Property and Equipment - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 5.7	$ 5.5	$ 6.0
Loss on disposal of property and equipment	0.4
Computer Hardware, Furniture and Office Equipment and Leasehold Improvements
Property, Plant and Equipment [Line Items]
Disposals	10.0	4.9
Accumulated depreciation	$ 9.6	4.9
Leasehold improvements
Property, Plant and Equipment [Line Items]
Disposals		0.8
Accumulated depreciation		0.3
Lease incentive obligation reduction		$ 0.5