Information Concerning Guarantor and Non-Guarantor Subsidiaries - Condensed Consolidating Statement of Cash Flows (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 75,610	$ 91,709
Purchases of property and equipment	(38,818)	(35,773)
Proceeds from sale of Peterson LOI	10,000
(Increase) decrease in restricted cash and cash equivalents	(7,860)	6,268
Other investing activities	340	398
Net cash provided by (used in) investing activities	(36,338)	(29,107)
Net borrowings under credit facility	(246,000)	(209,500)
Borrowings under term loan B	(2,000)	400,000
Issuance of senior notes	400,000
Repurchase and conversion of convertible notes		(126,541)
Repurchase of common stock warrants	(154,681)	(50,775)
Deferred financing costs paid	(10,723)	(8,158)
Payment of dividend	(62,070)	(53,389)
Proceeds from exercise of stock option and purchase plans	1,430	2,309
Other financing activities, net	(317)	(284)
Net cash provided by (used in) financing activities	(74,361)	(46,338)
Net change in cash and cash equivalents	(35,089)	16,264
Cash and cash equivalents - unrestricted, beginning of period	76,408	61,579
Cash and cash equivalents - unrestricted, end of period	41,319	77,843
Parent Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	205,079	235,131
Purchases of property and equipment	(53)	(6,649)
Proceeds from sale of Peterson LOI	10,000
Net cash provided by (used in) investing activities	9,947	(6,649)
Repurchase and conversion of convertible notes		(126,541)
Repurchase of common stock warrants	(154,681)	(50,775)
Payment of dividend	(62,070)	(53,389)
Proceeds from exercise of stock option and purchase plans	1,430	2,309
Other financing activities, net		12
Net cash provided by (used in) financing activities	(215,321)	(228,384)
Net change in cash and cash equivalents	(295)	98
Cash and cash equivalents - unrestricted, beginning of period	392
Cash and cash equivalents - unrestricted, end of period	97	98
Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(140,988)	(174,452)
Net borrowings under credit facility	(246,000)	(209,500)
Borrowings under term loan B	(2,000)	400,000
Issuance of senior notes	400,000
Deferred financing costs paid	(10,723)	(8,158)
Net cash provided by (used in) financing activities	141,277	182,342
Net change in cash and cash equivalents	289	7,890
Cash and cash equivalents - unrestricted, beginning of period	1,001	714
Cash and cash equivalents - unrestricted, end of period	1,290	8,604
Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	398	35
Purchases of property and equipment	(387)	(7)
Net cash provided by (used in) investing activities	(387)	(7)
Net change in cash and cash equivalents	11	28
Cash and cash equivalents - unrestricted, beginning of period	36
Cash and cash equivalents - unrestricted, end of period	47	28
Non-Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	11,121	30,995
Purchases of property and equipment	(38,378)	(29,117)
(Increase) decrease in restricted cash and cash equivalents	(7,860)	6,268
Other investing activities	340	398
Net cash provided by (used in) investing activities	(45,898)	(22,451)
Other financing activities, net	(317)	(296)
Net cash provided by (used in) financing activities	(317)	(296)
Net change in cash and cash equivalents	(35,094)	8,248
Cash and cash equivalents - unrestricted, beginning of period	74,979	60,865
Cash and cash equivalents - unrestricted, end of period	$ 39,885	$ 69,113