Finance Receivables (Recorded Investment Of Retail and Wholesale Finance Receivables By Credit Quality Indicator) (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Apr. 01, 2018
Financing Receivable, Recorded Investment
Financing receivable, gross	$ 7,629,464	$ 7,411,816	$ 7,316,792
Retail
Financing Receivable, Recorded Investment
Financing receivable, gross	6,290,036	6,328,201	6,064,192
Retail | Prime
Financing Receivable, Recorded Investment
Financing receivable, gross	5,160,942	5,183,754	4,923,237
Retail | Sub-prime
Financing Receivable, Recorded Investment
Financing receivable, gross	1,129,094	1,144,447	1,140,955
Wholesale
Financing Receivable, Recorded Investment
Financing receivable, gross	1,339,428	1,083,615	1,252,600
Wholesale | Doubtful
Financing Receivable, Recorded Investment
Financing receivable, gross	8,679	2,210	1,582
Wholesale | Substandard
Financing Receivable, Recorded Investment
Financing receivable, gross	7,866	9,660	3,368
Wholesale | Special Mention
Financing Receivable, Recorded Investment
Financing receivable, gross	11,484	10,299	33,085
Wholesale | Medium Risk
Financing Receivable, Recorded Investment
Financing receivable, gross	917	25,802	10,512
Wholesale | Low Risk
Financing Receivable, Recorded Investment
Financing receivable, gross	$ 1,310,482	$ 1,035,644	$ 1,204,053