Allowance for Loan Losses - Additional Information (Detail) - USD ($)	9 Months Ended
Sep. 30, 2016	Dec. 31, 2015
Financing Receivable, Impaired [Line Items]
Loans considered nonperforming (in days)	90 days
Evaluation for impairment of substandard and nonaccrual commercial loans	$ 500,000.0
Impaired fiinancing receivables	38,059,000	$ 45,650,000
Integrity Bancshares, Inc.
Financing Receivable, Impaired [Line Items]
Acquired loans that experienced credit deterioration since acquisition	$ 14,400,000

Minimum amount over which evaluation for impairment of substandard and nonaccrual commercial loans are made.

No definition available.

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- Definition

Period interest and principal of loan due treated as loans considered nonperforming.

+ References

No definition available.

+ Details

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- Definition

The recorded amount of loans and debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it was probable, at acquisition, that the investor would be unable to collect all contractually required payments receivable. They are deemed to be impaired since the acquisition and an allowance for credit losses has been recorded. Disclosure is gross of the allowance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5275-111524

+ Details

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- Definition

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.

+ References

No definition available.

+ Details

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- Definition

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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953550-111524

+ Details

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