Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash Flows from Operating Activities:
Net (loss) income	$ (321,855)	$ 2,809,737
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Equity in net loss (income) of partially owned entities	272,770	(30,193)
Net unrealized loss on real estate fund investments	211,196	16,162
Depreciation and amortization (including amortization of deferred financing costs)	193,920	240,866
Net gains on disposition of wholly owned and partially owned assets	(124,284)	(332,007)
Distributions of income from partially owned entities	79,436	31,820
Non-cash (gain on extinguishment of 608 Fifth Avenue lease liability) impairment loss on 608 Fifth Avenue right-of-use asset	(70,260)	75,220
Write-off of lease receivables deemed uncollectible	38,631	15,382
Stock-based compensation expense	33,468	42,174
Straight-lining of rents	15,856	3,733
Credit losses on loans receivable	13,369	0
Amortization of below-market leases, net	(9,406)	(11,168)
Decrease (increase) in fair value of marketable securities	4,938	(1,773)
Net gain on transfer to Fifth Avenue and Times Square JV	0	(2,571,099)
Real estate impairment losses	0	26,140
Prepayment penalty on redemption of senior unsecured notes due 2022	0	22,058
Other non-cash adjustments	4,370	3,206
Changes in operating assets and liabilities:
Real estate fund investments	(6,000)	(4,000)
Tenant and other receivables, net	(28,864)	(12,759)
Prepaid assets	3,078	(5,702)
Other assets	(12,480)	(8,498)
Accounts payable and accrued expenses	(26,611)	(11,482)
Other liabilities	(3,557)	(4,965)
Net cash provided by operating activities	267,715	292,852
Cash Flows from Investing Activities:
Proceeds from sale of condominium units at 220 Central Park South	437,188	690,734
Development costs and construction in progress	(319,294)	(289,532)
Moynihan Train Hall expenditures	(183,007)	(205,783)
Additions to real estate	(85,252)	(120,060)
Proceeds from sales of marketable securities	28,375	167,852
Investments in partially owned entities	(3,157)	(15,588)
Distributions of capital from partially owned entities	1,090	24,880
Proceeds from transfer of interest in Fifth Avenue and Times Square JV (net of $35,562 of transaction costs and $10,899 of deconsolidated cash and restricted cash)	0	1,255,756
Proceeds from redemption of 640 Fifth Avenue preferred equity	0	500,000
Proceeds from sale of real estate and related investments	0	108,512
Acquisitions of real estate and other	0	(3,260)
Net cash (used in) provided by investing activities	(124,057)	2,113,511
Cash Flows from Financing Activities:
Dividends paid on common shares / Distributions to Vornado	(624,627)	(251,803)
Proceeds from borrowings	554,297	458,955
Moynihan Train Hall reimbursement from Empire State Development	183,007	205,783
Contributions from noncontrolling interests / noncontrolling interests in consolidated subsidiaries	98,268	8,315
Distribution to noncontrolling interests / redeemable security holders and noncontrolling interests in consolidated subsidiaries	(54,440)	(49,140)
Dividends paid on preferred shares / Distributions to preferred unitholders	(37,593)	(25,066)
Repayments of borrowings	(11,347)	(1,943,157)
Proceeds received from exercise of employee share options (Vornado stock options) and other	5,267	2,046
Debt issuance costs	(143)	(13,522)
Repurchase of shares (Class A units) related to stock compensation arrangements and related tax withholdings	(137)	(8,692)
Purchase of marketable securities in connection with defeasance of mortgage payable	0	(407,126)
Prepayment penalty on redemption of senior unsecured notes due 2022	0	(22,058)
Redemption of preferred shares / units	0	(893)
Net cash provided by (used in) financing activities	112,552	(2,046,358)
Net increase in cash and cash equivalents and restricted cash	256,210	360,005
Cash and cash equivalents and restricted cash at beginning of period	1,607,131	716,905
Cash and cash equivalents and restricted cash at end of period	1,863,341	1,076,910
Reconciliation of Cash and Cash Equivalents and Restricted Cash:
Cash and cash equivalents at beginning of period	1,515,012	570,916
Restricted cash at beginning of period	92,119	145,989
Cash and cash equivalents and restricted cash at beginning of period	1,607,131	716,905
Cash and cash equivalents at end of period	1,768,459	922,604
Restricted cash at end of period	94,882	154,306
Cash and cash equivalents and restricted cash at end of period	1,863,341	1,076,910
Supplemental Disclosure of Cash Flow Information:
Cash payments for interest, excluding capitalized interest of $21,255 and $39,643	107,069	165,022
Cash payments for income taxes	9,276	28,697
Non-Cash Investing and Financing Activities:
Adjustments to carry redeemable Class A units at redemption value	248,879	99,407
Reclassification of condominium units from development costs and construction in progress to 220 Central Park South condominium units ready for sale	240,707	647,683
Accrued capital expenditures included in accounts payable and accrued expenses	89,036	68,900
Write-off of fully depreciated assets	(66,931)	(93,390)
Lease liabilities arising from the recognition of right-of-use assets	0	526,866
Amounts related to our investment in Pennsylvania Real Estate Investment Trust reclassified from investments in partially owned entities and accumulated other comprehensive loss to marketable securities upon conversion of operating partnership units to common shares	0	54,962
Investments received in exchange for transfer to Fifth Avenue and Times Square JV:
Investments received in exchange for transfer to joint venture, preferred equity	0	2,327,750
Investments received in exchange for transfer to joint venture, common equity	0	1,449,495
Marketable securities transferred in connection with the defeasance of mortgage payable	0	(407,126)
Defeasance of mortgage payable	0	390,000
Vornado Realty L.P.
