UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Shares of Common Stock (no par value)	Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2020		49,868
Beginning balance at Dec. 31, 2020	$ 577,051		$ 47,317	$ 534,440	$ (4,706)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	997,430			997,430
Unrealized income on interest rate hedge, net of tax	4,706				4,706
Dividends declared ($18.75 per share)	(936,850)			(936,850)
Stock based compensation (in shares)		118
Stock-based compensation	2,041		2,041
Stock options exercised (in shares)		15
Stock options exercised	85		85
Common stock issued	16		16
Shares surrendered for settlement of employee taxes upon issuance of vested equity awards (in shares)		(36)
Shares surrendered for settlement of employee taxes upon issuance of vested equity awards	(1,627)		(1,627)
Ending balance (in shares) at Sep. 30, 2021		49,965
Ending balance at Sep. 30, 2021	642,852		47,832	595,020	0
Beginning balance (in shares) at Jun. 30, 2021		49,950
Beginning balance at Jun. 30, 2021	682,110		46,681	639,049	(3,620)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	892,821			892,821
Unrealized income on interest rate hedge, net of tax	3,620				3,620
Dividends declared ($18.75 per share)	(936,850)			(936,850)
Stock based compensation (in shares)		0
Stock-based compensation	1,061		1,061
Stock options exercised (in shares)		15
Stock options exercised	85		85
Common stock issued	5		5
Ending balance (in shares) at Sep. 30, 2021		49,965
Ending balance at Sep. 30, 2021	$ 642,852		47,832	595,020	0
Beginning balance (in shares) at Dec. 31, 2021	49,965	49,965
Beginning balance at Dec. 31, 2021	$ 642,275		49,351	592,924	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(6,556)			(6,556)
Stock based compensation (in shares)		176
Stock-based compensation	7,751		7,751
Common stock issued (in shares)		1
Common stock issued	27		27
Shares surrendered for settlement of employee taxes upon issuance of vested equity awards (in shares)		(44)
Shares surrendered for settlement of employee taxes upon issuance of vested equity awards	$ (986)		(986)
Ending balance (in shares) at Sep. 30, 2022	50,098	50,098
Ending balance at Sep. 30, 2022	$ 642,511		56,143	586,368	0
Beginning balance (in shares) at Jun. 30, 2022		50,077
Beginning balance at Jun. 30, 2022	643,370		54,274	589,096	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(2,728)			(2,728)
Stock based compensation (in shares)		25
Stock-based compensation	1,942		1,942
Common stock issued	11		11
Shares surrendered for settlement of employee taxes upon issuance of vested equity awards (in shares)		(4)
Shares surrendered for settlement of employee taxes upon issuance of vested equity awards	$ (84)		(84)
Ending balance (in shares) at Sep. 30, 2022	50,098	50,098
Ending balance at Sep. 30, 2022	$ 642,511		$ 56,143	$ 586,368	$ 0