Condensed Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Capital in Excess of Par Value	Retained Earnings (Deficit)	Non-controlling Interest in Consolidated Subsidiaries
Stockholders' equity, beginning balance at Dec. 31, 2020	$ 425,593	$ 120	$ 0	$ 197,242	$ (18,140)	$ 246,371
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(591)				(1,937)	1,346
Activity in stock-based compensation plans	90			74		16
Stockholders' equity, ending balance at Mar. 31, 2021	425,092	120	0	197,316	(20,077)	247,733
Stockholders' equity, beginning balance at Dec. 31, 2020	425,593	120	0	197,242	(18,140)	246,371
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(10,706)
Stockholders' equity, ending balance at Jun. 30, 2021	393,845	120	(9,048)	197,561	(33,071)	238,283
Stockholders' equity, beginning balance at Mar. 31, 2021	425,092	120	0	197,316	(20,077)	247,733
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(10,115)				(12,994)	2,879
Distributions to non-controlling interests	(12,344)					(12,344)
Activity in stock-based compensation plans	260			245		15
Share repurchase program, aggregate purchase price	(9,048)		9,048
Stockholders' equity, ending balance at Jun. 30, 2021	393,845	120	(9,048)	197,561	(33,071)	238,283
Stockholders' equity, beginning balance at Dec. 31, 2021	399,668	120	(51,965)	198,171	41,071	212,271
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(52,705)				(46,877)	(5,828)
Distributions to non-controlling interests	(9,479)					(9,479)
Deconsolidation of Superior	(196,964)					(196,964)
Activity in stock-based compensation plans	1,038			1,038
Stockholders' equity, ending balance at Mar. 31, 2022	141,558	120	(51,965)	199,209	(5,806)	0
Stockholders' equity, beginning balance at Dec. 31, 2021	399,668	120	(51,965)	198,171	41,071	212,271
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	27,388
Stockholders' equity, ending balance at Jun. 30, 2022	260,368	120	(65,241)	251,202	74,287	0
Stockholders' equity, beginning balance at Mar. 31, 2022	141,558	120	(51,965)	199,209	(5,806)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	80,093				80,093
Activity in stock-based compensation plans	2,848			2,848
Share repurchase program, aggregate purchase price	(13,276)		(13,276)
Warrant Reclassified	49,145			49,145
Stockholders' equity, ending balance at Jun. 30, 2022	$ 260,368	$ 120	$ (65,241)	$ 251,202	$ 74,287	$ 0