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, 2018		11,620
Beginning balance at Dec. 31, 2018	$ 507,371	$ 1,166	$ 108,422	$ (426)	$ 443,040	$ (44,831)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income	16,143				15,253	890
Stock-based compensation expense	627		627
Repurchased shares (in shares)		(15)
Repurchased shares	(1,490)			(1,490)
Stock-based compensation transactions (in shares)		11
Stock-based compensation transactions	237	$ 1	236
Dividends paid	(1,404)				(1,404)
Ending balance (in shares) at Mar. 31, 2019		11,616
Ending balance at Mar. 31, 2019	521,484	$ 1,167	109,285	(1,916)	456,889	(43,941)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income	22,019				20,667	1,352
Stock-based compensation expense	948		948
Repurchased shares (in shares)		(15)
Repurchased shares	(1,465)		0	(1,465)
Stock-based compensation transactions (in shares)		64
Stock-based compensation transactions	1,250	$ 7	1,243
Dividends paid	(1,404)				(1,404)
Ending balance (in shares) at Jun. 30, 2019		11,665
Ending balance at Jun. 30, 2019	542,832	$ 1,174	111,476	(3,381)	476,152	(42,589)
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)