Consolidated Balance Sheets (Parentheticals) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
ASSETS
Accounts receivable, allowance for doubtful accounts	$ 42,166	$ 43,241
Receivable arising from the straight-lining of rents, allowance	2,909	3,290
Deferred leasing and financing costs, amortization	222,123	241,073
Identified intangible assets: Accumulated amortization	$ 349,060	$ 347,105
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	185,814,787	185,080,020
Common shares of beneficial interest: outstanding shares	185,814,787	185,080,020
Common Class A [Member]
LIABILITIES, REDEEMABLE NONCONTROLLING INTERESTS AND EQUITY
Redeemable noncontrolling interests units outstanding	12,036,494	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