Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands		Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings (Accumulated Deficit)
Beginning 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	3	(3)	0	0
Amortization of share-based compensation		5,802	0	5,802	0	0
Net Loss		(1,653,971)	0	0	0	(1,653,971)
Ending Balance at Dec. 31, 2015		(852,724)	448	776,358	(2,491)	(1,627,039)
Purchase of treasury shares		(4)	0	0	(4)	0
Issuance of restricted stock		0	2	(2)	0	0
Amortization of share-based compensation		913	0	913	0	0
Net Loss		(108,303)	0	0	0	(108,303)
Ending Balance at Mar. 31, 2016	[1]	$ (960,118)	$ 450	$ 777,269	$ (2,495)	$ (1,735,342)

[1] Unaudited