LOANS AND ALLOWANCE FOR CREDIT LOSSES - Summary of Past Due Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 15,728	$ 21,403
Current	2,535,336	2,541,482
Total loans	2,551,064	2,562,885
Past Due More Than 90 days and Accruing	189	267
30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	9,236	12,307
60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,722	4,263
90 Days or Greater Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	4,770	4,833
Total commercial real estate
Financing Receivable, Past Due [Line Items]
Total loans		1,084,381
Total commercial and industrial
Financing Receivable, Past Due [Line Items]
Total loans		441,069
Commercial construction \| Total commercial loans
Financing Receivable, Past Due [Line Items]
Total Past Due		75
Current	117,464	117,807
Total loans	117,464	117,882
Commercial construction \| Total commercial loans \| 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due		74
Commercial construction \| Total commercial loans \| 90 Days or Greater Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due		1
Commercial real estate owner occupied \| Total commercial real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	341	2,211
Current	233,506	217,006
Total loans	233,847	219,217
Commercial real estate owner occupied \| Total commercial real estate \| 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	10	1,309
Commercial real estate owner occupied \| Total commercial real estate \| 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due		464
Commercial real estate owner occupied \| Total commercial real estate \| 90 Days or Greater Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	331	438
Commercial real estate non-owner occupied \| Total commercial real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	1,140	1,801
Current	732,367	714,975
Total loans	733,507	716,776
Past Due More Than 90 days and Accruing	50
Commercial real estate non-owner occupied \| Total commercial real estate \| 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	644	503
Commercial real estate non-owner occupied \| Total commercial real estate \| 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	179	674
Commercial real estate non-owner occupied \| Total commercial real estate \| 90 Days or Greater Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	317	624
Tax exempt
Financing Receivable, Past Due [Line Items]
Current	46,541	47,862
Total loans	46,541	47,862
Commercial and industrial \| Total commercial and industrial
Financing Receivable, Past Due [Line Items]
Total Past Due	763	354
Current	375,632	355,330
Total loans	376,395	355,684
Past Due More Than 90 days and Accruing	15
Commercial and industrial \| Total commercial and industrial \| 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	364	161
Commercial and industrial \| Total commercial and industrial \| 90 Days or Greater Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	399	193
Residential mortgages \| Total residential real estate
Financing Receivable, Past Due [Line Items]
Total Past Due	12,354	14,889
Current	927,773	980,327
Total loans	940,127	995,216
Past Due More Than 90 days and Accruing	24
Residential mortgages \| Total residential real estate \| 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	7,815	9,178
Residential mortgages \| Total residential real estate \| 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	1,345	2,511
Residential mortgages \| Total residential real estate \| 90 Days or Greater Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	3,194	3,200
Home equity
Financing Receivable, Past Due [Line Items]
Total Past Due	1,026	2,051
Current	92,599	98,045
Total loans	93,625	100,096
Past Due More Than 90 days and Accruing		267
Home equity \| 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	399	1,062
Home equity \| 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	198	614
Home equity \| 90 Days or Greater Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	429	375
Consumer other \| Total consumer
Financing Receivable, Past Due [Line Items]
Total Past Due	104	22
Current	9,454	10,130
Total loans	9,558	10,152
Past Due More Than 90 days and Accruing	100
Consumer other \| Total consumer \| 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	4	20
Consumer other \| Total consumer \| 90 Days or Greater Past Due
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 100	$ 2