Auto Loans Receivable - Financing Receivable Credit Quality Indicators (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)
Auto Loans Receivable
Auto loans receivable, 2022 Origination	$ 198.1	[1]
Auto loans receivable, 2021 Origination	97.8	[1]
Auto loans receivable, 2020 Origination	39.7	[1]
Auto loans receivable, 2019 Origination	31.5	[1]
Auto loans receivable, 2018 Origination	9.0	[1]
Auto loans receivable, Prior to 2018 Origination	0.9	[1]
Total auto loans receivable	377.0
Auto Loans Receivable, Current Period Write-offs
Current-period gross write-offs, 2022 origination	5.3	[1]
Current-period gross write-offs, 2021 origination	5.9	[1]
Current-period gross write-offs, 2020 origination	1.4	[1]
Current-period gross write-offs, 2019 origination	1.1	[1]
Current-period gross write-offs, 2018 origination	0.2	[1]
Current-period gross write-offs, Prior to 2018 origination	0.0	[1]
Current-period gross write-offs	13.9
Platinum
Auto Loans Receivable
Auto loans receivable, 2022 Origination	21.9	[1]
Auto loans receivable, 2021 Origination	12.9	[1]
Auto loans receivable, 2020 Origination	6.4	[1]
Auto loans receivable, 2019 Origination	7.4	[1]
Auto loans receivable, 2018 Origination	2.2	[1]
Auto loans receivable, Prior to 2018 Origination	0.2	[1]
Total auto loans receivable	51.0
Gold
Auto Loans Receivable
Auto loans receivable, 2022 Origination	53.7	[1]
Auto loans receivable, 2021 Origination	30.0	[1]
Auto loans receivable, 2020 Origination	12.9	[1]
Auto loans receivable, 2019 Origination	10.6	[1]
Auto loans receivable, 2018 Origination	3.2	[1]
Auto loans receivable, Prior to 2018 Origination	0.4	[1]
Total auto loans receivable	110.8
Silver
Auto Loans Receivable
Auto loans receivable, 2022 Origination	61.9	[1]
Auto loans receivable, 2021 Origination	29.8	[1]
Auto loans receivable, 2020 Origination	10.4	[1]
Auto loans receivable, 2019 Origination	8.0	[1]
Auto loans receivable, 2018 Origination	1.9	[1]
Auto loans receivable, Prior to 2018 Origination	0.1	[1]
Total auto loans receivable	112.1
Bronze
Auto Loans Receivable
Auto loans receivable, 2022 Origination	41.4	[1]
Auto loans receivable, 2021 Origination	17.1	[1]
Auto loans receivable, 2020 Origination	7.4	[1]
Auto loans receivable, 2019 Origination	3.7	[1]
Auto loans receivable, 2018 Origination	1.0	[1]
Auto loans receivable, Prior to 2018 Origination	0.1	[1]
Total auto loans receivable	70.7
Copper
Auto Loans Receivable
Auto loans receivable, 2022 Origination	19.2	[1]
Auto loans receivable, 2021 Origination	8.0	[1]
Auto loans receivable, 2020 Origination	2.6	[1]
Auto loans receivable, 2019 Origination	1.8	[1]
Auto loans receivable, 2018 Origination	0.7	[1]
Auto loans receivable, Prior to 2018 Origination	0.1	[1]
Total auto loans receivable	$ 32.4

[1] Classified based on credit grade assigned when customer was initially approved for financing