Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Operating - consolidated variable interest entities	$ 485,971	$ 282,303
Accumulated depreciation and amortization of consolidated variable interest entities	35,782	26,618
Accumulated amortization of debt issuance costs	11,092	11,441
Mortgages payable - consolidated variable interest entities	$ 254,241	$ 187,632
Preferred shares, authorized	15,000,000	15,000,000
Preferred shares, par	$ 0.01	$ 0.01
Series 1 Cumulative Convertible Preferred interest rate	5.417%	5.417%
Preferred Shares, 5.417% Series 1 Cumulative Convertible liquidation preference	$ 25	$ 25
Preferred shares, shares issued	399,896	399,896
Preferred shares, shares outstanding	399,896	399,896
Common shares of beneficial interest, par	$ 0.01	$ 0.01
Common shares of beneficial interest, shares authorized	100,000,000	100,000,000
Common shares of beneficial interest, shares issued	69,493,392	68,605,783
Common shares of beneficial interest, shares outstanding	69,493,392	68,605,783