ALLOWANCE FOR LOAN LOSSES AND CREDIT QUALITY OF FINANCING RECEIVABLES - Age Analysis Of Loans Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 25,480	$ 24,492
Current	1,489,272	1,451,335
Total Financing Receivables	1,514,752	1,475,827
Recorded Investment 90 Days and Accruing	0	0
30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,441	3,170
60-89 days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,401	618
Greater Than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	20,638	20,704
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	323	863
Current	93,244	80,846
Total Financing Receivables	93,567	81,709
Recorded Investment 90 Days and Accruing	0	0
Commercial and Industrial | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	491
Commercial and Industrial | 60-89 days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Commercial and Industrial | Greater Than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	323	372
Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	582
Current	120,340	141,739
Total Financing Receivables	120,340	142,321
Recorded Investment 90 Days and Accruing	0	0
Construction | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Construction | 60-89 days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	582
Construction | Greater Than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	20,012	18,042
Current	909,079	860,407
Total Financing Receivables	929,091	878,449
Recorded Investment 90 Days and Accruing	0	0
Commercial Real Estate | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,643	2,282
Commercial Real Estate | 60-89 days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,131	0
Commercial Real Estate | Greater Than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	16,238	15,760
Residential Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,089	5,000
Current	364,011	365,955
Total Financing Receivables	369,100	370,955
Recorded Investment 90 Days and Accruing	0	0
Residential Real Estate | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	743	393
Residential Real Estate | 60-89 days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	269	35
Residential Real Estate | Greater Than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,077	4,572
Consumer and Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	56	5
Current	2,598	2,388
Total Financing Receivables	2,654	2,393
Recorded Investment 90 Days and Accruing	0	0
Consumer and Other | 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	55	4
Consumer and Other | 60-89 days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1	1
Consumer and Other | Greater Than 90 Days
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 0	$ 0