Asset-Backed Financing - Assets And Liabilities Of Variable Interest Entities (Details) - USD ($) $ in Thousands	Jun. 27, 2021	Dec. 31, 2020	Jun. 28, 2020	Apr. 30, 2020
Unconsolidated VIEs
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, assets, carrying amount				$ 27,400
Finance receivables
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, assets, carrying amount	$ 2,505,413	$ 2,704,750	$ 3,530,118
Transfers accounted for as secured borrowings, assets, allowance for credit losses, carrying amount	(127,615)	(156,928)	(209,242)
Finance receivables | Asset-backed securitizations | Consolidated VIEs
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, assets, carrying amount	2,090,041	2,129,372	2,780,217
Transfers accounted for as secured borrowings, assets, allowance for credit losses, carrying amount	(107,174)	(124,627)	(166,635)
Finance receivables | Asset-backed U.S. commercial paper conduit facility | Consolidated VIEs
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, assets, carrying amount	316,467	441,402	584,153
Transfers accounted for as secured borrowings, assets, allowance for credit losses, carrying amount	(16,205)	(25,793)	(34,938)
Finance receivables | Asset-backed Canadian commercial paper conduit facility | Unconsolidated VIEs
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, assets, carrying amount	98,905	133,976	165,748
Transfers accounted for as secured borrowings, assets, allowance for credit losses, carrying amount	(4,236)	(6,508)	(7,669)
Restricted cash
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, assets, carrying amount	172,978	151,965	210,949
Restricted cash | Asset-backed securitizations | Consolidated VIEs
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, assets, carrying amount	140,276	116,268	161,257
Restricted cash | Asset-backed U.S. commercial paper conduit facility | Consolidated VIEs
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, assets, carrying amount	24,540	26,624	38,491
Restricted cash | Asset-backed Canadian commercial paper conduit facility | Unconsolidated VIEs
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, assets, carrying amount	8,162	9,073	11,201
Other assets
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, assets, carrying amount	3,377	3,879	2,572
Other assets | Asset-backed securitizations | Consolidated VIEs
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, assets, carrying amount	2,522	2,622	1,235
Other assets | Asset-backed U.S. commercial paper conduit facility | Consolidated VIEs
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, assets, carrying amount	726	1,131	1,195
Other assets | Asset-backed Canadian commercial paper conduit facility | Unconsolidated VIEs
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, assets, carrying amount	129	126	142
Total assets
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, assets, carrying amount	2,554,153	2,703,666	3,534,397
Total assets | Asset-backed securitizations | Consolidated VIEs
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, assets, carrying amount	2,125,665	2,123,635	2,776,074
Total assets | Asset-backed U.S. commercial paper conduit facility | Consolidated VIEs
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, assets, carrying amount	325,528	443,364	588,901
Total assets | Asset-backed Canadian commercial paper conduit facility | Unconsolidated VIEs
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, assets, carrying amount	102,960	136,667	169,422
Asset-backed debt, net
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, associated liabilities, carrying amount	2,106,472	2,310,839	3,146,608
Asset-backed debt, net | Asset-backed securitizations | Consolidated VIEs
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, associated liabilities, carrying amount	1,727,522	1,791,956	2,461,107
Asset-backed debt, net | Asset-backed U.S. commercial paper conduit facility | Consolidated VIEs
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, associated liabilities, carrying amount	291,511	402,205	540,840
Asset-backed debt, net | Asset-backed Canadian commercial paper conduit facility | Unconsolidated VIEs
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings
Transfers accounts for as secured borrowings, associated liabilities, carrying amount	$ 87,439	$ 116,678	$ 144,661