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
Stock options exercised, net of tax withholdings
Stock options exercised, net of tax withholdings (in shares)					1
Other comprehensive income (loss)		(31)				(31)
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
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)						57,756
Balance at Jun. 30, 2019	(673,349)	(25)	$ 2,157	810,401	$ (13,968)	125,216
Balance (in shares) at Jun. 30, 2019			21,573		921
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
Net income (loss)	36,093					36,093
Restricted stock awards, forfeitures and shares repurchased for tax withholdings, net				(1,220)	$ 1,189	(31)
Restricted stock awards, forfeitures and shares repurchased for tax withholdings, net (in shares)					(77)
Stock-based compensation expense				269		269
Other comprehensive income (loss)		6				6
Balance at Jun. 30, 2019	(673,349)	(25)	$ 2,157	810,401	$ (13,968)	125,216
Balance (in shares) at Jun. 30, 2019			21,573		921
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
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)						(25,919)
Balance at Jun. 30, 2020	(724,943)	(25)	$ 2,157	809,255	$ (12,130)	74,314
Balance (in shares) at Jun. 30, 2020			21,573		810
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
Net income (loss)	(9,911)					(9,911)
Restricted stock awards, forfeitures and shares repurchased for tax withholdings, net				(1,718)	$ 1,790	72
Restricted stock awards, forfeitures and shares repurchased for tax withholdings, net (in shares)					(114)
Stock-based compensation expense				146		146
Change in accounting at ownership interests	(1,801)					(1,801)
Balance at Jun. 30, 2020	$ (724,943)	$ (25)	$ 2,157	$ 809,255	$ (12,130)	$ 74,314
Balance (in shares) at Jun. 30, 2020			21,573		810