Other Assets - Narrative (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2026	Dec. 31, 2025
Other Assets [Abstract]
Increase other assets	$ 45,800
Other receivables/assets	$ 89,865	$ 44,108

Increase (Decrease) In Other Assets, Miscellaneous

No definition available.

Name:	banc_IncreaseDecreaseInOtherAssetsMiscellaneous
Namespace Prefix:	banc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration