Note 13 - Short-term Borrowings (Details Textual) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Federal Home Loan Bank Advances [Member]
Federal Home Loan Bank, Advances, General Debt Obligations, Amount of Available, Unused Funds	$ 1,200,000	$ 706,600
Federal Funds Purchased [Member]
Line of Credit Facility, Maximum Borrowing Capacity	87,000
Federal Funds Purchased	15,000	$ 0
Unsecured Line of Credit [Member] \| Bank of North Dakota [Member]
Line of Credit Facility, Commitment Fee Amount	$ 20,000

Amount of short term borrowing where a bank borrows, at the federal funds rate, from another bank.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13)(1))
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(b))
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Period Type:	instant

- Definition

Amount of the fee for available but unused credit capacity under the credit facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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Balance Type:	credit
Period Type:	instant

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Namespace Prefix:
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