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	63,730	0	0	63,730
Cash dividends	0	0	(25,745)	0	0	(25,745)
Purchase of treasury shares	0	0	0	0	(2,778)	(2,778)
Net issuance of shares to employee and other stock plans	0	(2,843)	0	0	827	(2,016)
Stock-based compensation	0	3,312	0	0	0	3,312
Other comprehensive income (loss)	0	0	0	(66)	0	(66)
Balance at Jun. 30, 2023	497	578,322	996,920	(190,100)	(175,146)	1,210,493
Balance at Mar. 31, 2023	497	577,952	979,722	(173,918)	(172,594)	1,211,659
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	30,072	0	0	30,072
Cash dividends	0	0	(12,874)	0	0	(12,874)
Purchase of treasury shares	0	0	0	0	(2,778)	(2,778)
Net issuance of shares to employee and other stock plans	0	(477)	0	0	226	(251)
Stock-based compensation	0	847	0	0	0	847
Other comprehensive income (loss)	0	0	0	(16,182)	0	(16,182)
Balance at Jun. 30, 2023	497	578,322	996,920	(190,100)	(175,146)	1,210,493
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	66,539	0	0	66,539
Cash dividends	0	0	(30,183)	0	0	(30,183)
Purchase of treasury shares	0	0	0	0	(251)	(251)
Net issuance of shares to employee and other stock plans	0	(3,201)	0	0	1,154	(2,047)
Stock-based compensation	0	4,191	0	0	0	4,191
Other comprehensive income (loss)	0	0	0	(1,985)	0	(1,985)
Balance at Jun. 30, 2024	540	741,933	1,058,187	(162,919)	(175,786)	1,461,955
Balance at Mar. 31, 2024	540	740,792	1,040,563	(164,492)	(175,988)	1,441,415
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	32,716	0	0	32,716
Cash dividends	0	0	(15,092)	0	0	(15,092)
Purchase of treasury shares	0	0	0	0	(188)	(188)
Net issuance of shares to employee and other stock plans	0	(766)	0	0	390	(376)
Stock-based compensation	0	1,907	0	0	0	1,907
Other comprehensive income (loss)	0	0	0	1,573	0	1,573
Balance at Jun. 30, 2024	$ 540	$ 741,933	$ 1,058,187	$ (162,919)	$ (175,786)	$ 1,461,955