Consolidated Balance Sheets (Parentheticals) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
ASSETS
Tenant and other receivables, net of allowance for doubtful accounts (in US dollars)	$ 21,869	$ 37,674
Mortgage and mezzanine loans receivable, allowance (in US dollars)	5,845
Receivable arising from the straight-lining of rents, allowance (in US dollars)	4,355	3,165
Deferred leasing and financing costs, accumulated amortization (in US dollars)	265,482	222,202
Identified intangible assets, accumulated amortization (in US dollars)	$ 282,593	$ 352,035
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Preferred shares of beneficial interest: authorized shares	110,000,000	110,000,000
Preferred shares of beneficial interest: issued shares	52,682,807	51,184,609
Preferred shares of beneficial interest: outstanding shares	52,682,807	51,184,609
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	187,284,688	186,734,711
Common shares of beneficial interest: outstanding shares	187,284,688	186,734,711
Common Class A [Member]
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Outstanding Partnership Units held by Third Parties	11,292,038	11,215,682
Cumulative Redeemable Preferred Unit [Member]
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Outstanding Partnership Units held by Third Parties	1	1,800,001