LOANS AND LEASES AND ALLOWANCE FOR LOAN AND LEASE LOSSES - Credit Quality Indicators and PCI Loans Additional Information (Details) - bulk_loan_acquisition	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Receivables [Abstract]
Loans delinquent	60 days
Number of bulk acquisitions	0	0

Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, Number of Bulk Loan Acquisitions

No definition available.

Name:	banc_CertainLoansAcquiredinTransferNotAccountedforasDebtSecuritiesAcquiredDuringPeriodNumberofBulkLoanAcquisitions
Namespace Prefix:	banc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration