Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash Flows from Operating Activities:
Net income	$ 3,173,586	$ 324,782
Adjustments to reconcile net income to net cash provided by operating activities:
Net gain on transfer to Fifth Avenue and Times Square JV	(2,571,099)	0
Net gains on disposition of wholly owned and partially owned assets	(641,664)	(164,828)
Depreciation and amortization (including amortization of deferred financing costs)	341,951	353,761
Non-cash impairment loss on 608 Fifth Avenue right-of-use asset	75,220	0
Distributions of income from partially owned entities	66,252	61,782
Equity in net income of partially owned entities	(56,139)	(6,059)
Stock-based compensation expense	48,045	26,190
Real estate impairment losses	26,140	0
Prepayment penalty on redemption of senior unsecured notes due 2022	22,058	0
Net realized and unrealized loss on real estate fund investments	16,162	33,709
Amortization of below-market leases, net	(15,561)	(31,480)
Straight-lining of rents	8,446	(10,279)
Decrease in fair value of marketable securities	3,095	24,801
Return of capital from real estate fund investments	0	20,291
Other non-cash adjustments	19,894	2,242
Changes in operating assets and liabilities:
Real estate fund investments	(4,000)	(68,950)
Tenant and other receivables, net	(28,110)	(11,662)
Prepaid assets	(74,502)	74,322
Other assets	(10,195)	(122,925)
Accounts payable and accrued expenses	1,496	(3,810)
Other liabilities	(3,104)	(13,849)
Net cash provided by operating activities	397,971	488,038
Cash Flows from Investing Activities:
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)	1,248,743	0
Proceeds from sale of condominium units at 220 Central Park South	1,039,493	0
Proceeds from redemption of 640 Fifth Avenue preferred equity	500,000	0
Development costs and construction in progress	(448,281)	(274,147)
Moynihan Train Hall expenditures	(352,211)	0
Proceeds from sale of real estate and related investments	255,534	219,731
Additions to real estate	(189,579)	(163,546)
Proceeds from sales of marketable securities	168,314	0
Distributions of capital from partially owned entities	24,880	98,609
Investments in partially owned entities	(16,480)	(32,728)
Acquisitions of real estate and other	(3,260)	(500,225)
Proceeds from repayments of loans receivable	1,395	0
Net cash provided by (used in) investing activities	2,228,548	(652,306)
Cash Flows from Financing Activities:
Repayments of borrowings	(2,635,028)	(264,482)
Proceeds from borrowings	1,107,852	312,763
Purchase of marketable securities in connection with defeasance of mortgage payable	(407,126)	0
Dividends paid on common shares / Distributions to Vornado	(377,750)	(359,456)
Moynihan Train Hall reimbursement from Empire State Development	352,211	0
Distribution to noncontrolling interests / redeemable security holders and noncontrolling interests in consolidated subsidiaries	(65,084)	(63,110)
Dividends paid on preferred shares / Distributions to preferred unitholders	(37,598)	(42,582)
Prepayment penalty on redemption of senior unsecured notes due 2022	(22,058)	0
Debt issuance costs	(15,328)	(7,451)
Contributions from noncontrolling interests	9,223	59,924
Repurchase of shares (Class A units) related to stock compensation arrangements and related tax withholdings	(8,692)	(784)
Proceeds received from exercise of employee share options (Vornado stock options) and other	2,403	5,262
Redemption of preferred shares / units	(893)	(470,000)
Debt prepayment and extinguishment costs	0	(818)
Net cash used in financing activities	(2,097,868)	(830,734)
Net increase (decrease) in cash and cash equivalents and restricted cash	528,651	(995,002)
Cash and cash equivalents and restricted cash at beginning of period	716,905	1,914,812
Cash and cash equivalents and restricted cash at end of period	1,245,556	919,810
Reconciliation of Cash and Cash Equivalents and Restricted Cash:
Cash and cash equivalents at beginning of period	570,916	1,817,655
Restricted cash at beginning of period	145,989	97,157
Cash and cash equivalents and restricted cash at beginning of period	716,905	1,914,812
Cash and cash equivalents at end of period	1,132,491	772,524
Restricted cash at end of period	113,065	147,286
Cash and cash equivalents and restricted cash at end of period	1,245,556	919,810
Supplemental Disclosure of Cash Flow Information:
Cash payments for interest, excluding capitalized interest of $55,186 and $45,292	227,310	245,628
Cash payments for income taxes	47,345	61,047
Investments received in exchange for transfer to Fifth Avenue and Times Square JV:
Investments received in exchange for transfer to joint venture, preferred equity	2,327,750	0
Investments received in exchange for transfer to joint venture, common equity	1,449,495	0
Reclassification of condominium units from development costs and construction in progress to 220 Central Park South condominium units ready for sale	825,520	307,552
Lease liabilities arising from the recognition of right-of-use assets	526,866	0
Marketable securities transferred in connection with the defeasance of mortgage payable	(407,126)	0
Defeased mortgage payable	390,000	0
Adjustments to carry redeemable Class A units at redemption value	123,635	57,970
Accrued capital expenditures included in accounts payable and accrued expenses	117,205	74,185
Write Off Of Fully Amortized And Depreciated Assets	(113,261)	(61,120)
Amounts related to our investment in Pennsylvania Real Estate Investment Trust reclassified from investments in partially owned entities and accumulated other comprehensive (loss) income to marketable securities upon conversion of operating partnership units to common shares	54,962	0
Vornado Realty L.P.
Cash Flows from Operating Activities:
Net income	3,173,586	324,782
Adjustments to reconcile net income to net cash provided by operating activities:
Net gain on transfer to Fifth Avenue and Times Square JV	(2,571,099)	0
Net gains on disposition of wholly owned and partially owned assets	(641,664)	(164,828)
Depreciation and amortization (including amortization of deferred financing costs)	341,951	353,761
Non-cash impairment loss on 608 Fifth Avenue right-of-use asset	75,220	0
Distributions of income from partially owned entities	66,252	61,782
Equity in net income of partially owned entities	(56,139)	(6,059)
Stock-based compensation expense	48,045	26,190
Real estate impairment losses	26,140	0
Prepayment penalty on redemption of senior unsecured notes due 2022	22,058	0
Net realized and unrealized loss on real estate fund investments	16,162	33,709
Amortization of below-market leases, net	(15,561)	(31,480)
Straight-lining of rents	8,446	(10,279)
Decrease in fair value of marketable securities	3,095	24,801
Return of capital from real estate fund investments	0	20,291
Other non-cash adjustments	19,894	2,242
Changes in operating assets and liabilities:
Real estate fund investments	(4,000)	(68,950)
Tenant and other receivables, net	(28,110)	(11,662)
Prepaid assets	(74,502)	74,322
Other assets	(10,195)	(122,925)
Accounts payable and accrued expenses	1,496	(3,810)
Other liabilities	(3,104)	(13,849)
Net cash provided by operating activities	397,971	488,038
Cash Flows from Investing Activities:
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)	1,248,743	0
Proceeds from sale of condominium units at 220 Central Park South	1,039,493	0
Proceeds from redemption of 640 Fifth Avenue preferred equity	500,000	0
Development costs and construction in progress	(448,281)	(274,147)
Moynihan Train Hall expenditures	(352,211)	0
Proceeds from sale of real estate and related investments	255,534	219,731
Additions to real estate	(189,579)	(163,546)
Proceeds from sales of marketable securities	168,314	0
Distributions of capital from partially owned entities	24,880	98,609
Investments in partially owned entities	(16,480)	(32,728)
Acquisitions of real estate and other	(3,260)	(500,225)
Proceeds from repayments of loans receivable	1,395	0
Net cash provided by (used in) investing activities	2,228,548	(652,306)
Cash Flows from Financing Activities:
Repayments of borrowings	(2,635,028)	(264,482)
Proceeds from borrowings	1,107,852	312,763
Purchase of marketable securities in connection with defeasance of mortgage payable	(407,126)	0
Dividends paid on common shares / Distributions to Vornado	(377,750)	(359,456)
Moynihan Train Hall reimbursement from Empire State Development	352,211	0
Distribution to noncontrolling interests / redeemable security holders and noncontrolling interests in consolidated subsidiaries	(65,084)	(63,110)
Dividends paid on preferred shares / Distributions to preferred unitholders	(37,598)	(42,582)
Prepayment penalty on redemption of senior unsecured notes due 2022	(22,058)	0
Debt issuance costs	(15,328)	(7,451)
Contributions from noncontrolling interests	9,223	59,924
Repurchase of shares (Class A units) related to stock compensation arrangements and related tax withholdings	(8,692)	(784)
Proceeds received from exercise of employee share options (Vornado stock options) and other	2,403	5,262
Redemption of preferred shares / units	(893)	(470,000)
Debt prepayment and extinguishment costs	0	(818)
Net cash used in financing activities	(2,097,868)	(830,734)
Net increase (decrease) in cash and cash equivalents and restricted cash	528,651	(995,002)
Cash and cash equivalents and restricted cash at beginning of period	716,905	1,914,812
Cash and cash equivalents and restricted cash at end of period	1,245,556	919,810
Reconciliation of Cash and Cash Equivalents and Restricted Cash:
Cash and cash equivalents at beginning of period	570,916	1,817,655
Restricted cash at beginning of period	145,989	97,157
Cash and cash equivalents and restricted cash at beginning of period	716,905	1,914,812
Cash and cash equivalents at end of period	1,132,491	772,524
Restricted cash at end of period	113,065	147,286
Cash and cash equivalents and restricted cash at end of period	1,245,556	919,810
Supplemental Disclosure of Cash Flow Information:
Cash payments for interest, excluding capitalized interest of $55,186 and $45,292	227,310	245,628
Cash payments for income taxes	47,345	61,047
Investments received in exchange for transfer to Fifth Avenue and Times Square JV:
Investments received in exchange for transfer to joint venture, preferred equity	2,327,750	0
Investments received in exchange for transfer to joint venture, common equity	1,449,495	0
Reclassification of condominium units from development costs and construction in progress to 220 Central Park South condominium units ready for sale	825,520	307,552
Lease liabilities arising from the recognition of right-of-use assets	526,866	0
Marketable securities transferred in connection with the defeasance of mortgage payable	(407,126)	0
Defeased mortgage payable	390,000	0
Adjustments to carry redeemable Class A units at redemption value	123,635	57,970
Accrued capital expenditures included in accounts payable and accrued expenses	117,205	74,185
Write Off Of Fully Amortized And Depreciated Assets	(113,261)	(61,120)
Amounts related to our investment in Pennsylvania Real Estate Investment Trust reclassified from investments in partially owned entities and accumulated other comprehensive (loss) income to marketable securities upon conversion of operating partnership units to common shares	$ 54,962	$ 0