Revenue Recognition (Costs to Obtain a Contract) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Deferred commission costs	$ 15.7	$ 15.7	$ 15.6
Commissions expense recognized	$ 1.3	$ 2.7
Minimum
Disaggregation of Revenue [Line Items]
Amortization period	3 years	3 years
Maximum
Disaggregation of Revenue [Line Items]
Amortization period	7 years	7 years