Condensed Consolidating Statement of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Condensed Financial Statements, Captions [Line Items]
Net cash provided by continuing operating activities	$ 129,266	$ 82,905
Net cash provided by (used in) discontinued operating activities	47	16
Net cash provided by operating activities	129,313	82,921
Purchases of property and equipment	(78,189)	(93,844)
Collection of notes receivable	4,480	2,465
Other investing activities	851	2,202
Net cash used in investing activities - continuing operations	(72,858)	(89,177)
Net cash used in investing activities - discontinued operations
Net cash used in investing activities	(72,858)	(89,177)
Net borrowings under credit facility	65,000	(100,000)
Deferred financing costs paid	(376)	(10,074)
Proceeds from issuance of common stock	32,722
Repurchase of Company stock for retirement	(185,400)
Proceeds from exercise of stock option and purchase plans	12,005	4,275
Other financing activities, net	(564)	(221)
Net cash provided by (used in) financing activities - continuing operations	(76,613)	(106,020)
Net cash provided by financing activities - discontinued operations
Net cash provided by (used in) financing activities	(76,613)	(106,020)
Net change in cash and cash equivalents	(20,158)	(112,276)
Cash and cash equivalents - unrestricted, beginning of period	44,388	124,398
Cash and cash equivalents - unrestricted, end of period	24,230	12,122
Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by continuing operating activities	62,976	682
Net cash provided by operating activities	62,976	682
Purchases of property and equipment	(6,648)	(4,428)
Other investing activities		10
Net cash used in investing activities - continuing operations	(6,648)	(4,418)
Net cash used in investing activities	(6,648)	(4,418)
Net borrowings under credit facility	65,000	(100,000)
Deferred financing costs paid	(376)	(10,074)
Proceeds from issuance of common stock	32,722
Repurchase of Company stock for retirement	(185,400)
Proceeds from exercise of stock option and purchase plans	12,005	4,275
Net cash provided by (used in) financing activities - continuing operations	(76,049)	(105,799)
Net cash provided by (used in) financing activities	(76,049)	(105,799)
Net change in cash and cash equivalents	(19,721)	(109,535)
Cash and cash equivalents - unrestricted, beginning of period	37,562	117,913
Cash and cash equivalents - unrestricted, end of period	17,841	8,378
Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by continuing operating activities	66,039	82,202
Net cash provided by (used in) discontinued operating activities		37
Net cash provided by operating activities	66,039	82,239
Purchases of property and equipment	(71,267)	(89,416)
Collection of notes receivable	4,480	2,465
Other investing activities	851	2,192
Net cash used in investing activities - continuing operations	(65,936)	(84,759)
Net cash used in investing activities	(65,936)	(84,759)
Other financing activities, net	(564)	(221)
Net cash provided by (used in) financing activities - continuing operations	(564)	(221)
Net cash provided by (used in) financing activities	(564)	(221)
Net change in cash and cash equivalents	(461)	(2,741)
Cash and cash equivalents - unrestricted, beginning of period	6,826	6,485
Cash and cash equivalents - unrestricted, end of period	6,365	3,744
Non-Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by continuing operating activities	251	21
Net cash provided by (used in) discontinued operating activities	47	(21)
Net cash provided by operating activities	298
Purchases of property and equipment	(274)
Net cash used in investing activities - continuing operations	(274)
Net cash used in investing activities	(274)
Net change in cash and cash equivalents	24
Cash and cash equivalents - unrestricted, end of period	24
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by continuing operating activities
Net cash provided by (used in) discontinued operating activities
Net cash provided by operating activities
Purchases of property and equipment
Collection of notes receivable
Other investing activities
Net cash used in investing activities - continuing operations
Net cash used in investing activities - discontinued operations
Net cash used in investing activities
Net borrowings under credit facility
Deferred financing costs paid
Proceeds from issuance of common stock
Repurchase of Company stock for retirement
Proceeds from exercise of stock option and purchase plans
Other financing activities, net
Net cash provided by (used in) financing activities - continuing operations
Net cash provided by financing activities - discontinued operations
Net cash provided by (used in) financing activities
Net change in cash and cash equivalents
Cash and cash equivalents - unrestricted, beginning of period
Cash and cash equivalents - unrestricted, end of period