Condensed Consolidating Statement of Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Condensed Financial Statements, Captions [Line Items]
REVENUES	$ 433,981	$ 442,866	$ 859,705	$ 878,171
EXPENSES:
Operating	314,277	316,584	621,807	632,118
General and administrative	25,360	23,095	56,592	44,935
Depreciation and amortization	28,097	28,302	55,727	56,689
Asset impairments	2,637		2,637
Costs and Expenses	370,371	367,981	736,763	733,742
Operating income	63,610	74,885	122,942	144,429
OTHER (INCOME) EXPENSE:
Interest expense, net	11,912	14,729	24,478	31,619
Expenses associated with debt refinancing transactions	36,303	287	36,528	1,828
Other (income) expense	(36)	41	65	53
Total non-operating expense (income)	48,179	15,057	61,071	33,500
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	15,431	59,828	61,871	110,929
Income tax (expense) benefit	4,998	(22,494)	139,650	(41,553)
INCOME (LOSS) FROM CONTINUING OPERATIONS	20,429	37,334	201,521	69,376
Loss from discontinued operations, net of taxes				(362)
NET INCOME	20,429	37,334	201,521	69,014
Parent
Condensed Financial Statements, Captions [Line Items]
REVENUES	318,939	356,070	632,376	705,644
EXPENSES:
Operating	237,181	239,708	471,841	477,239
General and administrative	8,086	18,384	17,695	35,768
Depreciation and amortization	18,936	18,459	37,587	36,710
Costs and Expenses	264,203	276,551	527,123	549,717
Operating income	54,736	79,519	105,253	155,927
OTHER (INCOME) EXPENSE:
Interest expense, net	10,621	14,433	20,716	31,027
Expenses associated with debt refinancing transactions	28,386	287	28,563	1,828
Other (income) expense	(1)	27	320	48
Total non-operating expense (income)	39,006	14,747	49,599	32,903
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	15,730	64,772	55,654	123,024
Income tax (expense) benefit	(13)	(23,124)	138,198	(43,920)
INCOME (LOSS) FROM CONTINUING OPERATIONS	15,717	41,648	193,852	79,104
Income (Loss) from equity in subsidiaries	4,712	(4,314)	7,669	(10,090)
NET INCOME	20,429	37,334	201,521	69,014
Combined Subsidiary Guarantors
Condensed Financial Statements, Captions [Line Items]
REVENUES	345,714	90,883	687,708	181,504
EXPENSES:
Operating	307,768	80,963	610,345	163,856
General and administrative	17,274	4,711	38,897	9,167
Depreciation and amortization	9,161	9,843	18,140	19,979
Asset impairments	2,637		2,637
Costs and Expenses	336,840	95,517	670,019	193,002
Operating income	8,874	(4,634)	17,689	(11,498)
OTHER (INCOME) EXPENSE:
Interest expense, net	1,291	296	3,762	592
Expenses associated with debt refinancing transactions	7,917		7,965
Other (income) expense	(16)	(5)	(217)	(34)
Total non-operating expense (income)	9,192	291	11,510	558
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(318)	(4,925)	6,179	(12,056)
Income tax (expense) benefit	5,011	630	1,452	2,367
INCOME (LOSS) FROM CONTINUING OPERATIONS	4,693	(4,295)	7,631	(9,689)
Loss from discontinued operations, net of taxes				(362)
NET INCOME	4,693	(4,295)	7,631	(10,051)
Consolidating Adjustments and Other
Condensed Financial Statements, Captions [Line Items]
REVENUES	(230,672)	(4,087)	(460,379)	(8,977)
EXPENSES:
Operating	(230,672)	(4,087)	(460,379)	(8,977)
Costs and Expenses	(230,672)	(4,087)	(460,379)	(8,977)
OTHER (INCOME) EXPENSE:
Other (income) expense	(19)	19	(38)	39
Total non-operating expense (income)	(19)	19	(38)	39
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	19	(19)	38	(39)
INCOME (LOSS) FROM CONTINUING OPERATIONS	19	(19)	38	(39)
Income (Loss) from equity in subsidiaries	(4,712)	4,314	(7,669)	10,090
NET INCOME	$ (4,693)	$ 4,295	$ (7,631)	$ 10,051