Related Party Transaction, Company Ownership Percentage Maximum Threshold

No definition available.

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- Definition

Stock Employee Compensation Trust, Shares Repurchased

+ References

No definition available.

+ Details

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Data Type:	xbrli:sharesItemType
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- Definition

Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21463-112644

+ Details

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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

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Balance Type:	na
Period Type:	duration

- Details

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- Details

Name:	us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis=us-gaap_VariableInterestEntityPrimaryBeneficiaryMember
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Data Type:	na
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- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=banc_GreaterThan5ShareholderEvercoreTrustCompanyMember
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Data Type:	na
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- Details

Name:	us-gaap_RelatedPartyTransactionAxis=banc_SpecialCommitteeInvestigationIndemnificationMember
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- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=banc_GeneralCounselMember
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RELATED-PARTY TRANSACTIONS - Current Related Party Indemnification Costs and SECT Transactions (Details) - USD ($) $ in Thousands			3 Months Ended	12 Months Ended
	Dec. 28, 2017	Apr. 06, 2015	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Feb. 13, 2017
Related Party Transaction [Line Items]
Expenses from transactions with related parties		$ 263
Common Stock \| Variable Interest Entity, Primary Beneficiary
Related Party Transaction [Line Items]
Number of shares repurchased (in shares)	2,500,000
Evercore Trust Company
Related Party Transaction [Line Items]
Common stock, shares outstanding (in shares)					2,500,000
Company ownership percentage maximum threshold						5.00%
Special Committee Investigation Indemnification \| General Counsel
Related Party Transaction [Line Items]
Expenses from transactions with related parties			$ 28	$ 501	$ 0