Note 4 - Securities (Details Textual) $ in Thousands	9 Months Ended
Sep. 30, 2024 USD ($) Securities	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 0		$ 0
Interest Receivable on Securities	3,379		3,281
Deferred Tax Asset, Debt Securities, Available-for-Sale, Unrealized Loss	$ 13,272		$ 16,629
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions \| Securities	563
Debt Securities, Available-for-Sale, Unrealized Loss Position	$ 599,897
Debt Securities, Available-for-Sale, Realized Gain (Loss)	0	$ (3,332)
Available-for-sale Securities Sold, Book Value		$ 46,850
National Bank of Blacksburg [Member] \| Federal Home Loan Bank of Atlanta [Member]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged	$ 507,498

Represents the book value of available-for-sale securities that had been sold.

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- Definition

The amount of interest receivable on securities

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- Definition

Amount of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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- Definition

Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss.

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- Definition

Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary difference from unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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- Definition

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

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