Condensed Consolidating Statement of Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Condensed Financial Statements, Captions [Line Items]
REVENUES	$ 421,466	$ 435,727	$ 1,263,194	$ 1,295,980
EXPENSES:
Operating	301,489	305,591	903,712	920,065
General and administrative	23,570	22,015	80,162	66,950
Depreciation and amortization	28,151	28,388	83,203	84,656
Asset impairments	985		985
Costs and Expenses	354,195	355,994	1,068,062	1,071,671
Operating income	67,271	79,733	195,132	224,309
OTHER (INCOME) EXPENSES:
Interest expense, net	10,378	13,722	34,856	45,341
Expenses associated with debt refinancing transactions		168	36,528	1,996
Other (income) expense	(184)	(422)	(120)	(370)
Total non-operating expense (income)	10,194	13,468	71,264	46,967
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	57,077	66,265	123,868	177,342
Income tax (expense) benefit	(4,571)	(24,025)	133,253	(65,634)
INCOME (LOSS) FROM CONTINUING OPERATIONS	52,506	42,240	257,121	111,708
(Loss) income from discontinued operations, net of taxes	(663)	99	(3,757)	(355)
NET INCOME	51,843	42,339	253,364	111,353
Parent
Condensed Financial Statements, Captions [Line Items]
REVENUES	312,837	357,515	945,213	1,063,159
EXPENSES:
Operating	232,380	238,115	704,221	715,354
General and administrative	6,954	17,524	24,649	53,292
Depreciation and amortization	19,268	18,805	56,855	55,515
Costs and Expenses	258,602	274,444	785,725	824,161
Operating income	54,235	83,071	159,488	238,998
OTHER (INCOME) EXPENSES:
Interest expense, net	8,877	13,426	29,593	44,453
Expenses associated with debt refinancing transactions		168	28,563	1,996
Other (income) expense	(275)	(70)	45	(22)
Total non-operating expense (income)	8,602	13,524	58,201	46,427
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	45,633	69,547	101,287	192,571
Income tax (expense) benefit	(217)	(24,828)	137,981	(68,748)
INCOME (LOSS) FROM CONTINUING OPERATIONS	45,416	44,719	239,268	123,823
Income (Loss) from equity in subsidiaries	6,427	(2,380)	14,096	(12,470)
NET INCOME	51,843	42,339	253,364	111,353
Combined Subsidiary Guarantors
Condensed Financial Statements, Captions [Line Items]
REVENUES	337,548	82,668	1,007,279	246,254
EXPENSES:
Operating	298,028	71,932	888,789	218,144
General and administrative	16,616	4,491	55,513	13,658
Depreciation and amortization	8,883	9,583	26,348	29,141
Asset impairments	985		985
Costs and Expenses	324,512	86,006	971,635	260,943
Operating income	13,036	(3,338)	35,644	(14,689)
OTHER (INCOME) EXPENSES:
Interest expense, net	1,501	296	5,263	888
Expenses associated with debt refinancing transactions			7,965
Other (income) expense	111	(1)	(107)	(36)
Total non-operating expense (income)	1,612	295	13,121	852
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	11,424	(3,633)	22,523	(15,541)
Income tax (expense) benefit	(4,354)	803	(4,728)	3,114
INCOME (LOSS) FROM CONTINUING OPERATIONS	7,070	(2,830)	17,795	(12,427)
(Loss) income from discontinued operations, net of taxes	(663)	99	(3,757)	(355)
NET INCOME	6,407	(2,731)	14,038	(12,782)
Consolidating Adjustments and Other
Condensed Financial Statements, Captions [Line Items]
REVENUES	(228,919)	(4,456)	(689,298)	(13,433)
EXPENSES:
Operating	(228,919)	(4,456)	(689,298)	(13,433)
Costs and Expenses	(228,919)	(4,456)	(689,298)	(13,433)
OTHER (INCOME) EXPENSES:
Other (income) expense	(20)	(351)	(58)	(312)
Total non-operating expense (income)	(20)	(351)	(58)	(312)
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	20	351	58	312
INCOME (LOSS) FROM CONTINUING OPERATIONS	20	351	58	312
Income (Loss) from equity in subsidiaries	(6,427)	2,380	(14,096)	12,470
NET INCOME	$ (6,407)	$ 2,731	$ (14,038)	$ 12,782