Consolidated Statements of 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
Balance at Dec. 31, 2020	$ 497	$ 578,082	$ 749,056	$ 417	$ (140,434)	$ 1,187,618
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	39,846	0	0	39,846
Cash dividends	0	0	(11,732)	0	0	(11,732)
Purchase of treasury shares	0	0	0	0	(9,020)	(9,020)
Net issuance of shares to employee and other stock plans	0	(2,153)	0	0	870	(1,283)
Stock-based compensation	0	2,668	0	0	0	2,668
Other comprehensive (loss)	0	0	0	(17,116)	0	(17,116)
Balance at Mar. 31, 2021	497	578,597	777,170	(16,699)	(148,584)	1,190,981
Balance at Dec. 31, 2021	497	576,976	856,203	(23,344)	(159,879)	1,250,453
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	39,126	0	0	39,126
Cash dividends	0	0	(12,083)	0	0	(12,083)
Purchase of treasury shares	0	0	0	0	(8,152)	(8,152)
Net issuance of shares to employee and other stock plans	0	(2,074)	0	0	539	(1,535)
Stock-based compensation	0	2,472	0	0	0	2,472
Other comprehensive (loss)	0	0	0	(68,031)	0	(68,031)
Balance at Mar. 31, 2022	$ 497	$ 577,374	$ 883,246	$ (91,375)	$ (167,492)	$ 1,202,250