REGULATORY CAPITAL MATTERS - Schedule of the Company's and Bank's actual capital amounts and ratios (Details) $ in Thousands	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Common equity Tier 1 capital / % of risk weighted assets
Actual, Ratio (as a percent)	0.045	0.070
Tier 1 Capital / % of risk weighted assets
Actual, Ratio (as a percent)	0.060	0.085
Total Capital / % of risk weighted assets
Actual, Ratio (as a percent)	0.080	0.105
Basel III
Tier 1 Capital / % of average total assets
Actual, Amount	$ 1,158,455	$ 1,103,498
Actual, Ratio (as a percent)	0.085	0.085
For Capital Adequacy Purposes, Amount	$ 544,529	$ 517,914
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	0.040	0.040
Common equity Tier 1 capital / % of risk weighted assets
Actual, Amount	$ 1,041,886	$ 986,928
Actual, Ratio (as a percent)	0.098	0.092
For Capital Adequacy Purposes, Amount	$ 476,341	$ 485,243
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	0.045%	0.045%
Tier 1 Capital / % of risk weighted assets
Actual, Amount	$ 1,158,455	$ 1,103,498
Actual, Ratio (as a percent)	0.109	0.102
For Capital Adequacy Purposes, Amount	$ 635,122	$ 646,990
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	0.060	0.060
Total Capital / % of risk weighted assets
Actual, Amount	$ 1,433,361	$ 1,390,272
Actual, Ratio (as a percent)	0.135	0.129
For Capital Adequacy Purposes, Amount	$ 846,829	$ 862,654
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	0.080	0.080
BNB Bank | Basel III
Tier 1 Capital / % of average total assets
Actual, Amount	$ 1,331,676	$ 1,286,656
Actual, Ratio (as a percent)	0.098	0.100
For Capital Adequacy Purposes, Amount	$ 544,254	$ 517,606
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	0.040	0.040
To Be Categorized as "Well Capitalized", Amount	$ 680,318	$ 647,008
To Be Categorized as "Well Capitalized", Minimum Ratio (as a percent)	0.050	0.050
Common equity Tier 1 capital / % of risk weighted assets
Actual, Amount	$ 1,331,676	$ 1,286,656
Actual, Ratio (as a percent)	0.126	0.119
For Capital Adequacy Purposes, Amount	$ 476,168	$ 485,062
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	0.045%	0.045%
To Be Categorized as "Well Capitalized", Amount	$ 687,798	$ 700,645
To Be Categorized as "Well Capitalized", Minimum Ratio (as a percent)	0.065%	0.065%
Tier 1 Capital / % of risk weighted assets
Actual, Amount	$ 1,331,676	$ 1,286,656
Actual, Ratio (as a percent)	0.126	0.119
For Capital Adequacy Purposes, Amount	$ 634,890	$ 646,749
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	0.060	0.060
To Be Categorized as "Well Capitalized", Amount	$ 846,520	$ 862,332
To Be Categorized as "Well Capitalized", Minimum Ratio (as a percent)	0.080	0.080
Total Capital / % of risk weighted assets
Actual, Amount	$ 1,406,581	$ 1,373,431
Actual, Ratio (as a percent)	0.133	0.127
For Capital Adequacy Purposes, Amount	$ 846,520	$ 862,332
For Capital Adequacy Purposes, Minimum Ratio (as a percent)	0.080	0.080
To Be Categorized as "Well Capitalized", Amount	$ 1,058,151	$ 1,077,915
To Be Categorized as "Well Capitalized", Minimum Ratio (as a percent)	0.100	0.100