Consolidated Statements of Changes in Equity (Unaudited) - USD ($) $ in Thousands	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive loss	Treasury stock	Noncontrolling interest	Total
Beginning Balance at Dec. 31, 2018	$ 31	$ 69,970	$ 448,731	$ (33,650)		$ 138,139
Foreign currency translation adjustment, net of tax				(16,569)		(6,702)
Transfer from other comprehensive income into earnings				(136)
Net derivative instrument loss, net of tax				(53)		(70)	$ (70)
Net income			52,059			15,176	67,235
Dividends			(25,950)			(9,654)
Shares issued upon exercise of stock options		2,781
Share-based compensation		1,052	1,637			190
Purchase of subsidiary shares from noncontrolling interest		(5,167)				(920)
Transfer of subsidiary shares purchased
Ending Balance at Sep. 30, 2019	31	68,636	476,477	(50,408)	$ (37,475)	136,159	593,420
Beginning Balance at Dec. 31, 2019	31	70,664	474,637	(39,853)		140,994	608,998
Foreign currency translation adjustment, net of tax				15,347		6,423
Transfer from other comprehensive income into earnings				(52)
Net derivative instrument loss, net of tax						(19)	(19)
Net income			23,480			8,688	32,168
Dividends			(10,406)			(324)
Shares issued upon exercise of stock options	1	796
Share-based compensation		1,283	482			178
Purchase of subsidiary shares from noncontrolling interest
Transfer of subsidiary shares purchased		525				(139)
Ending Balance at Sep. 30, 2020	$ 32	$ 73,268	$ 488,193	$ (24,558)	$ (37,475)	$ 155,801	$ 655,261