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, 2022	$ 5,396	$ 124,043	$ 1,702,700	$ (631,853)	$ (200,688)	$ 999,598
Beginning balance (in shares) at Dec. 31, 2022				12,058,773
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	0	0	67,684	$ 0	0	67,684
Other comprehensive income (loss)	0	0	0	0	23,467	23,467
Cash dividends paid	0	0	(34,577)	0	0	(34,577)
Share-based compensation	0	4,766	0	0	0	4,766
Non-vested stock issued upon vesting	0	(12,619)	0	$ 12,619	0	0
Non-vested stock issued upon vesting (in shares)				(240,825)
Benefit plans	0	375	0	$ 952	0	1,327
Benefit plans (in shares)				(18,172)
Other	0	(2,235)	0	$ (5,766)	0	(8,001)
Other (in shares)				110,057
Ending balance at Jun. 30, 2023	5,396	114,330	1,735,807	$ (624,048)	(177,221)	1,054,264
Ending balance (in shares) at Jun. 30, 2023				11,909,833
Beginning balance at Mar. 31, 2023	5,396	112,589	1,719,096	$ (624,473)	(184,387)	1,028,221
Beginning balance (in shares) at Mar. 31, 2023				11,917,944
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	0	0	34,033	$ 0	0	34,033
Other comprehensive income (loss)	0	0	0	0	7,166	7,166
Cash dividends paid	0	0	(17,322)	0	0	(17,322)
Share-based compensation	0	2,499	0	0	0	2,499
Non-vested stock issued upon vesting	0	(663)	0	$ 663	0	0
Non-vested stock issued upon vesting (in shares)				(12,644)
Other	0	(95)	0	$ (238)	0	(333)
Other (in shares)				4,533
Ending balance at Jun. 30, 2023	5,396	114,330	1,735,807	$ (624,048)	(177,221)	1,054,264
Ending balance (in shares) at Jun. 30, 2023				11,909,833
Beginning balance at Dec. 31, 2023	5,396	115,941	1,726,872	$ (622,768)	(172,117)	1,053,324
Beginning balance (in shares) at Dec. 31, 2023				11,885,398
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	0	0	61,872	$ 0	0	61,872
Other comprehensive income (loss)	0	0	0	0	(26,060)	(26,060)
Cash dividends paid	0	0	(34,685)	0	0	(34,685)
Share-based compensation	0	4,911	0	0	0	4,911
Non-vested stock issued upon vesting	0	(5,893)	0	$ 5,893	0	0
Non-vested stock issued upon vesting (in shares)				(112,472)
Benefit plans	0	299	0	$ 1,122	0	1,421
Benefit plans (in shares)				(21,405)
Other	0	(528)	0	$ (2,480)	0	(3,008)
Other (in shares)				47,332
Ending balance at Jun. 30, 2024	5,396	114,730	1,754,059	$ (618,233)	(198,177)	1,057,775
Ending balance (in shares) at Jun. 30, 2024				11,798,853
Beginning balance at Mar. 31, 2024	5,396	112,389	1,740,500	$ (618,621)	(175,728)	1,063,936
Beginning balance (in shares) at Mar. 31, 2024				11,806,249
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	0	0	30,932	$ 0	0	30,932
Other comprehensive income (loss)	0	0	0	0	(22,449)	(22,449)
Cash dividends paid	0	0	(17,373)	0	0	(17,373)
Share-based compensation	0	2,916	0	0	0	2,916
Non-vested stock issued upon vesting	0	(528)	0	$ 528	0	0
Non-vested stock issued upon vesting (in shares)				(10,076)
Other	0	(47)	0	$ (140)	0	(187)
Other (in shares)				2,680
Ending balance at Jun. 30, 2024	$ 5,396	$ 114,730	$ 1,754,059	$ (618,233)	$ (198,177)	$ 1,057,775
Ending balance (in shares) at Jun. 30, 2024				11,798,853