Combined statements of income for the unconsolidated joint ventures
Total revenues	292,929	286,010	846,967	883,977
Operating expenses	44,650	50,759	131,578	153,397
Real estate taxes	56,459	53,321	161,566	159,544
Operating lease rent	6,385	6,713	18,947	18,848
Interest expense, net of interest income	79,723	92,601	245,685	282,917
Amortization of deferred financing costs	5,575	4,436	15,197	14,434
Depreciation and amortization	103,262	100,736	300,700	308,748
Total expenses	296,054	308,566	873,673	937,888
Loss on early extinguishment of debt	0	(1,031)	0	(1,031)
Net loss before gain on sale	(3,125)	(23,587)	(26,706)	(54,942)
Company's equity in net (loss) income from unconsolidated joint ventures	(432)	(9,864)	(15,445)	(22,644)
Management Service, Base | Joint venture
Investment in Unconsolidated Joint Ventures
Escalation and reimbursement	$ 2,200	$ 2,400	$ 6,100	$ 8,800

Deferred Costs (Details)

Deferred Costs (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Deferred leasing costs	$ 496,812	$ 466,136
Less: accumulated amortization	(290,523)	(260,853)
Deferred costs, net	$ 206,289	$ 205,283

Mortgages and Other Loans Pay_3

Mortgages and Other Loans Payable (Details)	1 Months Ended	9 Months Ended
	Jun. 30, 2020	Sep. 30, 2020USD ($)extension	Jan. 31, 2020	Dec. 31, 2019USD ($)	Apr. 30, 2018USD ($)	Mar. 31, 2018USD ($)
Debt Instrument [Line Items]
Total fixed rate debt		$ 1,086,141,000		$ 1,383,449,000
Total floating rate debt		1,338,581,000		828,434,000
Total mortgages and other loans payable		2,424,722,000		2,211,883,000
Deferred financing costs, net of amortization		(32,978,000)		(28,630,000)
Total mortgages and other loans payable, net		2,391,744,000		2,183,253,000
Liabilities held for sale		0		0
Book value of collateral		3,200,000,000		3,300,000,000
Outstanding under line of credit facility		184,840,000		234,013,000
FHLB Facility, January 2021, 1
Debt Instrument [Line Items]
Total floating rate debt		$ 10,000,000		0
FHLB Facility, January 2021, 1 | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		0.28%
FHLB Facility, January 2021, 2
Debt Instrument [Line Items]
Total floating rate debt		$ 15,000,000		0
FHLB Facility, January 2021, 2 | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		0.23%
FHLB Facility January 2021
Debt Instrument [Line Items]
Total floating rate debt		$ 35,000,000		0
FHLB Facility January 2021 | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		0.18%
2017 Master Repurchase Agreement
Debt Instrument [Line Items]
Total floating rate debt		$ 0		152,684,000
Maximum facility capacity		$ 400,000,000			$ 400,000,000	$ 300,000,000
Extension option exercised, term	1 year	1 year
Outstanding under line of credit facility		$ 0
FHLB Facility January 2020
Debt Instrument [Line Items]
Total floating rate debt		0		10,000,000
FHLB Facility June 2020
Debt Instrument [Line Items]
Total floating rate debt		0		15,000,000
FHLB Facility, February 2020
Debt Instrument [Line Items]
Total floating rate debt		0		14,500,000
100 Church Street
Debt Instrument [Line Items]
Total fixed rate debt		$ 206,013,000		209,296,000
100 Church Street | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		4.68%
420 Lexington Avenue
Debt Instrument [Line Items]
Total fixed rate debt		$ 295,355,000		299,165,000
420 Lexington Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		3.99%
Landmark Square
Debt Instrument [Line Items]
Total fixed rate debt		$ 100,000,000		100,000,000
Landmark Square | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		4.90%
485 Lexington Avenue
Debt Instrument [Line Items]
Total fixed rate debt		$ 450,000,000		450,000,000
485 Lexington Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		4.25%
1080 Amsterdam Avenue
Debt Instrument [Line Items]
Total fixed rate debt		$ 34,773,000		35,123,000
Total fixed rate debt		33,900,000
Subordinate loan		$ 900,000
1080 Amsterdam Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		3.59%
Term (in Years)		5 years
1080 Amsterdam Avenue | Mortgage loan | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		3.50%
1080 Amsterdam Avenue | Subordinate loan | Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)		7.00%
762 Madison Avenue
Debt Instrument [Line Items]
Total fixed rate debt		$ 0		771,000
315 West 33rd Street
Debt Instrument [Line Items]
Total fixed rate debt		0		250,000,000
400 East 58th Street
Debt Instrument [Line Items]
Total fixed rate debt				39,094,000
133 Greene Street
Debt Instrument [Line Items]
Total floating rate debt		$ 15,523,000		15,523,000
133 Greene Street | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		2.00%
106 Spring Street
Debt Instrument [Line Items]
Total floating rate debt		$ 38,025,000		38,025,000
106 Spring Street | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		2.50%
609 Fifth Avenue
Debt Instrument [Line Items]
Total floating rate debt		$ 57,651,000		53,773,000
609 Fifth Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		2.40%
185 Broadway
Debt Instrument [Line Items]
Total floating rate debt		$ 144,448,000		120,110,000
185 Broadway | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		2.85%
712 Madison Avenue
Debt Instrument [Line Items]
Total floating rate debt		$ 28,000,000		28,000,000
712 Madison Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		1.85%
220 East 42nd Street
Debt Instrument [Line Items]
Total floating rate debt		$ 510,000,000		0
220 East 42nd Street | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		2.75%
410 Tenth Avenue
Debt Instrument [Line Items]
Total floating rate debt		$ 434,934,000		330,819,000
410 Tenth Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		2.25%
719 Seventh Avenue
Debt Instrument [Line Items]
Total floating rate debt		$ 50,000,000		$ 50,000,000
719 Seventh Avenue | Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)		1.20%
Construction Loans | 185 Broadway
Debt Instrument [Line Items]
Term (in Years)		3 years
Maximum facility capacity		$ 225,000,000
Number of extension options | extension		2
Period of extension options		1 year
Construction Loans | 410 Tenth Avenue
Debt Instrument [Line Items]
Term (in Years)		3 years
Maximum facility capacity		$ 600,000,000
Number of extension options | extension		2
Period of extension options		1 year
LIBOR Plus 21 Basis Points | Ticonderoga Insurance Company
Debt Instrument [Line Items]
FHLB advances		$ 60,000,000
LIBOR Plus 21 Basis Points | Ticonderoga Insurance Company | LIBOR
Debt Instrument [Line Items]
Interest rate added to base rate (as a percent)		21.00%
762 Madison Avenue
Debt Instrument [Line Items]
Interest acquired			10.00%

