Loans and the Allowance for Credit Losses - Loans Identified as TDRs (Detail) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($) Contract	Dec. 31, 2018 USD ($) Contract
Financing Receivable, Modifications [Line Items]
Number of Modifications \| Contract	11	17
Pre-Modification Outstanding Recorded Investment	$ 1,093	$ 1,455
Post-Modification Outstanding Recorded Investment	$ 1,037	$ 1,316
Commercial Real Estate - Improved Property [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications \| Contract	1	2
Pre-Modification Outstanding Recorded Investment	$ 610	$ 837
Post-Modification Outstanding Recorded Investment	$ 603	$ 805
Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications \| Contract	2	4
Pre-Modification Outstanding Recorded Investment	$ 57	$ 240
Post-Modification Outstanding Recorded Investment	$ 48	$ 188
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications \| Contract	1	2
Pre-Modification Outstanding Recorded Investment	$ 610	$ 837
Post-Modification Outstanding Recorded Investment	$ 603	$ 805
Residential Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications \| Contract	4	4
Pre-Modification Outstanding Recorded Investment	$ 194	$ 218
Post-Modification Outstanding Recorded Investment	$ 177	$ 190
Consumer [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications \| Contract	2	5
Pre-Modification Outstanding Recorded Investment	$ 45	$ 69
Post-Modification Outstanding Recorded Investment	$ 28	$ 49
Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Number of Modifications \| Contract	2	2
Pre-Modification Outstanding Recorded Investment	$ 187	$ 91
Post-Modification Outstanding Recorded Investment	$ 181	$ 84

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Number of financing receivables that have been modified by troubled debt restructurings.

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

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

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