Capitalized Contract Costs (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
Capitalized Contract Cost [Line Items]
Costs to fulfill a contract - amortization expense	$ 7.9	$ 5.9	$ 20.6	$ 17.8
Costs to fulfill contract, net	74.2		74.2		$ 75.8
Deferred Commissions
Capitalized Contract Cost [Line Items]
Deferred commissions	9.2		9.2		$ 9.1
Costs to fulfill a contract - amortization expense	$ 0.8	$ 0.7	$ 2.3	$ 2.4