Corporate Indebtedness - Additi

Corporate Indebtedness - Additional Information (Details)	9 Months Ended
	Sep. 30, 2020USD ($)extension	Dec. 31, 2019USD ($)
Corporate Indebtedness
Outstanding under line of credit facility	$ 184,840,000	$ 234,013,000
Term Loan B, Maturity November 21, 2024 | Term loan
Corporate Indebtedness
Credit facility, maximum borrowing capacity	$ 200,000,000
Term Loan B, Maturity November 21, 2024 | LIBOR | Term loan
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.00%
Term Loan B, Maturity November 21, 2024 | LIBOR | Minimum | Term loan
Corporate Indebtedness
Interest rate added to base rate (as a percent)	0.85%
Term Loan B, Maturity November 21, 2024 | LIBOR | Maximum | Term loan
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.65%
Revolving credit facility
Corporate Indebtedness
Facility fee (as a percent)	0.20%
Outstanding under line of credit facility	$ 190,000,000
Revolving credit facility | Minimum
Corporate Indebtedness
Facility fee (as a percent)	0.125%
Revolving credit facility | Maximum
Corporate Indebtedness
Facility fee (as a percent)	0.30%
Term loan
Corporate Indebtedness
Long-term debt, carrying value	$ 1,500,000,000
Term loan | Line of Credit
Corporate Indebtedness
Long-term debt, carrying value	1,500,000,000	1,500,000,000
2012 Credit Facility
Corporate Indebtedness
Letters of credit	26,000,000
Ability to borrow under line of credit facility	1,300,000,000
2012 Credit Facility | Line of Credit
Corporate Indebtedness
Long-term debt, carrying value	184,800,000	$ 234,000,000
Term Loan A, Maturity March 31, 2023 | Term loan
Corporate Indebtedness
Credit facility, maximum borrowing capacity	$ 1,300,000,000
Term Loan A, Maturity March 31, 2023 | LIBOR | Term loan
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.10%
Term Loan A, Maturity March 31, 2023 | LIBOR | Minimum | Term loan
Corporate Indebtedness
Interest rate added to base rate (as a percent)	0.90%
Term Loan A, Maturity March 31, 2023 | LIBOR | Maximum | Term loan
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.75%
Revolving credit facility | Revolving Credit Facility, Maturity March 31, 2022 | Line of Credit
Corporate Indebtedness
Credit facility, maximum borrowing capacity	$ 1,500,000,000
Number of extensions | extension	2
Term of extension	6 months
Maximum borrowing capacity, optional expansion	$ 4,500,000,000
Revolving credit facility | Revolving Credit Facility, Maturity March 31, 2022 | LIBOR | Line of Credit
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.00%
Revolving credit facility | Revolving Credit Facility, Maturity March 31, 2022 | LIBOR | Minimum | Line of Credit
Corporate Indebtedness
Interest rate added to base rate (as a percent)	0.825%
Revolving credit facility | Revolving Credit Facility, Maturity March 31, 2022 | LIBOR | Maximum | Line of Credit
Corporate Indebtedness
Interest rate added to base rate (as a percent)	1.55%

Corporate Indebtedness - Senior

Corporate Indebtedness - Senior Unsecured Notes (Details) - USD ($)	1 Months Ended	9 Months Ended
	Oct. 31, 2017	Sep. 30, 2020	Apr. 30, 2020	Dec. 31, 2019
Debt disclosures by scheduled maturity date
Accreted Balance		$ 1,494,793,000		$ 1,494,024,000
Senior unsecured notes
Debt disclosures by scheduled maturity date
Unpaid Principal Balance		1,250,000,000
Accreted Balance		1,252,127,000		1,502,837,000
Deferred financing costs, net		(4,332,000)		(5,990,000)
Accreted Balance, net of deferred financing costs		1,247,795,000		1,496,847,000
Senior unsecured notes | Senior Unsecured Notes Due August 2021
Debt disclosures by scheduled maturity date
Unpaid Principal Balance		350,000,000
Accreted Balance		$ 350,000,000		350,000,000
Coupon Rate (as a percent)		1.52%
Initial Term (in Years)		3 years
Redemption price, percentage		100.00%
Senior unsecured notes | 3.25 Percent Senior Unsecured Notes Due October 2022
Debt disclosures by scheduled maturity date
Unpaid Principal Balance		$ 500,000,000
Accreted Balance		$ 499,775,000		499,695,000
Coupon Rate (as a percent)		3.25%
Initial Term (in Years)		5 years
Senior unsecured notes | 4.50% Senior unsecured notes maturing on December 1, 2022
Debt disclosures by scheduled maturity date
Unpaid Principal Balance		$ 300,000,000
Accreted Balance		$ 302,352,000		303,142,000
Coupon Rate (as a percent)	4.50%	4.50%
Initial Term (in Years)		10 years
Face amount of loan	$ 100,000,000
Redemption price, percentage	105.334%
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%
Initial Term (in Years)		10 years
Senior unsecured notes | Senior Unsecured Note Due March 16, 2020
Debt disclosures by scheduled maturity date
Unpaid Principal Balance		$ 0
Accreted Balance		$ 0		$ 250,000,000
Interest Rate Swap | Senior Unsecured Notes Due August 2021
Debt disclosures by scheduled maturity date
Notional amount			$ 350,000,000
Derivative, fixed interest rate			0.54375%

