Variable Interest Entity and Equity Method Investment (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Statement of operations
Revenue	$ 395,421	$ 306,755	$ 768,879	$ 702,733
Total revenue	415,120	442,822	788,393	790,085
Facility expenses	62,797	48,230	122,307	96,555
Selling, general and administrative expenses	25,499	21,700	50,741	46,748
Depreciation	71,562	41,336	139,579	80,918
Accretion of asset retirement obligations	157	160	509	396
Total operating expenses	275,098	185,081	584,708	481,852
Income from operations	140,022	257,741	203,685	308,233
Earnings from unconsolidated affiliate	430	1,109	665	1,548
Income before provision for income tax	101,781	231,006	87,207	251,325
Net income	85,498	186,533	64,367	202,307
Net (income) loss attributable to non-controlling interest	(1,799)	375	3,874	621
As previously reported
Statement of operations
Revenue		309,986		709,167
Total revenue		446,053		796,519
Facility expenses		48,538		97,378
Selling, general and administrative expenses		21,879		47,103
Depreciation		42,918		84,063
Accretion of asset retirement obligations		161		399
Total operating expenses		187,151		486,178
Income from operations		258,902		310,341
Earnings from unconsolidated affiliate		551		542
Income before provision for income tax		231,609		252,427
Net income		187,136		203,409
Net (income) loss attributable to non-controlling interest		$ (228)		$ (481)