Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
ASSETS
Operating (including $281,311 and $265,138 of consolidated variable interest entities, respectively)	$ 5,004,993	$ 4,618,258
Construction-in-progress	472,570	531,205
Real Estate Investment Property, At Cost, Total	5,477,563	5,149,463
Less accumulated depreciation and amortization (including $22,840 and $19,086 of consolidated variable interest entities, respectively)	(1,417,376)	(1,350,471)
Net real estate	4,060,187	3,798,992
Cash and cash equivalents	41,312	88,927
Accounts and notes receivable, net	97,741	84,838
Mortgage notes receivable, net	54,932	55,155
Investment in real estate partnership	35,511	32,264
Prepaid expenses and other assets	128,564	145,062
Debt issuance costs, net of accumulated amortization of $10,969 and $9,535, respectively	13,238	14,056
TOTAL ASSETS	4,431,485	4,219,294
Liabilities
Mortgages payable (including $188,739 and $202,782 of consolidated variable interest entities, respectively)	634,045	588,456
Capital lease obligations	71,659	71,671
Notes payable	290,765	300,822
Senior notes and debentures	1,361,282	1,360,913
Accounts payable and accrued expenses	168,615	156,270
Dividends payable	53,631	52,385
Security deposits payable	13,502	12,772
Other liabilities and deferred credits	109,242	100,283
Total liabilities	2,702,741	2,643,572
Commitments and contingencies (Note 7)
Redeemable noncontrolling interests	110,688	104,425
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, 67,712,366 and 66,701,422 shares issued and outstanding, respectively	678	667
Additional paid-in capital	2,170,152	2,062,708
Accumulated dividends in excess of net income	(647,006)	(623,795)
Accumulated other comprehensive loss	(4,060)	(1,417)
Total shareholders' equity of the Trust	1,529,761	1,448,160
Noncontrolling interests	88,295	23,137
Total shareholders' equity	1,618,056	1,471,297
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$ 4,431,485	$ 4,219,294