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Allowance for Loan Losses - Additional Information (Detail) | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Jul. 01, 2006
Schedule Of Allowance For Credit Losses And Recorded Investment In Financing Receivables Table [Line Items] |  |  |
Loans And Leases Receivable, Percentage Of Loans In Full And Interest Repayment Status That Are Subject To Interest Rate Reductions | 6.40% | 4.90% |
Percentage of loans granted forbearance (as a percentage) | 57.00% | 66.00% |
Criteria for loans to be considered as nonperforming | 90 days |  |
Tier 1 of government guarantee (at least) |  |  | 97.00%
TDR payment default period | 60 days |  |
Period of loans past due that have accrued interest | 90 days |  |
FFELP Loans |  |  |
Schedule Of Allowance For Credit Losses And Recorded Investment In Financing Receivables Table [Line Items] |  |  |
Tier 1 of government guarantee (at least) | 97.00% |  |

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- Definition Criteria for loans to be considered as nonperforming. + References No definition available. + Details
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- Definition Loans and Leases Receivable, Impaired, Loans Granted Forbearance Qualified as Trouble Debt Restructuring + References No definition available. + Details
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- Definition Tier One of Government Guarantee + References No definition available. + Details
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- Details
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