Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]
Beginning balance at Dec. 31, 2011	$ 533,532	$ 279	$ 178,598	$ 354,239	$ 416
Beginning balance, shares at Dec. 31, 2011	27,875,158
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(22,134)			(22,134)
Other comprehensive loss, net of tax	77				77
Secondary offering, net of issuance cost (in shares)	6,900,000
Secondary offering, net of issuance costs	276,013	69	275,944
Equity portion of Convertible Notes, net of issuance costs	48,697		48,697
Shares issued for RMS acquisition (in shares)	891,265
Shares issued for RMS acquisition	41,346	9	41,337
Share-based compensation	14,206		14,206
Excess tax benefit on share-based compensation	2,376		2,376
Issuance of shares under incentive plans, net	815	10	805
Issuance of shares under incentive plans, net (in shares)	1,021,362
Ending balance at Dec. 31, 2012	894,928	367	561,963	332,105	493
Ending balance, shares at Dec. 31, 2012	36,687,785
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	253,467			253,467
Other comprehensive loss, net of tax	5				5
Share-based compensation	13,011		13,011
Excess tax benefit on share-based compensation	2,705		2,705
Issuance of shares under incentive plans, net	2,900	7	2,893
Issuance of shares under incentive plans, net (in shares)	689,489
Ending balance at Dec. 31, 2013	1,167,016	374	580,572	585,572	498
Ending balance, shares at Dec. 31, 2013	37,377,274
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(110,328)			(110,328)
Other comprehensive loss, net of tax	(103)				(103)
Share-based compensation	14,533		14,533
Excess tax benefit on share-based compensation	42		42
Issuance of shares under incentive plans, net	5,499	3	5,496
Issuance of shares under incentive plans, net (in shares)	334,349
Ending balance at Dec. 31, 2014	$ 1,076,659	$ 377	$ 600,643	$ 475,244	$ 395
Ending balance, shares at Dec. 31, 2014	37,711,623