Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Operating Leases
Operating lease right-of-use assets	$ 24.5	$ 24.7
Operating lease liabilities, current portion	4.5	3.6
Operating lease liabilities	21.6	22.1
Total operating lease liabilities	$ 26.1	$ 25.7
Operating leases:
Weighted average remaining lease term (years)	7 years 6 months	8 years
Operating leases:
Weighted average discount rate	4.20%	4.20%