[Line Items] for Fair Value Inputs, Assets and Liabilities, Quantitative Information [Table]

No definition available.

Name:	banr_FairValueInputsAssetsAndLiabilitiesQuantitativeInformationLineItems
Namespace Prefix:	banr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair Value Inputs, Discount Rate, Basis Spread on Variable Rate Basis

+ References

No definition available.

+ Details

Name:	banr_FairValueInputsDiscountRateBasisSpreadOnVariableRateBasis
Namespace Prefix:	banr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Fair Value Inputs, Discount Rate, Description of Variable Rate Basis

+ References

No definition available.

+ Details

Name:	banr_FairValueInputsDiscountRateDescriptionOfVariableRateBasis
Namespace Prefix:	banr_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

- Definition

fair value inputs, discount to appraised value

+ References

No definition available.

+ Details

Name:	banr_Fairvalueinputsdiscounttoappraisedvalue
Namespace Prefix:	banr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueInputsDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FairValueByLiabilityClassAxis=us-gaap_JuniorSubordinatedDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationTechniqueAxis=us-gaap_IncomeApproachValuationTechniqueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_WeightedAverageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=banr_TrustPreferredSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=banr_ImpairedLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationTechniqueAxis=banr_DiscounttoappraisedvalueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationTechniqueAxis=us-gaap_MarketApproachValuationTechniqueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=banr_RealEstateOwnedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

FAIR VALUE OF FINANCIAL INSTRUMENTS (Valuation Technique) (Details) - Level 3 [Member]	3 Months Ended		9 Months Ended	12 Months Ended
	Sep. 30, 2016	Mar. 31, 2015	Sep. 30, 2017	Dec. 31, 2016
Junior Subordinated Debt [Member] \| Discounted cash flows [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Inputs, Discount Rate, Description of Variable Rate Basis	three-month LIBOR
Fair Value Inputs, Discount Rate, Basis Spread on Variable Rate Basis	5.00%
Junior Subordinated Debt [Member] \| Weighted Average [Member] \| Discounted cash flows [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Discount rate			6.33%	6.00%
Corporate Bonds (TPS securities) [Member] \| Weighted Average [Member] \| Discounted cash flows [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Discount rate			6.33%	6.00%
Impaired Loans [Member] \| Weighted Average [Member] \| discount to appraised value [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
fair value inputs, discount to appraised value			8.5% to 9.0%
Impaired Loans [Member] \| Minimum [Member] \| Market Approach Valuation Technique [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Discount rate			0.00%
Impaired Loans [Member] \| Maximum [Member] \| Market Approach Valuation Technique [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Discount rate			0.00%
Real Estate Owned [Member] \| Weighted Average [Member] \| discount to appraised value [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
fair value inputs, discount to appraised value				0% to 45%
Real Estate Owned [Member] \| Minimum [Member] \| Discounted cash flows [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Discount rate			17.00%	0.00%
Real Estate Owned [Member] \| Maximum [Member] \| Discounted cash flows [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Discount rate			42.00%	45.00%