Deposits Deposits (Details 1) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Time Deposits Balance [Line Items]
Time Deposit Maturities, Next Twelve Months	$ 6,452,402
Time Deposit Maturities, Year Two	166,408
Time Deposit Maturities, Year Three	7,779
Time Deposit Maturities, Year Four	4,410
Time Deposit Maturities, Year Five	1,874
Time Deposit Maturities, after Year Five	0
Time Deposits	6,632,873	$ 4,737,843
Deposits Exceeding FDIC Insurance Limit of $250,000 [Member]
Time Deposits Balance [Line Items]
Time Deposit Maturities, Next Twelve Months	1,065,900
Time Deposit Maturities, Year Two	34,807
Time Deposit Maturities, Year Three	2,087
Time Deposit Maturities, Year Four	2,910
Time Deposit Maturities, Year Five	773
Time Deposit Maturities, after Year Five	0
Time Deposits	1,106,477
Deposits FDC Insured $250,000 and Under [Member]
Time Deposits Balance [Line Items]
Time Deposit Maturities, Next Twelve Months	5,386,502
Time Deposit Maturities, Year Two	131,601
Time Deposit Maturities, Year Three	5,692
Time Deposit Maturities, Year Four	1,500
Time Deposit Maturities, Year Five	1,101
Time Deposit Maturities, after Year Five	0
Time Deposits	$ 5,526,396

[Line Items] for Time Deposits Balance [Table]

No definition available.

Name:	banc_TimeDepositsBalanceLineItems
Namespace Prefix:	banc_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of time deposit maturing after fifth fiscal year following current fiscal year. Time deposit includes, but is not limited to, certificate of deposit. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-SubTopic 10
-Topic 470
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481544/470-10-50-1

+ Details

Name:	us-gaap_TimeDepositMaturitiesAfterYearFive
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of time deposit maturing in fifth fiscal year following current fiscal year. Time deposit includes, but is not limited to, certificate of deposit. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_TimeDepositMaturitiesYearFive
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of time deposit maturing in fourth fiscal year following current fiscal year. Time deposit includes, but is not limited to, certificate of deposit. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_TimeDepositMaturitiesYearFour
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of time deposit maturing in next fiscal year following current fiscal year. Time deposit includes, but is not limited to, certificate of deposit. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_TimeDepositMaturitiesYearOne
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of time deposit maturing in third fiscal year following current fiscal year. Time deposit includes, but is not limited to, certificate of deposit. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_TimeDepositMaturitiesYearThree
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of time deposit maturing in second fiscal year following current fiscal year. Time deposit includes, but is not limited to, certificate of deposit. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

Name:	us-gaap_TimeDepositMaturitiesYearTwo
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of time deposit liabilities, including certificates of deposit.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-SubTopic 405
-Topic 942
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481047/942-405-50-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.12)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1

+ Details

Name:	us-gaap_TimeDeposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	banc_TimeDepositsBalanceAxis=banc_DepositsExceedingFDICInsuranceLimitof250000Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	banc_TimeDepositsBalanceAxis=banc_DepositsFDCInsured250000andUnderMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: