CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - UNAUDITED - USD ($) $ in Thousands	Total	Common Stock	Additional Contributed Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Beginning Balance at Dec. 31, 2020	$ 423,682	$ 311,190	$ 41,654	$ 539,281	$ (95,921)	$ (372,522)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss)	11,990			11,990
Changes in fair market value of derivatives, net of tax	124				124
Changes in unrealized pension cost, net of tax	1,422				1,422
Cumulative translation adjustment, net of tax	12				12
Cash dividends	(1,294)			(1,294)
Issued shares on vesting of restricted stock units	(1,400)	1,818	(3,218)
Stock compensation	1,180		1,180
Ending Balance at Mar. 31, 2021	435,716	313,008	39,616	549,977	(94,363)	(372,522)
Beginning Balance at Dec. 31, 2020	423,682	311,190	41,654	539,281	(95,921)	(372,522)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss)	(51,031)
Changes in fair market value of derivatives, net of tax	100
Changes in unrealized pension cost, net of tax	90,976
Cumulative translation adjustment, net of tax	2
Acquired shares for treasury stock	(4,939)
Ending Balance at Sep. 30, 2021	457,374	314,351	40,958	484,368	(4,842)	(377,461)
Beginning Balance at Mar. 31, 2021	435,716	313,008	39,616	549,977	(94,363)	(372,522)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss)	875			875
Changes in fair market value of derivatives, net of tax	268				268
Changes in unrealized pension cost, net of tax	17,024				17,024
Cumulative translation adjustment, net of tax	1				1
Cash dividends	(1,299)			(1,299)
Issued shares on vesting of restricted stock units	(80)	1,333	(1,413)
Stock compensation	1,804		1,804
Ending Balance at Jun. 30, 2021	454,309	314,341	40,007	549,553	(77,070)	(372,522)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss)	(63,896)			(63,896)
Changes in fair market value of derivatives, net of tax	(292)				(292)
Changes in unrealized pension cost, net of tax	72,530				72,530
Cumulative translation adjustment, net of tax	(10)				(10)
Cash dividends	(1,289)			(1,289)
Acquired shares for treasury stock	(4,939)					(4,939)
Issued shares on vesting of restricted stock units	(10)	10	(20)
Stock compensation	971		971
Ending Balance at Sep. 30, 2021	457,374	314,351	40,958	484,368	(4,842)	(377,461)
Beginning Balance at Dec. 31, 2021	463,578	314,620	42,549	492,242	(4,525)	(381,308)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss)	20,239			20,239
Changes in fair market value of derivatives, net of tax	1,235				1,235
Changes in unrealized pension cost, net of tax	94				94
Cumulative translation adjustment, net of tax	(249)				(249)
Cash dividends	(1,284)			(1,284)
Acquired shares for treasury stock	(3,920)					(3,920)
Issued shares on vesting of restricted stock units	(1,413)	1,876	(3,289)
Stock compensation	1,898		1,898
Ending Balance at Mar. 31, 2022	480,178	316,496	41,158	511,197	(3,445)	(385,228)
Beginning Balance at Dec. 31, 2021	463,578	314,620	42,549	492,242	(4,525)	(381,308)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss)	44,635
Changes in fair market value of derivatives, net of tax	3,667
Changes in unrealized pension cost, net of tax	341
Cumulative translation adjustment, net of tax	(8,332)
Acquired shares for treasury stock	(13,446)
Ending Balance at Sep. 30, 2022	490,612	316,520	44,659	533,036	(8,849)	(394,754)
Beginning Balance at Mar. 31, 2022	480,178	316,496	41,158	511,197	(3,445)	(385,228)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss)	12,598			12,598
Changes in fair market value of derivatives, net of tax	705				705
Changes in unrealized pension cost, net of tax	2,082				2,082
Cumulative translation adjustment, net of tax	(2,012)				(2,012)
Cash dividends	(1,289)			(1,289)
Acquired shares for treasury stock	(7,748)					(7,748)
Issued shares on vesting of restricted stock units	(78)	6	(84)
Stock compensation	1,511		1,511
Ending Balance at Jun. 30, 2022	485,947	316,502	42,585	522,506	(2,670)	(392,976)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss)	11,798			11,798
Changes in fair market value of derivatives, net of tax	1,727				1,727
Changes in unrealized pension cost, net of tax	(1,835)				(1,835)
Cumulative translation adjustment, net of tax	(6,071)				(6,071)
Cash dividends	(1,268)			(1,268)
Acquired shares for treasury stock	(1,778)					(1,778)
Issued shares on vesting of restricted stock units	(12)	18	(30)
Stock compensation	2,104		2,104
Ending Balance at Sep. 30, 2022	$ 490,612	$ 316,520	$ 44,659	$ 533,036	$ (8,849)	$ (394,754)