Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities:
Net income	$ 264,128	$ 981,922	$ 859,430
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization (including amortization of deferred financing costs)	529,826	595,270	566,207
Return of capital from real estate fund investments	91,606	71,888	91,458
Distributions of income from partially owned entities	82,095	214,800	66,819
Amortization of below-market leases, net	(46,790)	(53,202)	(79,053)
Straight-lining of rents	(45,792)	(146,787)	(153,668)
Change in allowance for deferred tax assets	34,800	0	(90,030)
Equity in net (income) loss of partially owned entities	(15,635)	(165,389)	11,882
Net realized and unrealized losses (gains) on real estate fund investments	15,267	40,655	(57,752)
Net gains on sale of real estate and other	(3,489)	(5,074)	(65,396)
Net gains on disposition of wholly owned and partially owned assets	(501)	(175,735)	(251,821)
Net gain on extinguishment of Skyline properties debt	0	(487,877)	0
Real estate impairment losses	0	161,165	256
Other non-cash adjustments	56,480	39,406	37,721
Changes in operating assets and liabilities:
Real estate fund investments	0	0	(95,010)
Tenant and other receivables, net	1,183	(4,271)	8,366
Prepaid assets	(12,292)	(7,893)	(16,836)
Other assets	(79,199)	(76,357)	(112,415)
Accounts payable and accrued expenses	3,760	13,278	(25,231)
Other liabilities	(15,305)	(719)	(22,836)
Net cash provided by operating activities	860,142	995,080	672,091
Cash Flows from Investing Activities:
Distributions of capital from partially owned entities	366,155	196,635	36,017
Development costs and construction in progress	(355,852)	(606,565)	(475,819)
Additions to real estate	(271,308)	(387,545)	(301,413)
Proceeds from the repayment of JBG SMITH Properties loan receivable	115,630	0	0
Investments in partially owned entities	(40,537)	(127,608)	(235,439)
Acquisitions of real estate and other	(30,607)	(91,103)	(558,484)
Proceeds from sales of real estate and related investments	9,543	183,173	786,924
Proceeds from repayments of mortgage loans receivable	659	45	16,790
Net deconsolidation of 7 West 34th Street	0	(48,000)	0
Investments in loans receivable	0	(11,700)	(1,000)
Purchases of marketable securities	0	(4,379)	0
Proceeds from the sale of marketable securities	0	3,937	0
Net cash used in investing activities	(206,317)	(893,110)	(732,424)
Cash Flows from Financing Activities:
Proceeds from borrowings	1,055,872	2,403,898	4,468,872
Repayments of borrowings	(631,681)	(1,894,990)	(2,936,578)
Dividends paid on common shares / Distributions to Vornado	(496,490)	(475,961)	(474,751)
Cash and cash equivalents and restricted cash included in the spin-off of JBG SMITH Properties ($275,000 plus The Bartlett financing proceeds less transaction costs and other mortgage items)	(416,237)	0	0
Proceeds from issuance of preferred shares / units	309,609	0	0
Distributions to noncontrolling interests / Distributions to redeemable security holders and noncontrolling interests in consolidated subsidiaries	(109,697)	(130,590)	(102,866)
Dividends paid on preferred shares / Distributions to preferred unitholders	(64,516)	(80,137)	(80,578)
Proceeds received from exercise of employee share options (Vornado stock options) and other	29,712	8,269	16,779
Debt issuance costs	(12,325)	(42,157)	(66,554)
Debt prepayment and extinguishment costs	(3,217)	0	(15,000)
Contributions from noncontrolling interests / noncontrolling interests in consolidated subsidiaries	1,044	11,950	51,975
Repurchase of shares (Class A units) related to stock compensation agreements and related tax withholdings and other	(418)	(186)	(7,473)
Redemption of preferred shares / units	0	(246,250)	0
Cash and cash equivalents and restricted cash included in the spin-off of Urban Edge Properties	0	0	(234,967)
Net cash (used in) provided by financing activities	(338,344)	(446,154)	618,859
Net increase (decrease) in cash and cash equivalents and restricted cash	315,481	(344,184)	558,526
Cash and cash equivalents and restricted cash at beginning of period	1,599,331	1,943,515	1,384,989
Cash and cash equivalents and restricted cash at end of period	1,914,812	1,599,331	1,943,515
Reconciliation of Cash and Cash Equivalents and Restricted Cash:
Cash and cash equivalents at beginning of period	1,501,027	1,835,707	1,198,477
Restricted cash at beginning of period	95,032	99,943	168,447
Restricted cash included in discontinued operations at beginning of period	3,272	7,865	18,065
Cash and cash equivalents and restricted cash at beginning of period	1,599,331	1,943,515	1,384,989
