Leases Leases (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Operating Leased Assets [Line Items]
Rent expense related to operating lease liabilities	$ 0.7	$ 2.2
Operating Lease, Right-of-Use Asset	11.1	11.1
Operating lease liabilities	15.7	15.7
Variable lease expense	0.3	1.0
Cash flows from operating leases	$ 0.7	$ 2.3
Weighted average remaining lease term (years)	5 years 7 months 6 days	5 years 7 months 6 days
Weighted average discount rate - operating leases (1)	4.90%	4.90%