Segment Information (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Segment information
Revenue	$ 376,137	$ 399,181
Derivative gain (loss) not allocated to segments	(185)	(48,715)
Total revenue	375,952	350,466
Selling, general and administrative expenses	(25,408)	(25,224)
Depreciation	(69,597)	(41,145)
Amortization of intangible assets	(14,830)	(10,985)
Loss on disposal of property, plant and equipment	(138)	(986)
Accretion of asset retirement obligations	(353)	(238)
Income from operations	64,350	51,439
Loss from unconsolidated affiliate	(85)	(9)
Interest income	149	72
Interest expense	(38,336)	(29,472)
Amortization of deferred financing costs and discount (a component of interest expense)	(1,830)	(1,270)
Loss on redemption of debt	(38,455)
Miscellaneous income (expense), net		58
(Loss) income before provision for income tax	(14,207)	20,818
Total reportable segments
Segment information
Revenue	377,902	401,449
Portion of operating income (loss) attributable to non-controlling interests	48	1,446
Income from operations	163,052	194,193
Southwest Segment
Segment information
Revenue	211,446	238,954
Revenue deferral adjustment	(200)	(200)
Portion of operating income (loss) attributable to non-controlling interests	1,387	1,446
Income from operations	66,834	100,645
Northeast Segment
Segment information
Revenue	57,336	86,918
Revenue deferral adjustment	(1,600)	(2,100)
Income from operations	31,150	54,853
Unallocated Segment
Segment information
Derivative gain (loss) not allocated to segments	10,851	(65,769)
Revenue deferral adjustment	(1,765)	(2,268)
Compensation expense included in facility expenses not allocated to segments	(387)	(449)
Facility expenses adjustments	$ 2,877	$ 2,864