CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-In Capital [Member]	Earnings Reinvested in the Business [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Beginning balance at Dec. 31, 2020	$ 5,396	$ 102,909	$ 1,578,662	$ (593,540)	$ (159,091)	$ 934,336
Beginning balance (in shares) at Dec. 31, 2020				11,647,627
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	0	0	91,516	$ 0	0	91,516
Other comprehensive loss	0	0	0	0	(12,062)	(12,062)
Cash dividends paid	0	0	(49,468)	0	0	(49,468)
Share-based compensation	0	6,431	0	0	0	6,431
Non-vested stock issued upon vesting	0	(1,264)	0	$ 1,264	0	0
Non-vested stock issued upon vesting (in shares)				(24,711)
Benefit plans	0	338	0	$ 756	0	1,094
Benefit plans (in shares)				(14,791)
Purchase of treasury stock	0	0	0	$ (31,874)	0	(31,874)
Purchase of treasury stock (in shares)				382,593
Other	0	(204)	0	$ (377)	0	(581)
Other (in shares)				7,379
Ending balance at Sep. 30, 2021	5,396	108,210	1,620,710	$ (623,771)	(171,153)	939,392
Ending balance (in shares) at Sep. 30, 2021				11,998,097
Beginning balance at Jun. 30, 2021	5,396	105,967	1,603,239	$ (614,404)	(155,921)	944,277
Beginning balance (in shares) at Jun. 30, 2021				11,892,497
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	0	0	33,912	$ 0	0	33,912
Other comprehensive loss	0	0	0	0	(15,232)	(15,232)
Cash dividends paid	0	0	(16,441)	0	0	(16,441)
Share-based compensation	0	2,243	0	0	0	2,243
Purchase of treasury stock	0	0	0	$ (9,367)	0	(9,367)
Purchase of treasury stock (in shares)				105,600
Ending balance at Sep. 30, 2021	5,396	108,210	1,620,710	$ (623,771)	(171,153)	939,392
Ending balance (in shares) at Sep. 30, 2021				11,998,097
Beginning balance at Dec. 31, 2021	5,396	111,352	1,630,713	$ (634,408)	(174,628)	938,425
Beginning balance (in shares) at Dec. 31, 2021				12,107,549
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	0	0	111,766	$ 0	0	111,766
Other comprehensive loss	0	0	0	0	(55,595)	(55,595)
Cash dividends paid	0	0	(51,681)	0	0	(51,681)
Share-based compensation	0	12,476	0	0	0	12,476
Non-vested stock issued upon vesting	0	(3,239)	0	$ 3,239	0	0
Non-vested stock issued upon vesting (in shares)				(61,821)
Benefit plans	0	560	0	$ 618	0	1,178
Benefit plans (in shares)				(11,786)
Other	0	(768)	15	$ (1,302)	0	(2,055)
Other (in shares)				24,831
Ending balance at Sep. 30, 2022	5,396	120,381	1,690,813	$ (631,853)	(230,223)	954,514
Ending balance (in shares) at Sep. 30, 2022				12,058,773
Beginning balance at Jun. 30, 2022	5,396	116,596	1,672,000	$ (631,853)	(203,172)	958,967
Beginning balance (in shares) at Jun. 30, 2022				12,058,773
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	0	0	36,048	$ 0	0	36,048
Other comprehensive loss	0	0	0	0	(27,051)	(27,051)
Cash dividends paid	0	0	(17,235)	0	0	(17,235)
Share-based compensation	0	3,785	0	0	0	3,785
Ending balance at Sep. 30, 2022	$ 5,396	$ 120,381	$ 1,690,813	$ (631,853)	$ (230,223)	$ 954,514
Ending balance (in shares) at Sep. 30, 2022				12,058,773