Restructuring (Narrative) (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) employees	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Restructuring Cost and Reserve [Line Items]
Fair value adjustment on available-for-sale assets				$ 3,212
Accrued liabilities for restructuring charges	$ 6,856		4,668	6,856
Restructuring reserve, noncurrent	3,320		908	3,320
Payments for restructuring			900
Scenario, Forecast [Member]
Restructuring Cost and Reserve [Line Items]
Payments for restructuring		$ 4,700
Reduced Employee Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges accrued			$ 2,600	11,400
Fair value adjustment on available-for-sale assets				3,300
Machine Clothing [Member] | Reduced Employee Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Reduction in employees | employees			200
Early Retirement Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges accrued	$ 8,100
Early Retirement Program [Member] | Machine Clothing and Corporate [Member]
Restructuring Cost and Reserve [Line Items]
Effect of cost savings				$ 4,300