Corporate Indebtedness - Junior

Corporate Indebtedness - Junior Subordinated Deferrable Interest Debentures and Principal Maturities (Details)	1 Months Ended	9 Months Ended
	Jun. 30, 2005USD ($)	Sep. 30, 2020USD ($)quarter
Principal Repayments and Joint Venture Debt
Remaining 2020		$ 18,158,000
2021		631,240,000
2022		1,064,214,000
2023		2,491,542,000
2024		478,043,000
Thereafter		781,525,000
Total principal repayments		$ 5,464,722,000
Trust Preferred Securities
Debt Instrument [Line Items]
Proceeds from issuance of debt	$ 100,000,000
LIBOR | Trust Preferred Securities
Debt Instrument [Line Items]
Interest rate added to base rate (as a percent)		1.25%
Interest payment deferment, number of consecutive quarters | quarter		8
Joint venture
Principal Repayments and Joint Venture Debt
Remaining 2020		$ 10,867,000
2021		1,444,277,000
2022		268,952,000
2023		311,436,000
2024		618,140,000
Thereafter		1,935,202,000
Total principal repayments		4,588,874,000
Joint venture | Trust Preferred Securities
Principal Repayments and Joint Venture Debt
Remaining 2020		0
2021		0
2022		0
2023		0
2024		0
Thereafter		100,000,000
Total principal repayments		100,000,000
Joint venture | Mortgages and other loans payable
Scheduled Amortization
Remaining 2020		2,635,000
2021		10,766,000
2022		8,779,000
2023		6,608,000
2024		5,294,000
Thereafter		1,779,000
Total amortization of debt		35,861,000
Principal Repayments and Joint Venture Debt
Remaining 2020		15,523,000
2021		270,474,000
2022		255,435,000
2023		994,934,000
2024		272,749,000
Thereafter		579,746,000
Total principal repayments		2,388,861,000
Joint venture | Revolving Credit Facility
Principal Repayments and Joint Venture Debt
Remaining 2020		0
2021		0
2022		0
2023		190,000,000
2024		0
Thereafter		0
Total principal repayments		190,000,000
Joint venture | Unsecured Term Loans
Principal Repayments and Joint Venture Debt
Remaining 2020		0
2021		0
2022		0
2023		1,300,000,000
2024		200,000,000
Thereafter		0
Total principal repayments		1,500,000,000
Joint venture | Senior Unsecured Notes
Principal Repayments and Joint Venture Debt
Remaining 2020		0
2021		350,000,000
2022		800,000,000
2023		0
2024		0
Thereafter		100,000,000
Total principal repayments		$ 1,250,000,000

Corporate Indebtedness - Schedu

Corporate Indebtedness - Schedule of Consolidated Interest Expense, Excluding Capitalized Interest (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Interest expense
Interest expense before capitalized interest	$ 42,595	$ 63,607	$ 144,345	$ 185,163
Interest on financing leases	2,198	813	6,010	2,425
Interest capitalized	(20,677)	(15,700)	(57,528)	(38,228)
Interest income	(580)	(608)	(1,727)	(3,563)
Interest expense, net	$ 23,536	$ 48,112	$ 91,100	$ 145,797

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Dec. 31, 2016	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Amounts due from/to related parties
Due from joint ventures		$ 24,912		$ 24,912		$ 9,352
Other		7,024		7,024		11,769
Related party receivables		31,936		31,936		$ 21,121
Alliance Building Services
Related Party Transactions
Profit participation from related party		100	$ 900	1,100	$ 2,700
Payments made for services		3,000	5,600	9,700	14,100
Entity with Stephen L Green ownership interest
Related Party Transactions
Property management fees from related party		100	$ 200	400	$ 500
One Vanderbilt | Marc Holliday
Related Party Transactions
Due from related party		1,400		1,400
One Vanderbilt | Andrew Mathias
Related Party Transactions
Due from related party		$ 1,000		$ 1,000
One Vanderbilt | Minimum | Marc Holliday
Related Party Transactions
Percentage of profits due to investors (as a percentage)	1.50%
One Vanderbilt | Minimum | Andrew Mathias
Related Party Transactions
Percentage of profits due to investors (as a percentage)	1.00%
One Vanderbilt | Maximum | Marc Holliday
Related Party Transactions
Percentage of profits due to investors (as a percentage)	1.80%
One Vanderbilt | Maximum | Andrew Mathias
Related Party Transactions
Percentage of profits due to investors (as a percentage)	1.20%

