Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
ASSETS
Operating (including $263,631 and $263,570 of consolidated variable interest entities, respectively)	$ 4,264,527	$ 4,232,608
Construction-in-progress	211,725	193,836
Real Estate Investment Property, At Cost, Total	4,476,252	4,426,444
Less accumulated depreciation and amortization (including $8,497 and $4,991 of consolidated variable interest entities, respectively)	(1,169,278)	(1,127,588)
Net real estate	3,306,974	3,298,856
Cash and cash equivalents	82,774	67,806
Accounts and notes receivable, net	76,601	75,921
Mortgage notes receivable, net	55,887	55,967
Investment in real estate partnership	34,055	34,352
Prepaid expenses and other assets	114,302	121,492
Debt issuance costs, net of accumulated amortization of $10,574 and $9,098, respectively	10,336	11,816
TOTAL ASSETS	3,680,929	3,666,210
Liabilities
Mortgages payable (including $206,506 and $207,683 of consolidated variable interest entities, respectively)	733,997	747,523
Capital lease obligations	71,703	63,093
Notes payable	300,089	295,159
Senior notes and debentures	1,004,532	1,004,635
Accounts payable and accrued expenses	110,786	104,660
Dividends payable	44,588	44,229
Security deposits payable	12,745	12,221
Other liabilities and deferred credits	54,173	68,761
Total liabilities	2,332,613	2,340,281
Commitments and contingencies (Note 7)
Redeemable noncontrolling interests	81,858	85,325
Shareholders' equity
Preferred shares, authorized 15,000,000 shares, $.01 par: 5.417% Series 1 Cumulative Convertible Preferred Shares, (stated at liquidation preference $25 per share), 399,896 shares issued and outstanding	9,997	9,997
Common shares of beneficial interest, $.01 par, 100,000,000 shares authorized, 64,099,840 and 63,544,150 shares issued and outstanding, respectively	641	636
Additional paid-in capital	1,810,359	1,764,940
Accumulated dividends in excess of net income	(568,541)	(555,541)
Accumulated other comprehensive loss	(10,375)	(3,940)
Total shareholders' equity of the Trust	1,242,081	1,216,092
Noncontrolling interests	24,377	24,512
Total shareholders' equity	1,266,458	1,240,604
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$ 3,680,929	$ 3,666,210