Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income (loss) from continuing operations before taxes:
United States operations	$ 2,177	$ (25,615)	$ (6,924)
Foreign operations	97,171	152,076	46,864
Income from continuing operations before taxes	99,348	126,461	39,940
Currently payable
United States federal	0	2,981	0
United States state and local	2,392	(1,038)	1,789
Foreign	28,201	26,906	17,317
Income tax expense (benefit)	30,593	28,849	19,106
Deferred
United States federal	(11,028)	(27,677)	(23,709)
United States state and local	(8,758)	(3,139)	(2,257)
Foreign	(4,312)	782	(19,708)
Deferred Income tax expense (benefit)	(24,098)	(30,034)	(45,674)
Income tax expense (benefit)	$ 6,495	$ (1,185)	$ (26,568)