Leases - Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Leases [Abstract]
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssets	us-gaap:OtherAssets
Operating lease ROU assets - non-current	$ 45.6	$ 44.3
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent	us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent
Operating lease liabilities - current	$ 17.2	$ 15.5
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent	us-gaap:OtherLiabilitiesNoncurrent
Operating lease liabilities - non-current	$ 31.0	$ 30.6
Total operating lease liabilities	$ 48.2	$ 46.1
Weighted average remaining lease term in years - operating leases	3 years 7 months 6 days	3 years 8 months 12 days
Weighted average discount rate - operating leases	3.20%	2.80%