Exit Activity Costs and Asset Impairments (Summary of Exit Activity Costs and Asset Impairments) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Restructuring Cost and Reserve [Line Items]
Net asset impairment and exit activity charges (gains)	$ 256	$ 3,919
Restructuring Charges	(471)	3,002
Cost of sales
Restructuring Cost and Reserve [Line Items]
Net asset impairment and exit activity charges (gains)	37	994
Selling, general, and administrative (recoveries) expense
Restructuring Cost and Reserve [Line Items]
Net asset impairment and exit activity charges (gains)	$ (508)	$ 2,008