Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
ASSETS
Tenant and other receivables, allowance for doubtful accounts (in US dollars)	$ 11,200	$ 11,908
Receivable arising from the straight-lining of rents, allowance (in US dollars)	2,539	2,751
Deferred leasing and financing costs, accumulated amortization (in US dollars)	218,709	218,239
Identified intangible assets, accumulated amortization (in US dollars)	$ 188,094	$ 187,360
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	52,676,629	52,676,629
Preferred shares of beneficial interest: outstanding shares	52,676,629	52,676,629
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	188,771,002	188,576,853
Common shares of beneficial interest: outstanding shares	188,771,002	188,576,853
Common Class A [Member]
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Outstanding Partnership Units held by Third Parties	12,414,019	12,242,820
Series D Cumulative Redeemable Preferred Unit [Member]
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Outstanding Partnership Units held by Third Parties	177,101	177,101