LOAN COMMITMENTS AND OTHER RELATED ACTIVITIES - Contractual Amount of Financial Instruments with Off-Balance-Sheet Risk (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2023	Dec. 31, 2022
Other Commitments [Line Items]
Unfunded commitment	$ 15,707	$ 17,480
LIHTC Investments
Other Commitments [Line Items]
Unfunded commitment	15,700	17,500
Small Business Investment Companies
Other Commitments [Line Items]
Unfunded commitment	7,500	8,600
Other Investments
Other Commitments [Line Items]
Unfunded commitment	20,000	9,800
Commitments to extend credit
Other Commitments [Line Items]
Fixed Rate	39,729	50,193
Variable Rate	161,036	180,696
Unused lines of credit
Other Commitments [Line Items]
Fixed Rate	47,334	8,392
Variable Rate	1,330,913	1,505,122
Letters of credit
Other Commitments [Line Items]
Fixed Rate	1,671	2,461
Variable Rate	$ 7,462	$ 7,016

Alternative Investments, Unfunded Investment Commitments

No definition available.

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Namespace Prefix:	banc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Reflects the amount of cash required to fully fund agreements to provide advances to borrowers and lessees at stated interest rates.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 942
-SubTopic 825
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480981/942-825-50-2

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 942
-SubTopic 825
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480981/942-825-50-1

+ Details

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Period Type:	duration

- Definition

Reflects the amount of cash required to fully fund agreements to provide advances to borrowers and lessees at interest rates that increase or decrease depending on certain facts or circumstances.

+ References

+ Details

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- Definition

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.

+ References

No definition available.

+ Details

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- Details

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- Details

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- Details

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