Disposal Group, Including Discontinued Operation, Servicing Asset at Fair Value

No definition available.

Name:	banc_DisposalGroupIncludingDiscontinuedOperationServicingAssetatFairValue
Namespace Prefix:	banc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Servicing Asset at Fair Value, Amount and Disposal Group, Including Discontinued Operation, Servicing Asset at Fair Value

+ References

No definition available.

+ Details

Name:	banc_ServicingAssetatFairValueAmountandDisposalGroupIncludingDiscontinuedOperationServicingAssetatFairValue
Namespace Prefix:	banc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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.

+ References

No definition available.

+ Details

Name:	us-gaap_FairValueInputsAssetsQuantitativeInformationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueInputsDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Rate at which loans or a loan portfolio are expected to prepay principal balances, used as an input to measure fair value.

+ References

+ Details

Name:	us-gaap_FairValueInputsPrepaymentRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122625-111746

+ Details

Name:	us-gaap_ServicingAssetAtFairValueAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=banc_BancHomeLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DisposalGroupClassificationAxis=us-gaap_DiscontinuedOperationsDisposedOfBySaleMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_ServicingContractsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationTechniqueAxis=us-gaap_IncomeApproachValuationTechniqueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_WeightedAverageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

FAIR VALUES OF FINANCIAL INSTRUMENTS - Quantitative Information About Level 3 Fair Value Measurements (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortgage servicing rights including discontinued operations	$ 42,833	$ 76,121	$ 48,370	$ 49,939
Banc Home Loan \| Discontinued Operations, Disposed of by Sale
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Servicing rights carried at fair value	0	37,681	$ 22,300	$ 23,000
Recurring \| Significant Unobservable Inputs (Level 3)
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortgage servicing rights, at fair value	42,833
Mortgage servicing rights including discontinued operations		76,121
Recurring \| Significant Unobservable Inputs (Level 3) \| Mortgage servicing rights
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortgage servicing rights, at fair value	$ 42,833
Mortgage servicing rights including discontinued operations		$ 76,121
Recurring \| Significant Unobservable Inputs (Level 3) \| Mortgage servicing rights \| Discounted cash flow \| Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate	9.25%	9.11%
Prepayment rate	7.00%	7.00%
Recurring \| Significant Unobservable Inputs (Level 3) \| Mortgage servicing rights \| Discounted cash flow \| Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate	15.00%	15.00%
Prepayment rate	37.80%	39.90%
Recurring \| Significant Unobservable Inputs (Level 3) \| Mortgage servicing rights \| Discounted cash flow \| Weighted Average
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate	10.95%	10.18%
Prepayment rate	12.83%	11.84%