Income Taxes - Components of Expense and Earnings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current Income Tax Expense (Benefit) [Abstract]
Federal	$ 4,680	$ 8,924	$ 8,086
State	518	188	796
Foreign	12,540	11,074	13,650
Current Income Tax Expense (Benefit), Total	17,738	20,186	22,532
Deferred Income Tax Expense (Benefit) [Abstract]
Federal	4,601	404	2,548
State	104	(16)	57
Foreign	783	(2,789)	(1,598)
Income Tax Expense (Benefit), Total	23,226	17,785	23,539
Components Of Earnings Before Taxes [Abstract]
Domestic	31,175	25,219	32,391
Foreign	52,834	45,011	45,902
Income before taxes and equity in net income of associated companies	$ 84,009	$ 70,230	$ 78,293