Allowance for Loan Losses - Summary of Performance and Related Loan Status of Loans Modified (Parenthetical) (Details) $ in Millions	3 Months Ended
Mar. 31, 2023 USD ($)
Private Education Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Loans modified, charged off	$ 0.4

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration