Consolidated Statements of Changes in Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2018	$ (731,105)		$ 2,157	$ 810,928	$ (15,001)	$ 66,979
Balance (in shares) at Dec. 31, 2018			21,573		914
Net income (loss)	21,663					21,663
Restricted stock awards, forfeitures and shares repurchased for tax withholdings, net				7	$ (156)	(149)
Restricted stock awards, forfeitures and shares repurchased for tax withholdings, net (in shares)					83
Stock-based compensation expense				417		417
Balance at Mar. 31, 2019	(709,442)	(31)	$ 2,157	811,352	$ (15,157)	88,879
Balance (in shares) at Mar. 31, 2019			21,573		998
Stock options exercised, net of tax withholdings
Stock options exercised, net of tax withholdings (in shares)					1
Other comprehensive loss		(31)				(31)
Balance at Dec. 31, 2019	(697,223)	(25)	$ 2,157	810,856	$ (14,024)	101,741
Balance (in shares) at Dec. 31, 2019			21,573		930
Net income (loss)	(16,008)					(16,008)
Restricted stock awards, forfeitures and shares repurchased for tax withholdings, net				(32)	$ 104	72
Restricted stock awards, forfeitures and shares repurchased for tax withholdings, net (in shares)					(6)
Stock-based compensation expense				3		3
Balance at Mar. 31, 2020	$ (713,231)	$ (25)	$ 2,157	$ 810,827	$ (13,920)	$ 85,808
Balance (in shares) at Mar. 31, 2020			21,573		924