REGULATORY CAPITAL MATTERS - Schedule of the Company's and Bank's actual capital amounts and ratios (Details) $ in Thousands	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Common equity Tier 1 capital / % of risk weighted assets
Actual, Ratio (as a percent)	4.5	7.0
Tier 1 Capital / % of risk weighted assets
Actual, Ratio (as a percent)	6.0	8.5
Total Capital / % of risk weighted assets
Actual, Ratio (as a percent)	8.0	10.5
Basel III
Tier 1 Capital / % of average total assets
Actual, Amount	$ 1,037,235	$ 651,382
Actual, Ratio (as a percent)	8.5	10.0
For Capital Adequacy Purposes, Amount	$ 490,420	$ 261,949
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	4.0	4.0
Common equity Tier 1 capital / % of risk weighted assets
Actual, Amount	$ 920,666	$ 534,813
Actual, Ratio (as a percent)	9.5	10.2
For Capital Adequacy Purposes, Amount	$ 436,700	$ 235,499
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	4.50%	4.50%
Tier 1 Capital / % of risk weighted assets
Actual, Amount	$ 1,037,235	$ 651,382
Actual, Ratio (as a percent)	10.7	12.4
For Capital Adequacy Purposes, Amount	$ 582,267	$ 313,999
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	6.0	6.0
Total Capital / % of risk weighted assets
Actual, Amount	$ 1,304,891	$ 808,289
Actual, Ratio (as a percent)	13.4	15.4
For Capital Adequacy Purposes, Amount	$ 776,356	$ 418,666
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	8.0	8.0
BNB Bank | Basel III
Tier 1 Capital / % of average total assets
Actual, Amount	$ 1,215,586	$ 653,393
Actual, Ratio (as a percent)	10.0	10.2
For Capital Adequacy Purposes, Amount	$ 488,506	$ 257,143
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	4.0	4.0
To Be Categorized as "Well Capitalized", Amount	$ 610,633	$ 321,428
To Be Categorized as "Well Capitalized", Minimum Ratio (as a percent)	5.0	5.0
Common equity Tier 1 capital / % of risk weighted assets
Actual, Amount	$ 1,215,586	$ 653,393
Actual, Ratio (as a percent)	12.5	12.5
For Capital Adequacy Purposes, Amount	$ 436,539	$ 235,243
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	4.50%	4.50%
To Be Categorized as "Well Capitalized", Amount	$ 630,557	$ 339,796
To Be Categorized as "Well Capitalized", Minimum Ratio (as a percent)	6.50%	6.50%
Tier 1 Capital / % of risk weighted assets
Actual, Amount	$ 1,215,586	$ 653,393
Actual, Ratio (as a percent)	12.5	12.5
For Capital Adequacy Purposes, Amount	$ 582,052	$ 313,658
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	6.0	6.0
To Be Categorized as "Well Capitalized", Amount	$ 776,070	$ 418,210
To Be Categorized as "Well Capitalized", Minimum Ratio (as a percent)	8.0	8.0
Total Capital / % of risk weighted assets
Actual, Amount	$ 1,304,242	$ 695,300
Actual, Ratio (as a percent)	13.4	13.3
For Capital Adequacy Purposes, Amount	$ 776,070	$ 418,210
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	8.0	8.0
To Be Categorized as "Well Capitalized", Amount	$ 970,087	$ 522,763
To Be Categorized as "Well Capitalized", Minimum Ratio (as a percent)	10.0	10.0