CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Total
Balance at Dec. 31, 2020	$ 21,495		$ 627,778	$ (17,706)	$ 631,567
Balance (in shares) at Dec. 31, 2020	214,951,000
Increase (Decrease) in Stockholders' Equity
Stock issued for stock incentive plans, net	$ 82	$ 6,494			6,576
Stock issued for stock incentive plans, net (in shares)	819,000
Stock purchased and retired	$ (14)	(6,494)	5,941		(567)
Stock purchased and retired (in shares)	(141,000)
Net income			7,217		7,217
Pension adjustment, net of taxes				(2,890)	(2,890)
Foreign currency translation				(112)	(112)
Balance at Dec. 31, 2021	$ 21,563		640,936	(20,708)	641,791
Balance (in shares) at Dec. 31, 2021	215,629,000
Increase (Decrease) in Stockholders' Equity
Stock issued for stock incentive plans, net	$ 114	6,261			6,375
Stock issued for stock incentive plans, net (in shares)	1,139,000
Stock purchased and retired	$ (16)	(6,261)	5,359		(918)
Stock purchased and retired (in shares)	(159,000)
Net income			218,363		218,363
Pension settlement and adjustment, net of tax				764	764
Foreign currency translation				5	5
Dividends			(8,645)		(8,645)
Balance at Dec. 31, 2022	$ 21,661		856,013	(19,939)	$ 857,735
Balance (in shares) at Dec. 31, 2022	216,609,000				216,609,191
Increase (Decrease) in Stockholders' Equity
Stock issued for stock incentive plans, net	$ 114	7,767			$ 7,881
Stock issued for stock incentive plans, net (in shares)	1,143,000
Stock purchased and retired	$ (273)	$ (7,767)	(13,184)		(21,224)
Stock purchased and retired (in shares)	(2,726,000)
Net income			195,113		195,113
Pension settlement and adjustment, net of tax				17,307	17,307
Foreign currency translation				263	263
Dividends			(34,562)		(34,562)
Balance at Dec. 31, 2023	$ 21,502		$ 1,003,380	$ (2,369)	$ 1,022,513
Balance (in shares) at Dec. 31, 2023	215,026,000				215,026,458