Loans - Average Recorded Investment and Interest Income Recognized on Impaired Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	$ 185,578	$ 170,675	$ 158,777
Interest Income Recognized	4,496	4,707	4,373
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	120,376	108,071	80,974
Interest Income Recognized	1,849	1,822	1,459
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	52,545	46,355	58,057
Interest Income Recognized	2,246	2,358	1,994
Commercial real estate \| Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	52,191	44,838	54,799
Interest Income Recognized	2,246	2,289	1,908
Commercial real estate \| Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	354	1,517	3,258
Interest Income Recognized	0	69	86
Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	12,081	15,384	15,451
Interest Income Recognized	390	506	760
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	576	865	4,295
Interest Income Recognized	11	21	160
Consumer \| Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average Recorded Investment	576	865	4,295
Interest Income Recognized	$ 11	$ 21	$ 160

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.

No definition available.

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- Definition

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5258-111524

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- Definition

Amount of interest income recognized on a cash-basis method of accounting that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

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