Revenue Recognition - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract asset	$ 0.0		$ 0.0		$ 0.5
Contract liability	0.6		0.6		0.4
Contract acquisition asset	0.6		0.6		$ 0.9
Amortization of contract acquisition costs	0.1	$ 0.3	0.4	$ 0.8
Selling services
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Remaining performance obligation	38.8		38.8
Professional services
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Remaining performance obligation	$ 0.4		$ 0.4