Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets
Allowance for doubtful accounts (in US dollars)	$ 1,778	$ 1,473
Unamortized leasing fees to Vornado (in US dollars)	$ 36,087	$ 36,960
Preferred stock: par value per share (in dollars per share)	$ 1	$ 1
Preferred stock: authorized shares	3,000,000	3,000,000
Preferred stock: issued shares	0	0
Preferred stock: outstanding shares	0	0
Common stock: par value per share (in dollars per share)	$ 1	$ 1
Common stock: authorized shares	10,000,000	10,000,000
Common stock: issued shares	5,173,450	5,173,450
Common stock: outstanding shares	5,107,290	5,106,196
Treasury stock: shares	66,160	67,254