Consolidated Statements of Changes in Shareholders' Equity - 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)	$ 0	$ 2,157	$ 810,928	$ (15,001)	$ 66,979
Balance (in shares) at Dec. 31, 2018			21,573		914
Net income (loss)	54,561	0	$ 0	0	$ 0	54,561
Restricted stock awards, forfeitures and shares repurchased for tax withholdings, net	0	0	$ 0	(1,213)	$ 977	(236)
Restricted stock awards, forfeitures and shares repurchased for tax withholdings, net (in shares)			0		16
Stock-based compensation	0	0	$ 0	1,141	$ 0	1,141
Other comprehensive income (loss)	0	(25)	0	0	0	(25)
Dividends paid	(20,679)	0	0	0	0	(20,679)
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)	(37,615)	0	$ 0	0	$ 0	(37,615)
Restricted stock awards, forfeitures and shares repurchased for tax withholdings, net	0	0	$ 0	(3,864)	$ 3,824	(40)
Restricted stock awards, forfeitures and shares repurchased for tax withholdings, net (in shares)			0		(242)
Stock-based compensation	0	0	$ 0	590	$ 0	590
Change in accounting at ownership interests	(1,801)	0	0	0	0	(1,801)
Balance at Dec. 31, 2020	$ (736,639)	$ (25)	$ 2,157	$ 807,582	$ (10,200)	$ 62,875
Balance (in shares) at Dec. 31, 2020			21,573		688