Loans and Allowance for Loan Losses - Schedule of Loans by Class Modified as Troubled Debt Restructuring (Detail) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($) SecurityLoan	Dec. 31, 2018 USD ($) SecurityLoan	Dec. 31, 2017 USD ($) SecurityLoan
Financing Receivable, Modifications [Line Items]
Number of Loans \| SecurityLoan	14	10	36
Pre-modification Outstanding Recorded Investment	$ 21,131	$ 5,691	$ 44,643
Post-modification Outstanding Recorded Investment	$ 21,131	$ 5,691	$ 44,643
Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans \| SecurityLoan	8	6	11
Pre-modification Outstanding Recorded Investment	$ 10,231	$ 3,544	$ 13,388
Post-modification Outstanding Recorded Investment	$ 10,231	$ 3,544	$ 13,388
Other [Member] \| Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans \| SecurityLoan	4	2	12
Pre-modification Outstanding Recorded Investment	$ 10,027	$ 1,213	$ 27,749
Post-modification Outstanding Recorded Investment	$ 10,027	$ 1,213	$ 27,749
Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans \| SecurityLoan	1	1	6
Pre-modification Outstanding Recorded Investment	$ 557	$ 502	$ 938
Post-modification Outstanding Recorded Investment	$ 557	$ 502	$ 938
Consumer - Other [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans \| SecurityLoan	1	1	7
Pre-modification Outstanding Recorded Investment	$ 316	$ 432	$ 2,568
Post-modification Outstanding Recorded Investment	$ 316	$ 432	$ 2,568

The number of loans included in the loan portfolio.

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- Definition

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.

+ References

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- Definition

Amount, after troubled debt restructuring, of modified financing receivable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524

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- Definition

Amount, before troubled debt restructuring, of financing receivable to be modified.

+ References

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