Subsequent Events (Details) $ in Thousands, kr in Millions				3 Months Ended		9 Months Ended
	Nov. 01, 2018 USD ($)	Nov. 01, 2018 DKK (kr)	Oct. 26, 2018 USD ($) employee	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)
Subsequent Event [Line Items]
Restructuring charges				$ 1,219	$ 5,439	$ 4,548	$ 5,439
Restructuring 2017
Subsequent Event [Line Items]
Restructuring charges				$ 7,423	$ 6,737	$ 15,580	$ 6,737
Subsequent Event
Subsequent Event [Line Items]
Proceeds from sale of productive assets	$ 1,600	kr 10.5
Tube-supply agreement, term (years)	5 years	5 years
Trade Name Entitlement Agreement, Term	5 years	5 years
Subsequent Event | Restructuring 2017
Subsequent Event [Line Items]
Restructuring charges			$ 25,000
Reduction of headcount | employee			150
Subsequent Event | Restructuring 2017 | Minimum
Subsequent Event [Line Items]
Restructuring charges			$ 8,000
Subsequent Event | Restructuring 2017 | Maximum
Subsequent Event [Line Items]
Restructuring charges			$ 10,000