Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
ASSETS
Tenant and other receivables, allowance for doubtful accounts (in US dollars)	$ 10,944	$ 12,210
Receivable arising from the straight-lining of rents, allowance (in US dollars)	3,229	3,190
Deferred leasing and financing costs, accumulated amortization (in US dollars)	280,286	281,109
Identified intangible assets, accumulated amortization (in US dollars)	$ 207,744	$ 199,821
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	52,678,429	52,678,939
Preferred shares of beneficial interest: outstanding shares	52,678,429	52,678,939
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	188,496,525	187,887,498
Common shares of beneficial interest: outstanding shares	188,496,525	187,887,498
Common Class A [Member]
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Outstanding Partnership Units held by Third Parties	11,455,453	11,356,550
Series D Cumulative Redeemable Preferred Unit [Member]
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Outstanding Partnership Units held by Third Parties	177,101	1