Consolidated Statements Of Stockholders' Equity And Comprehensive (Loss) Income (USD $) In Thousands, except Share data, unless otherwise specified	Comprehensive Income [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Loss (Income) [Member]	Retained Earnings [Member]	Noncontrolling Interests [Member]	Total
Balance, value at Dec. 31, 2008		$ 27	$ 326,120	$ (617)	$ (447)	$ 236,252	$ 783	$ 562,118
Balance, shares at Dec. 31, 2008		27,083,231
Issuance of stock-employee stock purchase plan			5,342					5,342
Issuance of stock-employee stock purchase plan, shares		179,272
Issuance of stock-401(k) plan		1	19,082					19,083
Issuance of stock-401(k) plan, shares		543,140
Exercise of stock options			3,772					3,772
Exercise of stock options, shares		227,887
Issuance of non-vested stock		157,644
Non-cash compensation			7,848					7,848
Tax benefit from stock option exercises			1,506					1,506
Surrendered shares				(118)				(118)
Comprehensive (loss) income:
Net (loss) income	135,837					135,837	386	136,223
Other comprehensive income (loss):
Unrealized gain (loss) on deferred compensation plan assets	561				561			561
Comprehensive (loss) income	136,398						386	136,784
Balance, value at Dec. 31, 2009		28	363,670	(735)	114	372,089	1,169	736,335
Balance, shares at Dec. 31, 2009		28,191,174
Issuance of stock-employee stock purchase plan			6,204					6,204
Issuance of stock-employee stock purchase plan, shares		188,089
Issuance of stock-401(k) plan		1	22,761					22,762
Issuance of stock-401(k) plan, shares		579,303
Exercise of stock options			1,501					1,501
Exercise of stock options, shares		118,220
Issuance of non-vested stock		156,021
Non-cash compensation			10,634					10,634
Tax benefit from stock option exercises			2,386					2,386
Surrendered shares				(1,491)				(1,491)
Shares repurchased				(11,796)				(11,796)
Acquired noncontrolling interests							300	300
Noncontrolling interest distribution							(304)	(304)
Comprehensive (loss) income:
Net (loss) income	112,580					112,580	693	113,273
Other comprehensive income (loss):
Unrealized gain (loss) on deferred compensation plan assets	(89)				(89)			(89)
Comprehensive (loss) income	112,491						693	113,184
Balance, value at Dec. 31, 2010		29	407,156	(14,022)	25	484,669	1,858	879,715
Balance, shares at Dec. 31, 2010		29,232,807
Issuance of stock-employee stock purchase plan			5,149					5,149
Issuance of stock-employee stock purchase plan, shares		242,789
Issuance of stock-401(k) plan		1	12,001					12,002
Issuance of stock-401(k) plan, shares		475,715
Exercise of stock options			245					245
Exercise of stock options, shares		7,336
Issuance of non-vested stock		369,902
Non-cash compensation			8,292					8,292
Tax benefit from stock option exercises			(453)					(453)
Surrendered shares				(1,748)				(1,748)
Noncontrolling interest distribution							(700)	(700)
Comprehensive (loss) income:
Net (loss) income	(382,464)					(382,464)	122	(382,342)
Other comprehensive income (loss):
Unrealized gain (loss) on deferred compensation plan assets	(12)				(12)			(12)
Comprehensive (loss) income	(382,476)						122	(382,354)
Balance, value at Dec. 31, 2011		$ 30	$ 432,390	$ (15,770)	$ 13	$ 102,205	$ 1,280	$ 520,148
Balance, shares at Dec. 31, 2011		30,328,549