Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating Activities
Net (loss) income	$ (3,855)	$ 127,114
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization	66,770	70,779
Equity in net loss from unconsolidated joint ventures	2,864	12,814
Distributions of cumulative earnings from unconsolidated joint ventures	69	108
Equity in net loss on sale of interest in unconsolidated joint venture interest/real estate	12,629	0
Purchase price and other fair value adjustments	(2,664)	0
Depreciable real estate reserves and impairment	8,241	0
Loss (gain) on sale of real estate, net	1,388	(72,636)
Loan loss reserves and other investment reserves, net of recoveries	0	11,248
Deferred rents receivable	(2,685)	3,717
Non-cash lease expense	3,375	3,390
Other non-cash adjustments	15,564	1,110
Changes in operating assets and liabilities:
Tenant and other receivables	(4,138)	(44,960)
Related party receivables	(683)	(4,711)
Deferred lease costs	(240)	(8,603)
Other assets	(24,354)	(48,130)
Accounts payable, accrued expenses, other liabilities and security deposits	(38,640)	(13,877)
Deferred revenue	4,121	7,622
Lease liability - operating leases	(19,160)	(2,959)
Net cash provided by operating activities	18,602	42,026
Investing Activities
Acquisitions of real estate property	0	(86,846)
Additions to land, buildings and improvements	(49,328)	(101,726)
Investments in unconsolidated joint ventures	(21,027)	(8,906)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	19,692	53,516
Net proceeds from disposition of real estate/joint venture interest	62,800	91,156
Cash assumed from consolidation of real estate investment	9,475	0
Proceeds from sale or redemption of marketable securities	4,528	0
Other investments	(54)	(4,786)
Origination of debt and preferred equity investments	(5,905)	(223,374)
Repayments or redemption of debt and preferred equity investments	0	151,548
Net cash provided by (used in) investing activities	20,181	(129,418)
Financing Activities
Proceeds from mortgages and other loans payable	10,391	101,103
Repayments of mortgages and other loans payable	(362,542)	(102,777)
Proceeds from revolving credit facility and unsecured notes	530,000	1,125,000
Repayments of revolving credit facility and unsecured notes	(10,000)	(315,000)
Proceeds from stock options exercised and DRSPP issuance	351	166
Repurchase of common stock	(84,089)	(219,576)
Redemption of preferred stock	(3,631)	(19,392)
Redemption of OP units	(13,261)	(18,066)
Distributions to noncontrolling interests in other partnerships	(110)	(492)
Contributions from noncontrolling interests in other partnerships	171	3,814
Acquisition of subsidiary interest from noncontrolling interest	0	(1,536)
Distributions to noncontrolling interests in the Operating Partnership	(4,148)	(1,284)
Dividends paid on common and preferred stock	(69,772)	(79,662)
Tax withholdings related to restricted share awards	(2,788)	(4,752)
Deferred loan costs	(288)	(562)
Principal payments of on financing lease liabilities	(255)	0
Net cash (used in) provided by financing activities	(9,971)	466,984
Net increase in cash, cash equivalents, and restricted cash	28,812	379,592
Cash, cash equivalents, and restricted cash at beginning of year	372,795	241,430
Cash, cash equivalents, and restricted cash at end of period	401,607	621,022
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Conversion of units in the Operating Partnership	0	84
Issuance of special dividend paid primarily in stock	123,529	0
Tenant improvements and capital expenditures payable	15,214	602
Fair value adjustment to noncontrolling interest in the Operating Partnership	26,609	0
Consolidation of real estate investment	119,444	0
Reversal of assets held for sale	0	391,664
Extinguishment of debt in connection with property dispositions	53,548	0
Seller financed purchases	0	100,000
Debt and preferred equity investments	10,000	4,638
Removal of fully depreciated commercial real estate properties	1,120	512
Share repurchase payable	3,779	0
Recognition of right of use assets and related lease liabilities	119,711	102,782
