Debt Instrument, Number of Classes

No definition available.

Name:	banc_DebtInstrumentNumberOfClasses
Namespace Prefix:	banc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Subordinated Debt Redemption

+ References

No definition available.

+ Details

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

- Definition

The value of the collateral (typically cash) that the entity receives in a financing transaction in exchange for securities lent. This item represents a liability in the financial statements of the lender of the securities.

+ References

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Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- 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.

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Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

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+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Period Type:	instant

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

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Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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- Definition

The carrying value as of the balance sheet date of the current portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Period Type:	instant

- Definition

The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time.

+ References

+ Details

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- Definition

The portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time.

+ References

No definition available.

+ Details

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- Definition

Weighted average interest rate of long-term debt outstanding calculated at point in time.

+ References

No definition available.

+ Details

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- Definition

Amount of borrowings classified as other, maturing within one year or the normal operating cycle, if longer.

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- Definition

Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

+ References

+ Details

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- Definition

Fair value of the securities pledged as collateral against securities loaned.

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- Details

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- Details

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Borrowings and Subordinated Debt - Narrative (Details)	3 Months Ended
Borrowings and Subordinated Debt - Narrative (Details)	Mar. 31, 2026 USD ($) Rate	Dec. 31, 2025 USD ($)	May 01, 2026 USD ($)	Sep. 29, 2022 class
Debt Instrument [Line Items]
Other Short-Term Borrowings	$ 440,000,000	$ 240,000,000
Subordinated Notes
Debt Instrument [Line Items]
Rate Index (Quarterly Reset)	4.195%	437.50%
Subordinated notes due May 2031 \| Subsequent Event
Debt Instrument [Line Items]
Subordinated Debt Redemption			$ 385,000,000
Federal Reserve Bank Advances
Debt Instrument [Line Items]
Long-Term Line of Credit		$ 0
Secured Debt \| Federal Reserve Bank Advances
Debt Instrument [Line Items]
Borrowing capacity description	$ 5,300,000,000
Collateralized financings	5,000,000,000.0
Securities loaned, fair value of collateral	1,400,000,000
Unused Lines of Credit
Debt Instrument [Line Items]
Current borrowing capacity	$ 215,000,000.0
Credit-linked notes
Debt Instrument [Line Items]
Credit-linked ,Variable interest, percentage rate	14.41%	14.63%
Weighted average interest rate	10.75%
Secured debt	$ 2,100,000,000
Number of note classes \| class				5
Credit-linked Notes	$ 111,250,000	$ 113,634,000
Credit-linked notes \| Highest Rate of Spread
Debt Instrument [Line Items]
Credit-linked ,Variable interest, percentage rate	13.25%
Credit-linked notes \| Lowest Rate of Spread
Debt Instrument [Line Items]
Credit-linked ,Variable interest, percentage rate	8.00%
Short-Term Debt
Debt Instrument [Line Items]
Long-Term Line of Credit	$ 440,000,000.0
Unsecured Debt [Member] \| 522110 Commercial Banking
Debt Instrument [Line Items]
Current borrowing capacity	100,000,000.0
Long-Term Line of Credit	$ 0	0
Rate Index (Quarterly Reset) \| Rate	2.25%
Federal Home Loan Bank of San Francisco
Debt Instrument [Line Items]
Collateralized financings	$ 10,100,000,000
Securities loaned, fair value of collateral	19,800,000
Letters of credit outstanding, amount		514,100,000
Federal Home Loan Bank of San Francisco \| Secured Debt
Debt Instrument [Line Items]
Borrowing capacity description	6,900,000,000
Line of credit, current	$ 2,000,000,000	$ 1,710,185,000