Number of Branch Offices in Which Entity Operates

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- Definition

Number of Loan Production Offices in Which Entity Operates

+ References

No definition available.

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- Definition

Number of Locations in which Entity Operates

+ References

No definition available.

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- Definition

Number of Wholly-Owned Subsidiaries

+ References

No definition available.

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- Details

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- Definition

Carrying amount as of the balance sheet date of amounts which could be received based on the terms of the insurance contract upon surrendering life policies owned by the entity.

+ 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 210.5-02.17)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 17

-Article 5

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 4

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6812-107765

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- Definition

Nominal or face amount used to calculate payments on the derivative asset.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1B

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5580258-113959

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5579245-113959

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Notional Amount

-URI http://asc.fasb.org/extlink&oid=6519104

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- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

The number of grants made 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).

+ 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)(2)(iii)(1)

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

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(3)

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

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BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Textuals) (Details) (USD $)	12 Months Ended			9 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2007
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Number of wholly-owned subsidiaries	2banr_NumberOfWhollyOwnedSubsidiaries			2banr_NumberOfWhollyOwnedSubsidiaries
Cash surrender value of bank-owned life insurance policies	63,800,000	61,900,000		63,800,000
Subsidiary, Banner Bank [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Number of offices	90			90
Number of production offices	10			10
Subsidiary, Islanders Bank [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Number of locations	3			3
Minimum [Member] \| Core Deposit Intangibles [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Intangible asset, useful life	3 years
Maximum [Member] \| Core Deposit Intangibles [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Intangible asset, useful life	8 years
Loans Receivable [Member] \| Interest Rate Swap [Member] \| F&M Bank [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Derivative Asset, Notional Amount	13,000,000			13,000,000	23,000,000
Other assets [Member] \| Interest Rate Swap [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Derivative Asset, Notional Amount	129,000,000			129,000,000
Restricted Stock [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Granted	90,181	98,891	92,035
Restricted Stock [Member] \| 2014 Omnibus Incentive Plan [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Number of shares authorized	900,000			900,000
Granted				9,352