Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
ASSETS
Tenant and other receivables, allowance for doubtful accounts (in US dollars)	$ 5,526	$ 6,708
Receivable arising from the straight-lining of rents, allowance (in US dollars)	954	1,913
Deferred leasing costs, accumulated amortization (in US dollars)	191,827	170,952
Identified intangible assets, accumulated amortization (in US dollars)	$ 150,837	$ 194,422
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Preferred Stock, Par Value Per Share	$ 0	$ 0
Preferred shares of beneficial interest: authorized shares	110,000,000	110,000,000
Preferred shares of beneficial interest: issued shares	36,799,573	42,824,829
Preferred shares of beneficial interest: outstanding shares	36,799,573	42,824,829
Common shares of beneficial interest: par value per share (in dollars per share)	$ 0.04	$ 0.04
Common shares of beneficial interest: authorized shares	250,000,000	250,000,000
Common shares of beneficial interest: issued shares	189,983,858	189,100,876
Common shares of beneficial interest: outstanding shares	189,983,858	189,100,876
Vornado Realty L.P.
ASSETS
Tenant and other receivables, allowance for doubtful accounts (in US dollars)	$ 5,526	$ 6,708
Receivable arising from the straight-lining of rents, allowance (in US dollars)	954	1,913
Deferred leasing costs, accumulated amortization (in US dollars)	191,827	170,952
Identified intangible assets, accumulated amortization (in US dollars)	$ 150,837	$ 194,422
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Outstanding Partnership Units held by Third Parties	12,528,899
Class A
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Outstanding Partnership Units held by Third Parties	12,528,899	12,197,162
Class A | Vornado Realty L.P.
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Outstanding Partnership Units held by Third Parties	12,528,899	12,197,162
Common shares of beneficial interest: outstanding shares	189,983,858
Series D Cumulative Redeemable Preferred Unit
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Outstanding Partnership Units held by Third Parties	177,101	177,101
Series D Cumulative Redeemable Preferred Unit | Vornado Realty L.P.
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Outstanding Partnership Units held by Third Parties	177,101	177,101