Revenue Recognition (Costs to Obtain a Contract) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred commission costs	$ 17.5	$ 15.6
Commissions expense recognized	$ 5.2
Minimum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Capitalized contract, amortization period	3 years
Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Capitalized contract, amortization period	7 years