- Schedule of Revenue Categories (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue Information
Revenues (includes related party revenue of $3,773 and $345 for the three months ended June 30, 2020 and 2019, respectively, and $5,020 and $509 for the six months ended June 30, 2020 and 2019, respectively)	$ 62,685	$ 88,075	$ 146,211	$ 173,657
Dealer revenue
Revenue Information
Revenues (includes related party revenue of $3,773 and $345 for the three months ended June 30, 2020 and 2019, respectively, and $5,020 and $509 for the six months ended June 30, 2020 and 2019, respectively)	50,049	78,977	123,847	155,791
OEM incentives revenue
Revenue Information
Revenues (includes related party revenue of $3,773 and $345 for the three months ended June 30, 2020 and 2019, respectively, and $5,020 and $509 for the six months ended June 30, 2020 and 2019, respectively)	4,771	4,143	8,294	8,344
Forecasts, consulting and other revenue
Revenue Information
Revenues (includes related party revenue of $3,773 and $345 for the three months ended June 30, 2020 and 2019, respectively, and $5,020 and $509 for the six months ended June 30, 2020 and 2019, respectively)	$ 7,865	$ 4,955	$ 14,070	$ 9,522