Loans and Allowance for Loan Losses - Schedule of Loans Modified and Considered Troubled Debt Restructurings (Detail) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017 USD ($) SecurityLoan	Sep. 30, 2016 USD ($) SecurityLoan	Sep. 30, 2017 USD ($) SecurityLoan	Sep. 30, 2016 USD ($) SecurityLoan
Financing Receivable, Modifications [Line Items]
Number \| SecurityLoan	4	7	13	24
Pre-Modification Recorded Investment	$ 770	$ 980	$ 1,336	$ 4,487
Post-Modification Recorded Investment	$ 770	$ 980	$ 1,336	$ 4,487
Commercial [Member]
Financing Receivable, Modifications [Line Items]
Number \| SecurityLoan	3	3	9	14
Pre-Modification Recorded Investment	$ 514	$ 230	$ 838	$ 3,156
Post-Modification Recorded Investment	$ 514	$ 230	$ 838	$ 3,156
Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number \| SecurityLoan	1	3	3	5
Pre-Modification Recorded Investment	$ 256	$ 706	$ 473	$ 1,169
Post-Modification Recorded Investment	$ 256	$ 706	$ 473	$ 1,169
Consumer [Member]
Financing Receivable, Modifications [Line Items]
Number \| SecurityLoan		1	1	5
Pre-Modification Recorded Investment		$ 44	$ 25	$ 162
Post-Modification Recorded Investment		$ 44	$ 25	$ 162

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-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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Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

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

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