LOANS AND ALLOWANCE FOR LOAN LOSSES - Schedule of Activity in Allowance for Loan Losses (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Activity in allowance for loan losses
Balance, beginning of year	$ 12,775	$ 13,568	$ 14,747
Provision for loan losses	1,000	250	(603)
Charge-offs	(1,266)	(1,722)	(1,502)
Recoveries	287	679	926
Balance, end of year	12,796	12,775	13,568
Unallocated
Activity in allowance for loan losses
Balance, beginning of year	414	774	1,218
Provision for loan losses	61	(360)	(444)
Charge-offs	0	0	0
Recoveries	0	0	0
Balance, end of year	475	414	774
Commercial
Activity in allowance for loan losses
Balance, beginning of year	9,238	9,803	11,148
Provision for loan losses	234	(38)	(1,336)
Charge-offs	(920)	(951)	(848)
Recoveries	158	424	839
Balance, end of year	8,710	9,238	9,803
Commercial \| Commercial Real Estate
Activity in allowance for loan losses
Balance, beginning of year	7,530	7,883	9,462
Provision for loan losses	38	107	(1,020)
Charge-offs	(835)	(872)	(711)
Recoveries	30	412	152
Balance, end of year	6,763	7,530	7,883
Commercial \| Acquisition and Development
Activity in allowance for loan losses
Balance, beginning of year	580	850	697
Provision for loan losses	(167)	(270)	(440)
Charge-offs	0	0	(22)
Recoveries	4	0	615
Balance, end of year	417	580	850
Commercial \| Commercial and Industrial
Activity in allowance for loan losses
Balance, beginning of year	1,074	1,012	806
Provision for loan losses	333	129	249
Charge-offs	(85)	(79)	(115)
Recoveries	124	12	72
Balance, end of year	1,446	1,074	1,012
Commercial \| Municipal
Activity in allowance for loan losses
Balance, beginning of year	54	58	183
Provision for loan losses	30	(4)	(125)
Charge-offs	0	0	0
Recoveries	0	0	0
Balance, end of year	84	54	58
Consumer
Activity in allowance for loan losses
Balance, beginning of year	3,123	2,991	2,381
Provision for loan losses	705	648	1,177
Charge-offs	(346)	(771)	(654)
Recoveries	129	255	87
Balance, end of year	3,611	3,123	2,991
Consumer \| Residential Mortgage
Activity in allowance for loan losses
Balance, beginning of year	2,979	2,870	2,262
Provision for loan losses	531	532	1,122
Charge-offs	(180)	(577)	(592)
Recoveries	70	154	78
Balance, end of year	3,400	2,979	2,870
Consumer \| Installment and Other
Activity in allowance for loan losses
Balance, beginning of year	144	121	119
Provision for loan losses	174	116	55
Charge-offs	(166)	(194)	(62)
Recoveries	59	101	9
Balance, end of year	$ 211	$ 144	$ 121

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 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.

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

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