Noncontrolling Interests on t_3

Noncontrolling Interests on the Company's Consolidated Financial Statements - Additional Information (Details) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020USD ($)shares$ / shares	Sep. 30, 2019USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2019USD ($)	Sep. 30, 2020USD ($)shares$ / shares	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)shares
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Redemption and conversion of common units | $	$ 0	$ (54)	$ (1,536)	$ (25,791)
Net income | $	802	1,719			$ 10,073	$ 12,306
Accumulated other comprehensive loss allocation | $	317	(607)			(2,664)	(2,869)
Partnership Interest
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Balance at beginning of period | $			409,862	387,805	409,862	387,805	$ 387,805
Distributions | $					(8,857)		(14,729)
Issuance of common units | $					7,976		19,403
Redemption and conversion of common units | $					(27,657)		(27,962)
Net income | $					10,073		13,301
Accumulated other comprehensive loss allocation | $					(2,664)		(2,276)
Fair value adjustment | $					(35,253)		34,320
Balance at end of period | $	$ 353,480				$ 353,480		$ 409,862
SL Green Operating Partnership
Organization
Number of units of operating partnership owned by the noncontrolling interest unit holders (shares)	4,027,317				4,027,317		4,195,875
Shares of common stock reserved for issuance upon redemption of units of limited partnership interest in operating partnership (shares)	4,027,317				4,027,317
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Redemption and conversion of common units | $	$ 0	(54)	$ (1,536)	$ (25,791)
Accumulated other comprehensive loss allocation | $	$ 317	$ (607)			$ (2,664)	$ (2,869)
SL Green Operating Partnership | 3.50% Series A
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Dividend rate preferred units (as a percent)					3.50%
Preferred units, shares authorized (in shares)	109,161				109,161
Number of preferred units issued (in shares)	109,161				109,161
Number of Units Outstanding (in shares)	109,161				109,161
Annual dividends on preferred units (in dollars per share) | $ / shares					$ 35
Liquidation preference of preferred units (in dollars per share) | $ / shares	$ 1,000				1,000
Operating partnership common stock value use for conversion of preferred units (in dollars per share) | $ / shares	$ 0				$ 0
Number of company common stock issued on conversion of Series B preferred units					6.71348
SL Green Operating Partnership | 7.00% Series F
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Dividend rate preferred units (as a percent)					7.00%
Preferred units, shares authorized (in shares)	60				60
Number of preferred units issued (in shares)	60				60
Number of Units Outstanding (in shares)	60				60
Annual dividends on preferred units (in dollars per share) | $ / shares					$ 70
Liquidation preference of preferred units (in dollars per share) | $ / shares	$ 1,000				1,000
Operating partnership common stock value use for conversion of preferred units (in dollars per share) | $ / shares	$ 29.12				$ 29.12
SL Green Operating Partnership | 4.50% Series G
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Dividend rate preferred units (as a percent)					4.50%
Preferred units, shares authorized (in shares)	1,902,000				1,902,000
Number of preferred units issued (in shares)	1,902,000				1,902,000
Number of Units Outstanding (in shares)	863,972				863,972
Annual dividends on preferred units (in dollars per share) | $ / shares					$ 1.1250
Liquidation preference of preferred units (in dollars per share) | $ / shares	$ 25				25
Operating partnership common stock value use for conversion of preferred units (in dollars per share) | $ / shares	$ 88.50				$ 88.50
Number of company common stock issue on redemption of operation partnership common units					1
SL Green Operating Partnership | 3.50% Series K
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Dividend rate preferred units (as a percent)					3.50%
Preferred units, shares authorized (in shares)	700,000				700,000
Number of preferred units issued (in shares)	563,954				563,954
Number of Units Outstanding (in shares)	341,677				341,677
Annual dividends on preferred units (in dollars per share) | $ / shares					$ 0.8750
Liquidation preference of preferred units (in dollars per share) | $ / shares	$ 25				25
Operating partnership common stock value use for conversion of preferred units (in dollars per share) | $ / shares	$ 134.67				$ 134.67
SL Green Operating Partnership | 4.00% Series L
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Dividend rate preferred units (as a percent)					4.00%
Preferred units, shares authorized (in shares)	500,000				500,000
Number of preferred units issued (in shares)	378,634				378,634
Number of Units Outstanding (in shares)	372,634				372,634
Annual dividends on preferred units (in dollars per share) | $ / shares					$ 1
Liquidation preference of preferred units (in dollars per share) | $ / shares	$ 25				25
Operating partnership common stock value use for conversion of preferred units (in dollars per share) | $ / shares	$ 0				$ 0
SL Green Operating Partnership | 3.75% Series M
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Dividend rate preferred units (as a percent)					3.75%
Preferred units, shares authorized (in shares)	1,600,000				1,600,000
Number of preferred units issued (in shares)	1,600,000				1,600,000
Number of Units Outstanding (in shares)	96,357				96,357
Annual dividends on preferred units (in dollars per share) | $ / shares					$ 0.9375
Liquidation preference of preferred units (in dollars per share) | $ / shares	$ 25				25
Operating partnership common stock value use for conversion of preferred units (in dollars per share) | $ / shares	$ 0				$ 0
SL Green Operating Partnership | 4.00% Series P
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Dividend rate preferred units (as a percent)					4.00%
Preferred units, shares authorized (in shares)	200,000				200,000
Number of preferred units issued (in shares)	200,000				200,000
Number of Units Outstanding (in shares)	200,000				200,000
Annual dividends on preferred units (in dollars per share) | $ / shares					$ 1
Liquidation preference of preferred units (in dollars per share) | $ / shares	$ 25				25
Operating partnership common stock value use for conversion of preferred units (in dollars per share) | $ / shares	$ 0				$ 0
SL Green Operating Partnership | 3.50% Series Q
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Dividend rate preferred units (as a percent)					3.50%
Preferred units, shares authorized (in shares)	268,000				268,000
Number of preferred units issued (in shares)	268,000				268,000
Number of Units Outstanding (in shares)	268,000				268,000
Annual dividends on preferred units (in dollars per share) | $ / shares					$ 0.8750
Liquidation preference of preferred units (in dollars per share) | $ / shares	$ 25				25
Operating partnership common stock value use for conversion of preferred units (in dollars per share) | $ / shares	$ 148.95				$ 148.95
SL Green Operating Partnership | 3.50% Series R
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Dividend rate preferred units (as a percent)					3.50%
Preferred units, shares authorized (in shares)	400,000				400,000
Number of preferred units issued (in shares)	400,000				400,000
Number of Units Outstanding (in shares)	400,000				400,000
Annual dividends on preferred units (in dollars per share) | $ / shares					$ 0.8750
Liquidation preference of preferred units (in dollars per share) | $ / shares	$ 25				25
Operating partnership common stock value use for conversion of preferred units (in dollars per share) | $ / shares	$ 154.89				$ 154.89
SL Green Operating Partnership | 4.00% Series S
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Dividend rate preferred units (as a percent)					4.00%
Preferred units, shares authorized (in shares)	1,077,280				1,077,280
Number of preferred units issued (in shares)	1,077,280				1,077,280
Number of Units Outstanding (in shares)	1,077,280				1,077,280
Annual dividends on preferred units (in dollars per share) | $ / shares					$ 1
Liquidation preference of preferred units (in dollars per share) | $ / shares	$ 25				25
Operating partnership common stock value use for conversion of preferred units (in dollars per share) | $ / shares	$ 0				$ 0
SL Green Operating Partnership | 3.50% Series V
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Dividend rate preferred units (as a percent)					3.50%
Preferred units, shares authorized (in shares)	40,000				40,000
Number of preferred units issued (in shares)	40,000				40,000
Number of Units Outstanding (in shares)	40,000				40,000
Annual dividends on preferred units (in dollars per share) | $ / shares					$ 0.8750
Liquidation preference of preferred units (in dollars per share) | $ / shares	$ 25				25
Operating partnership common stock value use for conversion of preferred units (in dollars per share) | $ / shares	$ 0				$ 0
SL Green Operating Partnership | Series W
Rollforward analysis of the activity relating to the noncontrolling interests in the operating partnership
Preferred units, shares authorized (in shares)	1				1
Number of preferred units issued (in shares)	1				1
Number of Units Outstanding (in shares)	1				1
Operating partnership common stock value use for conversion of preferred units (in dollars per share) | $ / shares	$ 0				$ 0
Preferred stock, dividend, multiplier per common unit distribution					1,350
Operating Partnership | SL Green Operating Partnership
Organization
Noncontrolling interest in the operating partnership (as a percent)	5.23%				5.23%		5.03%

