Consolidated Balance Sheets (Parentheticals) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
ASSETS
Accounts receivable, allowance for doubtful accounts	$ 43,241	$ 62,979
Mezzanine loans receivable, allowance	0	73,216
Receivable arising from the straight-lining of rents, allowance	4,046	7,316
Deferred leasing and financing costs, accumulated amortization	245,087	219,965
Identified intangible assets (included in other assets): Accumulated amortization	$ 359,944	$ 335,113
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	42,186,709	32,340,009
Preferred shares of beneficial interest: outstanding shares	42,186,709	32,340,009
Common shares of beneficial interest: par value 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	185,080,020	183,661,875
Common shares of beneficial interest: outstanding shares	185,080,020	183,661,875
Common Class A [Member]
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Outstanding Partnership Units held by Third Parties	12,160,771	12,804,202
Cumulative Redeemable Preferred Unit [Member]
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Outstanding Partnership Units held by Third Parties	9,000,001	10,400,001