Income (Loss) Per Share /Income (Loss) Per Class A Unit (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator:
Income from continuing operations, net of income attributable to noncontrolling interests	$ 203,122	$ 32,050	$ 336,570	$ 196,684
Income (loss) from discontinued operations, net of income attributable to noncontrolling interests	57	(44,948)	357	(13,600)
Net income (loss) attributable to Vornado / Vornado Realty L.P.	203,179	(12,898)	336,927	183,084
Preferred share dividends / unit distributions	(12,534)	(16,128)	(38,103)	(48,386)
Preferred share / unit issuance costs	0	0	(14,486)	0
NET INCOME (LOSS) attributable to common shareholders / Class A unitholders	190,645	(29,026)	284,338	134,698
Earnings allocated to unvested participating securities	(17)	(9)	(33)	(37)
Numerator for basic income (loss) per share / per Class A unit	190,628	(29,035)	284,305	134,661
Convertible preferred share dividends / unit distributions	15	0	47	0
Earnings allocated to Out-Performance Plan units	0	0	127	195
Numerator for diluted income (loss) per share	$ 190,643	$ (29,035)	$ 284,479	$ 134,856
Denominator:
Denominator for basic income (loss) per share - weighted average shares (in shares)	190,245	189,593	190,176	189,401
Vornado employee stock options and restricted share / unit awards (in shares)	1,045	1,254	972	1,553
Convertible preferred shares/units	37	0	38	303
Out-Performance Plan units	0	0	106	0
Denominator for diluted income (loss) per share - weighted average shares and assumed conversions (in shares)	191,327	190,847	191,292	191,257
INCOME (LOSS) PER COMMON SHARE – BASIC:
Income from continuing operations, net (in dollars per share)	$ 1.00	$ 0.09	$ 1.50	$ 0.78
Loss from discontinued operations, net (in dollars per share)	0.00	(0.24)	0.00	(0.07)
Net income (loss) per common share (in dollars per share)	1.00	(0.15)	1.50	0.71
INCOME (LOSS) PER COMMON SHARE – DILUTED:
Income from continuing operations, net (in dollars per share)	1.00	0.09	1.49	0.78
Loss from discontinued operations, net (in dollars per share)	0.00	(0.24)	0.00	(0.07)
Net income (loss) per common share (in dollars per share)	$ 1.00	$ (0.15)	$ 1.49	$ 0.71
Vornado Realty L.P.
Numerator:
Income from continuing operations, net of income attributable to noncontrolling interests	$ 215,789	$ 33,154	$ 355,538	$ 206,642
Income (loss) from discontinued operations, net of income attributable to noncontrolling interests	61	(47,930)	381	(14,501)
Net income (loss) attributable to Vornado / Vornado Realty L.P.	215,850	(14,776)	355,919	192,141
Preferred share dividends / unit distributions	(12,582)	(16,176)	(38,248)	(48,531)
Preferred share / unit issuance costs	0	0	(14,486)	0
NET INCOME (LOSS) attributable to common shareholders / Class A unitholders	203,268	(30,952)	303,185	143,610
Earnings allocated to unvested participating securities	(997)	(740)	(2,259)	(2,499)
Numerator for basic income (loss) per share / per Class A unit	202,271	(31,692)	300,926	141,111
Convertible preferred share dividends / unit distributions	15	0	47	0
Numerator for diluted income (loss) per Class A unit	$ 202,286	$ (31,692)	$ 300,973	$ 141,111
Denominator:
Denominator for basic income (loss) per Class A unit – weighted average units (in shares)	202,103	201,300	202,033	201,093
Vornado employee stock options and restricted share / unit awards (in shares)	1,454	1,813	1,329	2,218
Convertible preferred shares/units	37	0	38	0
Denominator for diluted income (loss) per Class A unit - weighted average units and assumed conversions	203,594	203,113	203,400	203,311
INCOME (LOSS) PER CLASS A UNIT – BASIC:
Income from continuing operations, net (in dollars per unit)	$ 1.00	$ 0.08	$ 1.49	$ 0.77
Loss from discontinued operations, net (in dollars per unit)	0.00	(0.24)	0.00	(0.07)
Net income (loss) per Class A unit (in dollars per unit)	1.00	(0.16)	1.49	0.70
INCOME (LOSS) PER CLASS A UNIT – DILUTED:
Income from continuing operations, net (in dollars per unit)	0.99	0.08	1.48	0.76
Loss from discontinued operations, net (in dollars per unit)	0.00	(0.24)	0.00	(0.07)
Net income (loss) per Class A unit (in dollars per unit)	$ 0.99	$ (0.16)	$ 1.48	$ 0.69