Summary of Significant Accounting Policies Warranties (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Product Warranty Liability [Line Items]
Standard Product Warranty Accrual	$ 7.1	$ 9.7	$ 7.4	$ 10.1
Standard Product Warranty Accrual, Decrease for Payments	0.9	1.2
Warranty_originations_and_revisions	0.7	0.8
Standard Product Warranty Accrual, Increase (Decrease) for Preexisting Warranties	$ (0.1)	$ 0.0
Minimum
Product Warranty Liability [Line Items]
Product Warranty Period	1 year
Maximum
Product Warranty Liability [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years