Description of Business (Percentage of Consumer Loans Assigned Based on Volumes)	3 Months Ended
	Sep. 30, 2021	Jun. 30, 2021		Mar. 31, 2021		Dec. 31, 2020		Sep. 30, 2020		Jun. 30, 2020		Mar. 31, 2020
Portfolio Program [Member]
Description Of Business [Line Items]
Percentage of new consumer loans unit volume	69.90%	66.90%		65.40%		65.30%		64.10%		62.50%		64.90%
Percentage of new consumer loans dollar volume	66.80%	64.00%	[1]	62.70%	[1]	62.70%	[1]	60.90%	[1]	59.10%	[1]	60.50%	[1]
Purchase Program [Member]
Description Of Business [Line Items]
Percentage of new consumer loans unit volume	30.10%	33.10%		34.60%		34.70%		35.90%		37.50%		35.10%
Percentage of new consumer loans dollar volume	33.20%	36.00%	[1]	37.30%	[1]	37.30%	[1]	39.10%	[1]	40.90%	[1]	39.50%	[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.