Noncontrolling Interests on t_4

Noncontrolling Interests on the Company's Consolidated Financial Statements - Common Unit Activity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		9 Months Ended	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Sep. 30, 2020	Dec. 31, 2019
Rollforward Analysis of Preferred Unit Activity
Redemption of preferred units	$ 0	$ (54)	$ (1,536)	$ (25,791)
SL Green Operating Partnership
Rollforward Analysis of Preferred Unit Activity
Redemption of preferred units	0	$ (54)	(1,536)	(25,791)
SL Green Operating Partnership | Preferred Units
Rollforward Analysis of Preferred Unit Activity
Balance at beginning of period			$ 283,285	$ 300,427	$ 283,285	$ 300,427
Issuance of preferred units					0	1,000
Redemption of preferred units					(82,750)	(18,142)
Accrued dividends on preferred units					1,634	0
Balance at end of period	$ 202,169				$ 202,169	$ 283,285

Stockholders' Equity of the C_3

Stockholders' Equity of the Company - Additional Information (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2020USD ($)increase$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2017USD ($)$ / sharesshares	Jun. 30, 2020shares	Sep. 30, 2019shares	Jun. 30, 2019shares	Jun. 30, 2018USD ($)	Aug. 31, 2016USD ($)
Equity, Class of Treasury Stock [Line Items]
Authorized capital stock (shares)	260,000,000
Authorized shares, par value (in dollars per share) | $ / shares	$ 0.01
Common stock, shares authorized (in shares)	160,000,000	160,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.01	$ 0.01
Excess stock, shares authorized (shares)	75,000,000
Excess stock, par value (in dollars per share) | $ / shares	$ 0.01
Preferred stock, shares authorized (shares)	25,000,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.01
Excess shares issued (shares)	0
Share repurchased (in shares)	6,243,165	4,596,171	9,744,911	8,342,411
Average price paid per share (in dollars per share) | $ / shares	$ 62.77	$ 83.62	$ 96.22	$ 101.64
2016 Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount | $		$ 500,000,000	$ 500,000,000	$ 500,000,000				$ 500,000,000	$ 1,000,000,000
Number of increases to share repurchase program | increase	4
Share repurchased (in shares)	28,926,658	22,683,493	18,087,322	8,342,411
Stock repurchase program, authorized amount | $	$ 3,000,000,000
Settled In July 2020
Equity, Class of Treasury Stock [Line Items]
Share repurchased (in shares)	216,101
Common Stock
Equity, Class of Treasury Stock [Line Items]
Shares, outstanding (in shares)	73,040,000	79,202,000	83,684,000		73,675,000	81,515,000	82,410,000
SL Green Operating Partnership | Common Stock
Equity, Class of Treasury Stock [Line Items]
Shares, outstanding (in shares)	73,040,291

Stockholders' Equity of the C_4

Stockholders' Equity of the Company - Perpetual Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	9 Months Ended
	Aug. 31, 2012	Sep. 30, 2020	Dec. 31, 2019	Feb. 28, 2018
Stockholders' Equity
Common stock, shares authorized (in shares)		160,000,000	160,000,000
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	$ 221.9
Dividend Reinvestment and Stock Purchase Plan (DRIP)
Stockholders' Equity
Common stock, shares authorized (in shares)				3,500,000

Stockholders' Equity of the C_5

Stockholders' Equity of the Company - Schedule of Common Stock Issued and Proceeds Received Dividend Reinvestments (Details) - Dividend Reinvestment and Stock Purchase Plan (DRIP) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Stockholders' Equity
Issuance of common stock (in shares)	4,205	490	9,884	3,485
Dividend reinvestments/stock purchases under the DRSPP	$ 202	$ 39	$ 566	$ 303

Stockholders' Equity of the C_6

Stockholders' Equity of the Company - Earnings per Share (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Basic Earnings:
Income attributable to SL Green common stockholders	$ 13,859	$ 33,157	$ 185,104	$ 238,052
Less: distributed earnings allocated to participating securities	(333)	(108)	(777)	(325)
Less: undistributed earnings allocated to participating securities	0	0	(141)	(41)
Net Income attributable to common unitholders (numerator for basic earnings per unit)	13,526	33,049	184,186	237,686
Effect of Dilutive Securities:
Add back: dilutive effect of earnings allocated to participating securities	333	108	777	325
Add back: undistributed earnings allocated to participating securities	0	0	141	41
Redemption of units to common shares	802	1,719	10,073	12,306
Diluted Earnings:
Income attributable to SL Green common stockholders	$ 14,661	$ 34,876	$ 195,177	$ 250,358
Basic Shares:
Weighted average common shares outstanding (shares)	73,020,000	82,292,000	75,521,000	82,855,000
Effect of Dilutive Securities:
Operating Partnership units redeemable for common shares (shares)	4,029,000	4,258,000	4,123,000	4,283,000
Stock-based compensation plans (shares)	442,000	164,000	441,000	171,000
Diluted weighted average common stock outstanding (shares)	77,491,000	86,714,000	80,085,000	87,309,000
Common stock shares excluded from the diluted shares outstanding (shares)	2,131,606		1,779,212

