Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
ASSETS
Operating (including $265,138 and $264,506 of consolidated variable interest entities, respectively)	$ 4,618,258	$ 4,473,813
Construction-in-progress	531,205	288,714
Assets held for sale/disposal (discontinued operations)	0	17,147
Real Estate Investment Property, At Cost, Total	5,149,463	4,779,674
Less accumulated depreciation and amortization (including $19,086 and $12,024 of consolidated variable interest entities, respectively)	(1,350,471)	(1,224,295)
Net real estate	3,798,992	3,555,379
Cash and cash equivalents	88,927	36,988
Accounts and notes receivable, net	84,838	73,861
Mortgage notes receivable, net	55,155	55,648
Investment in real estate partnership	32,264	33,169
Prepaid expenses and other assets	145,062	132,659
Debt issuance costs, net of accumulated amortization of $9,535 and $10,140, respectively	14,056	10,861
TOTAL ASSETS	4,219,294	3,898,565
Liabilities
Mortgages payable (including $202,782 and $205,299 of consolidated variable interest entities, respectively)	588,456	760,789
Capital lease obligations	71,671	71,693
Notes payable	300,822	299,575
Senior notes and debentures	1,360,913	1,076,545
Accounts payable and accrued expenses	156,270	120,929
Dividends payable	52,385	47,685
Security deposits payable	12,772	12,957
Other liabilities and deferred credits	100,283	103,379
Total liabilities	2,643,572	2,493,552
Commitments and contingencies (Note 9)
Redeemable Noncontrolling Interests	104,425	94,420
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, 66,701,422 and 64,815,446 shares issued and outstanding, respectively	667	648
Additional paid-in capital	2,062,708	1,875,525
Accumulated dividends in excess of net income	(623,795)	(586,970)
Accumulated other comprehensive loss	(1,417)	(12,388)
Total shareholders' equity of the Trust	1,448,160	1,286,812
Noncontrolling interests	23,137	23,781
Total shareholders' equity	1,471,297	1,310,593
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$ 4,219,294	$ 3,898,565