CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Accumulated Other Comprehensive Loss (Income)	Retained Earnings	Noncontrolling Interests
Beginning Balance at Dec. 31, 2009	$ 736,335	$ 28	$ 363,670	$ (735)	$ 114	$ 372,089	$ 1,169
Beginning Balance (in 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 (in shares)		188,089
Issuance of stock-401(k) plan (in shares)		579,303
Issuance of stock-401(k) plan	22,762	1	22,761
Exercise of stock options	1,501		1,501
Exercise of stock options (in shares)		118,220
Issuance of non-vested stock (in shares)		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)
Net income (loss)	113,273					112,580	693
Unrealized gain (loss) on deferred compensation plan assets	(89)				(89)
Ending Balance at Dec. 31, 2010	879,715	29	407,156	(14,022)	25	484,669	1,858
Ending Balance (in 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 (in shares)		242,789
Issuance of stock-401(k) plan (in shares)		475,715
Issuance of stock-401(k) plan	12,002	1	12,001
Exercise of stock options	245		245
Exercise of stock options (in shares)		7,336
Issuance of non-vested stock (in shares)		369,902
Non-cash compensation	8,292		8,292
Tax deficit from stock options cancelled or exercised, restricted stock vesting and employee stock purchase plan	(453)		(453)
Surrendered shares	(1,748)			(1,748)
Noncontrolling interest distribution	(700)						(700)
Net income (loss)	(382,342)					(382,464)	122
Unrealized gain (loss) on deferred compensation plan assets	(12)				(12)
Ending Balance at Dec. 31, 2011	520,148	30	432,390	(15,770)	13	102,205	1,280
Ending Balance (in shares) at Dec. 31, 2011		30,328,549
Issuance of stock-employee stock purchase plan	3,913		3,913
Issuance of stock-employee stock purchase plan (in shares)	2,485,604	360,114
Issuance of stock-401(k) plan (in shares)		729,915
Issuance of stock-401(k) plan	9,324	1	9,323
Exercise of stock options	156		156
Exercise of stock options (in shares)	22,119	22,119
Issuance of non-vested stock		1	(1)
Issuance of non-vested stock (in shares)		373,824
Non-cash compensation	7,217		7,217
Tax deficit from stock options cancelled or exercised, restricted stock vesting and employee stock purchase plan	(3,045)		(3,045)
Surrendered shares	(1,346)			(1,346)
Surrendered shares (in shares)		61,987
Acquired noncontrolling interests	15,931						15,931
Noncontrolling interest distribution	(323)						(323)
Assets contributed to equity investment	839		839
Net income (loss)	(98,583)					(83,588)	(14,995)
Unrealized gain (loss) on deferred compensation plan assets	2				2
Ending Balance at Dec. 31, 2012	$ 454,233	$ 32	$ 450,792	$ (17,116)	$ 15	$ 18,617	$ 1,893
Ending Balance (in shares) at Dec. 31, 2012		31,876,508