Interim Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	AdditionalPaid-in Capital	Treasury Stock	Retained Earnings	AccumulatedOtherComprehensive Loss
Beginning balance ( in shares) at Dec. 31, 2019		11,670
Beginning balance at Dec. 31, 2019	$ 569,757	$ 1,175	$ 113,666	$ (4,566)	$ 500,320	$ (40,838)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income	(9,122)				15,528	(24,650)
Stock-based compensation expense	933		933
Stock-based compensation transactions (in shares)		9
Stock-based compensation transactions	369	$ 1	368
Dividends paid	(1,528)				(1,528)
Ending balance (in shares) at Mar. 31, 2020		11,679
Ending balance at Mar. 31, 2020	560,409	$ 1,176	114,967	(4,566)	514,320	(65,488)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income	17,643				12,989	4,654
Stock-based compensation expense	1,103		1,103
Stock-based compensation transactions (in shares)		25
Stock-based compensation transactions	(473)	$ 3	(476)
Dividends paid	(1,531)				(1,531)
Ending balance (in shares) at Jun. 30, 2020		11,704
Ending balance at Jun. 30, 2020	577,151	$ 1,179	115,594	(4,566)	525,778	(60,834)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income	27,847				20,033	7,814
Stock-based compensation expense	1,079		1,079
Stock-based compensation transactions (in shares)		16
Stock-based compensation transactions	667	$ 1	666
Dividends paid	(1,531)				(1,531)
Ending balance (in shares) at Sep. 30, 2020		11,720
Ending balance at Sep. 30, 2020	605,213	$ 1,180	117,339	(4,566)	544,280	(53,020)
Beginning balance ( in shares) at Dec. 31, 2020		11,727
Beginning balance at Dec. 31, 2020	635,003	$ 1,181	118,528	(4,566)	560,186	(40,326)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income	15,876				17,462	(1,586)
Stock-based compensation expense	1,240		1,240
Stock-based compensation transactions (in shares)		29
Stock-based compensation transactions	776	$ 3	773
Dividends paid	(1,654)				(1,654)
Ending balance (in shares) at Mar. 31, 2021		11,756
Ending balance at Mar. 31, 2021	651,241	$ 1,184	120,541	(4,566)	575,994	(41,912)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income	30,943				26,037	4,906
Stock-based compensation expense	1,316		1,316
Stock-based compensation transactions (in shares)		23
Stock-based compensation transactions	(602)	$ 2	(604)
Dividends paid	(1,657)				(1,657)
Ending balance (in shares) at Jun. 30, 2021		11,779
Ending balance at Jun. 30, 2021	681,241	$ 1,186	121,253	(4,566)	600,374	(37,006)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income	9,885				17,519	(7,634)
Stock-based compensation expense	2,840		2,840
Stock-based compensation transactions (in shares)		9
Stock-based compensation transactions	(646)	$ 1	(647)
Dividends paid	(1,658)				(1,658)
Ending balance (in shares) at Sep. 30, 2021		11,788
Ending balance at Sep. 30, 2021	$ 691,662	$ 1,187	$ 123,446	$ (4,566)	$ 616,235	$ (44,640)