REGULATORY CAPITAL MATTERS - Schedule of the Company's and Bank's actual capital amounts and ratios (Details) $ in Thousands	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Common equity Tier 1 capital / % of risk weighted assets
Actual, Ratio (as a percent)	0.045	0.07
Tier 1 Capital / % of risk weighted assets
Actual, Ratio (as a percent)	0.06	0.085
Total Capital / % of risk weighted assets
Actual, Ratio (as a percent)	0.08	0.105
Basel III
Tier 1 Capital / % of average total assets
Actual, Amount	$ 1,283,038	$ 1,158,455
Actual, Ratio (as a percent)	0.094	0.085
For Capital Adequacy Purposes, Amount	$ 547,024	$ 544,529
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	0.04	0.04
Common equity Tier 1 capital / % of risk weighted assets
Actual, Amount	$ 1,166,469	$ 1,041,886
Actual, Ratio (as a percent)	0.111	0.098
For Capital Adequacy Purposes, Amount	$ 474,521	$ 476,341
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	0.045%	0.045%
Tier 1 Capital / % of risk weighted assets
Actual, Amount	$ 1,283,038	$ 1,158,455
Actual, Ratio (as a percent)	0.122	0.109
For Capital Adequacy Purposes, Amount	$ 632,694	$ 635,122
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	0.06	0.06
Total Capital / % of risk weighted assets
Actual, Amount	$ 1,649,617	$ 1,433,361
Actual, Ratio (as a percent)	0.156	0.135
For Capital Adequacy Purposes, Amount	$ 843,592	$ 846,829
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	0.08	0.08
BNB Bank | Basel III
Tier 1 Capital / % of average total assets
Actual, Amount	$ 1,469,047	$ 1,331,676
Actual, Ratio (as a percent)	0.107	0.098
For Capital Adequacy Purposes, Amount	$ 546,759	$ 544,254
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	0.04	0.04
To Be Categorized as "Well Capitalized", Amount	$ 683,449	$ 680,318
To Be Categorized as "Well Capitalized", Minimum Ratio (as a percent)	0.05	0.05
Common equity Tier 1 capital / % of risk weighted assets
Actual, Amount	$ 1,469,047	$ 1,331,676
Actual, Ratio (as a percent)	0.139	0.126
For Capital Adequacy Purposes, Amount	$ 474,269	$ 476,168
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	0.045%	0.045%
To Be Categorized as "Well Capitalized", Amount	$ 685,055	$ 687,798
To Be Categorized as "Well Capitalized", Minimum Ratio (as a percent)	0.065%	0.065%
Tier 1 Capital / % of risk weighted assets
Actual, Amount	$ 1,469,047	$ 1,331,676
Actual, Ratio (as a percent)	0.139	0.126
For Capital Adequacy Purposes, Amount	$ 632,358	$ 634,890
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	0.06	0.06
To Be Categorized as "Well Capitalized", Amount	$ 843,144	$ 846,520
To Be Categorized as "Well Capitalized", Minimum Ratio (as a percent)	0.08	0.08
Total Capital / % of risk weighted assets
Actual, Amount	$ 1,560,876	$ 1,406,581
Actual, Ratio (as a percent)	0.148	0.133
For Capital Adequacy Purposes, Amount	$ 843,144	$ 846,520
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	0.08	0.08
To Be Categorized as "Well Capitalized", Amount	$ 1,053,931	$ 1,058,151
To Be Categorized as "Well Capitalized", Minimum Ratio (as a percent)	0.10	0.10