Interim Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - 3 months ended Mar. 31, 2017 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Loss
Balance at Dec. 31, 2016	$ 387,717	$ 1,146	$ 99,765	$ (426)	$ 334,988	$ (47,756)
Balance (shares) at Dec. 31, 2016		11,420
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	12,167				12,167
Translation adjustment	3,046					3,046
Net actuarial gain arising during period	138					138
Stock-based compensation	328		328
Exercise of stock options	606	$ 4	602
Exercise of stock options (shares)		36
Dividends paid ($.10 per share)	(1,146)				(1,146)
Balance at Mar. 31, 2017	$ 402,856	$ 1,150	$ 100,695	$ (426)	$ 346,009	$ (44,572)
Balance (shares) at Mar. 31, 2017		11,456