Notes Receivable (Percentage Of Gross Notes Receivable Outstanding By FICO Score At Origination) (Details)		3 Months Ended	12 Months Ended
		Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment [Line Items]
Percentage of gross notes receivable outstanding		100.00%	100.00%
700+ [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of gross notes receivable outstanding		57.00%	57.00%
600-699 [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of gross notes receivable outstanding		39.00%	39.00%
Less Than 600 [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of gross notes receivable outstanding		3.00%	3.00%
No Score [Member]
Financing Receivable, Recorded Investment [Line Items]
Percentage of gross notes receivable outstanding	[1]	1.00%	1.00%

[1] VOI notes receivable attributable to borrowings without a FICO score are primarily related to foreign borrowers.