INTEREST-BEARING DEPOSITS AND SECURITIES (Securities Pledged) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013
Pledged Financial Instruments, Not Separately Reported, Securities [Abstract]
State and local governments public deposits, amortized cost	$ 116,770
Interest rate swap counterparties, amortized cost	6,782
Retail repurchase transaction accounts, amortized cost	105,167
Total pledged securities, amortized cost	231,464
State and local governments public deposits, fair value	114,301
Interest rate swap counterparties, fair value	6,402
Retail repurchase transaction accounts, fair value	105,412
Pledged Financial Instruments, Not Separately Reported, Securities for Other Debt Facilities, Amortized Cost	2,745
Pledged Financial Instruments, Not Separately Reported, Securities for Other Debt Facilities, Fair Value	2,712
Total pledged securities, fair value	$ 228,827

Pledged Financial Instruments, Not Separately Reported, Securities, Amortized Cost

No definition available.

Name:	banr_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesAmortizedCost
Namespace Prefix:	banr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Pledged Financial Instruments, Not Separately Reported, Securities, Fair Value

+ References

No definition available.

+ Details

Name:	banr_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesFairValue
Namespace Prefix:	banr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Pledged Financial Instruments, Not Separately Reported, Securities for Interest Rate Swap Counterparties

+ References

No definition available.

+ Details

Name:	banr_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForInterestRateSwapCounterpartiesAmortizedCost
Namespace Prefix:	banr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Pledged Financial Instruments, Not Separately Reported, Securities for Interest Rate Swap Counterparties, Fair Value

+ References

No definition available.

+ Details

Name:	banr_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForInterestRateSwapCounterpartiesFairValue
Namespace Prefix:	banr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Pledged Financial Instruments, Not Separately Reported, Securities for Other Debt Facilities, Amortized Cost

+ References

No definition available.

+ Details

Name:	banr_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForOtherDebtFacilitiesAmortizedCost
Namespace Prefix:	banr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Pledged Financial Instruments, Not Separately Reported, Securities for Other Debt Facilities, Fair Value

+ References

No definition available.

+ Details

Name:	banr_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForOtherDebtFacilitiesFairValue
Namespace Prefix:	banr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Pledged Financial Instruments, Not Separately Reported, Securities for Repurchase Agreements, Fair Value

+ References

No definition available.

+ Details

Name:	banr_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreementsFairValue
Namespace Prefix:	banr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Pledged Financial Instruments, Not Separately Reported, State and Local Government Public Deposits

+ References

No definition available.

+ Details

Name:	banr_PledgedFinancialInstrumentsNotSeparatelyReportedStateAndLocalGovernmentPublicDepositsAmortizedCost
Namespace Prefix:	banr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Pledged Financial Instruments, Not Separately Reported, State and Local Government Public Deposits, Fair Value

+ References

No definition available.

+ Details

Name:	banr_PledgedFinancialInstrumentsNotSeparatelyReportedStateAndLocalGovernmentPublicDepositsFairValue
Namespace Prefix:	banr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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

- Definition

The carrying amount as of the date of the latest financial statement presented of securities which are owned but transferred to serve as collateral for repurchase agreements, and for which the transferee does not have the right by contract or custom to sell or re-pledge them to an unrelated party.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 30

-Section 50

-Paragraph 1A

-Subparagraph (b)(1)(i)

-URI http://asc.fasb.org/extlink&oid=7523297&loc=SL6224234-111729

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS140-4/FIN46(R)-8

-Paragraph B6

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 140

-Paragraph 17

-Subparagraph a(2)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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