Summary of Significant Accounting Policies - Fair Value Methods Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
ROU asset impairment charges		$ 1,700,000	$ 2,100,000	$ 0
Goodwill impairment charge, including discontinued operations		10,200,000
Impairment charges recorded on goodwill		0	$ 8,264,000	$ 0
Accu-Trade, LLC
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
ROU asset impairment charges		4,100,000
Discontinued Operations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment charges recorded on goodwill	$ 1,900,000	$ 1,900,000
Discontinued And Continuing Operations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment charges recorded on goodwill	$ 10,200,000