Commitments and Contingencies - Operating and Capital Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Future minimum payments under operating leases
2017	$ 17.1
2018	13.2
2019	12.3
2020	5.6
2021	4.1
2022 and beyond	3.1
Future minimum rentals to be received under operating subleases
2017	0.2
2018	0.1
2019	0.2
Rent expense	16.2	$ 15.2	$ 17.4
Future minimum payments under capital leases net of leasehold improvement allowances
2017	5.5
2018	3.8
2019	2.9
2020	3.5
2021	3.6
2022 and beyond	11.3
Capital lease obligations imputed interest	$ 4.6