Finance Receivables (Allowance For Credit Losses And Finance Receivables By Portfolio, Individually And Collectively Evaluated For Impairment) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	$ 0	$ 0
Collectively evaluated for impairment	189,885	192,471
Total allowance for credit losses	189,885	192,471	$ 173,343	$ 147,178	$ 127,364
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	7,411,816	7,157,557
Total finance receivables	7,411,816	7,157,557	7,008,801	7,015,331	6,560,245
Retail
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	182,098	186,254
Total allowance for credit losses	182,098	186,254	166,810	139,320
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	6,328,201	6,140,600
Total finance receivables	6,328,201	6,140,600	5,982,211	5,991,471	5,607,924
Wholesale
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	7,787	6,217
Total allowance for credit losses	7,787	6,217	6,533	7,858
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	1,083,615	1,016,957
Total finance receivables	$ 1,083,615	$ 1,016,957	$ 1,026,590	$ 1,023,860	$ 952,321