Consolidated Statement of Stockholders' Equity - USD ($) $ in Thousands	Stockholders' Equity of the Company Common Stock [Member]	Stockholders' Equity of the Company Treasury Stock [Member]	Stockholders' Equity of the Company Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss)	Stockholders' Equity of the Company Retained Earnings [Member]	Noncontrolling Interest [Member]	Total
Beginning balance, value at Dec. 31, 2016				$ (126,964)
Net income							$ 51,536
Dividends distributed to noncontrolling interest							(2,745)
Foreign currency translation adjustments							$ 8,414
Ending balance, value at Sep. 30, 2017				(103,893)
Preferred stock beginning balance, share at Dec. 31, 2017							0
Common stock beginning balance, share at Dec. 31, 2017	45,862,000						45,861,959
Beginning balance, value at Dec. 31, 2017	$ 459	$ (615,677)	$ 351,725	(102,304)	$ 721,664	$ 6,978	$ 362,845
Net income					15,484	3,489	18,973
Dividends to shareholders					(25,346)		(25,346)
Dividends distributed to noncontrolling interest						(2,025)	(2,025)
Foreign currency translation adjustments				(27,921)		(218)	(28,139)
Derivatives valuation, net of tax				3,935			3,935
Vesting of restricted stock units, share	315,000
Vesting of restricted stock units, value	$ 3	5,215	(9,836)				(4,618)
Exercise of stock options, share	15,000
Exercise of stock options, value		248	(40)				208
Equity-based compensation expense			9,292				9,292
Other, net of tax.				317			$ 317
Preferred stock ending balance, share at Sep. 30, 2018							0
Common stock ending balance, share at Sep. 30, 2018	46,192,000						46,192,458
Ending balance, value at Sep. 30, 2018	$ 462	$ (610,214)	$ 351,141	$ (125,973)	705,218	$ 8,224	$ 328,858
Cumulative Effect of New Accounting Principle in Period of Adoption					$ (6,584)		$ (6,584)