Note 11 - Minimum Regulatory Capital Requirement - Minimum Capital Requirements (Details) - National Bank of Blacksburg [Member] $ in Thousands		Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Total capital (to risk weighted assets), actual, amount		$ 191,883	$ 192,907
Total capital (to risk weighted assets), actual, ratio		0.1757	0.1950
Total capital (to risk weighted assets), minimum capital requirement, amount	[1]	$ 114,671	$ 103,898
Total capital (to risk weighted assets), minimum capital requirement, ratio	[1]	0.1050	0.1050
Total capital (to risk weighted assets), minimum to be well capitalized, amount		$ 109,210	$ 98,950
Total capital (to risk weighted assets), minimum to be well capitalized, ratio		0.1000	0.1000
Tier 1 capital (to risk weighted assets), actual, amount		$ 183,623	$ 185,187
Tier 1 capital (to risk weighted assets), actual, ratio		0.1681	0.1872
Tier 1 capital (to risk weighted assets), minimum capital requirement, amount	[1]	$ 92,829	$ 84,108
Tier 1 capital (to risk weighted assets), minimum capital requirement, ratio	[1]	0.0850	0.0850
Tier 1 capital (to risk weighted assets), minimum to be well capitalized, amount		$ 87,368	$ 79,160
Tier 1 capital (to risk weighted assets), minimum to be well capitalized, ratio		0.0800	0.0800
Common equity tier 1 capital (to risk weighted assets), actual, amount		$ 183,623	$ 185,187
Common equity tier 1 capital (to risk weighted assets), actual, ratio		0.1681	0.1872
Common equity tier 1 capital (to risk weighted assets), minimum capital requirement, amount	[1]	$ 76,447	$ 69,265
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		$ 70,987	$ 64,318
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		$ 183,623	$ 185,187
Tier 1 capital (to average assets), actual, ratio		0.1050	0.1116
Tier 1 capital (to average assets), minimum capital requirement, amount	[1]	$ 69,925	$ 66,348
Tier 1 capital (to average assets), minimum capital requirement, ratio	[1]	0.0400	0.0400
Tier 1 capital (to average assets), minimum to be well capitalized, amount		$ 87,406	$ 82,935
Tier 1 capital (to average assets), minimum to be well capitalized, ratio		0.0500	0.0500

[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.