Consolidated Balance Sheets (Parentheticals) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
ASSETS
Accounts receivable, allowance for doubtful accounts	$ 42,785	$ 43,241
Receivable arising from the straight-lining of rents, net of allowance of	3,986	4,046
Deferred leasing and financing costs, net of accumulated amortization of	218,111	245,087
Identified intangible assets: Accumulated amortization	$ 361,856	$ 359,944
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	42,184,609	42,186,709
Preferred shares of beneficial interest: outstanding shares	42,184,609	42,186,709
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	185,642,051	185,080,020
Common shares of beneficial interest: outstanding shares	185,642,051	185,080,020
Common Class A [Member]
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Redeemable noncontrolling interests units outstanding	12,172,197	12,160,771
Cumulative Redeemable Preferred Unit [Member]
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Redeemable noncontrolling interests units outstanding	9,000,001	9,000,001