ADVANCES FROM FEDERAL HOME LOAN BANK OF DES MOINES (Details) - USD ($)	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Advances from Federal Home Loan Banks [Abstract]
Federal Home Loan Bank, advances, collateral pledged	$ 0	$ 0
Federal Home Loan Bank, Advances, Fiscal Year Maturity [Abstract]
Maturing in one year or less	$ 50,000,000	$ 100,000,000
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Interest Rate	2.72%	2.51%
Maturing after one year through three years	$ 0	$ 50,000,000
Federal Home Loan Bank, Advance, Maturity, Average Interest Rate, Year Three	0.00%	2.72%
Maturing after three years through five years	$ 0	$ 0
Federal Home Loan Bank, Advances, Maturities Summary, Average Interest Rate, Three to Four Years from Balance Sheet Date	0.00%	0.00%
Maturing after five years	$ 0	$ 0
Federal Home Loan Bank, Advance, Maturity, Average Interest Rate, after Year Five	0.00%	0.00%
Total FHLB advances	$ 50,000,000	$ 150,000,000
Federal Home Loan Bank, advances, average interest rate for year	2.72%	2.58%
Federal Home Loan Bank, advances, maximum outstanding at any month end	$ 150,000,000	$ 380,000,000
Federal Home Loan Bank, advances, average balance outstanding	$ 97,900,000	$ 215,100,000
Federal Home Loan Bank, Advances, Activity for Year, Average Interest Rate for Year	2.65%	2.34%
Federal Home Loan Bank, Advances, General Debt Obligations, Amount of Available, Unused Funds	$ 2,380,000,000
Subsidiary, Banner Bank [Member]
Federal Home Loan Bank, Advances, Fiscal Year Maturity [Abstract]
Federal Home Loan Bank, advances, percentage of total assets to support credit line	45.00%

Federal Home Loan Bank, Advances, General Debt Obligations, Percentage of Total Assets to Support Credit Line

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Federal Home Loan Bank, Advances, Maturities Summary, Average Interest Rate Three to Five Years from Balance Sheet Date

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Federal Home Loan Bank, Advances, Maturities Summary, Due After One Year Through Three Years

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Federal Home Loan Bank, Advances, Maturities Summary, Due After Three Years Through Five Years

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Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

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The calculated average balance outstanding for the year for all Federal Home Loan Bank advances as of the Balance Sheet date.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
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The calculated weighted average interest rate for Federal Home Loan Bank advances for the period ended as of the Balance Sheet date.

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The maximum balance outstanding at any month end during the period as of the Balance Sheet date.

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Amount of advances or credit lines available from the Federal Home Loan Bank (FHLB).

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Amount of the collateral pledged in support of federal home loan bank advances outstanding.

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Interest rate of advances made and reported by Federal Home Loan Bank (FHLBank).

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Weighted average interest rate of advance from Federal Home Loan Bank (FHLBank) due after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Weighted average interest rate of advance from Federal Home Loan Bank (FHLBank) due in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Weighted average interest rate of advance from Federal Home Loan Bank (FHLBank) due in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of advance from Federal Home Loan Bank (FHLBank) maturing after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of advance from Federal Home Loan Bank (FHLBank) maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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