Finance Receivables - Recorded Investment Of Retail and Wholesale Finance Receivables By Credit Quality Indicator (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jul. 01, 2018
Financing Receivable, Recorded Investment
Financing receivable, gross	$ 7,789,401	$ 7,411,816	$ 7,507,132
Retail
Financing Receivable, Recorded Investment
Financing receivable, gross	6,549,707	6,328,201	6,373,926
Retail | Prime
Financing Receivable, Recorded Investment
Financing receivable, gross	5,372,712	5,183,754	5,193,641
Retail | Sub-prime
Financing Receivable, Recorded Investment
Financing receivable, gross	1,176,995	1,144,447	1,180,285
Wholesale
Financing Receivable, Recorded Investment
Financing receivable, gross	1,239,694	1,083,615	1,133,206
Wholesale | Doubtful
Financing Receivable, Recorded Investment
Financing receivable, gross	6,850	2,210	251
Wholesale | Substandard
Financing Receivable, Recorded Investment
Financing receivable, gross	7,643	9,660	803
Wholesale | Special Mention
Financing Receivable, Recorded Investment
Financing receivable, gross	12,642	10,299	2,154
Wholesale | Medium Risk
Financing Receivable, Recorded Investment
Financing receivable, gross	6,170	25,802	37,045
Wholesale | Low Risk
Financing Receivable, Recorded Investment
Financing receivable, gross	$ 1,206,389	$ 1,035,644	$ 1,092,953