Loans and Allowance for Loan Losses - Schedule of Loans by Class Modified as Troubled Debt Restructuring (Detail) $ in Thousands	9 Months Ended
Sep. 30, 2018 USD ($) SecurityLoan	Sep. 30, 2017 USD ($) SecurityLoan
Financing Receivable, Modifications [Line Items]
Number of Loans \| SecurityLoan	9	32
Pre-modification Outstanding Recorded Investment	$ 5,185	$ 33,533
Post-modification Outstanding Recorded Investment	$ 5,185	$ 33,533
Commercial Loan [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans \| SecurityLoan	5	9
Pre-modification Outstanding Recorded Investment	$ 3,038	$ 12,599
Post-modification Outstanding Recorded Investment	$ 3,038	$ 12,599
Other [Member] \| Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans \| SecurityLoan	2	10
Pre-modification Outstanding Recorded Investment	$ 1,213	$ 17,429
Post-modification Outstanding Recorded Investment	$ 1,213	$ 17,429
Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans \| SecurityLoan	1	6
Pre-modification Outstanding Recorded Investment	$ 502	$ 937
Post-modification Outstanding Recorded Investment	$ 502	$ 937
Consumer - Other [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans \| SecurityLoan	1	7
Pre-modification Outstanding Recorded Investment	$ 432	$ 2,568
Post-modification Outstanding Recorded Investment	$ 432	$ 2,568

The number of loans included in the loan portfolio.

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- Definition

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+ References

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- Definition

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953676-111524

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Pre-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

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