STOCK COMPENSATION PLANS - Summary of all Outstanding SARs (Detail) - Jun. 30, 2015 - $ / shares	Total
Initial SAR \| 8/21/2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares	500,000
Base price per share	$ 12.12
Granted	$ 2.77
Additional Stock Appreciation Rights I-V, VII \| 6/21/2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares	150,933
Base price per share	$ 13.06
Granted	$ 2.38
Additional Stock Appreciation Rights I-V, VII \| 7/1/2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares	88,366
Base price per share	$ 13.60
Granted	$ 2.17
Additional Stock Appreciation Rights I-V, VII \| 7/2/2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares	15,275
Base price per share	$ 13.55
Granted	$ 2.19
Additional Stock Appreciation Rights I-V, VII \| 12/10/2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares	70,877
Base price per share	$ 12.83
Granted	$ 2.47
Additional Stock Appreciation Rights I-V, VII \| 5/21/2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares	252,023
Base price per share	$ 10.09
Granted	$ 1.65
Additional Stock Appreciation Rights I-V, VII \| 11/07/2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares	216,334
Base price per share	$ 11.62
Granted	$ 1.84
Additional SAR VI \| 5/21/2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares	279,469
Base price per share	$ 10.09
Granted	$ 2.22

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(iii)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
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

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

- Definition

Net number of non-option equity instruments granted to participants.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

Name:	us-gaap_SharePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_AwardTypeAxis=banc_InitialStockAppreciationRightsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardDateAxis=banc_AwardDateAugust212012Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=banc_AdditionalStockAppreciationRightsIVVIIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardDateAxis=banc_AwardDateJune212013Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardDateAxis=banc_AwardDateJuly12013Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardDateAxis=banc_AwardDateJuly22013Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardDateAxis=banc_AwardDateDecember102013Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardDateAxis=banc_AwardDateMay212014Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardDateAxis=banc_AwardDateNov72014Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=banc_AdditionalStockAppreciationRightVIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: