Note 6 - Regulatory Capital - Summary of Community Bank Leverage Ratio Information (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Community Bank Leverage Ratio, Amount, Actual	$ 377,995	$ 368,150
Community Bank Leverage Ratio, Ratio, Actual	11.10%	11.20%
Community Bank Leverage Ratio, Regulatory Minimum Capital Requirement, Amount	$ 289,047	$ 279,400
Community Bank Leverage Ratio, Regulatory Minimum Capital Requirement, Ratio	8.50%	8.50%
Wilson Bank [Member]
Community Bank Leverage Ratio, Amount, Actual	$ 376,682	$ 364,976
Community Bank Leverage Ratio, Ratio, Actual	11.10%	11.10%
Community Bank Leverage Ratio, Regulatory Minimum Capital Requirement, Amount	$ 288,966	$ 279,486
Community Bank Leverage Ratio, Regulatory Minimum Capital Requirement, Ratio	8.50%	8.50%