Loans Held for Investment - Student Loan Portfolio Average Balances (Details) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2024 |
Mar. 31, 2023 |
|
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Average Balance | $ 21,969,756 | $ 22,357,274 |
| Private Education Loans | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Average Balance | $ 21,442,744 | $ 21,755,202 |
| Weighted Average Interest Rate | 11.01% | 10.66% |
| FFELP Loans | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Average Balance | $ 527,012 | $ 602,072 |
| Weighted Average Interest Rate | 7.24% | 6.87% |