Total cash, cash equivalents, and restricted cash	401,607	621,022
SL Green Operating Partnership
Operating Activities
Net (loss) income	(3,855)	127,114
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization	66,770	70,779
Equity in net loss from unconsolidated joint ventures	2,864	12,814
Distributions of cumulative earnings from unconsolidated joint ventures	69	108
Equity in net loss on sale of interest in unconsolidated joint venture interest/real estate	12,629	0
Purchase price and other fair value adjustments	(2,664)	0
Depreciable real estate reserves and impairment	8,241	0
Loss (gain) on sale of real estate, net	1,388	(72,636)
Loan loss reserves and other investment reserves, net of recoveries	0	11,248
Deferred rents receivable	(2,685)	3,717
Non-cash lease expense	3,375	3,390
Other non-cash adjustments	15,564	1,110
Changes in operating assets and liabilities:
Tenant and other receivables	(4,138)	(44,960)
Related party receivables	(683)	(4,711)
Deferred lease costs	(240)	(8,603)
Other assets	(24,354)	(48,130)
Accounts payable, accrued expenses, other liabilities and security deposits	(38,640)	(13,877)
Deferred revenue	4,121	7,622
Lease liability - operating leases	(19,160)	(2,959)
Net cash provided by operating activities	18,602	42,026
Investing Activities
Acquisitions of real estate property	0	(86,846)
Additions to land, buildings and improvements	(49,328)	(101,726)
Investments in unconsolidated joint ventures	(21,027)	(8,906)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	19,692	53,516
Net proceeds from disposition of real estate/joint venture interest	62,800	91,156
Cash assumed from consolidation of real estate investment	9,475	0
Proceeds from sale or redemption of marketable securities	4,528	0
Other investments	(54)	(4,786)
Origination of debt and preferred equity investments	(5,905)	(223,374)
Repayments or redemption of debt and preferred equity investments	0	151,548
Net cash provided by (used in) investing activities	20,181	(129,418)
Financing Activities
Proceeds from mortgages and other loans payable	10,391	101,103
Repayments of mortgages and other loans payable	(362,542)	(102,777)
Proceeds from revolving credit facility and unsecured notes	530,000	1,125,000
Repayments of revolving credit facility and unsecured notes	(10,000)	(315,000)
Proceeds from stock options exercised and DRSPP issuance	351	166
Repurchase of common stock	(84,089)	(219,576)
Redemption of preferred stock	(3,631)	(19,392)
Redemption of OP units	(13,261)	(18,066)
Distributions to noncontrolling interests in other partnerships	(110)	(492)
Contributions from noncontrolling interests in other partnerships	171	3,814
Acquisition of subsidiary interest from noncontrolling interest	0	(1,536)
Dividends paid on common and preferred stock	(73,920)	(80,946)
Tax withholdings related to restricted share awards	(2,788)	(4,752)
Deferred loan costs	(288)	(562)
Principal payments of on financing lease liabilities	(255)	0
Net cash (used in) provided by financing activities	(9,971)	466,984
Net increase in cash, cash equivalents, and restricted cash	28,812	379,592
Cash, cash equivalents, and restricted cash at beginning of year	372,795	241,430
Cash, cash equivalents, and restricted cash at end of period	401,607	621,022
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Conversion of units in the Operating Partnership	0	84
Issuance of special dividend paid primarily in stock	123,529	0
Tenant improvements and capital expenditures payable	15,214	602
Fair value adjustment to noncontrolling interest in the Operating Partnership	26,609	0
Consolidation of real estate investment	119,444	0
Reversal of assets held for sale	0	391,664
Extinguishment of debt in connection with property dispositions	53,548	0
Seller financed purchases	0	100,000
Debt and preferred equity investments	10,000	4,638
Removal of fully depreciated commercial real estate properties	1,120	512
Share repurchase payable	3,779	0
Recognition of right of use assets and related lease liabilities	119,711	102,782
Total cash, cash equivalents, and restricted cash	$ 401,607	$ 621,022