Revenue Recognition (Extended Warranties and Post-Contract Support) (Details) - Extended warranties and post contract support - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Post-contract support contract, term		12 months
Deferred revenue	$ 38.9	$ 38.9	$ 40.7
Deferred revenue recognized	3.0	15.7
Estimation of future revenues	$ 25.6	$ 25.6
Minimum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Extended product warranty, term		1 year
Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Extended product warranty, term		5 years