Information Concerning Guarantor and Non-Guarantor Subsidiaries (Details 2) (USD $) In Thousands, unless otherwise specified	1 Months Ended	12 Months Ended
	Sep. 30, 2009	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 Parent Company [Member]	Dec. 31, 2010 Parent Company [Member]	Dec. 31, 2009 Parent Company [Member]	Dec. 31, 2011 Guarantor Subsidiaries [Member]	Dec. 31, 2010 Guarantor Subsidiaries [Member]	Dec. 31, 2009 Guarantor Subsidiaries [Member]	Dec. 31, 2011 Non-Guarantor Subsidiaries [Member]	Dec. 31, 2010 Non-Guarantor Subsidiaries [Member]	Dec. 31, 2009 Non-Guarantor Subsidiaries [Member]	Dec. 31, 2011 Consolidation, Eliminations [Member]	Dec. 31, 2009 Consolidation, Eliminations [Member]	Dec. 31, 2008 Consolidation, Eliminations [Member]
CONDENSED CONSOLIDATING STATEMENT OF CASH FLOWS
Net cash provided by (used in) continuing operating activities		$ 153,904	$ 138,910	$ 125,010	$ 31,002	$ (54,296)	$ 93,089	$ 122,880	$ 192,298	$ 31,414	$ 22	$ 908	$ 507	$ 0
Net cash provided by (used in) discontinued operating activities		15	574	(1,951)				37	22	(1,444)	(22)	552	(507)	0
Net cash flows provided by operating activities		153,919	139,484	123,059	31,002	(54,296)	93,089	122,917	192,320	29,970		1,460		0
Purchases of property and equipment		(132,592)	(194,647)	(53,065)	(6,110)	(1,772)	(1,638)	(126,482)	(192,875)	(51,427)				0
Collection of notes receivable		2,465	4,161	17,621				2,465	4,161	17,621				0
Other investing activities		1,848	148	1,955	3		4	1,845	148	1,951				0
Net cash used in investing activities - continuing operations		(128,279)	(190,338)	(33,489)	(6,107)	(1,772)	(1,634)	(122,172)	(188,566)	(31,855)				0
Net cash used investing activities - discontinued operations			(1,460)	(6)						(6)		(1,460)		0
Net cash flows used in investing activities		(128,279)	(191,798)	(33,495)	(6,107)	(1,772)	(1,634)	(122,172)	(188,566)	(31,861)		(1,460)		0
Repayments under credit facility		(100,000)		(22,500)	(100,000)		(22,500)							0
Repurchases of senior notes			(26,965)	(329,571)		(26,965)	(329,571)
Proceeds from the issuance of convertible notes, net of equity-related issuance costs				358,107			358,107
Deferred financing costs paid		(10,074)		(8,077)	(10,074)		(8,077)							0
Purchase of convertible note hedge				(76,680)			(76,680)
Proceeds from issuance of common stock warrants				43,740			43,740
Issuance of common stock	125,300			125,297			125,297
Purchases of treasury stock				(4,599)			(4,599)
Proceeds from the termination of an interest rate swap on Senior Notes				5,000			5,000
Proceeds from exercise of stock option and purchase plans		4,828	26,075	566	4,828	26,075	566							0
Decrease in restricted cash and cash equivalents				15			15
Other financing activities, net		(404)	(2,427)	(1,869)		(1,000)	(1,158)	(404)	(1,427)	(711)				0
Net cash flows provided by financing activities - discontinued operations		0	0	0										0
Net cash used in financing activities - continuing operations		(105,650)	(3,317)	89,429	(105,246)	(1,890)	90,140	(404)	(1,427)	(711)				0
Net cash flows provided by (used in) financing activities		(105,650)	(3,317)	89,429	(105,246)	(1,890)	90,140	(404)	(1,427)	(711)				0
Net change in cash and cash equivalents		(80,010)	(55,631)	178,993	(80,351)	(57,958)	181,595	341	2,327	(2,602)				0
Cash and cash equivalents - unrestricted, beginning of period		124,398	180,029	1,036	117,913	175,871	(5,724)	6,485	4,158	6,760	0	0	0	0	0	0
Cash and cash equivalents - unrestricted, end of period		$ 44,388	$ 124,398	$ 180,029	$ 37,562	$ 117,913	$ 175,871	$ 6,826	$ 6,485	$ 4,158	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0