Finance Receivables (Aging Of Past Due Finance Receivables Including Non-Accrual Status Finance Receivables) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	$ 7,181,915	$ 6,929,473
Total Past Due	229,901	228,084
Total finance receivables	7,411,816	7,157,557	$ 7,008,801	$ 7,015,331	$ 6,560,245
31-60 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	137,467	140,224
61-90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	50,098	47,784
Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	42,336	40,076
Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	6,100,186	5,913,473
Total Past Due	228,015	227,127
Total finance receivables	6,328,201	6,140,600	5,982,211	5,991,471	5,607,924
Retail | 31-60 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	136,945	139,629
Retail | 61-90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	49,825	47,539
Retail | Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	41,245	39,959
Wholesale
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	1,081,729	1,016,000
Total Past Due	1,886	957
Total finance receivables	1,083,615	1,016,957	$ 1,026,590	$ 1,023,860	$ 952,321
Wholesale | 31-60 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	522	595
Wholesale | 61-90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	273	245
Wholesale | Greater than 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 1,091	$ 117