Consolidated Statements of Changes in Stockholders' Equity (unaudited) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in-Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Common Stock in Treasury [Member]	Total	Cumulative Effect Adjustment for ASU Implementation [Member] Common Stock [Member]	Cumulative Effect Adjustment for ASU Implementation [Member] Additional Paid-in-Capital [Member]	Cumulative Effect Adjustment for ASU Implementation [Member] Retained Earnings [Member]	Cumulative Effect Adjustment for ASU Implementation [Member] Accumulated Other Comprehensive (Loss) Income [Member]	Cumulative Effect Adjustment for ASU Implementation [Member] Common Stock in Treasury [Member]	Cumulative Effect Adjustment for ASU Implementation [Member]
Balance at Dec. 31, 2022	$ 497	$ 577,853	$ 958,433	$ (190,034)	$ (173,195)	$ 1,173,554
Balance (ASU 2022-02 [Member]) at Dec. 31, 2022							$ 0	$ 0	$ 502	$ 0	$ 0	$ 502
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	88,336	0	0	88,336
Cash dividends	0	0	(40,812)	0	0	(40,812)
Issuance of common stock for acquisition	43	161,680	0	0	0	161,723
Purchase of treasury shares	0	0	0	0	(4,944)	(4,944)
Net issuance of shares to employee and other stock plans	0	(3,093)	0	0	963	(2,130)
Stock-based compensation	0	4,137	0	0	0	4,137
Other comprehensive income (loss)	0	0	0	(17,545)	0	(17,545)
Balance at Sep. 30, 2023	540	740,577	1,006,459	(207,579)	(177,176)	1,362,821
Balance at Jun. 30, 2023	497	578,322	996,920	(190,100)	(175,146)	1,210,493
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	24,606	0	0	24,606
Cash dividends	0	0	(15,067)	0	0	(15,067)
Issuance of common stock for acquisition	43	161,680	0	0	0	161,723
Purchase of treasury shares	0	0	0	0	(2,166)	(2,166)
Net issuance of shares to employee and other stock plans	0	(250)	0	0	136	(114)
Stock-based compensation	0	825	0	0	0	825
Other comprehensive income (loss)	0	0	0	(17,479)	0	(17,479)
Balance at Sep. 30, 2023	540	740,577	1,006,459	(207,579)	(177,176)	1,362,821
Balance at Dec. 31, 2023	540	740,943	1,021,831	(160,934)	(176,689)	1,425,691
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	104,636	0	0	104,636
Cash dividends	0	0	(46,222)	0	0	(46,222)
Purchase of treasury shares	0	0	0	0	(251)	(251)
Net issuance of shares to employee and other stock plans	0	(3,574)	0	0	1,347	(2,227)
Stock-based compensation	0	5,155	0	0	0	5,155
Other comprehensive income (loss)	0	0	0	35,198	0	35,198
Balance at Sep. 30, 2024	540	742,524	1,080,245	(125,736)	(175,593)	1,521,980
Balance at Jun. 30, 2024	540	741,933	1,058,187	(162,919)	(175,786)	1,461,955
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	38,097	0	0	38,097
Cash dividends	0	0	(16,039)	0	0	(16,039)
Net issuance of shares to employee and other stock plans	0	(373)	0	0	193	(180)
Stock-based compensation	0	964	0	0	0	964
Other comprehensive income (loss)	0	0	0	37,183	0	37,183
Balance at Sep. 30, 2024	$ 540	$ 742,524	$ 1,080,245	$ (125,736)	$ (175,593)	$ 1,521,980