CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net income	$ 35,235	$ 32,352
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	38,302	33,377
Amortization of deferred financing fees and debt discounts	1,065	1,555
Straight line rental income	(1,833)	(2,858)
Amortization of acquired real estate leases and other intangible assets	995	546
Impairment of assets	1,304	3,071
Equity in earnings of an investee	(76)	(45)
Change in assets and liabilities:
Restricted cash	(2,444)	(3,168)
Other assets	(3,822)	2,987
Accrued interest	5,838	(2,677)
Other liabilities	(868)	7,234
Cash provided by operating activities	73,696	72,374
Cash flows from investing activities:
Real estate acquisitions and deposits	(73,406)	(30,273)
Real estate improvements	(3,265)	(2,577)
Cash used for investing activities	(76,671)	(32,850)
Cash flows from financing activities:
Proceeds from issuance of common shares, net	261,859
Proceeds from borrowings on revolving credit facility		284,000
Repayments of borrowings on revolving credit facility	(190,000)	(19,000)
Redemption of senior notes		(225,000)
Repayment of other debt	(3,199)	(15,907)
Payment of deferred financing fees	(221)	(69)
Distributions to shareholders	(68,857)	(61,806)
Cash used for financing activities	(418)	(37,782)
(Decrease) increase in cash and cash equivalents	(3,393)	1,742
Cash and cash equivalents at beginning of period	42,382	23,560
Cash and cash equivalents at end of period	38,989	25,302
Supplemental cash flow information:
Interest paid	22,660	30,011
Income taxes paid	81
Non-cash investing activities:
Acquisitions funded by assumed debt	(12,266)
Non-cash financing activities:
Assumption of mortgage notes payable	12,266
Issuance of common shares	$ 582	$ 453