Finance Receivables (Recorded Investment Of Retail and Wholesale Finance Receivables By Credit Quality Indicator) (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 24, 2017
Financing Receivable, Recorded Investment
Financing receivable, gross	$ 7,497,009	$ 7,157,557	$ 7,296,607
Retail
Financing Receivable, Recorded Investment
Financing receivable, gross	6,508,670	6,140,600	6,336,447
Retail | Prime
Financing Receivable, Recorded Investment
Financing receivable, gross	5,321,464	4,966,193	5,107,718
Retail | Sub-prime
Financing Receivable, Recorded Investment
Financing receivable, gross	1,187,206	1,174,407	1,228,729
Wholesale
Financing Receivable, Recorded Investment
Financing receivable, gross	988,339	1,016,957	960,160
Wholesale | Doubtful
Financing Receivable, Recorded Investment
Financing receivable, gross	0	688	4,666
Wholesale | Substandard
Financing Receivable, Recorded Investment
Financing receivable, gross	8,953	3,837	8,724
Wholesale | Special Mention
Financing Receivable, Recorded Investment
Financing receivable, gross	25,459	26,866	5,261
Wholesale | Medium Risk
Financing Receivable, Recorded Investment
Financing receivable, gross	15,825	9,917	4,987
Wholesale | Low Risk
Financing Receivable, Recorded Investment
Financing receivable, gross	$ 938,102	$ 975,649	$ 936,522