Condensed Consolidating Statement of Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Condensed Financial Statements, Captions [Line Items]
REVENUES	$ 425,724	$ 435,305
EXPENSES:
Operating	307,530	315,534
General and administrative	31,232	21,840
Depreciation and amortization	27,630	28,387
Costs and Expenses	366,392	365,761
Operating income	59,332	69,544
OTHER (INCOME) EXPENSE:
Interest expense, net	12,566	16,890
Expenses associated with debt refinancing transactions	225	1,541
Other (income) expense	101	12
Total non-operating expense (income)	12,892	18,443
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	46,440	51,101
Income tax (expense) benefit	134,652	(19,059)
INCOME (LOSS) FROM CONTINUING OPERATIONS	181,092	32,042
Loss from discontinued operations, net of taxes		(362)
NET INCOME	181,092	31,680
Parent
Condensed Financial Statements, Captions [Line Items]
REVENUES	313,437	349,574
EXPENSES:
Operating	234,660	237,531
General and administrative	9,609	17,384
Depreciation and amortization	18,651	18,251
Costs and Expenses	262,920	273,166
Operating income	50,517	76,408
OTHER (INCOME) EXPENSE:
Interest expense, net	10,095	16,594
Expenses associated with debt refinancing transactions	177	1,541
Other (income) expense	321	21
Total non-operating expense (income)	10,593	18,156
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	39,924	58,252
Income tax (expense) benefit	138,211	(20,796)
INCOME (LOSS) FROM CONTINUING OPERATIONS	178,135	37,456
Gain/Loss from equity in subsidiaries	2,957	(5,776)
NET INCOME	181,092	31,680
Combined Subsidiary Guarantors
Condensed Financial Statements, Captions [Line Items]
REVENUES	341,994	90,621
EXPENSES:
Operating	302,577	82,893
General and administrative	21,623	4,456
Depreciation and amortization	8,979	10,136
Costs and Expenses	333,179	97,485
Operating income	8,815	(6,864)
OTHER (INCOME) EXPENSE:
Interest expense, net	2,471	296
Expenses associated with debt refinancing transactions	48
Other (income) expense	(201)	(29)
Total non-operating expense (income)	2,318	267
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	6,497	(7,131)
Income tax (expense) benefit	(3,559)	1,737
INCOME (LOSS) FROM CONTINUING OPERATIONS	2,938	(5,394)
Loss from discontinued operations, net of taxes		(362)
NET INCOME	2,938	(5,756)
Consolidating Adjustments and Other
Condensed Financial Statements, Captions [Line Items]
REVENUES	(229,707)	(4,890)
EXPENSES:
Operating	(229,707)	(4,890)
Costs and Expenses	(229,707)	(4,890)
OTHER (INCOME) EXPENSE:
Other (income) expense	(19)	20
Total non-operating expense (income)	(19)	20
INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	19	(20)
INCOME (LOSS) FROM CONTINUING OPERATIONS	19	(20)
Gain/Loss from equity in subsidiaries	(2,957)	5,776
NET INCOME	$ (2,938)	$ 5,756