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.

No definition available.

+ Details

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

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13531-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13537-108611

+ Details

Name:	us-gaap_ConcentrationRiskPercentage1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65884687&loc=d3e4428-111522

+ Details

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

- Definition

Indicates the number of mortgages under each classification.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29.3)
-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 10
-Section S99
-Paragraph 6
-Subparagraph (SX 210.5-04.(c) Schedule IV)
-URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674

+ Details

Name:	us-gaap_MortgageLoansOnRealEstateNumberOfLoans
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=banc_LoansAndFinanceReceivablesNonTraditionalMortgagesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=banc_NontraditionalMortgageLoansPortfolioMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=banc_LoanPortfolioConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=banc_LoanPortfolioMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=banc_GreenLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=banc_InterestOnlyLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ProductOrServiceAxis=banc_NegativeAmortizationLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionLoanCategoryAxis=us-gaap_FirstMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionLoanCategoryAxis=us-gaap_SecondMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

LOANS AND LEASES AND ALLOWANCE FOR LOAN AND LEASE LOSSES - Non Traditional Mortgages Portfolio (Detail) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016 USD ($) Loan	Dec. 31, 2015 USD ($) Loan	Jun. 30, 2015 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 6,236,115	$ 5,184,394	$ 4,473,095
Non-Traditional Mortgages (NTM)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 842,634	$ 785,908
Non-Traditional Mortgages (NTM) \| Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Count \| Loan	699	689
Gross loans	$ 842,634	$ 785,908
Non-Traditional Mortgages (NTM) \| Consumer \| Nontraditional Mortgage Loans Portfolio \| Loan Portfolio Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk percentage	100.00%	100.00%
Non-Traditional Mortgages (NTM) \| Consumer \| Loan Portfolio \| Loan Portfolio Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk percentage	13.50%	15.20%
Non-Traditional Mortgages (NTM) \| Consumer \| Green Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 103,900	$ 109,800
Non-Traditional Mortgages (NTM) \| Consumer \| Interest Only Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	727,500	664,500
Non-Traditional Mortgages (NTM) \| Consumer \| Negative amortization
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 11,200	$ 11,600
Non-Traditional Mortgages (NTM) \| Consumer \| Green Loans (HELOC) - first liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
Count \| Loan	684	672
Gross loans	$ 838,336	$ 781,091
Non-Traditional Mortgages (NTM) \| Consumer \| Green Loans (HELOC) - first liens \| Nontraditional Mortgage Loans Portfolio \| Loan Portfolio Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk percentage	99.50%	99.30%
Non-Traditional Mortgages (NTM) \| Consumer \| Green Loans (HELOC) - first liens \| Green Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Count \| Loan	116	121
Gross loans	$ 99,620	$ 105,131
Non-Traditional Mortgages (NTM) \| Consumer \| Green Loans (HELOC) - first liens \| Green Loans \| Nontraditional Mortgage Loans Portfolio \| Loan Portfolio Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk percentage	11.80%	13.40%
Non-Traditional Mortgages (NTM) \| Consumer \| Green Loans (HELOC) - first liens \| Interest Only Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Count \| Loan	540	521
Gross loans	$ 727,527	$ 664,358
Non-Traditional Mortgages (NTM) \| Consumer \| Green Loans (HELOC) - first liens \| Interest Only Loans \| Nontraditional Mortgage Loans Portfolio \| Loan Portfolio Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk percentage	86.40%	84.40%
Non-Traditional Mortgages (NTM) \| Consumer \| Green Loans (HELOC) - first liens \| Negative amortization
Accounts, Notes, Loans and Financing Receivable [Line Items]
Count \| Loan	28	30
Gross loans	$ 11,189	$ 11,602
Non-Traditional Mortgages (NTM) \| Consumer \| Green Loans (HELOC) - first liens \| Negative amortization \| Nontraditional Mortgage Loans Portfolio \| Loan Portfolio Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk percentage	1.30%	1.50%
Non-Traditional Mortgages (NTM) \| Consumer \| Green Loans (HELOC) - second liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
Count \| Loan	15	17
Gross loans	$ 4,298	$ 4,817
Non-Traditional Mortgages (NTM) \| Consumer \| Green Loans (HELOC) - second liens \| Nontraditional Mortgage Loans Portfolio \| Loan Portfolio Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk percentage	0.50%	0.70%
Non-Traditional Mortgages (NTM) \| Consumer \| Green Loans (HELOC) - second liens \| Green Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Count \| Loan	15	16
Gross loans	$ 4,298	$ 4,704
Non-Traditional Mortgages (NTM) \| Consumer \| Green Loans (HELOC) - second liens \| Green Loans \| Nontraditional Mortgage Loans Portfolio \| Loan Portfolio Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk percentage	0.50%	0.60%
Non-Traditional Mortgages (NTM) \| Consumer \| Green Loans (HELOC) - second liens \| Interest Only Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Count \| Loan	0	1
Gross loans	$ 0	$ 113
Non-Traditional Mortgages (NTM) \| Consumer \| Green Loans (HELOC) - second liens \| Interest Only Loans \| Nontraditional Mortgage Loans Portfolio \| Loan Portfolio Concentration Risk
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk percentage	0.00%	0.10%