Equity Investments (Details 3) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Statements:
Rental income	$ 264,692	$ 255,225	$ 249,797	$ 243,378	$ 233,528	$ 232,282	$ 208,883	$ 199,539	$ 1,013,092	$ 874,232	$ 720,747
Operating expenses									(419,681)	(363,464)	(302,901)
Loss on asset impairment									(242,497)		(139,673)
Acquisition related costs									(5,648)	(10,073)	(21,553)
General and administrative									(51,697)	(43,682)	(36,672)
Operating income									290,337	247,280	141,992
Interest and other income									1,428	1,662	2,171
Interest expense									(204,244)	(195,024)	(179,642)
Loss on extinguishment of debt									(1,895)	(35)	(796)
Equity in earnings (losses) of investees									11,420	11,377	8,464
Income before income tax expense									104,292	76,437	27,389
Income tax expense									(3,207)	(1,347)	(550)
Net (loss) income									(79,845)	109,984	135,409
GOV
Income Statements:
Rental income									211,076	178,950	117,219
Operating expenses									(78,781)	(66,445)	(41,178)
Depreciation and amortization									(51,166)	(40,089)	(24,239)
Loss on asset impairment									(494)
Acquisition related costs									(1,614)	(3,504)	(5,750)
General and administrative									(12,355)	(10,898)	(7,061)
Operating income									66,666	58,014	38,991
Interest and other income									29	104	103
Interest expense									(16,892)	(12,057)	(7,351)
Loss on extinguishment of debt											(3,786)
Equity in earnings (losses) of investees									316	139	(1)
Income before income tax expense									50,119	46,200	27,956
Income tax expense									(159)	(203)	(161)
Net (loss) income									$ 49,960	$ 45,997	$ 27,795
Weighted average common shares outstanding									48,617	43,368	34,341
Net income per common share (in dollars per share)									$ 1.03	$ 1.06	$ 0.81
AIC
Income Statements:
Number of other companies which are shareholders of related party	5								5
Equity method investments, ownership percentage by each of CWH and SIR	12.50%								12.50%