Summary of Financial Effects of Troubled Debt Restructurings (Detail) - Commercial and Industrial $ in Thousands	3 Months Ended
Mar. 31, 2020 USD ($) Investment	Mar. 31, 2019 USD ($) Investment
Financing Receivable, Modifications [Line Items]
Number of loans classified as a non-accrual TDRs \| Investment	8	15
Pre-Modification Recorded Investment	$ 1,920	$ 4,194
Post-Modification Recorded Investment	$ 1,572	$ 3,088
Weighted Average Interest Rate, Pre-Modification	3.29%	3.26%
Weighted Average Interest Rate, Post-Modification	3.24%	2.98%
Trouble debt restructuring, charge-off amount	$ 348	$ 1,106
Capitalized interest

Weighted Average Interest Rate Post Modification

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Weighted Average Interest Rate Pre Modification

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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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Reflects the amount of the write-down related to a troubled debt restructuring.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=118939409&loc=d3e18845-111554

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The gross interest income that would have been recorded in the period on troubled debt restructurings, if the loans had been current in accordance with their original terms and had been outstanding throughout the period or since origination, if held for part of the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118939409&loc=d3e18794-111554

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