Partners' Capital of the Oper_3

Partners' Capital of the Operating Partnership - Additional Information (Details) - shares	9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Common Stock
Stockholders' Equity
Units outstanding (units)	73,040,000	73,675,000	79,202,000	81,515,000	82,410,000	83,684,000
SL Green Operating Partnership
Stockholders' Equity
Number of units of operating partnership owned by the noncontrolling interest unit holders (units)	4,027,317		4,195,875
SL Green Operating Partnership | Series I Preferred Units
Stockholders' Equity
Units outstanding (units)	9,200,000
Period of restriction to redeem OP Units	1 year
Conversion of stock, shares issued	1
SL Green Operating Partnership | Common Stock
Stockholders' Equity
Units outstanding (units)	73,040,291

Partners' Capital of the Oper_4

Partners' Capital of the Operating Partnership - EPS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator
Less: distributed earnings allocated to participating securities	$ (333)	$ (108)	$ (777)	$ (325)
Less: undistributed earnings allocated to participating securities	0	0	(141)	(41)
Net Income attributable to common unitholders (numerator for basic earnings per unit)	13,526	33,049	184,186	237,686
Add back: dilutive effect of earnings allocated to participating securities	(333)	(108)	(777)	(325)
Add back: undistributed earnings allocated to participating securities	0	0	(141)	(41)
Income attributable to SL Green common stockholders	$ 14,661	34,876	$ 195,177	250,358
Denominator
Common stock shares excluded from the diluted shares outstanding (shares)	2,131,606		1,779,212
SL Green Operating Partnership
Numerator
Net income attributable to SLGOP common unitholders	$ 14,661	34,876	$ 195,177	250,358
Less: distributed earnings allocated to participating securities	(333)	(108)	(777)	(325)
Less: undistributed earnings allocated to participating securities	0	0	(141)	(41)
Net Income attributable to common unitholders (numerator for basic earnings per unit)	14,328	34,768	194,259	249,992
Add back: dilutive effect of earnings allocated to participating securities	333	108	777	325
Add back: undistributed earnings allocated to participating securities	0	0	141	41
Income attributable to SL Green common stockholders	$ 14,661	$ 34,876	$ 195,177	$ 250,358
Denominator
Basic weighted average common units outstanding (in shares)	77,049,000	86,550,000	79,644,000	87,138,000
Stock-based compensation plans (shares)	442,000	164,000	441,000	171,000
Diluted weighted average common units outstanding (shares)	77,491,000	86,714,000	80,085,000	87,309,000
Common stock shares excluded from the diluted shares outstanding (shares)	2,131,606	1,317,803	1,779,212	1,266,296

Share-based Compensation - Addi

Share-based Compensation - Additional Information (Details) fungible_unit in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020USD ($)unit / sharesfungible_unitunitshares	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)unit / sharesfungible_unitunitshares	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)shares	Dec. 31, 2018shares	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	$ 600,000	$ 500,000	$ 1,700,000	$ 1,400,000
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
Options granted (in shares) | shares			0		0
Remaining weighted average contractual life of the options outstanding (in years)			2 years
Remaining average contractual life of the options exercisable (in years)			2 years
Total unrecognized compensation cost related to unvested stock awards	$ 10,000		$ 10,000
Weighted average period for recognition of compensation cost related to unvested stock awards (in years)			6 months
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
Class O LTIP Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred unit distributions as a percentage of common unit distributions	10.00%		10.00%
Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense			$ 8,528,991		$ 12,892,249
Total unrecognized compensation cost related to unvested stock awards	$ 11,000,000		$ 11,000,000
Weighted average period for recognition of compensation cost related to unvested stock awards (in years)			1 year 6 months
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			$ 12,500,000		12,100,000
Weighted average fair value of options granted during the period			$ 734,315		$ 11,131,181
Awards granted (in shares) | shares			9,220		126,350
Awards outstanding (in shares) | shares	3,549,643		3,549,643		3,566,466	3,452,016
LTIP units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value of options granted during the period			$ 33,700,000		$ 58,300,000
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 6,400,000	3,000,000	20,400,000	14,000,000
Total unrecognized compensation cost related to unvested stock awards	$ 41,800,000		$ 41,800,000
Weighted average period for recognition of compensation cost related to unvested stock awards (in years)			2 years
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) | 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	3.4		3.4
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	$ 0	600,000	$ 30,000	1,800,000
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
Deferred Stock Compensation Plan for Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 200,000	$ 200,000	$ 2,100,000	$ 2,200,000
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			18,167
Shares issued (in shares) | shares			8,285
Awards outstanding (in shares) | shares	138,189		138,189
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
Discount from market price			85.00%
Shares of common stock issued (shares) | shares	152,690		152,690

Share-based Compensation - Stoc

Share-based Compensation - Stock Options and Restricted Stock Activity (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Stock options
Options Outstanding
Balance at beginning of period (in shares)	1,037,068	1,137,017
Granted (in shares)	0	0
Exercised (in shares)	0	0
Lapsed or cancelled (in shares)	(53,700)	(99,949)
Balance at end of period (in shares)	983,368	1,037,068
Options exercisable at end of period (in shares)	982,368	914,929
Weighted Average Exercise Price
Balance at beginning of year (in dollars per share)	$ 102.36	$ 103.54
Granted (in dollars per share)	0	0
Exercised (in dollars per share)	0	0
Lapsed or cancelled (in dollars per share)	111.18	115.81
Balance at end of period (in dollars per share)	101.88	102.36
Options exercisable at end of period (in dollars per share)	$ 101.88	$ 101.69
Restricted Stock Awards
Options Outstanding
Total fair value of options granted during the period	$ 734,315	$ 11,131,181
Summary of restricted stock
Balance at beginning of year (in shares)	3,566,466	3,452,016
Granted (in shares)	9,220	126,350
Cancelled (in shares)	(26,043)	(11,900)
Balance at end of period (in shares)	3,549,643	3,566,466
Vested during the period (in shares)	132,652	113,259

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	$ 5,517,198
Other comprehensive loss before reclassifications	(60,039)
Amounts reclassified from accumulated other comprehensive loss	12,324
Ending Balance	5,134,005
Deferred net losses from terminated hedges	(500)	$ (700)
Net unrealized (loss) gain on derivative instruments
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	(22,780)
Other comprehensive loss before reclassifications	(50,038)
Amounts reclassified from accumulated other comprehensive loss	9,120
Ending Balance	(63,698)
Net unrealized gain (loss) on marketable securities
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	2,277
Other comprehensive loss before reclassifications	(2,047)
Amounts reclassified from accumulated other comprehensive loss	0
Ending Balance	230
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	(28,485)
Ending Balance	(76,200)
Joint venture | Net unrealized (loss) gain on derivative instruments
Accumulated Other Comprehensive Income (Loss) of the Company [Roll Forward]
Beginning Balance	(7,982)
Other comprehensive loss before reclassifications	(7,954)
Amounts reclassified from accumulated other comprehensive loss	3,204
Ending Balance	$ (12,732)

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Fair Value of Financial Instruments
Marketable securities	$ 27,734		$ 27,734		$ 29,887
Interest rate cap and swap agreements (included in other assets)	39		39		4,419
Purchase price and other fair value adjustments	0	$ 3,799	0	$ 69,389
Debt and preferred equity investments	1,153,363		1,153,363		1,580,306
Equity method investments	2,946,673		2,946,673		2,912,842
Additional amount of financing receivables included in other assets	110,900		110,900		131,100
Carrying Value
Fair Value of Financial Instruments
Debt and preferred equity investments	1,153,363		1,153,363		1,580,306
Fixed rate debt	3,338,268		3,338,268		3,536,286
Variable rate debt	2,128,581		2,128,581		2,018,434
Total	5,466,849		5,466,849		5,554,720
Fair Value
Fair Value of Financial Instruments
Marketable securities	27,734		27,734		29,887
Total	5,540,320		5,540,320		5,661,484
Estimated fair value of debt and preferred equity investments, low end of range	1,040,000		1,040,000		1,580,000
Estimated fair value of debt and preferred equity investments, high end of range	1,150,000		1,150,000		1,740,000
Level 1
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in other assets)	0		0		0
Level 2
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in other assets)	39		39		4,419
Level 3
Fair Value of Financial Instruments
Marketable securities	0		0		0
Interest rate cap and swap agreements (included in other assets)	0		0		0
Level 3 | Fair Value
Fair Value of Financial Instruments
Fixed rate debt	3,427,731		3,427,731		3,642,770
Variable rate debt	2,112,589		2,112,589		2,018,714
Equity marketable securities | Level 1
Fair Value of Financial Instruments
Marketable securities	0		0		0
Commercial mortgage-backed securities
Fair Value of Financial Instruments
Marketable securities	27,734		27,734		29,887
Commercial mortgage-backed securities | Level 2
Fair Value of Financial Instruments
Marketable securities	27,734		27,734		29,887
Joint venture
Fair Value of Financial Instruments
Equity method investments	2,946,673		2,946,673		2,912,842
Accrued Interest Payable And Other
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in other liabilities)	67,680		67,680		29,110
Accrued Interest Payable And Other | Level 1
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in other liabilities)	0		0		0
Accrued Interest Payable And Other | Level 2
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in other liabilities)	67,680		67,680		29,110
Accrued Interest Payable And Other | Level 3
Fair Value of Financial Instruments
Interest rate cap and swap agreements (included in other liabilities)	$ 0		$ 0		$ 0

Financial Instruments_ Deriva_3

Financial Instruments: Derivatives and Hedging (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Financial Instruments: Derivatives and Hedging
Fair Value	$ 39,000		$ 39,000		$ 4,419,000
Gain (loss) from changes in fair value	0	$ 0	0	$ 0
Fair value of derivatives in a net liability position	68,900,000		68,900,000
Aggregate termination value	70,200,000		70,200,000
Estimated current balance held in accumulated other comprehensive loss to be reclassified into earnings within the next 12 months			17,700,000
Share of joint venture of accumulated other comprehensive loss reclassified into equity in net income from unconsolidated joint ventures within the next 12 months			7,400,000
Amount of Loss Recognized in Other Comprehensive Loss	(517,000)	(12,606,000)	(61,183,000)	(54,971,000)
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income	(6,616,000)	(297,000)	(12,957,000)	1,599,000
Interest Rate Swap Expiring November 2020
Financial Instruments: Derivatives and Hedging
Notional Value	$ 100,000,000		$ 100,000,000
Strike Rate	1.928%		1.928%
Fair Value	$ (295,000)		$ (295,000)
Interest Rate Swap Expiring November 2020, 2
Financial Instruments: Derivatives and Hedging
Notional Value	$ 100,000,000		$ 100,000,000
Strike Rate	1.934%		1.934%
Fair Value	$ (296,000)		$ (296,000)
Interest Rate Swap Expiring December 2020
Financial Instruments: Derivatives and Hedging
Notional Value	$ 111,869,000		$ 111,869,000
Strike Rate	3.50%		3.50%
Fair Value	$ 0		$ 0
Interest Rate Cap Expiring March 2021
Financial Instruments: Derivatives and Hedging
Notional Value	$ 85,000,000		$ 85,000,000
Strike Rate	4.00%		4.00%
Fair Value	$ 0		$ 0
Interest Rate Swap Expiring August 2021
Financial Instruments: Derivatives and Hedging
Notional Value	$ 350,000,000		$ 350,000,000
Strike Rate	0.544%		0.544%
Fair Value	$ (978,000)		$ (978,000)
Interest Rate Cap Expiring December 2021
Financial Instruments: Derivatives and Hedging
Notional Value	$ 510,000,000		$ 510,000,000
Strike Rate	3.00%		3.00%
Fair Value	$ 1,000		$ 1,000
Interest Rate Swap Expiring in July 2023
Financial Instruments: Derivatives and Hedging
Notional Value	$ 200,000,000		$ 200,000,000
Strike Rate	1.131%		1.131%
Fair Value	$ (5,599,000)		$ (5,599,000)
Interest Rate Swap Expiring in July 2023, 2
Financial Instruments: Derivatives and Hedging
Notional Value	$ 100,000,000		$ 100,000,000
Strike Rate	1.161%		1.161%
Fair Value	$ (2,883,000)		$ (2,883,000)
Interest Rate Cap Expiring September 2023
Financial Instruments: Derivatives and Hedging
Notional Value	$ 600,000,000		$ 600,000,000
Strike Rate	4.00%		4.00%
Fair Value	$ 38,000		$ 38,000
Interest Rate Swap Expiring January 2024
Financial Instruments: Derivatives and Hedging
Notional Value	$ 150,000,000		$ 150,000,000
Strike Rate	2.696%		2.696%
Fair Value	$ (12,430,000)		$ (12,430,000)
Interest Rate Swap Expiring January 2026
Financial Instruments: Derivatives and Hedging
Notional Value	$ 150,000,000		$ 150,000,000
Strike Rate	2.721%		2.721%
Fair Value	$ (19,286,000)		$ (19,286,000)
Interest Rate Swap Expiring January 2026, 2
Financial Instruments: Derivatives and Hedging
Notional Value	$ 200,000,000		$ 200,000,000
Strike Rate	2.74%		2.74%
Fair Value	$ (25,913,000)		$ (25,913,000)
Interest Rate Contract
Financial Instruments: Derivatives and Hedging
Fair Value	(67,641,000)		(67,641,000)
Interest Rate Swaps/Caps
Financial Instruments: Derivatives and Hedging
Amount of Loss Recognized in Other Comprehensive Loss	(318,000)	(10,169,000)	(52,808,000)	(43,008,000)
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income	(5,162,000)	(105,000)	(9,610,000)	886,000
Joint venture
Financial Instruments: Derivatives and Hedging
Amount of Loss Recognized in Other Comprehensive Loss	(199,000)	(2,437,000)	(8,375,000)	(11,963,000)
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income	$ (1,454,000)	$ (192,000)	$ (3,347,000)	$ 713,000

