DEPOSITS DEPOSITS (Certificates of Deposit by Balance) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Time Deposits [Abstract]
Certificates of deposit less than $100,000	$ 358,189,000us-gaap_TimeDepositsLessThan100000	$ 386,745,000us-gaap_TimeDepositsLessThan100000
Certificates of deposit $100,000 through $250,000	275,156,000banr_TimeDeposits100000to250000	308,130,000banr_TimeDeposits100000to250000
Certificates of deposit more than $250,000	137,171,000banr_TimeDepositsMorethan250000	177,820,000banr_TimeDepositsMorethan250000
Total certificates of deposit	770,516,000	872,695,000
Certificates of deposit $250,000 or more	$ 141,000,000banr_TimeDeposits250000orMore	$ 184,000,000banr_TimeDeposits250000orMore

The aggregate amount of time deposits in denominations of $100,000 to $250,000.

No definition available.

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Data Type:	xbrli:monetaryItemType
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- Definition

The aggregate amount of Time Deposits in denominations of $250,000 or More

+ References

No definition available.

+ Details

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Namespace Prefix:	banr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The aggregate amount of time deposits in denominations more than $250,000.

+ References

No definition available.

+ Details

Name:	banr_TimeDepositsMorethan250000
Namespace Prefix:	banr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of interest-bearing domestic certificate of deposit liabilities.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.12)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 12

-Article 9

+ Details

Name:	us-gaap_InterestBearingDomesticDepositCertificatesOfDeposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_TimeDepositsAbstract
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- Definition

The aggregate amount of domestic or foreign time deposits (including certificates of deposits, individual retirement accounts and open accounts) that total to less than $100,000.

+ References

No definition available.

+ Details

Name:	us-gaap_TimeDepositsLessThan100000
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant