Guarantor/Non-Guarantor Condensed Consolidated Financial Statements - Statements of Operations (Unaudited) (Details) (USD $) In Thousands, 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
Revenues	$ 227,868	$ 229,773	$ 229,824	$ 231,978	$ 203,656	$ 187,651	$ 171,285	$ 153,349	$ 919,443	$ 715,941	$ 487,210
Costs and expenses:
Operating costs									586,621	456,924	332,431
Depreciation and amortization									164,717	132,832	120,811
General and administrative									85,603	67,318	52,047
Intercompany leasing									0	0	0
Bad debt expense (recovery)									(440)	925	493
Impairment of equipment									1,131	484	0
Total costs and expenses									837,632	658,483	505,782
Income (loss) from operations	15,529	13,222	23,312	29,748	20,297	19,324	11,918	5,919	81,811	57,458	(18,572)
Other (expense) income:
Equity in earnings of subsidiaries									0	0	0
Interest expense									(37,049)	(29,721)	(26,567)
Impairment of investments									0	0	(3,331)
Other									1,624	(6,904)	912
Total other expense									(35,425)	(36,625)	(28,986)
Income (loss) before income taxes									46,386	20,833	(47,558)
Income tax (expense) benefit	(1,943)	(1,461)	(5,997)	(6,953)	(5,469)	(5,250)	(1,039)	2,102	(16,354)	(9,656)	14,297
Net income (loss)	3,560	2,615	9,685	14,172	6,818	6,744	3,650	(6,035)	30,032	11,177	(33,261)
Parent [Member]
Revenues									0	0	0
Costs and expenses:
Operating costs									0	0	0
Depreciation and amortization									873	847	1,271
General and administrative									22,212	19,797	15,337
Intercompany leasing									0	0	0
Bad debt expense (recovery)									0	0	0
Impairment of equipment									0	0
Total costs and expenses									23,085	20,644	16,608
Income (loss) from operations									(23,085)	(20,644)	(16,608)
Other (expense) income:
Equity in earnings of subsidiaries									68,352	43,182	(1,982)
Interest expense									(37,011)	(29,497)	(26,240)
Impairment of investments											(3,331)
Other									268	311	0
Total other expense									31,609	13,996	(31,553)
Income (loss) before income taxes									8,524	(6,648)	(48,161)
Income tax (expense) benefit									21,508	17,825	14,900
Net income (loss)									30,032	11,177	(33,261)
Guarantor Subsidiaries [Member]
Revenues									779,163	606,402	400,778
Costs and expenses:
Operating costs									485,342	372,945	263,649
Depreciation and amortization									142,972	119,520	109,971
General and administrative									54,715	45,152	34,177
Intercompany leasing									(4,860)	(4,860)	(4,323)
Bad debt expense (recovery)									(612)	925	493
Impairment of equipment									1,131	484
Total costs and expenses									678,688	534,166	403,967
Income (loss) from operations									100,475	72,236	(3,189)
Other (expense) income:
Equity in earnings of subsidiaries									4,029	(2,982)	1,335
Interest expense									(59)	(248)	(333)
Impairment of investments											0
Other									940	1,163	953
Total other expense									4,910	(2,067)	1,955
Income (loss) before income taxes									105,385	70,169	(1,234)
Income tax (expense) benefit									(37,033)	(26,987)	(748)
Net income (loss)									68,352	43,182	(1,982)
Non-Guarantor Subsidiaries [Member]
Revenues									140,280	109,539	86,432
Costs and expenses:
Operating costs									101,279	83,979	68,782
Depreciation and amortization									20,872	12,465	9,569
General and administrative									9,228	2,921	2,959
Intercompany leasing									4,860	4,857	4,323
Bad debt expense (recovery)									172	0	0
Impairment of equipment									0	0
Total costs and expenses									136,411	104,222	85,633
Income (loss) from operations									3,869	5,317	799
Other (expense) income:
Equity in earnings of subsidiaries									0	0	0
Interest expense									21	24	6
Impairment of investments											0
Other									968	(7,829)	385
Total other expense									989	(7,805)	391
Income (loss) before income taxes									4,858	(2,488)	1,190
Income tax (expense) benefit									(829)	(494)	145
Net income (loss)									4,029	(2,982)	1,335
Eliminations [Member]
Revenues									0	0	0
Costs and expenses:
Operating costs									0	0	0
Depreciation and amortization									0	0	0
General and administrative									(552)	(552)	(426)
Intercompany leasing									0	3	0
Bad debt expense (recovery)									0	0	0
Impairment of equipment									0	0
Total costs and expenses									(552)	(549)	(426)
Income (loss) from operations									552	549	426
Other (expense) income:
Equity in earnings of subsidiaries									(72,381)	(40,200)	647
Interest expense									0	0	0
Impairment of investments											0
Other									(552)	(549)	(426)
Total other expense									(72,933)	(40,749)	221
Income (loss) before income taxes									(72,381)	(40,200)	647
Income tax (expense) benefit									0	0	0
Net income (loss)									$ (72,381)	$ (40,200)	$ 647