CREDIT QUALITY ASSESSMENT (Recorded Investment with Respect to Impaired loans, Associated Allowance by Applicable Portfolio Segment and Principal Balance of Impaired Loans prior to Amounts Charged-off) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	$ 11,693	$ 13,563	$ 14,208
Impaired loans without a specific allowance	9,116	10,529	14,719
Impaired loans	20,809	24,092	$ 28,927
Impaired Financing Receivable, Related Allowance	4,014	4,825
Unpaid principal balance in total impaired loans	32,689	39,016
Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	9,673	11,720
Impaired loans without a specific allowance	2,127	3,207
Impaired loans	11,800	14,927
Restructuring | Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	1,129	1,140
Impaired loans without a specific allowance	1,659	1,349
Impaired loans	2,788	2,489
Restructuring | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	891	703
Impaired loans without a specific allowance	5,330	5,973
Impaired loans	6,221	6,676
Commercial
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	5,753	4,011
Impaired loans without a specific allowance	2,352	3,007
Impaired loans	8,105	7,018
Impaired Financing Receivable, Related Allowance	3,220	2,604
Unpaid principal balance in total impaired loans	11,263	10,082
Commercial | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	4,516	2,807
Impaired loans without a specific allowance	391	1,562
Impaired loans	4,907	4,369
Commercial | Restructuring | Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	1,129	1,140
Impaired loans without a specific allowance	273	45
Impaired loans	1,402	1,185
Commercial | Restructuring | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	108	64
Impaired loans without a specific allowance	1,688	1,400
Impaired loans	1,796	1,464
All Other
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	2,915	3,263
Impaired loans	2,915	3,263
Impaired Financing Receivable, Related Allowance	0	0
Unpaid principal balance in total impaired loans	3,681	3,971
All Other | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	0	0
Impaired loans	0	0
All Other | Restructuring | Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	890	560
Impaired loans	890	560
All Other | Restructuring | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	2,025	2,703
Impaired loans	2,025	2,703
Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	136	137
Impaired loans	136	137
Impaired Financing Receivable, Related Allowance	0	0
Unpaid principal balance in total impaired loans	1,248	4,398
Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	0	0
Impaired loans	0	0
Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction | Restructuring | Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	0	0
Impaired loans	0	0
Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction | Restructuring | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	136	137
Impaired loans	136	137
Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	5,157	7,029
Impaired loans without a specific allowance	418	1,078
Impaired loans	5,575	8,107
Impaired Financing Receivable, Related Allowance	663	1,736
Unpaid principal balance in total impaired loans	10,166	12,805
Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	5,157	7,029
Impaired loans without a specific allowance	418	562
Impaired loans	5,575	7,591
Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate | Restructuring | Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	0	0
Impaired loans	0	0
Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate | Restructuring | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	0	516
Impaired loans	0	516
Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	783	2,523
Impaired loans without a specific allowance	3,295	3,044
Impaired loans	4,078	5,567
Impaired Financing Receivable, Related Allowance	131	485
Unpaid principal balance in total impaired loans	6,331	7,760
Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	1,884
Impaired loans without a specific allowance	1,318	1,083
Impaired loans	1,318	2,967
Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate | Restructuring | Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	0	0
Impaired loans without a specific allowance	496	744
Impaired loans	496	744
Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate | Restructuring | Non Accrual Loans
Financing Receivable Impaired [Line Items]
Impaired loans with a specific allowance	783	639
Impaired loans without a specific allowance	1,481	1,217
Impaired loans	$ 2,264	$ 1,856