Goodwill and Intangible Assets - Narrative (Details) - USD ($) $ in Thousands, shares in Millions		12 Months Ended
	Apr. 12, 2018	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Goodwill		$ 9,353	$ 9,353
Amortization expense		$ 1,600	1,100
Weighted average amortization period, definite-lived intangible assets		4 years 10 months 24 days
Class A Units
Business Acquisition [Line Items]
Number of shares issued to former stockholders (in shares)	0.5
Car360
Business Acquisition [Line Items]
Payment to acquire business, net of cash acquired	$ 16,700
Cash acquired	400
Payments to acquire business, net	6,700
Fair value, equity interests issued	10,000
Acquired net working capital	200
Intangible assets, acquired cost	9,900	$ 9,939	9,939
Deferred tax liability	$ 2,500
Deferred tax liability, amortization expense		400	300
Goodwill		$ 9,353	$ 9,353
Car360 | Minimum
Business Acquisition [Line Items]
Deferred tax liability, amortization period	2 years	2 years
Car360 | Maximum
Business Acquisition [Line Items]
Deferred tax liability, amortization period	7 years	7 years