Allowance for Loan Losses - Changes in the Allowance for Loan Losses and Loan Balances Outstanding (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Allowance for loan losses:
Beginning balance	$ 14,707	$ 15,395	$ 14,268	$ 16,528
Charge-offs	(634)	(456)	(1,524)	(3,440)
Recoveries	287	506	816	857
Provision	400		1,200	1,500
Ending Balance	14,760	15,445	14,760	15,445
Commercial and Agriculture [Member]
Allowance for loan losses:
Beginning balance	1,395	2,067	1,822	2,841
Charge-offs	(187)	(13)	(187)	(326)
Recoveries	127	143	157	238
Provision	52	(592)	(405)	(1,148)
Ending Balance	1,387	1,605	1,387	1,605
Commercial Real Estate Owner Occupied [Member]
Allowance for loan losses:
Beginning balance	3,383	3,135	2,580	3,263
Charge-offs	(164)	(146)	(363)	(1,615)
Recoveries	13	241	223	316
Provision	(286)	(364)	506	902
Ending Balance	2,946	2,866	2,946	2,866
Commercial Real Estate Non Owner Occupied [Member]
Allowance for loan losses:
Beginning balance	5,427	4,853	4,798	4,296
Charge-offs	(18)		(81)	(105)
Recoveries	14	10	105	34
Provision	(89)	115	512	753
Ending Balance	5,334	4,978	5,334	4,978
Residential Real Estate [Member]
Allowance for loan losses:
Beginning balance	3,470	4,439	3,747	5,224
Charge-offs	(237)	(275)	(779)	(1,329)
Recoveries	124	95	289	216
Provision	864	53	964	201
Ending Balance	4,221	4,312	4,221	4,312
Real Estate Construction [Member]
Allowance for loan losses:
Beginning balance	434	287	428	184
Recoveries	1	2	4	5
Provision	(7)	76	(4)	176
Ending Balance	428	365	428	365
Consumer and Other [Member]
Allowance for loan losses:
Beginning balance	190	196	196	214
Charge-offs	(28)	(22)	(114)	(65)
Recoveries	8	15	38	48
Provision	195	26	245	18
Ending Balance	365	215	365	215
Unallocated [Member]
Allowance for loan losses:
Beginning balance	408	418	697	506
Provision	(329)	686	(618)	598
Ending Balance	$ 79	$ 1,104	$ 79	$ 1,104

Changes in allowance for loan losses and loan balances outstanding.

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- Definition

For an unclassified balance sheet, a valuation allowance for receivables due a company that are expected to be uncollectible.

+ References

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-Publisher FASB

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Amount of recoveries of receivables doubtful of collection that were previously charged off.

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Amount of direct write-downs of accounts receivable charged against the allowance.

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- Definition

Amount of expense related to estimated loss from loan and lease transactions.

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