Leases (Details) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) lease_termination_option	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Variable lease costs		$ 0.3	$ 0.5	$ 0.7	$ 0.8
Lease renewal term	15 years	15 years		15 years
Notice required for termination of lease				6 months
Security deposit	$ 0.8	$ 0.8		$ 0.8
Letters of credit outstanding, amount	$ 5.5	5.5		5.5
Number of operating lease termination options exercised | lease_termination_option	1
Reduction in operating lease liability	$ 6.1
Decrease In operating lease asset	$ 5.3
Operating lease impairment		$ 2.7	$ 0.0	$ 2.7	$ 0.0
Minimum
Lessee, Lease, Description [Line Items]
Lease term	1 year	1 year		1 year
Sublease term				1 year
Maximum
Lessee, Lease, Description [Line Items]
Lease term	9 years	9 years		9 years
Sublease term				2 years