Description of Business (Percentage of Consumer Loans Assigned Based on Volumes) (Details)	3 Months Ended
	Sep. 30, 2023	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	74.80%	72.40%		72.10%		73.10%		74.30%		74.00%		72.70%
Percentage of new consumer loans dollar volume	71.70%	68.60%	[1]	68.10%	[1]	69.60%	[1]	70.50%	[1]	70.40%	[1]	68.60%	[1]
Purchase Program [Member]
Description Of Business [Line Items]
Percentage of new consumer loans unit volume	25.20%	27.60%		27.90%		26.90%		25.70%		26.00%		27.30%
Percentage of new consumer loans dollar volume	28.30%	31.40%	[1]	31.90%	[1]	30.40%	[1]	29.50%	[1]	29.60%	[1]	31.40%	[1]

[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.