Leases - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
ROU asset	$ 236.2	$ 0.0
Total lease liability	234.3
Operating lease costs	24.2
Amount of lease not yet commenced	$ 42.7
Minimum
Lessee, Lease, Description [Line Items]
Amount of lease not yet commenced lease terms	7 years
Maximum
Lessee, Lease, Description [Line Items]
Amount of lease not yet commenced lease terms	15 years