Leases - Summary of Lease Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Leases [Abstract]
Operating lease cost	$ 4.0	$ 3.4	$ 11.9	$ 10.3
Variable lease cost	0.1	0.1	0.2	0.2
Sublease income	(0.1)	0.0	(0.1)	0.0
Total operating lease expense	4.0	3.5	12.0	10.5
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	3.6	3.7	11.1	11.0
Right of use assets obtained in exchange for new operating lease liabilities	$ 0.2	$ 0.1	$ 77.3	$ 5.5