Customer Liabilities - Schedule of Customer Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Other Liabilities Disclosure [Abstract]
Accrued service costs, current	$ 27.8	$ 23.7
Customer deposits, current	0.0	0.0
Refund liabilities, current	0.7	0.5
Deferred revenue (contract liabilities), current	3.8	4.0
Current portion of customer liabilities	32.3	28.2
Refund liabilities, non-current	0.0	0.0
Customer deposits, non-current	0.0	0.0
Deferred revenue (contract liabilities), non-current	14.5	11.5
Non-current portion of customer liabilities	14.5	11.5
Total customer liabilities	$ 46.8	$ 39.7