Summary of Significant Accounting Policies (Changes in Product Warranty Liability) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Changes in product warranty liability
Balance at January 1	$ 6.2	$ 7.9	$ 7.1
Claims paid during the year	(4.1)	(5.3)	(4.0)
Warranty expense	4.3	3.6	4.7
Acquired warranty liabilities	0.0	0.0	0.1
Balance at December 31	$ 6.4	$ 6.2	$ 7.9