Asset-Backed Financing - Assets And Liabilities Of Variable Interest Entities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Apr. 30, 2020
Unconsolidated VIEs:
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, assets, carrying amount			$ 27,400
Total assets
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, assets, carrying amount	$ 2,474,757	$ 2,703,666
Total assets | Term asset-backed securitizations | Consolidated VIEs:
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, assets, carrying amount	2,071,460	2,123,635
Total assets | Asset-backed U.S. commercial paper conduit facility | Consolidated VIEs:
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, assets, carrying amount	303,777	443,364
Total assets | Asset-backed Canadian commercial paper conduit facility | Unconsolidated VIEs:
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, assets, carrying amount	99,520	136,667
Finance receivables
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, assets, carrying amount	2,442,828	2,704,750
Transfers accounts for as secured borrowings, assets, allowance for loan losses, carrying amount	(121,667)	(156,928)
Finance receivables | Term asset-backed securitizations | Consolidated VIEs:
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, assets, carrying amount	2,048,194	2,129,372
Transfers accounts for as secured borrowings, assets, allowance for loan losses, carrying amount	(102,779)	(124,627)
Finance receivables | Asset-backed U.S. commercial paper conduit facility | Consolidated VIEs:
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, assets, carrying amount	297,454	441,402
Transfers accounts for as secured borrowings, assets, allowance for loan losses, carrying amount	(14,898)	(25,793)
Finance receivables | Asset-backed Canadian commercial paper conduit facility | Unconsolidated VIEs:
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, assets, carrying amount	97,180	133,976
Transfers accounts for as secured borrowings, assets, allowance for loan losses, carrying amount	(3,990)	(6,508)
Restricted cash
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, assets, carrying amount	150,475	151,965
Restricted cash | Term asset-backed securitizations | Consolidated VIEs:
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, assets, carrying amount	123,717	116,268
Restricted cash | Asset-backed U.S. commercial paper conduit facility | Consolidated VIEs:
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, assets, carrying amount	20,567	26,624
Restricted cash | Asset-backed Canadian commercial paper conduit facility | Unconsolidated VIEs:
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, assets, carrying amount	6,191	9,073
Other assets
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, assets, carrying amount	3,121	3,879
Other assets | Term asset-backed securitizations | Consolidated VIEs:
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, assets, carrying amount	2,328	2,622
Other assets | Asset-backed U.S. commercial paper conduit facility | Consolidated VIEs:
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, assets, carrying amount	654	1,131
Other assets | Asset-backed Canadian commercial paper conduit facility | Unconsolidated VIEs:
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, assets, carrying amount	139	126
Asset-backed debt
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, liabilities, carrying amount	1,984,785	2,310,839
Asset-backed debt | Term asset-backed securitizations | Consolidated VIEs:
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, liabilities, carrying amount	1,627,142	1,791,956
Asset-backed debt | Asset-backed U.S. commercial paper conduit facility | Consolidated VIEs:
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, liabilities, carrying amount	272,589	402,205
Asset-backed debt | Asset-backed Canadian commercial paper conduit facility | Unconsolidated VIEs:
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Transfers accounts for as secured borrowings, liabilities, carrying amount	$ 85,054	$ 116,678