Restructuring (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 2,064	$ 2,840
Payments for Restructuring	(1,211)
Severance Costs	435	$ 3,300
Accounts Payable and Accrued Liabilities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	1,700
Other Noncurrent Liabilities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 400