CONSOLIDATED CONDENSED STATEMENT OF SHAREHOLDERS' EQUITY (Unaudited) - 9 months ended Sep. 30, 2016 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock	Non-Controlling Interests
Beginning Balance (in shares) at Dec. 31, 2015		93,769				(2)
Beginning Balance at Dec. 31, 2015	$ 412,945	$ 938	$ 322,793	$ 101,047	$ (11,813)	$ (20)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Acquisition of treasury stock (in shares)						(572)
Acquisition of treasury stock	(5,133)					$ (5,133)
Exercise of stock options (in shares)		0				373
Exercise of stock options	2,625	$ 0	(690)			$ 3,315
Compensatory awards released from restriction (in shares)		440				99
Compensatory awards released from restriction		$ 4	(897)			$ 893
Share-based compensation	6,465		6,465
Stock dividends (in shares)		5				1
Stock dividends			45	(54)		$ 9
Cash dividends	(2,822)			(2,822)
Equity adjustment from foreign currency translation	4,195				4,271		(76)
Change in fair value of derivative instruments	(1,677)				(1,677)
Non-controlling interests	9,538						9,538
Net income	66,756			66,629			127
Ending Balance (in shares) at Sep. 30, 2016		94,214				(101)
Ending Balance at Sep. 30, 2016	$ 492,892	$ 942	$ 327,716	$ 164,800	$ (9,219)	$ (936)	$ 9,589