Note 11 - Minimum Regulatory Capital Requirement - Minimum Capital Requirements (Details) - National Bank of Blacksburg [Member] $ in Thousands		Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Total capital (to risk weighted assets), actual, amount		$ 195,782	$ 191,883
Total capital (to risk weighted assets), actual, ratio		0.1809	0.1757
Total capital (to risk weighted assets), minimum capital requirement, amount	[1]	$ 113,627	$ 114,671
Total capital (to risk weighted assets), minimum capital requirement, ratio	[1]	0.105	0.105
Total capital (to risk weighted assets), minimum to be well capitalized, amount		$ 108,216	$ 109,210
Total capital (to risk weighted assets), minimum to be well capitalized, ratio		0.10	0.10
Tier 1 capital (to risk weighted assets), actual, amount		$ 186,429	$ 183,623
Tier 1 capital (to risk weighted assets), actual, ratio		0.1723	0.1681
Tier 1 capital (to risk weighted assets), minimum capital requirement, amount	[1]	$ 91,983	$ 92,829
Tier 1 capital (to risk weighted assets), minimum capital requirement, ratio	[1]	0.085	0.085
Tier 1 capital (to risk weighted assets), minimum to be well capitalized, amount		$ 86,573	$ 87,368
Tier 1 capital (to risk weighted assets), minimum to be well capitalized, ratio		0.08	0.08
Common equity tier 1 capital (to risk weighted assets), actual, amount		$ 186,429	$ 183,623
Common equity tier 1 capital (to risk weighted assets), actual, ratio		0.1723	0.1681
Common equity tier 1 capital (to risk weighted assets), minimum capital requirement, amount	[1]	$ 75,751	$ 76,447
Common equity tier 1 capital (to risk weighted assets), minimum capital requirement, ratio	[1]	7.00%	7.00%
Common equity tier 1 capital (to risk weighted assets), minimum to be well capitalized, amount		$ 70,340	$ 70,987
Common equity tier 1 capital (to risk weighted assets), minimum to be well capitalized, ratio		6.50%	6.50%
Tier 1 capital (to average assets), actual, amount		$ 186,429	$ 183,623
Tier 1 capital (to average assets), actual, ratio		0.1105	0.105
Tier 1 capital (to average assets), minimum capital requirement, amount	[1]	$ 67,491	$ 69,925
Tier 1 capital (to average assets), minimum capital requirement, ratio	[1]	0.04	0.04
Tier 1 capital (to average assets), minimum to be well capitalized, amount		$ 84,364	$ 87,406
Tier 1 capital (to average assets), minimum to be well capitalized, ratio		0.05	0.05

[1] Except with regard to NBB’s Tier 1 capital to average assets ratio, the minimum capital requirement includes the Basel III Capital Rules’ capital conservation buffer (2.50%) which is added to the minimum capital requirements for capital adequacy purposes. NBB’s capital conservation buffer consists of additional CET1 above regulatory minimum requirement. Failure to maintain the prescribed levels would result in limitations on capital distributions and discretionary bonuses to executives.