Note 1 - Organization and Summary of Significant Accounting Policies (Details Textual) - USD ($)	Jun. 30, 2023		Jan. 01, 2023	Dec. 31, 2022		Jun. 30, 2022
Investments	$ 3,915,000			$ 1,237,000
Allowance for Credit Loss	15,560,000	[1]	$ 14,000,000	14,000,000	[1]
Allowance for Unfunded Loan Commitments			0
Retained Earnings (Accumulated Deficit)	93,462,000			$ 92,023,000
Accounting Standards Update 2016-13 [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Credit Loss			700,000
Allowance for Unfunded Loan Commitments			1,500,000
Retained Earnings (Accumulated Deficit)	$ (1,616,000)		$ (1,616,000)			$ 0
Opportunity Bank of Montana [Member]
Noncontrolling Interest, Ownership Percentage by Parent	100.00%
Opportunity Bank of Montana [Member] | Accrued Expenses and Other Liabilities [Member]
Qualified Affordable Housing Project Investments, Commitment	$ 4,972,000

[1] Allowance for credit losses for the quarter ended June 30, 2023; allowance for loan losses for prior periods.