Finance Receivables, Credit Quality Information, and Allowance for Credit Losses - Summary of Financial Effects of Borrowers Experiencing Financial Difficulty (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Large Loans [Member] \| Interest Rate Reduction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Reduced weighted-average contractual interest	17.90%	18.40%	18.00%	18.40%
Large Loans [Member] \| Term Extension [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Added weighted-average period to loans	1 year 3 months 18 days	1 year 3 months 18 days	1 year 4 months 24 days	1 year 4 months 24 days
Large Loans [Member] \| Principal Forgiveness [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Reduced amortized cost basis	$ 0.2	$ 0.3	$ 0.6	$ 0.6
Small Loans [Member] \| Interest Rate Reduction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Reduced weighted-average contractual interest	28.70%	28.80%	28.60%	29.30%
Small Loans [Member] \| Term Extension [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Added weighted-average period to loans	1 year 3 months 18 days	1 year 3 months 18 days	1 year 3 months 18 days	1 year 3 months 18 days
Small Loans [Member] \| Principal Forgiveness [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Reduced amortized cost basis	$ 0.1	$ 0.1	$ 0.3	$ 0.2