Information Concerning Guarantor And Non-Guarantor Subsidiaries (Details 2) (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Cash and Cash Equivalents, Period Increase (Decrease) [Abstract]
Net cash provided by (used in) continuing operating activities	$ 82,905	$ 88,032
Net cash provided by (used in) discontinued operating activities	16	667
Net cash flows provided by operating activities	82,921	88,699
Purchases of property and equipment	(93,844)	(109,933)
Collection of notes receivable	2,465	4,073
Other investing activities	2,202	130
Net cash used in investing activities - continuing operations	(89,177)	(105,730)
Net cash flows used in investing activities - discontinued operations	0	(1,460)
Net cash flows used in investing activities	(89,177)	(107,190)
Net repayments under credit facility	(100,000)
Deferred financing costs paid	(10,074)
Repurchases of senior notes	0	(26,965)
Proceeds from exercise of stock option and purchase plans	4,275	2,297
Other financing activities, net	(221)	(924)
Net cash provided by (used in) financing activities continuing operations	(106,020)	(25,592)
Net cash flows provided by financing activities - discontinued operations	0	0
Net cash flows used in financing activities	(106,020)	(25,592)
Net change in cash and cash equivalents	(112,276)	(44,083)
Cash and cash equivalents - unrestricted, beginning of period	124,398	180,029
Cash and cash equivalents - unrestricted, end of period	12,122	135,946
Parent Company [Member]
Cash and Cash Equivalents, Period Increase (Decrease) [Abstract]
Net cash provided by (used in) continuing operating activities	682	(18,938)
Net cash flows provided by operating activities	682	(18,938)
Purchases of property and equipment	(4,428)	(1,669)
Other investing activities	10
Net cash used in investing activities - continuing operations	(4,418)	(1,669)
Net cash flows used in investing activities - discontinued operations	0
Net cash flows used in investing activities	(4,418)	(1,669)
Net repayments under credit facility	(100,000)
Deferred financing costs paid	(10,074)
Repurchases of senior notes		(26,965)
Proceeds from exercise of stock option and purchase plans	4,275	2,297
Other financing activities, net		411
Net cash provided by (used in) financing activities continuing operations	(105,799)	(24,257)
Net cash flows provided by financing activities - discontinued operations	0	0
Net cash flows used in financing activities	(105,799)	(24,257)
Net change in cash and cash equivalents	(109,535)	(44,864)
Cash and cash equivalents - unrestricted, beginning of period	117,913	175,871
Cash and cash equivalents - unrestricted, end of period	8,378	131,007
Guarantor Subsidiaries [Member]
Cash and Cash Equivalents, Period Increase (Decrease) [Abstract]
Net cash provided by (used in) continuing operating activities	82,202	106,154
Net cash provided by (used in) discontinued operating activities	37	23
Net cash flows provided by operating activities	82,239	106,177
Purchases of property and equipment	(89,416)	(108,264)
Collection of notes receivable	2,465	4,073
Other investing activities	2,192	130
Net cash used in investing activities - continuing operations	(84,759)	(104,061)
Net cash flows used in investing activities - discontinued operations	0
Net cash flows used in investing activities	(84,759)	(104,061)
Other financing activities, net	(221)	(1,335)
Net cash provided by (used in) financing activities continuing operations	(221)	(1,335)
Net cash flows provided by financing activities - discontinued operations	0	0
Net cash flows used in financing activities	(221)	(1,335)
Net change in cash and cash equivalents	(2,741)	781
Cash and cash equivalents - unrestricted, beginning of period	6,485	4,158
Cash and cash equivalents - unrestricted, end of period	3,744	4,939
Non-Guarantor Subsidiaries [Member]
Cash and Cash Equivalents, Period Increase (Decrease) [Abstract]
Net cash provided by (used in) continuing operating activities	21	816
Net cash provided by (used in) discontinued operating activities	(21)	644
Net cash flows provided by operating activities		1,460
Net cash flows used in investing activities - discontinued operations	0	(1,460)
Net cash flows used in investing activities		(1,460)
Net cash flows provided by financing activities - discontinued operations	0	0
Cash and cash equivalents - unrestricted, beginning of period	0
Cash and cash equivalents - unrestricted, end of period	0
Consolidation, Eliminations [Member]
Cash and Cash Equivalents, Period Increase (Decrease) [Abstract]
Net cash flows used in investing activities - discontinued operations	0
Net cash flows provided by financing activities - discontinued operations	0	0
Cash and cash equivalents - unrestricted, beginning of period	0
Cash and cash equivalents - unrestricted, end of period	$ 0