Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating Activities
Net income	$ 528,813	$ 214,418
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	179,039	265,048
Equity in net loss from unconsolidated joint ventures	31,321	15,445
Distributions of cumulative earnings from unconsolidated joint ventures	719	576
Equity in net loss on sale of interest in unconsolidated joint venture interest/real estate	5,438	0
Purchase price and other fair value adjustments	(209,527)	0
Depreciable real estate reserves and impairment	5,696	6,627
Gain on sale of real estate, net	(285,338)	(163,624)
Loan loss reserves and other investment reserves, net of recoveries	0	27,018
Deferred rents receivable	(6,963)	(3,459)
Non-cash lease expense	11,670	9,735
Other non-cash adjustments	27,868	14,874
Changes in operating assets and liabilities:
Tenant and other receivables	(11,827)	(43,069)
Related party receivables	(4,626)	4,195
Deferred lease costs	(1,267)	(12,472)
Other assets	(118)	(55,301)
Accounts payable, accrued expenses, other liabilities and security deposits	(54,009)	43,256
Deferred revenue	7,412	13,206
Lease liability - operating leases	(33,289)	(8,530)
Net cash provided by operating activities	191,012	327,943
Investing Activities
Acquisitions of real estate property	(152,791)	(86,846)
Additions to land, buildings and improvements	(208,380)	(281,651)
Investments in unconsolidated joint ventures	(76,471)	(39,724)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	749,997	104,300
Net proceeds from disposition of real estate/joint venture interest	541,268	333,037
Cash assumed from consolidation of real estate investment	9,475	0
Proceeds from sale or redemption of marketable securities	4,528	0
Purchases of marketable securities	(10,000)	0
Other investments	2,401	(3,921)
Origination of debt and preferred equity investments	(83,924)	(353,797)
Repayments or redemption of debt and preferred equity investments	110,774	703,625
Net cash provided by investing activities	886,877	375,023
Financing Activities
Proceeds from mortgages and other loans payable	31,219	1,128,775
Repayments of mortgages and other loans payable	(372,300)	(710,352)
Proceeds from revolving credit facility and unsecured notes	925,000	1,275,000
Repayments of revolving credit facility and unsecured notes	(1,165,000)	(1,575,000)
Proceeds from stock options exercised and DRSPP issuance	613	566
Repurchase of common stock	(280,623)	(381,992)
Redemption of preferred stock	(3,631)	(82,750)
Redemption of OP units	(13,930)	(18,913)
Distributions to noncontrolling interests in other partnerships	(5,403)	(13,126)
Contributions from noncontrolling interests in other partnerships	310	12,404
Acquisition of subsidiary interest from noncontrolling interest	0	(1,536)
Distributions to noncontrolling interests in the Operating Partnership	(11,882)	(8,857)
Dividends paid on common and preferred stock	(205,131)	(224,147)
Tax withholdings related to restricted share awards	(2,989)	(4,752)
Deferred loan costs	(570)	(34,687)
Principal payments of on financing lease liabilities	(434)	(580)
Net cash used in financing activities	(1,104,751)	(639,947)
Net (decrease) increase in cash, cash equivalents, and restricted cash	(26,862)	63,019
Cash, cash equivalents, and restricted cash at beginning of year	372,795	241,430
Cash, cash equivalents, and restricted cash at end of period	345,933	304,449
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Conversion of units in the Operating Partnership	0	8,744
Redemption of units in the Operating Partnership for a joint venture sale	27,586	0
Exchange of preferred equity investment for real estate or equity in joint venture	0	119,467
Exchange of debt investment for real estate or equity in joint venture	9,468	104,211
Assumption of mortgage loan	60,000	0
Issuance of special dividend paid primarily in stock	121,418	0
Tenant improvements and capital expenditures payable	16,684	11,993
Fair value adjustment to noncontrolling interest in the Operating Partnership	17,245	35,253
Consolidation of real estate investment	119,444	0
Deconsolidation of a subsidiary	66,837	0
Deconsolidation of a subsidiary mortgage	510,000	5,593
Reversal of assets held for sale	0	391,664
Extinguishment of debt in connection with property dispositions	53,548	0
Mortgages assumed in connection with sale of real estate	0	250,000
Seller financed purchases	0	100,000
Debt and preferred equity investments	8,372	4,638
Removal of fully depreciated commercial real estate properties	7,030	7,906
Distributions to noncontrolling interests	358	0
Share repurchase payable	3,779	10,003
Sale of interest in partially owned entity	4,476	0
Recognition of sales-type leases and related lease liabilities	0	114,974
Recognition of right of use assets and related lease liabilities	115,812	57,500
Cash and cash equivalents	257,941	221,404
Restricted cash	87,992	83,045
