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
Common stock beginning balance, share at Dec. 31, 2014	48,453,000
Beginning balance, value at Dec. 31, 2014	$ 485	$ (527,595)	$ 356,792	$ (52,274)	$ 677,859	$ 7,983	$ 463,250
Net income					61,666	3,382	65,885
Net income excluding mandatorily redeemable noncontrolling interest							65,048
Dividends to shareholders					(17,423)		(17,423)
Dividends distributed to noncontrolling interest						(3,960)	(3,960)
Adjustments to redemption value of mandatorily redeemable noncontrolling interest					(1,113)		(1,113)
Foreign currency translation adjustments				(37,844)		(356)	(38,200)
Derivatives valuation, net of tax				(8,540)			(8,540)
Vesting of restricted stock units, share	372,000
Vesting of restricted stock units, value	$ 4	5,768	(10,016)				(4,244)
Exercise of stock options, share	342,000
Exercise of stock options, value	$ 3	5,307	(9,737)				(4,427)
Excess tax benefit from equity-based awards			(823)				(823)
Equity-based compensation expense			11,035			152	11,187
Purchases of common stock, share	(686,000)
Purchases of common stock, value	$ (7)	(17,224)					(17,231)
Other, net of tax				(2,707)			(2,707)
Common stock ending balance, share at Dec. 31, 2015	48,481,000
Ending balance, value at Dec. 31, 2015	$ 485	(533,744)	347,251	(101,365)	720,989	7,201	440,817
Net income					33,678	3,757	37,435
Net income excluding mandatorily redeemable noncontrolling interest							37,435
Dividends to shareholders					(18,262)		(18,262)
Dividends distributed to noncontrolling interest						(3,825)	(3,825)
Adjustments to redemption value of mandatorily redeemable noncontrolling interest					(466)		(466)
Foreign currency translation adjustments				(20,812)		(243)	(21,055)
Derivatives valuation, net of tax				(5,508)			(5,508)
Vesting of restricted stock units, share	297,000
Vesting of restricted stock units, value	$ 3	4,681	(8,614)				(3,930)
Exercise of stock options, share	29,000
Exercise of stock options, value		458	(82)				376
Excess tax benefit from equity-based awards			557				557
Equity-based compensation expense			9,627			81	9,708
Purchases of common stock, share	(2,693,000)
Purchases of common stock, value	$ (26)	(74,657)					(74,683)
Other, net of tax				721		10	$ 731
Preferred stock ending balance, share at Dec. 31, 2016							0
Common stock ending balance, share at Dec. 31, 2016	46,114,000						46,113,693
Ending balance, value at Dec. 31, 2016	$ 462	(603,262)	348,739	(126,964)	735,939	6,981	$ 361,895
Net income					7,256	3,556	10,812
Dividends to shareholders					(21,531)		(21,531)
Dividends distributed to noncontrolling interest						(3,645)	(3,645)
Foreign currency translation adjustments				7,908		377	8,285
Derivatives valuation, net of tax				16,647			16,647
Vesting of restricted stock units, share	298,000
Vesting of restricted stock units, value	$ 3	4,913	(10,313)				$ (5,397)
Exercise of stock options, share	60,000						60,000
Exercise of stock options, value		994	1,156				$ 2,150
Equity-based compensation expense			12,143			(291)	11,852
Purchases of common stock, share	(610,000)
Purchases of common stock, value	$ (6)	(18,322)					(18,328)
Other, net of tax				105			$ 105
Preferred stock ending balance, share at Dec. 31, 2017							0
Common stock ending balance, share at Dec. 31, 2017	45,862,000						45,861,959
Ending balance, value at Dec. 31, 2017	$ 459	$ (615,677)	$ 351,725	$ (102,304)	$ 721,664	$ 6,978	$ 362,845