CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Real estate properties:
Land	$ 627,696	$ 615,623
Buildings and improvements	4,633,644	4,567,684
Total real estate properties, gross	5,261,340	5,183,307
Less accumulated depreciation	782,111	750,903
Total real estate properties, net	4,479,229	4,432,404
Cash and cash equivalents	38,989	42,382
Restricted cash	11,876	9,432
Deferred financing fees, net	28,409	29,410
Acquired real estate leases and other intangible assets, net	120,732	115,837
Other assets	132,034	118,537
Total assets	4,811,269	4,748,002
LIABILITIES AND SHAREHOLDERS' EQUITY
Unsecured revolving credit facility		190,000
Senior unsecured notes, net of discount	1,092,374	1,092,053
Secured debt and capital leases	734,227	724,477
Accrued interest	21,595	15,757
Assumed real estate lease obligations, net	15,121	13,692
Other liabilities	63,807	65,455
Total liabilities	1,927,124	2,101,434
Commitments and contingencies
Shareholders' equity:
Common shares of beneficial interest, $.01 par value: 199,700,000 shares authorized, 188,075,568 and 176,553,600 shares issued and outstanding at March 31, 2013 and December 31, 2012, respectively	1,880	1,765
Additional paid in capital	3,495,681	3,233,354
Cumulative net income	1,079,056	1,043,821
Cumulative other comprehensive income	13,318	4,562
Cumulative distributions	(1,705,790)	(1,636,934)
Total shareholders' equity	2,884,145	2,646,568
Total liabilities and shareholders' equity	$ 4,811,269	$ 4,748,002