Long-Term Debt - Schedule of Impact of Corrections on Affected Financial Statements (Previously Issued Annual Periods) (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Selected Statements of Comprehensive Income Data:
Operating expenses									$ 727,659	$ 743,322	$ 730,582
Interest expense									81,543	90,622	110,565
Loss on early extinguishment of debt and write-off of discounts and deferred financing costs							29,858		461	29,858	2,053
Income before income taxes									78,791	77,634	111,661
Provision for income taxes									28,872	25,714	37,440
Net income	(25,446)	87,176	37,406	(49,217)	(12,969)	120,740	(15,900)	(39,951)	49,919	51,920	74,221
Earnings per share:
Net income per share, basic	$ (0.29)	$ 1.01	$ 0.43	$ (0.56)	$ (0.14)	$ 1.35	$ (0.18)	$ (0.48)	$ 0.57	$ 0.59	$ 0.90
Net income per share, diluted	$ (0.29)	$ 1.00	$ 0.43	$ (0.56)	$ (0.14)	$ 1.34	$ (0.18)	$ (0.48)	$ 0.57	$ 0.59	$ 0.89
Selected Statements of Cash Flows Data:
Net cash provided by operating activities									261,532	286,461	299,440
Net cash used in financing activities									(177,921)	(48,919)	(116,110)
As Previously Reported [Member]
Selected Statements of Comprehensive Income Data:
Operating expenses	169,430	202,625	189,190	167,912			194,674	173,260		739,989	726,509
Interest expense	20,986	21,018	20,638	20,046			22,926	28,606		93,536	111,426
Loss on early extinguishment of debt and write-off of discounts and deferred financing costs							32,429			32,429
Income before income taxes	(20,433)	184,589	59,994	(79,471)			(24,268)	(64,406)		75,482	116,926
Provision for income taxes	(6,926)	64,390	22,658	(30,040)			(8,414)	(24,046)		25,004	39,482
Net income	(13,507)	120,199	37,336	(49,431)			(15,854)	(40,360)		50,478	77,444
Earnings per share:
Net income per share, basic	$ (0.15)	$ 1.34	$ 0.43	$ (0.56)			$ (0.18)	$ (0.49)		$ 0.58	$ 0.94
Net income per share, diluted	$ (0.15)	$ 1.33	$ 0.43	$ (0.56)			$ (0.18)	$ (0.49)		$ 0.57	$ 0.93
Selected Statements of Cash Flows Data:
Net cash provided by operating activities										289,794	303,513
Net cash used in financing activities										(52,252)	(120,183)
Adjustments [Member]
Selected Statements of Comprehensive Income Data:
Operating expenses							3,333			3,333	4,073
Interest expense	(803)	(807)	(112)	(342)			(694)	(610)		(2,914)	(861)
Loss on early extinguishment of debt and write-off of discounts and deferred financing costs							(2,571)			(2,571)	2,053
Income before income taxes	803	807	112	342			(68)	610		2,152	(5,265)
Provision for income taxes	265	266	42	128			(22)	201		710	(2,042)
Net income	538	541	70	214			(46)	409		1,442	(3,223)
Earnings per share:
Net income per share, basic	$ 0.01	$ 0.01						$ 0.01		$ 0.01	$ (0.04)
Net income per share, diluted	$ 0.01	$ 0.01						$ 0.01		$ 0.02	$ (0.04)
Selected Statements of Cash Flows Data:
Net cash provided by operating activities										(3,333)	(4,073)
Net cash used in financing activities										3,333	4,073
Scenario as Revised [Member]
Selected Statements of Comprehensive Income Data:
Operating expenses	169,430	202,625	189,190	167,912			198,007	173,260		743,322	730,582
Interest expense	20,183	20,211	20,526	19,704			22,232	27,996		90,622	110,565
Loss on early extinguishment of debt and write-off of discounts and deferred financing costs							29,858			29,858	2,053
Income before income taxes	(19,630)	185,396	60,106	(79,129)			(24,336)	(63,796)		77,634	111,661
Provision for income taxes	(6,661)	64,656	22,700	(29,912)			(8,436)	(23,845)		25,714	37,440
Net income	(12,969)	120,740	37,406	(49,217)			(15,900)	(39,951)		51,920	74,221
Earnings per share:
Net income per share, basic	$ (0.14)	$ 1.35	$ 0.43	$ (0.56)			$ (0.18)	$ (0.48)		$ 0.59	$ 0.90
Net income per share, diluted	$ (0.14)	$ 1.34	$ 0.43	$ (0.56)			$ (0.18)	$ (0.48)		$ 0.59	$ 0.89
Selected Statements of Cash Flows Data:
Net cash provided by operating activities										286,461	299,440
Net cash used in financing activities										$ (48,919)	$ (116,110)