Notes Receivable (Percentage Of Gross Notes Receivable Outstanding By FICO Score At Origination) (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Percentage of gross notes receivable outstanding	100.00%	100.00%
701+ [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Percentage of gross notes receivable outstanding	59.00%	59.00%
601-700 [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Percentage of gross notes receivable outstanding	37.00%	37.00%
Less Than 601 [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Percentage of gross notes receivable outstanding	4.00%	4.00%