Description of Business (Percentage of Consumer Loans Assigned Based on Volumes) (Details)		3 Months Ended
		Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022
Portfolio Program [Member]
Description Of Business [Line Items]
Percentage of new consumer loans unit volume		72.40%	72.10%	73.10%	74.30%	74.00%	72.70%
Percentage of new consumer loans dollar volume	[1]	68.60%	68.10%	69.60%	70.50%	70.40%	68.60%
Purchase Program [Member]
Description Of Business [Line Items]
Percentage of new consumer loans unit volume		27.60%	27.90%	26.90%	25.70%	26.00%	27.30%
Percentage of new consumer loans dollar volume	[1]	31.40%	31.90%	30.40%	29.50%	29.60%	31.40%

[1] Represents advances paid to Dealers on Consumer Loans assigned under our Portfolio Program and one-time payments made to Dealers to purchase Consumer Loans assigned under our Purchase Program. Payments of Dealer Holdback (as defined below) and accelerated Dealer Holdback are not included.