Leases - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Lessee, Lease, Description [Line Items]
Operating lease expense	$ 2.5		$ 4.6
Rent expense		$ 2.2		$ 4.2
Variable lease payments	$ 0.3		0.6
Operating cash flows for amounts included in measurement of operating lease liabilities			3.8
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability			$ 9.1
Weighted average remaining lease term (in years)	4 years		4 years
Weighted average incremental borrowing rate (as a percentage)	4.90%		4.90%
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease terms (in years)	1 year		1 year
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease terms (in years)	7 years		7 years