(Statements of Operations (Unaudited)) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Mar. 31, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues	$ 243,979	$ 229,773		$ 722,003	$ 691,575
Operating Costs	161,260	153,583		470,292	439,670
Costs and expenses:
Depreciation and amortization	47,414	42,067		141,047	120,429
General and administrative	23,896	21,269		70,872	64,677
Intercompany leasing	0	0		0	0
Bad debt expense (recovery)	35	(368)		453	(515)
Impairment charges	9,504	0	1,000	54,292	1,032
Total costs and expenses	242,109	216,551		736,956	625,293
Income (loss) from operations	1,870	13,222		(14,953)	66,282
Other (expense) income:
Equity in earnings of subsidiaries	0	0		0	0
Interest expense	(12,324)	(9,453)		(36,117)	(26,658)
Other	610	307		(1,460)	1,259
Total other expense	(11,714)	(9,146)		(37,577)	(25,399)
Income (loss) before income taxes	(9,844)	4,076		(52,530)	40,883
Income tax (expense) benefit	3,614	(1,461)		19,113	(14,411)
Net income (loss)	(6,230)	2,615		(33,417)	26,472
Parent [Member]
Revenues	0	0		0	0
Operating Costs	0	0		0	0
Costs and expenses:
Depreciation and amortization	294	201		828	658
General and administrative	7,052	5,653		18,563	16,713
Intercompany leasing	0	0		0	0
Bad debt expense (recovery)	0	0		67	0
Impairment charges	0			0	0
Total costs and expenses	7,346	5,854		19,458	17,371
Income (loss) from operations	(7,346)	(5,854)		(19,458)	(17,371)
Other (expense) income:
Equity in earnings of subsidiaries	6,377	11,274		2,111	52,794
Interest expense	(12,320)	(9,440)		(36,110)	(26,648)
Other	3	477		5	337
Total other expense	(5,940)	2,311		(33,994)	26,483
Income (loss) before income taxes	(13,286)	(3,543)		(53,452)	9,112
Income tax (expense) benefit	7,056	6,158		20,035	17,360
Net income (loss)	(6,230)	2,615		(33,417)	26,472
Guarantor Subsidiaries [Member]
Revenues	214,020	191,753		630,642	575,927
Operating Costs	138,961	125,295		406,806	356,880
Costs and expenses:
Depreciation and amortization	43,794	35,727		130,241	102,216
General and administrative	16,110	12,780		50,272	40,151
Intercompany leasing	(1,215)	(1,215)		(3,645)	(3,645)
Bad debt expense (recovery)	35	(412)		386	(687)
Impairment charges	9,504			54,292	1,032
Total costs and expenses	207,189	172,175		638,352	495,947
Income (loss) from operations	6,831	19,578		(7,710)	79,980
Other (expense) income:
Equity in earnings of subsidiaries	1,845	(441)		5,698	3,820
Interest expense	(13)	(26)		(33)	(23)
Other	568	210		1,425	710
Total other expense	2,400	(257)		7,090	4,507
Income (loss) before income taxes	9,231	19,321		(620)	84,487
Income tax (expense) benefit	(2,854)	(8,047)		2,731	(31,693)
Net income (loss)	6,377	11,274		2,111	52,794
Non-Guarantor Subsidiaries [Member]
Revenues	29,959	38,020		91,361	115,648
Operating Costs	22,299	28,288		63,486	82,790
Costs and expenses:
Depreciation and amortization	3,326	6,139		9,978	17,555
General and administrative	872	2,974		2,451	8,227
Intercompany leasing	1,215	1,215		3,645	3,645
Bad debt expense (recovery)	0	44		0	172
Impairment charges	0			0	0
Total costs and expenses	27,712	38,660		79,560	112,389
Income (loss) from operations	2,247	(640)		11,801	3,259
Other (expense) income:
Equity in earnings of subsidiaries	0	0		0	0
Interest expense	9	13		26	13
Other	177	(242)		(2,476)	626
Total other expense	186	(229)		(2,450)	639
Income (loss) before income taxes	2,433	(869)		9,351	3,898
Income tax (expense) benefit	(588)	428		(3,653)	(78)
Net income (loss)	1,845	(441)		5,698	3,820
Eliminations [Member]
Revenues	0	0		0	0
Operating Costs	0	0		0	0
Costs and expenses:
Depreciation and amortization	0	0		0	0
General and administrative	(138)	(138)		(414)	(414)
Intercompany leasing	0	0		0	0
Bad debt expense (recovery)	0	0		0	0
Impairment charges	0			0	0
Total costs and expenses	(138)	(138)		(414)	(414)
Income (loss) from operations	138	138		414	414
Other (expense) income:
Equity in earnings of subsidiaries	(8,222)	(10,833)		(7,809)	(56,614)
Interest expense	0	0		0	0
Other	(138)	(138)		(414)	(414)
Total other expense	(8,360)	(10,971)		(8,223)	(57,028)
Income (loss) before income taxes	(8,222)	(10,833)		(7,809)	(56,614)
Income tax (expense) benefit	0	0		0	0
Net income (loss)	$ (8,222)	$ (10,833)		$ (7,809)	$ (56,614)