Rental Income - Lease Income (D

Rental Income - Lease Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Leases [Abstract]
Fixed lease payments	$ 171,866	$ 214,282	$ 538,601	$ 641,007
Variable lease payments	21,979	32,581	70,892	88,539
Total lease payments	193,845	246,863	609,493	729,546
Amortization of acquired above and below-market leases	1,670	1,165	4,539	3,559
Total rental revenue	195,515	248,028	614,032	733,105
Loss recognized at commencement, net(1)	(5,973)	0	(5,973)	0
Interest income(2)	484	0	484	0
Total loss recognized on sales-type leases	$ (5,489)	$ 0	$ (5,489)	$ 0

Commitments and Contingencies_2

Commitments and Contingencies (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Operating leases, minimum lease term	1 year
Operating lease, weighted average discount rate, percent	7.98%
Operating lease, weighted average remaining lease term	32 years
Financing leases
Remaining 2020	$ 1,974
2021	34,885
2022	5,881
2023	5,927
2024	5,999
2025	6,266
Thereafter	1,018,013
Total minimum lease payments	1,078,945
Amount representing interest	(903,962)
Lease liabilities	174,983	$ 44,448
Operating leases
Remaining 2020	7,363
2021	29,452
2022	27,148
2023	24,844
2024	24,863
2025	24,962
Thereafter	618,326
Total minimum lease payments	756,958
Amount discounted using incremental borrowing rate	(398,539)
Lease liabilities	358,419	$ 381,671
Total minimum sublease rentals to be received	$ 1,700,000
711 Third Avenue
Lessee, Lease, Description [Line Items]
Ownership Interest	50.00%

Commitments and Contingencies -

Commitments and Contingencies - Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Operating Lease Costs
Operating lease costs before capitalized operating lease costs	$ 7,751	$ 8,315	$ 24,486	$ 24,918
Operating lease costs capitalized	(778)	(20)	(2,315)	(27)
Operating Lease, Cost	6,973	8,295	22,171	24,891
Finance Lease, Costs [Abstract]
Interest on financing leases before capitalized interest	2,198	813	6,010	2,425
Interest on financing leases capitalized	(588)	0	(2,378)	0
Interest on financing leases, net	1,610	813	3,632	2,425
Amortization of right-of-use assets	304	304	914	914
Financing lease costs, net	$ 1,914	$ 1,117	$ 4,546	$ 3,339

Segment Information - Additiona

Segment Information - Additional Information (Details) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)segment	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)
Segment information
Number of reportable segments | segment				2
Total revenues		$ 249,844	$ 313,634	$ 817,846	$ 930,913
Net income		20,677	40,722	214,418	267,232
Total assets	[1]	12,324,039		12,324,039		$ 12,766,320
Marketing, general and administrative		23,602	23,841	66,682	75,300
Operating Segments | Real Estate Segment
Segment information
Total revenues		226,856	262,115	716,382	777,745
Net income		10,097	6,133	161,388	168,639
Total assets		11,079,252		11,079,252		11,063,155
Operating Segments | Debt and Preferred Equity Segment
Segment information
Total revenues		22,988	51,519	101,464	153,168
Net income		10,580	$ 34,589	53,030	$ 98,593
Total assets		$ 1,244,787		$ 1,244,787		$ 1,703,165
[1]	The Company's consolidated balance sheets include assets and liabilities of consolidated variable interest entities ("VIEs"). See Note 2. The consolidated balance sheets include the following amounts related to our consolidated VIEs, excluding the Operating Partnership: $375.9 million and $205.2 million of land, $1.4 billion and $481.9 million of building and improvements, $2.0 million and $2.0 million of building and leasehold improvements, $61.7 million and $61.7 million of right of use assets, $296.3 million and $17.6 million of accumulated depreciation, $322.8 million and $169.5 million of other assets included in other line items, $510.7 million and $457.1 million of real estate debt, net, $1.1 million and $1.2 million of accrued interest payable, $58.4 million and 57.7 million of lease liabilities, and $48.9 million and $43.7 million of other liabilities included in other line items as of September 30, 2020 and December 31, 2019, respectively.