Allowance for Loan Losses - Allowance for Loan Losses (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of the period	$ 15,054	$ 14,236	$ 14,837	$ 14,534
Total loans charged-off	609	593	1,020	1,702
Total loan recoveries	252	351	550	630
Net loans charged-off (recovered)	357	242	470	1,072
Total provision charged to operating expense	330	232	660	764
Balance at the end of the period	15,027	14,226	15,027	14,226
Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans charged-off	42	204	42	689
Total loan recoveries	18	100	152	182
Total provision charged to operating expense	41	(305)	928	(639)
Commercial [Member] \| Owner Occupied Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans charged-off		31		178
Total loan recoveries	1	4	1	29
Commercial [Member] \| Non Owner Occupied Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans charged-off		173		472
Total loan recoveries	3	31	25	54
Commercial [Member] \| Residential Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loan recoveries	2	2	4	4
Commercial [Member] \| Development & Spec Land Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans charged-off	1		1
Commercial [Member] \| Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans charged-off	41		41	39
Total loan recoveries	12	63	122	95
Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans charged-off	1		52	115
Total loan recoveries	9	31	22	63
Total provision charged to operating expense	93	343	(474)	(249)
Real Estate [Member] \| Residential Mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans charged-off	1		52	115
Total loan recoveries	9	31	22	63
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans charged-off	566	389	926	898
Total loan recoveries	225	220	376	385
Total provision charged to operating expense	196	194	206	1,652
Consumer [Member] \| Direct Installment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans charged-off	222	46	247	104
Total loan recoveries	34	28	51	44
Consumer [Member] \| Indirect Installment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans charged-off	323	279	608	555
Total loan recoveries	152	146	265	240
Consumer [Member] \| Home Equity Loan [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total loans charged-off	21	64	71	239
Total loan recoveries	$ 39	$ 46	$ 60	$ 101

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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Amount, after recoveries, of loans and leases that have been written-off.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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Amount of expense related to estimated loss from loan and lease transactions.

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