Property, Plant and Equipment (Additional Information) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Proceeds from sale of vacant land		$ 0	$ 0	$ 69
Book value	$ 871	871
Depreciation		26,600	$ 23,200	$ 20,100
Belgium
Property, Plant and Equipment [Line Items]
Book value	900	$ 900
Land | Belgium
Property, Plant and Equipment [Line Items]
Proceeds from sale of vacant land	$ 1,600