Note 7 - Regulatory Capital - Summary of Company's and Wilson Banks Actual Capital Amounts and Ratios (Details) $ in Thousands	Jun. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Total capital to risk weighted assets actual amount	$ 538,392	$ 512,025
Total capital to risk weighted assets actual ratio	0.139	0.135
Total capital to risk weighted assets regulatory minimum capital requirement amount	$ 310,487	$ 303,440
Total capital to risk weighted assets regulatory minimum capital requirement ratio (	0.080	0.080
Well capitalized amount	$ 388,109	$ 379,300
Total capital to risk weighted assets regulatory minimum capital requirement well capitalized ratio	0.100	0.100
Tier 1 capital to risk weighted assets actual amount	$ 491,192	$ 466,076
Tier 1 capital to risk weighted assets actual ratio	0.127	0.123
Tier 1 capital to risk weighted assets regulatory minimum capital requirement amount	$ 232,864	$ 227,580
Tier 1 capital to risk weighted assets regulatory minimum capital requirement ratio	0.060	0.060
Tier 1 capital to risk well capitalized amount	$ 310,486	$ 303,440
Tier 1 capital to risk weighted assets regulatory well capitalized ratio	0.080	0.080
Common equity Tier 1 capital to risk weighted assets actual amount	$ 491,129	$ 466,061
Common equity Tier 1 capital to risk weighted assets actual ratio	0.127	0.123
Common equity Tier 1 capital to risk weighted assets regulatory minimum capital requirement amount	$ 174,648	$ 170,685
Common equity Tier 1 capital to risk weighted assets regulatory minimum capital requirement ratio	0.045	0.045
Tier 1 capital to average assets actual amount	$ 491,192	$ 466,076
Tier 1 capital to average assets actual ratio	0.107	0.112
Tier 1 capital to average assets regulatory minimum capital requirement amount	$ 184,444	$ 166,712
Tier 1 capital to average assets regulatory minimum capital requirement ratio (as a percent)	0.040	0.040
Wilson Bank [Member]
Total capital to risk weighted assets actual amount	$ 534,956	$ 509,169
Total capital to risk weighted assets actual ratio	0.138	0.134
Total capital to risk weighted assets regulatory minimum capital requirement amount	$ 310,376	$ 303,334
Total capital to risk weighted assets regulatory minimum capital requirement ratio (	0.080	0.080
Well capitalized amount	$ 387,970	$ 379,168
Total capital to risk weighted assets regulatory minimum capital requirement well capitalized ratio	0.100	0.100
Tier 1 capital to risk weighted assets actual amount	$ 487,756	$ 463,220
Tier 1 capital to risk weighted assets actual ratio	0.126	0.122
Tier 1 capital to risk weighted assets regulatory minimum capital requirement amount	$ 232,780	$ 227,500
Tier 1 capital to risk weighted assets regulatory minimum capital requirement ratio	0.060	0.060
Tier 1 capital to risk well capitalized amount	$ 310,374	$ 303,333
Tier 1 capital to risk weighted assets regulatory well capitalized ratio	0.080	0.080
Common equity Tier 1 capital to risk weighted assets actual amount	$ 487,693	$ 463,205
Common equity Tier 1 capital to risk weighted assets actual ratio	0.126	0.122
Common equity Tier 1 capital to risk weighted assets regulatory minimum capital requirement amount	$ 174,586	$ 170,625
Common equity Tier 1 capital to risk weighted assets regulatory minimum capital requirement ratio	0.045	0.045
Common equity Tier 1 capital to risk weighted assets regulatory well capitalized	$ 252,180	$ 246,458
Common equity Tier 1 capital to risk weighted assets well capitalized ratio	0.065	0.065
Tier 1 capital to average assets actual amount	$ 487,756	$ 463,220
Tier 1 capital to average assets actual ratio	0.106	0.111
Tier 1 capital to average assets regulatory minimum capital requirement amount	$ 184,379	$ 166,648
Tier 1 capital to average assets regulatory minimum capital requirement ratio (as a percent)	0.040	0.040
Tier 1 capital to average assets well capitalized	$ 230,474	$ 208,310
Tier 1 capital to average assets well capitalized ratio (as a percent)	0.050	0.050