Stock Repurchase Program, Number of Shares Authorized to be Repurchased, Percent of Total Outstanding

No definition available.

Name:	banr_StockRepurchaseProgramNumberofSharesAuthorizedtobeRepurchasedPercentofTotalOutstanding
Namespace Prefix:	banr_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Stock Repurchased During Period, Average Price Per Share

+ References

No definition available.

+ Details

Name:	banr_StockRepurchasedDuringPeriodAveragePricePerShare
Namespace Prefix:	banr_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Stock surrendered during period, shares by employees to satisfy tax withholding obligations upon vesting of restricted stock grants

+ References

No definition available.

+ Details

Name:	banr_Stocksurrenderedduringperiodshares
Namespace Prefix:	banr_
Data Type:	xbrli:sharesItemType
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_EquityClassOfTreasuryStockLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

+ Details

Name:	us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The remaining number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

+ Details

Name:	us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=123467817&loc=d3e21463-112644

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShareRepurchaseProgramAxis=banr_BannerCorp2019ShareRepurchaseAuthorizationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShareRepurchaseProgramAxis=banr_BannerCorp2020ShareRepurchaseAuthorizationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShareRepurchaseProgramAxis=banr_BannerCorp2021ShareRepurchaseAuthorizationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

STOCK REPURCHASES (Details) - Common Stock [Member] - $ / shares	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 22, 2021	Dec. 21, 2020	Mar. 27, 2019
Stock repurchases
Stock surrendered during period, shares			59,730	41,507	33,777
Banner Corp 2019 Share Repurchase Authorization [Member]
Stock repurchases
Stock Repurchase Program, Number of Shares Authorized to be Repurchased								1,757,637
Stock Repurchase Program, Number of Shares Authorized to be Repurchased, Percent of Total Outstanding								5.00%
Stock Repurchased During Period, Shares	624,780	1,000,000
Stock Repurchased During Period, Average Price Per Share	$ 50.84	$ 53.90
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased				757,637
Banner Corp 2020 Share Repurchase Authorization
Stock repurchases
Stock Repurchase Program, Number of Shares Authorized to be Repurchased							1,757,781
Stock Repurchase Program, Number of Shares Authorized to be Repurchased, Percent of Total Outstanding							5.00%
Stock Repurchased During Period, Shares			1,050,000
Stock Repurchased During Period, Average Price Per Share			$ 53.84
Banner Corp 2021 Share Repurchase Authorization
Stock repurchases
Stock Repurchase Program, Number of Shares Authorized to be Repurchased						1,712,510
Stock Repurchase Program, Number of Shares Authorized to be Repurchased, Percent of Total Outstanding						5.00%