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 [Member]	Treasury stock [Member]	Noncontrolling interest [Member]
Balance at Dec. 31, 2010		$ 30	$ 48,887	$ 205,453	$ 14,757	$ (34,151)	$ 64,970
Net income	42,949			32,303			10,646
Foreign currency translation adjustments					(7,021)		(2,659)
Net derivative instrument gain, net of tax					11		7
Transfer from OCI into earnings
Shares issued upon exercise of stock options		1	1,092
Shares received as proceeds of option exercises
Sale of subsidiary shares to noncontrolling interests			626				2,130
Dividends				(9,768)			(3,149)
Purchase of subsidiary shares from noncontrolling interests			(417)				(333)
Stock compensation			695	176			64
Balance at Dec. 31, 2011	324,350	31	50,883	228,164	7,747	(34,151)	71,676
Net income	176,890			131,136			45,754
Foreign currency translation adjustments					4,735		1,684
Net derivative instrument gain, net of tax					16		6
Transfer from OCI into earnings
Shares issued upon exercise of stock options			2,568			409
Shares received as proceeds of option exercises						(1,662)
Sale of subsidiary shares to noncontrolling interests			737				2,659
Dividends				(9,789)			(3,333)
Purchase of subsidiary shares from noncontrolling interests
Stock compensation			491	161			59
Balance at Dec. 31, 2012	499,981	31	54,679	349,672	12,498	(35,404)	118,505
Net income	50,966			39,211			11,755
Foreign currency translation adjustments					13,602		5,425
Net derivative instrument gain, net of tax
Transfer from OCI into earnings					(240)		(87)
Shares issued upon exercise of stock options			2,882			203
Shares received as proceeds of option exercises						(815)
Sale of subsidiary shares to noncontrolling interests			(173)				830
Dividends				(29,582)			(8,341)
Purchase of subsidiary shares from noncontrolling interests
Stock compensation			489	158			58
Balance at Dec. 31, 2013	$ 535,356	$ 31	$ 57,877	$ 359,459	$ 25,860	$ (36,016)	$ 128,145