Capitalized Contract Costs (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Capitalized Contract Cost [Line Items]
Amortization of costs to fulfill contracts	$ 6.2	$ 3.6
Cost to fulfill contract, net	79.3		$ 79.5
Sales Commissions
Capitalized Contract Cost [Line Items]
Deferred commissions	12.2		$ 12.1
Amortization of costs to fulfill contracts	$ 1.0	$ 1.7