Condensed Consolidating Statement of Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Condensed Financial Statements, Captions [Line Items]
REVENUES	$ 410,694	$ 425,005	$ 814,916	$ 841,728
EXPENSES:
Operating	287,610	304,001	574,990	602,223
General and administrative	26,559	25,360	51,951	56,592
Depreciation and amortization	28,752	27,675	57,136	55,052
Asset impairments	2,238		2,238
Costs and Expenses	345,159	357,036	686,315	713,867
OPERATING INCOME	65,535	67,969	128,601	127,861
OTHER (INCOME) EXPENSE:
Interest expense (income), net	8,364	11,912	18,712	24,478
Expenses associated with debt refinancing transactions		36,303		36,528
Other (income) expense	(613)	(37)	(1,000)	64
Total non-operating expense (income)	7,751	48,178	17,712	61,070
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	57,784	19,791	110,889	66,791
Income tax benefit (expense)	(2,052)	3,377	(3,419)	137,824
Income from continuing operations	55,732	23,168	107,470	204,615
Loss from discontinued operations, net of taxes		(2,739)		(3,094)
NET INCOME	55,732	20,429	107,470	201,521
Parent
Condensed Financial Statements, Captions [Line Items]
REVENUES	314,311	318,939	620,559	632,376
EXPENSES:
Operating	225,389	237,181	445,094	471,841
General and administrative	8,253	8,086	16,929	17,695
Depreciation and amortization	20,108	18,936	39,877	37,587
Asset impairments	2,238		2,238
Costs and Expenses	255,988	264,203	504,138	527,123
OPERATING INCOME	58,323	54,736	116,421	105,253
OTHER (INCOME) EXPENSE:
Interest expense (income), net	8,809	10,621	17,411	20,716
Expenses associated with debt refinancing transactions		28,386		28,563
Other (income) expense	(125)	(1)	(163)	320
Total non-operating expense (income)	8,684	39,006	17,248	49,599
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	49,639	15,730	99,173	55,654
Income tax benefit (expense)	86	(13)	(134)	138,198
Income from continuing operations	49,725	15,717	99,039	193,852
Income from equity in subsidiaries	6,007	4,712	8,431	7,669
NET INCOME	55,732	20,429	107,470	201,521
Combined Subsidiary Guarantors
Condensed Financial Statements, Captions [Line Items]
REVENUES	314,508	336,738	625,755	669,731
EXPENSES:
Operating	280,346	297,492	561,294	590,761
General and administrative	18,306	17,274	35,022	38,897
Depreciation and amortization	8,644	8,739	17,259	17,465
Costs and Expenses	307,296	323,505	613,575	647,123
OPERATING INCOME	7,212	13,233	12,180	22,608
OTHER (INCOME) EXPENSE:
Interest expense (income), net	(445)	1,291	1,301	3,762
Expenses associated with debt refinancing transactions		7,917		7,965
Other (income) expense	(449)	(17)	(528)	(218)
Total non-operating expense (income)	(894)	9,191	773	11,509
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	8,106	4,042	11,407	11,099
Income tax benefit (expense)	(2,138)	3,390	(3,285)	(374)
Income from continuing operations	5,968	7,432	8,122	10,725
Loss from discontinued operations, net of taxes		(2,739)		(3,094)
NET INCOME	5,968	4,693	8,122	7,631
Consolidating Adjustments and Other
Condensed Financial Statements, Captions [Line Items]
REVENUES	(218,125)	(230,672)	(431,398)	(460,379)
EXPENSES:
Operating	(218,125)	(230,672)	(431,398)	(460,379)
Costs and Expenses	(218,125)	(230,672)	(431,398)	(460,379)
OTHER (INCOME) EXPENSE:
Other (income) expense	(39)	(19)	(309)	(38)
Total non-operating expense (income)	(39)	(19)	(309)	(38)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	39	19	309	38
Income from continuing operations	39	19	309	38
Income from equity in subsidiaries	(6,007)	(4,712)	(8,431)	(7,669)
NET INCOME	$ (5,968)	$ (4,693)	$ (8,122)	$ (7,631)