Note 12 - Commitments and Contingencies (Details Textual) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Off-Balance-Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal)	$ 1,100	$ 549	$ 3,900	$ 31
Bank of North Dakota [Member]
Letters of Credit Outstanding, Amount	0		0		$ 50,000
Bank of North Dakota [Member] | Letter of Credit [Member]
Debt Instrument, Collateral Amount	540,300		540,300		524,900
Federal Home Loan Bank of Des Moines [Member]
Letters of Credit Outstanding, Amount	8,600		8,600		12,000
Unfunded Loan Commitment [Member]
Off-Balance-Sheet, Credit Loss, Liability	$ 3,700		3,700		$ 7,500
Off-Balance-Sheet, Credit Loss, Liability, Credit Loss Expense (Reversal)			$ (3,900)	$ (31,000)