CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
CASH FLOWS FROM OPERATING ACTIVITIES:
Net (loss) income	$ (79,845)	$ 109,984	$ 135,409
Adjustments to reconcile net (loss) income to cash provided by operating activities:
Depreciation	188,123	166,444	180,619
Net amortization of debt discounts, premiums and deferred financing fees	3,405	6,943	7,534
Straight line rental income	(38,812)	(31,474)	(12,200)
Amortization of acquired real estate leases	60,176	48,441	34,032
Other amortization	19,955	16,744	16,324
Loss on asset impairment	168,632	10,355	129,264
Loss on early extinguishment of debt	1,895	35	1,044
Equity in earnings of investees	(11,420)	(11,377)	(8,464)
Gain on issuance of shares by an equity investee	(7,246)	(11,177)	(34,808)
Distributions of earnings from investees	10,835	11,238	8,465
Net gain on sale of properties	(2,039)	(42,752)	(172,104)
Gain on asset acquisition			(20,392)
Change in assets and liabilities:
Restricted cash	(6,216)	(2,787)	6,580
Rents receivable and other assets	(38,801)	(31,362)	(22,580)
Accounts payable and accrued expenses	6,034	12,589	3,129
Rent collected in advance	(1,104)	8,479	(1,200)
Security deposits	1,548	1,933	719
Due to related persons	1,663	1,076	683
Cash provided by operating activities	276,783	263,332	252,054
CASH FLOWS FROM INVESTING ACTIVITIES:
Real estate acquisitions	(631,279)	(768,060)	(895,549)
Real estate improvements	(131,300)	(100,339)	(77,389)
Investment in direct financing lease, net		(38,635)
Principal payments received from direct financing lease	6,645	5,256
Principal payments received from real estate mortgage receivable		8,183	105
Proceeds from investment in marketable pass through certificates			8,000
Proceeds from sale of properties, net	9,643	264,284	603,800
Distributions in excess of earnings from investees	5,981	5,379	7,654
Investment in Affiliates Insurance Company	(5,335)		(76)
Increase in restricted cash	(2,541)
Cash used in investing activities	(748,186)	(623,932)	(353,455)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common shares, net	363,657	264,056	430,778
Proceeds from issuance of preferred shares, net		265,391
Redemption of preferred shares	(150,000)		(175,000)
Proceeds from borrowings	1,702,500	1,007,000	1,828,632
Payments on borrowings	(1,312,982)	(975,030)	(1,618,101)
Deferred financing fees	(15,117)	(7,131)	(13,055)
Distributions to common shareholders	(146,539)	(150,074)	(126,237)
Distributions to preferred shareholders	(52,710)	(44,405)	(49,656)
Distributions to noncontrolling interest in consolidated subsidiary	(8,386)
Purchase of noncontrolling equity interest			(2,500)
Cash provided by financing activities	380,423	359,807	274,861
Effect of exchange rate changes on cash	436	(484)	2,376
(Decrease) increase in cash and cash equivalents	(90,544)	(1,277)	175,836
Cash and cash equivalents at beginning of year	192,763	194,040	18,204
Cash and cash equivalents at end of year	102,219	192,763	194,040
SUPPLEMENTAL CASH FLOW INFORMATION:
Interest paid	204,772	186,774	173,221
Taxes paid	779	966	690
NON-CASH INVESTING ACTIVITIES:
Real estate acquisitions	(370,139)	(321,235)
Investment in real estate mortgages receivable	(1,419)		(8,288)
Working capital acquired			1,153
NON-CASH FINANCING ACTIVITIES:
Issuance of common shares	1,124	1,039	896
Assumption of mortgage notes payable	359,213	321,235
Liabilities assumed	10,926
Assumption of note payable		4,059
Common distributions declared			$ (26,863)