Fair Value Option, Credit-linked Notes, Balance (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Fair Value Disclosures [Abstract]
Other Borrowings, Fair Value Disclosure	$ 111,250	$ 113,634
Aggregate Unpaid Principal Balance in Excess of (Less Than) Fair Value	$ 1,203	$ 1,220

Aggregate Unpaid Principal Balance in Excess of (Less Than) Fair Value

No definition available.

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