Fair Value of Assets and Liabilities - Loans, Loan Servicing Rights, Related Notes and Certificates (Detail) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Assets
Loans held for sale at fair value		$ 142,370	$ 121,902
Retail and certificate loans held for investment at fair value	[1]	229,719	636,686
Other loans held for investment at fair value	[1]	21,240	49,954
Securities available for sale:
Securities available for sale at fair value		263,530	142,226
Servicing assets		67,726	56,347
Other assets		6,124
Total assets		730,709	1,007,115
Liabilities
Retail notes, certificates and secured borrowings	[1]	229,719	636,774
Payable on Structured Program borrowings	[1]	65,451	152,808
Other liabilities		12,911	12,270
Total liabilities		308,081	801,852
Principal balance of underlying loan servicing rights		10,300,000	10,100,000
Fair Value, Measurements, Recurring
Securities available for sale:
Servicing assets		67,726	56,347	$ 89,680
Liabilities
Retail notes, certificates and secured borrowings		229,719	636,774
Loans held for sale at fair value | Fair Value, Measurements, Recurring
Assets
Loans held for sale at fair value		142,370	121,902
U.S. agency residential mortgage-backed securities
Securities available for sale:
Securities available for sale at fair value		123,699
Asset-backed senior securities and subordinated securities
Securities available for sale:
Securities available for sale at fair value		39,891	91,887
U.S. agency securities
Securities available for sale:
Securities available for sale at fair value		26,172
Other asset-backed securities
Securities available for sale:
Securities available for sale at fair value		26,133	200
Commercial mortgage-backed securities
Securities available for sale:
Securities available for sale at fair value		26,098
CLUB Certificate asset-backed securities
Securities available for sale:
Securities available for sale at fair value		18,285	50,139
Municipal securities
Securities available for sale:
Securities available for sale at fair value		3,252
Level 1 Inputs
Assets
Loans held for sale at fair value		0	0
Retail and certificate loans held for investment at fair value		0	0
Other loans held for investment at fair value		0	0
Securities available for sale:
Securities available for sale at fair value		0	0
Servicing assets		0	0
Other assets		0
Total assets		0	0
Liabilities
Retail notes, certificates and secured borrowings		0	0
Payable on Structured Program borrowings		0	0
Other liabilities		0	0
Total liabilities		0	0
Level 1 Inputs | U.S. agency residential mortgage-backed securities
Securities available for sale:
Securities available for sale at fair value		0
Level 1 Inputs | Asset-backed senior securities and subordinated securities
Securities available for sale:
Securities available for sale at fair value		0	0
Level 1 Inputs | U.S. agency securities
Securities available for sale:
Securities available for sale at fair value		0
Level 1 Inputs | Other asset-backed securities
Securities available for sale:
Securities available for sale at fair value		0	0
Level 1 Inputs | Commercial mortgage-backed securities
Securities available for sale:
Securities available for sale at fair value		0
Level 1 Inputs | CLUB Certificate asset-backed securities
Securities available for sale:
Securities available for sale at fair value		0	0
Level 1 Inputs | Municipal securities
Securities available for sale:
Securities available for sale at fair value		0
Level 2 Inputs
Assets
Loans held for sale at fair value		0	0
Retail and certificate loans held for investment at fair value		0	0
Other loans held for investment at fair value		0	0
Securities available for sale:
Securities available for sale at fair value		233,483	75,572
Servicing assets		0	0
Other assets		2,812
Total assets		236,295	75,572
Liabilities
Retail notes, certificates and secured borrowings		0	0
Payable on Structured Program borrowings		0	0
Other liabilities		0	0
Total liabilities		0	0
Level 2 Inputs | U.S. agency residential mortgage-backed securities
Securities available for sale:
Securities available for sale at fair value		123,699
Level 2 Inputs | Asset-backed senior securities and subordinated securities
Securities available for sale:
Securities available for sale at fair value		28,129	75,372
Level 2 Inputs | U.S. agency securities
Securities available for sale:
Securities available for sale at fair value		26,172
Level 2 Inputs | Other asset-backed securities
Securities available for sale:
Securities available for sale at fair value		26,133	200
Level 2 Inputs | Commercial mortgage-backed securities
Securities available for sale:
Securities available for sale at fair value		26,098
Level 2 Inputs | CLUB Certificate asset-backed securities
Securities available for sale:
Securities available for sale at fair value		0	0
Level 2 Inputs | Municipal securities
Securities available for sale:
Securities available for sale at fair value		3,252
Level 3 Inputs
Assets
Loans held for sale at fair value		142,370	121,902
Retail and certificate loans held for investment at fair value		229,719	636,686
Other loans held for investment at fair value		21,240	49,954
Securities available for sale:
Securities available for sale at fair value		30,047	66,654
Servicing assets		67,726	56,347
Other assets		3,312
Total assets		494,414	931,543
Liabilities
Retail notes, certificates and secured borrowings		229,719	636,774
Payable on Structured Program borrowings		65,451	152,808
Other liabilities		12,911	12,270
Total liabilities		308,081	801,852
Level 3 Inputs | U.S. agency residential mortgage-backed securities
Securities available for sale:
Securities available for sale at fair value		0
Level 3 Inputs | Asset-backed senior securities and subordinated securities
Securities available for sale:
Securities available for sale at fair value		11,762	16,515
Level 3 Inputs | U.S. agency securities
Securities available for sale:
Securities available for sale at fair value		0
Level 3 Inputs | Other asset-backed securities
Securities available for sale:
Securities available for sale at fair value		0	0
Level 3 Inputs | Commercial mortgage-backed securities
Securities available for sale:
Securities available for sale at fair value		0
Level 3 Inputs | CLUB Certificate asset-backed securities
Securities available for sale:
Securities available for sale at fair value		18,285	$ 50,139
Level 3 Inputs | Municipal securities
Securities available for sale:
Securities available for sale at fair value		$ 0

[1] Includes amounts in variable interest entities (VIEs) presented separately in the table below. The following table presents the assets and liabilities of consolidated VIEs, which are included on the Consolidated Balance Sheets (Balance Sheet) above. The assets in the table below may only be used to settle obligations of consolidated VIEs and are in excess of those obligations. Additionally, the assets and liabilities in the table below include third-party assets and liabilities of consolidated VIEs only and exclude intercompany balances that eliminate in consolidation. December 31,20212020Assets of consolidated VIEs, included in total assets aboveRestricted cash $13,462 $15,983 Loans held for sale at fair value41,734 98,190  Retail and certificate loans held for investment at fair value 10,281 52,620 Other loans held for investment at fair value20,929 50,102 Other assets 584 1,270 Total assets of consolidated VIEs$86,990 $218,165 Liabilities of consolidated VIEs, included in total liabilities aboveRetail notes, certificates and secured borrowings at fair value$10,281 $52,620 Payable on Structured Program borrowings65,451 152,808 Other liabilities467 729 Total liabilities of consolidated VIEs$76,199 $206,157