Finance Receivables (Allowance For Credit Losses And Finance Receivables By Portfolio, Individually And Collectively Evaluated For Impairment) (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	$ 0	$ 0
Collectively evaluated for impairment	173,343,000	147,178,000
Total allowance for credit losses	173,343,000	147,178,000	$ 127,364,000	$ 110,693,000	$ 107,667,000
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	7,008,801,000	7,015,331,000
Total finance receivables	7,008,801,000	7,015,331,000	6,560,245,000	6,110,256,000	5,889,519,000
Retail
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	166,761,000	139,320,000
Total allowance for credit losses	166,761,000	139,320,000	122,025,000	106,063,000
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	5,982,211,000	5,991,471,000
Total finance receivables	5,982,211,000	5,991,471,000	5,607,924,000	5,265,044,000	5,073,115,000
Wholesale
Financing Receivable, Allowance for Credit Losses [Line Items]
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	6,582,000	7,858,000
Total allowance for credit losses	6,582,000	7,858,000	5,339,000	4,630,000
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	1,026,590,000	1,023,860,000
Total finance receivables	$ 1,026,590,000	$ 1,023,860,000	$ 952,321,000	$ 845,212,000	$ 816,404,000