CAPITAL REQUIREMENTS AND RESTRICTIONS ON RETAINED EARNINGS - Summary Of Capital Adequacy Requirements (Details) $ in Thousands	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Consolidated Entities [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets), Actual Amount	$ 682,778	$ 631,723
Total Capital (to Risk Weighted Assets), Actual Ratio	14.65	14.36
Tier I Capital (to Risk Weighted Assets), Actual Amount	$ 624,381	$ 580,982
Tier I Capital (to Risk Weighted Assets), Actual Ratio	13.39	13.21
Common Equity Tier 1 (CET1), Actual Amount	$ 624,381	$ 580,982
Common Equity Tier 1 (CET1), Actual Ratio	13.39%	13.21%
Tier I Capital (to Average Assets), Actual Amount	$ 624,381	$ 580,982
Tier I Capital (to Average Assets), Actual Ratio	10.93	11.67
Total Capital (to Risk Weighted Assets), Minimum Required For Capital Adequacy Purposes Amount	$ 372,921	$ 351,894
Total Capital (to Risk Weighted Assets), Minimum Required For Capital Adequacy Purposes Ratio	8.00	8.00
Tier I Capital (to Risk Weighted Assets), Minimum Required For Capital Adequacy Purposes Amount	$ 279,691	$ 263,921
Tier I Capital (to Risk Weighted Assets), Minimum Required For Capital Adequacy Purposes Ratio	6.00	6.00
Common Equity Tier 1 (CET1), Minimum Required For Capital Adequacy Purposes Amount	$ 209,768	$ 197,941
Common Equity Tier 1 (CET1), Minimum Required For Capital Adequacy Purposes Ratio	4.50%	4.50%
Tier I Capital (to Average Assets), Minimum Required For Capital Adequacy Purposes Amount	$ 228,406	$ 199,099
Tier I Capital (to Average Assets), Minimum Required For Capital Adequacy Purposes Ratio	4.00	4.00
Excess Capital, For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 489,459	$ 461,862
Tier I Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	396,229	373,887
Common Equity Tier 1 (CET1), For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	326,306	307,908
Tier I Capital (to Average Assets), For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	228,406	199,099
Bank [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital (to Risk Weighted Assets), Actual Amount	$ 678,034	$ 616,386
Total Capital (to Risk Weighted Assets), Actual Ratio	14.56	14.04
Tier I Capital (to Risk Weighted Assets), Actual Amount	$ 619,693	$ 565,645
Tier I Capital (to Risk Weighted Assets), Actual Ratio	13.31	12.88
Common Equity Tier 1 (CET1), Actual Amount	$ 619,693	$ 565,645
Common Equity Tier 1 (CET1), Actual Ratio	13.31%	12.88%
Tier I Capital (to Average Assets), Actual Amount	$ 619,693	$ 565,645
Tier I Capital (to Average Assets), Actual Ratio	10.88	11.43
Total Capital (to Risk Weighted Assets), Minimum Required For Capital Adequacy Purposes Amount	$ 372,560	$ 351,227
Total Capital (to Risk Weighted Assets), Minimum Required For Capital Adequacy Purposes Ratio	8.00	8.00
Tier I Capital (to Risk Weighted Assets), Minimum Required For Capital Adequacy Purposes Amount	$ 279,420	$ 263,420
Tier I Capital (to Risk Weighted Assets), Minimum Required For Capital Adequacy Purposes Ratio	6.00	6.00
Common Equity Tier 1 (CET1), Minimum Required For Capital Adequacy Purposes Amount	$ 209,565	$ 197,565
Common Equity Tier 1 (CET1), Minimum Required For Capital Adequacy Purposes Ratio	4.50%	4.50%
Tier I Capital (to Average Assets), Minimum Required For Capital Adequacy Purposes Amount	$ 227,900	$ 197,923
Tier I Capital (to Average Assets), Minimum Required For Capital Adequacy Purposes Ratio	4.00	4.00
Excess Capital, For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 488,985	$ 460,985
Excess Capital to Risk Weighted Assets, For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	10.50	10.50
Tier I Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 395,845	$ 373,179
Tier I Capital (to Risk Weighted Assets), For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	8.50	8.50
Common Equity Tier 1 (CET1), For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 325,990	$ 307,324
Common Equity Tier 1 (CET1), For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	7.00%	7.00%
Tier I Capital (to Average Assets), For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 227,900	$ 197,923
Tier I Capital (to Average Assets), For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	4.00	4.00
Total Capital (to Risk Weighted Assets), Minimum Required to Be Well Capitalized Under Prompt Corrective Action Regulations Amount	$ 465,700	$ 439,034
Total Capital (to Risk Weighted Assets), Minimum Required to Be Well Capitalized Under Prompt Corrective Action Regulations Ratio	10.00	10.00
Tier I Capital (to Risk Weighted Assets), Minimum Required to Be Well Capitalized Under Prompt Corrective Action Regulations Amount	$ 372,560	$ 351,227
Tier I Capital (to Risk Weighted Assets), Minimum Required to Be Well Capitalized Under Prompt Corrective Action Regulations Ratio	8.00	8.00
Common Equity Tier 1 (CET1), Minimum Required to Be Well Capitalized Under Prompt Corrective Action Regulations Amount	$ 302,705	$ 285,372
Common Equity Tier 1 (CET1), Minimum Required to Be Well Capitalized Under Prompt Corrective Action Regulations Ratio	6.50%	6.50%
Tier I Capital (to Average Assets), Minimum Required to Be Well Capitalized Under Prompt Corrective Action Regulations Amount	$ 284,875	$ 247,404
Tier I Capital (to Average Assets), Minimum Required to Be Well Capitalized Under Prompt Corrective Action Regulations Ratio	5.00	5.00