Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Shares	Common Shares Held in Treasury	Common Stock	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Common Stock In Treasury	Accumulated Other Comprehensive Income (Loss)	Other Equity
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Retained earnings		$ (179)					$ (179)
Common shares beginning balances at Dec. 31, 2018			20,242
Common shares held in treasury beginning balances at Dec. 31, 2018				6,906
Beginning balances at Dec. 31, 2018	$ 586,238				$ 234,704	$ 580,706		$ (175,426)	$ (58,234)	$ 4,488
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	53,394					53,394
Other comprehensive income	9,444								9,444
Net pension curtailments and settlements	3,328								3,328
Cash dividends declared	(8,856)					(8,856)
Stock-based compensation activity (in shares)			(252)	(252)
Stock-based compensation activity	7,170				14,876	(111)		(7,595)
Payments for withholding taxes for stock-based compensation awards (in shares)			(89)	(89)
Payments for withholding taxes for stock-based compensation awards	(4,846)							(4,846)
Repurchase of shares (in shares)			(5)	(5)
Repurchase of shares	(199)							(199)
Directors' deferred compensation (in shares)			(4)	(4)
Directors' deferred compensation	249				94			1,221		(1,066)
Common shares ending balances at Dec. 31, 2019			20,404
Common shares held in treasury ending balances at Dec. 31, 2019				6,744
Ending balances at Dec. 31, 2019	645,743				249,674	624,954		(186,845)	(45,462)	3,422
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	15,462					15,462
Other comprehensive income	6,729								6,729
Net pension curtailments and settlements	94								94
Cash dividends declared	(9,257)					(9,257)
Stock-based compensation activity (in shares)			(117)	(117)
Stock-based compensation activity	5,619				8,867	(101)		(3,147)
Payments for withholding taxes for stock-based compensation awards (in shares)			(39)	(39)
Payments for withholding taxes for stock-based compensation awards	(2,221)							(2,221)
Repurchase of shares (in shares)			(158)	(158)
Repurchase of shares	(6,766)							(6,766)
Directors' deferred compensation (in shares)			(4)	(4)
Directors' deferred compensation	$ 227				101			(208)		334
Common shares ending balances at Dec. 31, 2020			20,328
Common shares held in treasury ending balances at Dec. 31, 2020	6,820			6,820
Ending balances at Dec. 31, 2020	$ 655,630				258,642	631,058		(199,187)	(38,639)	3,756
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Retained earnings	631,058
Net income	72,474					72,474
Other comprehensive income	(1,530)								(1,530)
Net pension curtailments and settlements	0
Cash dividends declared	(9,697)					(9,697)
Stock-based compensation activity (in shares)			(164)	(164)
Stock-based compensation activity	6,517				13,142	(79)		(6,546)
Payments for withholding taxes for stock-based compensation awards (in shares)			(49)	(49)
Payments for withholding taxes for stock-based compensation awards	(3,318)							(3,318)
Directors' deferred compensation (in shares)			(5)	(5)
Directors' deferred compensation	$ 364				193			(869)		1,040
Common shares ending balances at Dec. 31, 2021			20,448
Common shares held in treasury ending balances at Dec. 31, 2021	6,700			6,700
Ending balances at Dec. 31, 2021	$ 720,440				$ 271,977	$ 693,756		$ (209,920)	$ (40,169)	$ 4,796
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Retained earnings	$ 693,756