Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive (Loss) Income
Beginning balance at Dec. 31, 2021	$ 672,813	$ 345	$ 646,945	$ 280,960	$ (255,437)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	(4,450)			(4,450)
Actuarially determined long-term liability adjustments	1,525				1,525
Interest Rate Hedge (Net of $130 Tax)	391				391
Investments in Available-for-Sale Securities (Net of $64 Tax)	0
Comprehensive Income (Loss)	(2,534)			(4,450)	1,916
Issuance of Common Stock	0	3	(3)
Amortization of Stock-Based Compensation Awards	4,201		4,201
Shares Withheld for Taxes	(6,072)		(6,072)
Ending balance at Mar. 31, 2022	668,408	348	645,071	276,510	(253,521)
Beginning balance at Dec. 31, 2022	1,165,826	347	646,237	668,882	(149,640)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	230,377			230,377
Actuarially determined long-term liability adjustments	(901)				(901)
Interest Rate Hedge (Net of $130 Tax)	0
Investments in Available-for-Sale Securities (Net of $64 Tax)	212				212
Comprehensive Income (Loss)	229,688			230,377	(689)
Issuance of Common Stock	0	3	(3)
Repurchases of Common Stock (1,207,409 Shares)	(67,133)	(11)	(22,446)	(44,676)
Excise Tax on Repurchases of Common Stock	(478)			(478)
Amortization of Stock-Based Compensation Awards	4,792		4,792
Shares Withheld for Taxes	(12,708)		(12,708)
Dividends on Common Shares ($1.10/share)	(38,287)			(38,287)
Dividend Equivalents Earned on Stock-Based Compensation Awards	(803)			(803)
Ending balance at Mar. 31, 2023	$ 1,280,897	$ 339	$ 615,872	$ 815,015	$ (150,329)