Condensed Consolidated Statements of Stockholders' Equity (USD $) In Thousands		Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings
Beginning Balance at Dec. 31, 2013		$ 1,065,350	$ 439	$ 762,242	$ (12,575)	$ 315,244
Stock issued for benefit plans		1,909	0	(1,876)	3,785	0
Purchase of treasury shares		(1,065)	0	0	(1,065)	0
Employee stock purchase plan		824	1	823	0	0
Issuance of restricted stock		0	4	(4)	0	0
Amortization of share-based compensation		10,787	0	10,787	0	0
Net Income		(283,427)	0	0	0	(283,427)
Ending Balance at Dec. 31, 2014		794,378	444	771,972	(9,855)	31,817
Stock issued for benefit plans		919	0	(1,714)	7,518	(4,885)
Purchase of treasury shares		(154)	0	0	(154)	0
Employee stock purchase plan		302	1	301	0	0
Issuance of restricted stock		0	1	(1)	0	0
Amortization of share-based compensation		1,066	0	1,066	0	0
Net Income		(477,077)	0	0	0	(477,077)
Ending Balance at Mar. 31, 2015	[1]	$ 319,434	$ 446	$ 771,624	$ (2,491)	$ (450,145)

[1] Unaudited