Total cash, cash equivalents, and restricted cash	345,933	304,449
SL Green Operating Partnership
Operating Activities
Net income	528,813	214,418
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	179,039	265,048
Equity in net loss from unconsolidated joint ventures	31,321	15,445
Distributions of cumulative earnings from unconsolidated joint ventures	719	576
Equity in net loss on sale of interest in unconsolidated joint venture interest/real estate	5,438	0
Purchase price and other fair value adjustments	(209,527)	0
Depreciable real estate reserves and impairment	5,696	6,627
Gain on sale of real estate, net	(285,338)	(163,624)
Loan loss reserves and other investment reserves, net of recoveries	0	27,018
Deferred rents receivable	(6,963)	(3,459)
Non-cash lease expense	11,670	9,735
Other non-cash adjustments	27,868	14,874
Changes in operating assets and liabilities:
Tenant and other receivables	(11,827)	(43,069)
Related party receivables	(4,626)	4,195
Deferred lease costs	(1,267)	(12,472)
Other assets	(118)	(55,301)
Accounts payable, accrued expenses, other liabilities and security deposits	(54,009)	43,256
Deferred revenue	7,412	13,206
Lease liability - operating leases	(33,289)	(8,530)
Net cash provided by operating activities	191,012	327,943
Investing Activities
Acquisitions of real estate property	(152,791)	(86,846)
Additions to land, buildings and improvements	(208,380)	(281,651)
Investments in unconsolidated joint ventures	(76,471)	(39,724)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	749,997	104,300
Net proceeds from disposition of real estate/joint venture interest	541,268	333,037
Cash assumed from consolidation of real estate investment	9,475	0
Proceeds from sale or redemption of marketable securities	4,528	0
Purchases of marketable securities	(10,000)	0
Other investments	2,401	(3,921)
Origination of debt and preferred equity investments	(83,924)	(353,797)
Repayments or redemption of debt and preferred equity investments	110,774	703,625
Net cash provided by investing activities	886,877	375,023
Financing Activities
Proceeds from mortgages and other loans payable	31,219	1,128,775
Repayments of mortgages and other loans payable	(372,300)	(710,352)
Proceeds from revolving credit facility and unsecured notes	925,000	1,275,000
Repayments of revolving credit facility and unsecured notes	(1,165,000)	(1,575,000)
Proceeds from stock options exercised and DRSPP issuance	613	566
Repurchase of common stock	(280,623)	(381,992)
Redemption of preferred stock	(3,631)	(82,750)
Redemption of OP units	(13,930)	(18,913)
Distributions to noncontrolling interests in other partnerships	(5,403)	(13,126)
Contributions from noncontrolling interests in other partnerships	310	12,404
Acquisition of subsidiary interest from noncontrolling interest	0	(1,536)
Dividends paid on common and preferred stock	(217,013)	(233,004)
Tax withholdings related to restricted share awards	(2,989)	(4,752)
Deferred loan costs	(570)	(34,687)
Principal payments of on financing lease liabilities	(434)	(580)
Net cash used in financing activities	(1,104,751)	(639,947)
Net (decrease) increase in cash, cash equivalents, and restricted cash	(26,862)	63,019
Cash, cash equivalents, and restricted cash at beginning of year	372,795	241,430
Cash, cash equivalents, and restricted cash at end of period	345,933	304,449
Supplemental Disclosure of Non-Cash Investing and Financing Activities:
Conversion of units in the Operating Partnership	0	8,744
Redemption of units in the Operating Partnership for a joint venture sale	27,586	0
Exchange of preferred equity investment for real estate or equity in joint venture	0	119,467
Exchange of debt investment for real estate or equity in joint venture	9,468	104,211
Assumption of mortgage loan	60,000	0
Issuance of special dividend paid primarily in stock	121,418	0
Tenant improvements and capital expenditures payable	16,684	11,993
Fair value adjustment to noncontrolling interest in the Operating Partnership	17,245	35,253
Consolidation of real estate investment	119,444	0
Deconsolidation of a subsidiary	66,837	0
Deconsolidation of a subsidiary mortgage	510,000	5,593
Reversal of assets held for sale	0	391,664
Extinguishment of debt in connection with property dispositions	53,548	0
Mortgages assumed in connection with sale of real estate	0	250,000
Seller financed purchases	0	100,000
Debt and preferred equity investments	8,372	4,638
Removal of fully depreciated commercial real estate properties	7,030	7,906
Distributions to noncontrolling interests	358	0
Share repurchase payable	3,779	10,003
Sale of interest in partially owned entity	4,476	0
Recognition of sales-type leases and related lease liabilities	0	114,974
Recognition of right of use assets and related lease liabilities	115,812	57,500
Cash and cash equivalents	257,941	221,404
Restricted cash	87,992	83,045
Total cash, cash equivalents, and restricted cash	$ 345,933	$ 304,449