Variable Interest Entities (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of operations
Revenue									$ 1,687,085	$ 1,383,279	$ 1,522,592
Total revenue	453,538	420,516	415,120	373,273	369,153	280,576	442,822	347,263	1,662,447	1,439,814	1,493,557
Facility expenses									291,069	206,861	171,497
Selling, general and administrative expenses									101,549	93,444	80,441
Depreciation									299,884	183,250	143,704
Accretion of asset retirement obligations									824	672	1,185
Total operating expenses									1,416,504	1,061,538	1,178,091
Income from operations	34,495	7,763	140,022	63,663	61,450	8,593	257,741	50,492	245,943	378,276	315,466
Earnings from unconsolidated affiliates									1,422	2,328	158
Income before provision for income tax									53,114	255,293	118,449
Net income	(3,895)	(20,027)	85,498	(21,131)	29,923	(15,265)	186,533	15,774	40,445	216,965	104,800
Net (income) loss attributable to non-controlling interest									(2,368)	3,437	(44,105)
As previously reported
Statement of operations
Revenue										1,395,231	1,534,434
Total revenue										1,451,766	1,505,399
Facility expenses										208,385	173,598
Selling, general and administrative expenses										94,116	81,229
Depreciation										189,549	149,954
Accretion of asset retirement obligations										677	1,190
Total operating expenses										1,070,038	1,187,235
Income from operations										381,728	318,164
Earnings from unconsolidated affiliates										699	(1,095)
Income before provision for income tax										257,116	119,894
Net income										218,788	106,245
Net (income) loss attributable to non-controlling interest										$ 1,614	$ (45,550)