Period of sustained repayment performance before a TDR may return to performing status.

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Interest Income On Nonaccrual Loan

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Loans Classified As Non Accrual Description

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Period for calculating loss migration rates for portfolio segments.

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Represents the number of days past due for loans and leases to be considered nonaccrual.

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Represents the number of days past due for loans and leases to be considered nonperforming.

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Range of amount of impaired loans tested for impairment.

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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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Fair value at acquisition of acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

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Amount of expense related to loan loss not accounted for as debt securities, with evidence of deterioration of credit quality.

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Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

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Carrying amount as of the balance sheet date of all assets obtained in full or partial satisfaction of a debt arrangement through foreclosure proceedings or defeasance; includes real and personal property; equity interests in corporations, partnerships, and joint ventures; and beneficial interests in trusts.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Reflects the amount of additional interest income that would have been recorded if impaired or nonperforming loans were instead current, in compliance with their original terms, and outstanding throughout the reporting period or since origination (if held for part of the period).

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Recorded investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process.

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Allowance for Loan Losses - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) SecurityLoan	Dec. 31, 2017 USD ($) SecurityLoan	Dec. 31, 2016 USD ($) SecurityLoan	Sep. 14, 2018 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Period for calculating Loss migration rates of portfolio segments	3 years
Allowance for loan losses	$ 13,679	$ 13,134
Proceeds from payoff on previously charged-off loans			$ 1,303
Number of days past due for loans to be considered as nonperforming	90 days
Reasonable period for nonperforming TDRs to be returned to performing status	6 months
Number of days reaching where loans are considered for nonaccrual status	90 days
Conditions where loans are considered for nonaccrual status	A loan may be returned to accruing status only if one of three conditions are met: the loan is well-secured and none of the principal and interest has been past due for a minimum of 90 days; the loan is a TDR and the borrower has made a minimum of six months payments; or the principal and interest payments are reasonably assured and a sustained period of performance has occurred, generally six months.
Gross interest income recorded on nonaccrual loans	$ 587	712	701
Interest income on nonaccrual loans recognized on cash basis	$ 360	$ 139	$ 1,138
Defaulted loans \| SecurityLoan	0	0	0
Impaired loans	greater than $350
Foreclosed assets	$ 0	$ 16
Loans acquired with credit deterioration				$ 878
Allowance for loan losses recorded for acquired loans	8	126
Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Residential mortgages in process of foreclosure	311	239
TDRs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	$ 143	$ 169	$ 278