Restructuring and Impairment Charges - Narrative (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended		12 Months Ended
	Apr. 24, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2019
Arizona
Restructuring Cost and Reserve [Line Items]
Restructuring charges			$ 0.6	$ 0.5	$ 2.4
Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 0.3		0.6
Restructuring charges, fair value				1.1
Restructuring costs				0.1	$ 0.4
Facility Consolidation
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 2.0	$ 0.5		$ 1.0
Restructuring costs	1.2
Severance and retention expenses	$ 0.8
Forecast | Facility Consolidation
Restructuring Cost and Reserve [Line Items]
Expected cost to be paid						$ 1.5	$ 0.5
Minimum | Forecast | Facility Consolidation
Restructuring Cost and Reserve [Line Items]
Estimated capital expenditures						1.2
Maximum | Forecast | Facility Consolidation
Restructuring Cost and Reserve [Line Items]
Estimated capital expenditures						$ 1.4