Cash and cash equivalents at end of period	1,817,655	1,501,027	1,835,707
Restricted cash at end of period	97,157	95,032	99,943
Restricted cash included in discontinued operations at end of period	0	3,272	7,865
Cash and cash equivalents and restricted cash at end of period	1,914,812	1,599,331	1,943,515
Supplemental Disclosure of Cash Flow Information:
Cash payments for interest, excluding capitalized interest of $43,071, $29,584 and $48,539	338,983	368,762	376,620
Cash payments for income taxes	6,727	9,716	8,287
Non-cash distribution to JBG SMITH and Urban Edge Properties:
Reclassification of Series G and Series I cumulative redeemable preferred shares / units to liabilities upon call for redemption	455,514	0	0
Adjustments to carry redeemable Class A units at redemption value	268,494	(26,251)	192,464
Loan receivable established upon the spin-off of JBG SMITH Properties	115,630	0	0
Accrued capital expenditures included in accounts payable and accrued expenses	102,976	120,564	122,711
Write-off of fully depreciated assets	(58,810)	(305,679)	(167,250)
(Reduction) increase in unrealized net gain on available-for-sale securities	(20,951)	52,057	(55,326)
Decrease in assets and liabilities resulting from the disposition or deconsolidation of real estate properties:
Real estate, net	0	(122,047)	0
Mortgages payable, net	0	(290,418)	0
Transfer of interest in real estate to Pennsylvania Real Estate Investment Trust	0	0	(145,313)
Class A units issued in connection with acquisition	0	0	80,000
Financing assumed in acquisition	0	0	62,000
JBGS
Cash Flows from Financing Activities:
Cash and cash equivalents and restricted cash included in the spin-off of JBG SMITH Properties ($275,000 plus The Bartlett financing proceeds less transaction costs and other mortgage items)	(275,000)
Non-cash distribution to JBG SMITH and Urban Edge Properties:
Assets	3,432,738	0	0
Liabilities	(1,414,186)	0	0
Equity	(2,018,552)	0	0
Vornado Realty L.P.
Cash Flows from Operating Activities:
Net income	264,128	981,922	859,430
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization (including amortization of deferred financing costs)	529,826	595,270	566,207
Return of capital from real estate fund investments	91,606	71,888	91,458
Distributions of income from partially owned entities	82,095	214,800	66,819
Amortization of below-market leases, net	(46,790)	(53,202)	(79,053)
Straight-lining of rents	(45,792)	(146,787)	(153,668)
Change in allowance for deferred tax assets	34,800	0	(90,030)
Equity in net (income) loss of partially owned entities	(15,635)	(165,389)	11,882
Net realized and unrealized losses (gains) on real estate fund investments	15,267	40,655	(57,752)
Net gains on sale of real estate and other	(3,489)	(5,074)	(65,396)
Net gains on disposition of wholly owned and partially owned assets	(501)	(175,735)	(251,821)
Net gain on extinguishment of Skyline properties debt	0	(487,877)	0
Real estate impairment losses	0	161,165	256
Other non-cash adjustments	56,480	39,406	37,721
Changes in operating assets and liabilities:
Real estate fund investments	0	0	(95,010)
Tenant and other receivables, net	1,183	(4,271)	8,366
Prepaid assets	(12,292)	(7,893)	(16,836)
Other assets	(79,199)	(76,357)	(112,415)
Accounts payable and accrued expenses	3,760	13,278	(25,231)
Other liabilities	(15,305)	(719)	(22,836)
Net cash provided by operating activities	860,142	995,080	672,091
Cash Flows from Investing Activities:
Distributions of capital from partially owned entities	366,155	196,635	36,017
Development costs and construction in progress	(355,852)	(606,565)	(475,819)
Additions to real estate	(271,308)	(387,545)	(301,413)
Proceeds from the repayment of JBG SMITH Properties loan receivable	115,630	0	0
Investments in partially owned entities	(40,537)	(127,608)	(235,439)
Acquisitions of real estate and other	(30,607)	(91,103)	(558,484)
Proceeds from sales of real estate and related investments	9,543	183,173	786,924
Proceeds from repayments of mortgage loans receivable	659	45	16,790
Net deconsolidation of 7 West 34th Street	0	(48,000)	0
Investments in loans receivable	0	(11,700)	(1,000)
Purchases of marketable securities	0	(4,379)	0
Proceeds from the sale of marketable securities	0	3,937	0
Net cash used in investing activities	(206,317)	(893,110)	(732,424)
Cash Flows from Financing Activities:
Proceeds from borrowings	1,055,872	2,403,898	4,468,872
Repayments of borrowings	(631,681)	(1,894,990)	(2,936,578)
Dividends paid on common shares / Distributions to Vornado	(496,490)	(475,961)	(474,751)
