For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Period remaining on line of credit facility before it terminates, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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.

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Amount of loss contingency liability.

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Amount of expected credit loss for credit exposure on off-balance-sheet commitment, including but not limited to, loan commitment, standby letter of credit, financial guarantee not accounted for as insurance. Excludes off-balance sheet credit exposure accounted for as insurance and instrument accounted for under derivatives and hedging.

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Maximum loan to value ratio.

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Percentage of commercial real estate Loans occupied by owners.

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Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Loss Contingencies [Line Items]
Letters of credit expiration period	1 year
Percentage of first liens initial loan to value ratio	75.00%
Percent of commercial real estate loans owner occupied	23.00%	28.00%
Off-Balance Sheet, Credit Loss, Liability	$ 37.6	$ 37.0		$ 9.0
Cumulative Effect, Period of Adoption, Adjustment [Member]
Loss Contingencies [Line Items]
Off-Balance Sheet, Credit Loss, Liability			$ 15.1
Commercial Real Estate Portfolio Segment [Member] \| Loans Receivable [Member] \| Credit Concentration Risk [Member]
Loss Contingencies [Line Items]
Percent of commercial real estate related loans	29.00%	38.00%
Unfunded Loan Commitment [Member]
Loss Contingencies [Line Items]
Loss Contingency Accrual	$ 37.6	$ 37.0