Cash Flows from Operating Activities:
Net (loss) income	(321,855)	2,809,737
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Equity in net loss (income) of partially owned entities	272,770	(30,193)
Net unrealized loss on real estate fund investments	211,196	16,162
Depreciation and amortization (including amortization of deferred financing costs)	193,920	240,866
Net gains on disposition of wholly owned and partially owned assets	(124,284)	(332,007)
Distributions of income from partially owned entities	79,436	31,820
Non-cash (gain on extinguishment of 608 Fifth Avenue lease liability) impairment loss on 608 Fifth Avenue right-of-use asset	(70,260)	75,220
Write-off of lease receivables deemed uncollectible	38,631	15,382
Stock-based compensation expense	33,468	42,174
Straight-lining of rents	15,856	3,733
Credit losses on loans receivable	13,369	0
Amortization of below-market leases, net	(9,406)	(11,168)
Decrease (increase) in fair value of marketable securities	4,938	(1,773)
Net gain on transfer to Fifth Avenue and Times Square JV	0	(2,571,099)
Real estate impairment losses	0	26,140
Prepayment penalty on redemption of senior unsecured notes due 2022	0	22,058
Other non-cash adjustments	4,370	3,206
Changes in operating assets and liabilities:
Real estate fund investments	(6,000)	(4,000)
Tenant and other receivables, net	(28,864)	(12,759)
Prepaid assets	3,078	(5,702)
Other assets	(12,480)	(8,498)
Accounts payable and accrued expenses	(26,611)	(11,482)
Other liabilities	(3,557)	(4,965)
Net cash provided by operating activities	267,715	292,852
Cash Flows from Investing Activities:
Proceeds from sale of condominium units at 220 Central Park South	437,188	690,734
Development costs and construction in progress	(319,294)	(289,532)
Moynihan Train Hall expenditures	(183,007)	(205,783)
Additions to real estate	(85,252)	(120,060)
Proceeds from sales of marketable securities	28,375	167,852
Investments in partially owned entities	(3,157)	(15,588)
Distributions of capital from partially owned entities	1,090	24,880
Proceeds from transfer of interest in Fifth Avenue and Times Square JV (net of $35,562 of transaction costs and $10,899 of deconsolidated cash and restricted cash)	0	1,255,756
Proceeds from redemption of 640 Fifth Avenue preferred equity	0	500,000
Proceeds from sale of real estate and related investments	0	108,512
Acquisitions of real estate and other	0	(3,260)
Net cash (used in) provided by investing activities	(124,057)	2,113,511
Cash Flows from Financing Activities:
Dividends paid on common shares / Distributions to Vornado	(624,627)	(251,803)
Proceeds from borrowings	554,297	458,955
Moynihan Train Hall reimbursement from Empire State Development	183,007	205,783
Contributions from noncontrolling interests / noncontrolling interests in consolidated subsidiaries	98,268	8,315
Distribution to noncontrolling interests / redeemable security holders and noncontrolling interests in consolidated subsidiaries	(54,440)	(49,140)
Dividends paid on preferred shares / Distributions to preferred unitholders	(37,593)	(25,066)
Repayments of borrowings	(11,347)	(1,943,157)
Proceeds received from exercise of employee share options (Vornado stock options) and other	5,267	2,046
Debt issuance costs	(143)	(13,522)
Repurchase of shares (Class A units) related to stock compensation arrangements and related tax withholdings	(137)	(8,692)
Purchase of marketable securities in connection with defeasance of mortgage payable	0	(407,126)
Prepayment penalty on redemption of senior unsecured notes due 2022	0	(22,058)
Redemption of preferred shares / units	0	(893)
Net cash provided by (used in) financing activities	112,552	(2,046,358)
Net increase in cash and cash equivalents and restricted cash	256,210	360,005
Cash and cash equivalents and restricted cash at beginning of period	1,607,131	716,905
Cash and cash equivalents and restricted cash at end of period	1,863,341	1,076,910
Reconciliation of Cash and Cash Equivalents and Restricted Cash:
Cash and cash equivalents at beginning of period	1,515,012	570,916
Restricted cash at beginning of period	92,119	145,989
Cash and cash equivalents and restricted cash at beginning of period	1,607,131	716,905
Cash and cash equivalents at end of period	1,768,459	922,604
Restricted cash at end of period	94,882	154,306
Cash and cash equivalents and restricted cash at end of period	1,863,341	1,076,910
Supplemental Disclosure of Cash Flow Information:
Cash payments for interest, excluding capitalized interest of $21,255 and $39,643	107,069	165,022
Cash payments for income taxes	9,276	28,697
Non-Cash Investing and Financing Activities:
Adjustments to carry redeemable Class A units at redemption value	248,879	99,407
Reclassification of condominium units from development costs and construction in progress to 220 Central Park South condominium units ready for sale	240,707	647,683
Accrued capital expenditures included in accounts payable and accrued expenses	89,036	68,900
Write-off of fully depreciated assets	(66,931)	(93,390)
Lease liabilities arising from the recognition of right-of-use assets	0	526,866
Amounts related to our investment in Pennsylvania Real Estate Investment Trust reclassified from investments in partially owned entities and accumulated other comprehensive loss to marketable securities upon conversion of operating partnership units to common shares	0	54,962
Investments received in exchange for transfer to Fifth Avenue and Times Square JV:
Investments received in exchange for transfer to joint venture, preferred equity	0	2,327,750
Investments received in exchange for transfer to joint venture, common equity	0	1,449,495
Marketable securities transferred in connection with the defeasance of mortgage payable	0	(407,126)
Defeasance of mortgage payable	$ 0	$ 390,000