Cash and cash equivalents and restricted cash included in the spin-off of JBG SMITH Properties ($275,000 plus The Bartlett financing proceeds less transaction costs and other mortgage items)	(416,237)	0	0
Proceeds from issuance of preferred shares / units	309,609	0	0
Distributions to noncontrolling interests / Distributions to redeemable security holders and noncontrolling interests in consolidated subsidiaries	(109,697)	(130,590)	(102,866)
Dividends paid on preferred shares / Distributions to preferred unitholders	(64,516)	(80,137)	(80,578)
Proceeds received from exercise of employee share options (Vornado stock options) and other	29,712	8,269	16,779
Debt issuance costs	(12,325)	(42,157)	(66,554)
Debt prepayment and extinguishment costs	(3,217)	0	(15,000)
Contributions from noncontrolling interests / noncontrolling interests in consolidated subsidiaries	1,044	11,950	51,975
Repurchase of shares (Class A units) related to stock compensation agreements and related tax withholdings and other	(418)	(186)	(7,473)
Redemption of preferred shares / units	0	(246,250)	0
Cash and cash equivalents and restricted cash included in the spin-off of Urban Edge Properties	0	0	(234,967)
Net cash (used in) provided by financing activities	(338,344)	(446,154)	618,859
Net increase (decrease) in cash and cash equivalents and restricted cash	315,481	(344,184)	558,526
Cash and cash equivalents and restricted cash at beginning of period	1,599,331	1,943,515	1,384,989
Cash and cash equivalents and restricted cash at end of period	1,914,812	1,599,331	1,943,515
Reconciliation of Cash and Cash Equivalents and Restricted Cash:
Cash and cash equivalents at beginning of period	1,501,027	1,835,707	1,198,477
Restricted cash at beginning of period	95,032	99,943	168,447
Restricted cash included in discontinued operations at beginning of period	3,272	7,865	18,065
Cash and cash equivalents and restricted cash at beginning of period	1,599,331	1,943,515	1,384,989
Cash and cash equivalents at end of period	1,817,655	1,501,027	1,835,707
Restricted cash at end of period	97,157	95,032	99,943
Restricted cash included in discontinued operations at end of period	0	3,272	7,865
Cash and cash equivalents and restricted cash at end of period	1,914,812	1,599,331	1,943,515
Supplemental Disclosure of Cash Flow Information:
Cash payments for interest, excluding capitalized interest of $43,071, $29,584 and $48,539	338,983	368,762	376,620
Cash payments for income taxes	6,727	9,716	8,287
Non-cash distribution to JBG SMITH and Urban Edge Properties:
Reclassification of Series G and Series I cumulative redeemable preferred shares / units to liabilities upon call for redemption	455,514	0	0
Adjustments to carry redeemable Class A units at redemption value	268,494	(26,251)	192,464
Loan receivable established upon the spin-off of JBG SMITH Properties	115,630	0	0
Accrued capital expenditures included in accounts payable and accrued expenses	102,976	120,564	122,711
Write-off of fully depreciated assets	(58,810)	(305,679)	(167,250)
(Reduction) increase in unrealized net gain on available-for-sale securities	(20,951)	52,057	(55,326)
Decrease in assets and liabilities resulting from the disposition or deconsolidation of real estate properties:
Real estate, net	0	(122,047)	0
Mortgages payable, net	0	(290,418)	0
Transfer of interest in real estate to Pennsylvania Real Estate Investment Trust	0	0	(145,313)
Class A units issued in connection with acquisition	0	0	80,000
Financing assumed in acquisition	0	0	62,000
Vornado Realty L.P. | JBGS
Cash Flows from Financing Activities:
Cash and cash equivalents and restricted cash included in the spin-off of JBG SMITH Properties ($275,000 plus The Bartlett financing proceeds less transaction costs and other mortgage items)	(275,000)
Non-cash distribution to JBG SMITH and Urban Edge Properties:
Assets	3,432,738	0	0
Liabilities	(1,414,186)	0	0
Equity	(2,018,552)	0	0
Skyline Properties
Decrease in assets and liabilities resulting from the disposition or deconsolidation of real estate properties:
Real estate, net	0	(189,284)	0
Mortgages payable, net	0	(690,263)	0
Skyline Properties | Vornado Realty L.P.
Decrease in assets and liabilities resulting from the disposition or deconsolidation of real estate properties:
Real estate, net	0	(189,284)	0
Mortgages payable, net	0	(690,263)	0
Urban Edge Properties
Non-cash distribution to JBG SMITH and Urban Edge Properties:
Assets	0	0	1,699,289
Liabilities	0	0	(1,469,659)
Equity	0	0	(229,630)
Urban Edge Properties | Vornado Realty L.P.
Non-cash distribution to JBG SMITH and Urban Edge Properties:
Assets	0	0	1,699,289
Liabilities	0	0	(1,469,659)
Equity	$ 0	$ 0	$ (229,630)