Revenue Recognition - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Contract asset	$ 0.0		$ 0.0		$ 0.5
Contract liability	0.5		0.5		0.4
Contract acquisition asset	0.7		0.7		$ 0.9
Amortization of contract acquisition costs	0.1	$ 0.2	0.3	$ 0.5
Selling services
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Remaining performance obligation	32.9		32.9
Professional services
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Remaining performance obligation	$ 0.4		$ 0.4