Capitalized Contract Costs (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
Capitalized Contract Cost [Line Items]
Costs to fulfill a contract - amortization expense	$ 6.8	$ 6.3	$ 12.7	$ 12.7
Costs to fulfill contract	67.2		67.2		$ 74.4
Deferred Commissions
Capitalized Contract Cost [Line Items]
Deferred commissions	7.7		7.7		$ 8.7
Costs to fulfill a contract - amortization expense	$ 0.8	$ 0.8	$ 1.6	$ 1.5