Leases (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Lease renewal term	5 years	5 years
Lease termination period		1 year
Operating lease right-of-use asset	$ 37.7	$ 37.7	$ 44.2
Operating lease liability	$ 42.5	$ 42.5	$ 49.9
Weighted average remaining lease term (in years)	4 years 3 months 18 days	4 years 3 months 18 days
Weighted average discount rate	4.14%	4.14%
Operating lease liability for lease not yet commenced	$ 7.5
Term of operating lease not yet commenced	12 years	12 years
Minimum
Lessee, Lease, Description [Line Items]
Lease term of contract	1 year	1 year
Maximum
Lessee, Lease, Description [Line Items]
Lease term of contract	9 years	9 years