CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common stock [Member]	Additional paid-in capital [Member]	Retained earnings [Member]	Accumulated other comprehensive income (loss) [Member]	Treasury stock [Member]	Noncontrolling interest [Member]
Balance at Dec. 31, 2013		$ 31	$ 57,877	$ 359,459	$ 25,860	$ (36,016)	$ 128,145
Net income	$ 19,817			15,003			4,814
Foreign currency translation adjustment					(3,120)		(1,510)
Shares issued upon exercise of stock options			1,014			101
Shares received as proceeds of option exercises						(351)
Sale of subsidiary shares to noncontrolling interest			(319)				1,309
Dividends				(7,424)			(4,667)
Stock-based compensation			335	55			21
Balance at Jun. 30, 2014	540,617	31	58,907	367,093	22,740	(36,266)	128,112
Balance at Dec. 31, 2014	498,724	31	60,200	374,121	(15,823)	$ (36,464)	116,659
Net income	18,825			14,358			4,467
Foreign currency translation adjustment					(23,636)		(8,953)
Shares issued upon exercise of stock options			429
Shares received as proceeds of option exercises
Sale of subsidiary shares to noncontrolling interest			(6)				654
Dividends				$ (8,058)			$ (3,836)
Stock-based compensation			392
Balance at Jun. 30, 2015	$ 474,535	$ 31	$ 61,015	$ 380,421	$ (39,459)	$ (36,464)	$ 108,991