Impairment, Restructuring and Other Charges - Narrative (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring and other charges				$ 60,000,000.0
Severance costs	$ 1,100,000		$ 0	7,300,000
Inventory write-down				32,100,000
Long-lived asset impairment		$ 38,600,000		14,900,000
Restructuring costs			4,400,000	5,700,000
Impairments		$ 38,600,000	0	$ 38,559,000
Goodwill
Restructuring Cost and Reserve [Line Items]
Impairments			0
Long-Lived Assets
Restructuring Cost and Reserve [Line Items]
Impairments			0
Inventories
Restructuring Cost and Reserve [Line Items]
Impairments			$ 0
Restructuring charges					$ 33,600,000
Property, Plant and Equipment
Restructuring Cost and Reserve [Line Items]
Restructuring charges					$ 27,400,000