Revenue, Deferred Revenue, Contract Balances and Performance Obligations - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Deferred revenue	$ 10.6		$ 10.6		$ 10.7
Contract with customer, asset, net	7.0		7.0		$ 0.4
Contract with customer liability, revenue recognized	7.8	$ 11.3	9.8	$ 18.5
Contract with customer, liability, cumulative catch-up adjustment to revenue, change in estimate of transaction price	$ 0.2	$ (0.1)	$ 2.3	$ 1.8