REGULATORY MATTERS, COMMITMENTS, AND CONTINGENCIES - Regulatory capital positions (Detail) $ in Thousands	Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
First BanCorp [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk-Weighted Assets) Actual	$ 2,385,079	$ 2,385,866
Total Capital (to Risk-Weighted Assets) Actual Ratio	0.1884	0.1921
Total Capital (to Risk-Weighted Assets) Required For Capital Adequacy	$ 1,012,868	$ 993,405
Total Capital (to Risk-Weighted Assets) Required For Capital Adequacy Ratio	0.080	0.080
Common Equity Tier 1 Capital (to Risk-Weighted Assets) Actual	$ 2,069,675	$ 2,052,333
Common Equity Tier 1 Capital (to Risk-Weighted Assets) Actual Ratio	0.1635	0.1653
Common Equity Tier 1 Capital (to Risk-Weighted Assets) Required For Capital Adequacy	$ 569,738	$ 558,790
Common Equity Tier 1 Capital (to Risk-Weighted Assets) Required For Capital Adequacy Ratio	0.045	0.045
Tier 1 Capital (to Risk-Weighted Assets) Actual	$ 2,069,675	$ 2,052,333
Tier 1 Capital (to Risk-Weighted Assets) Actual Ratio	0.1635	0.1653
Tier 1 Capital (to Risk-Weighted Assets) Required For Capital Adequacy	$ 759,651	$ 745,054
Tier 1 Capital (to Risk-Weighted Assets) Required For Capital Adequacy Ratio	0.060	0.060
Leverage Ratio Actual Amount	$ 2,069,675	$ 2,052,333
Leverage Ratio Actual Ratio	0.1057	0.1070
Leverage Ratio Required For Capital Adequacy	$ 783,163	$ 767,075
Leverage Ratio Required For Capital Adequacy Ratio	0.040	0.040
FirstBank [Member]
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Total Capital (to Risk-Weighted Assets) Actual	$ 2,335,546	$ 2,346,093
Total Capital (to Risk-Weighted Assets) Actual Ratio	0.1845	0.1890
Total Capital (to Risk-Weighted Assets) Required For Capital Adequacy	$ 1,012,710	$ 993,264
Total Capital (to Risk-Weighted Assets) Required For Capital Adequacy Ratio	0.080	0.080
Total Capital (to Risk-Weighted Assets) Required To Be Well Capitalized	$ 1,265,888	$ 1,241,580
Total Capital (to Risk-Weighted Assets) Required To Be Well Capitalized Ratio	0.100	0.100
Common Equity Tier 1 Capital (to Risk-Weighted Assets) Actual	$ 2,077,017	$ 2,090,832
Common Equity Tier 1 Capital (to Risk-Weighted Assets) Actual Ratio	0.1641	0.1684
Common Equity Tier 1 Capital (to Risk-Weighted Assets) Required For Capital Adequacy	$ 569,649	$ 558,711
Common Equity Tier 1 Capital (to Risk-Weighted Assets) Required For Capital Adequacy Ratio	0.045	0.045
Common Equity Tier 1 Capital (to Risk-Weighted Assets) Required To Be Well Capitalized	$ 822,827	$ 807,027
Common Equity Tier 1 Capital (to Risk-Weighted Assets) Required To Be Well Capitalized Ratio	0.065	0.065
Tier 1 Capital (to Risk-Weighted Assets) Actual	$ 2,177,017	$ 2,190,832
Tier 1 Capital (to Risk-Weighted Assets) Actual Ratio	0.1720	0.1765
Tier 1 Capital (to Risk-Weighted Assets) Required For Capital Adequacy	$ 759,533	$ 744,948
Tier 1 Capital (to Risk-Weighted Assets) Required For Capital Adequacy Ratio	0.060	0.060
Tier 1 Capital (to Risk-Weighted Assets) Required To Be Well Capitalized	$ 1,012,710	$ 993,264
Tier 1 Capital (to Risk-Weighted Assets) Required To Be Well Capitalized Ratio	0.080	0.080
Leverage Ratio Actual Amount	$ 2,177,017	$ 2,190,832
Leverage Ratio Actual Ratio	0.1112	0.1143
Leverage Ratio Required For Capital Adequacy	$ 782,913	$ 766,714
Leverage Ratio Required For Capital Adequacy Ratio	0.040	0.040
Leverage Ratio Required To Be Well Capitalized	$ 978,641	$ 958,392
Leverage Ratio Required To Be Well Capitalized Ratio	0.050	0.050

Common Equity Tier 1 Capital (to Risk-Weighted Assets) Actual Ratio

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Common Equity Tier 1 Capital (to Risk-Weighted Assets) Required For Capital Adequacy Ratio

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Common Equity Tier 1 Capital (to Risk-Weighted Assets) Required To Be Well Capitalized Ratio

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Amount of total capital as defined by regulatory framework.

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Amount of minimum total risk-based capital required for capital adequacy as defined by regulatory framework.

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-Name Accounting Standards Codification
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
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