Revenue Information and Deferred Sales Commissions Revenue Information and Deferred Sales Commissions - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue Information
Revenues	$ 231,698	$ 278,678	$ 335,046
Contract with Customer, Asset, Reclassified to Receivable	2,300	2,800
Dealer revenue
Revenue Information
Revenues	222,000	252,928	317,965
OEM incentives revenue
Revenue Information
Revenues	8,676	16,833	16,569
Other revenue
Revenue Information
Revenues	$ 1,022	$ 8,917	$ 512