Note 27 - Supplemental Disclosure for Earnings Per Share - Supplemental Disclosure for Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net income attributable to First Capital, Inc.	$ 3,110	$ 3,138	$ 2,726	$ 3,816	$ 3,540	$ 3,125	$ 2,710	$ 2,527	$ 2,819	$ 2,936	$ 2,730	$ 2,939	$ 12,790	$ 11,902	$ 11,424
Weighted average common shares outstanding (in shares)													3,347,341	3,355,023	3,346,038
Net income attributable to First Capital, Inc. per common share, basic (in dollars per share)	$ 0.93	$ 0.94	$ 0.82	$ 1.14	$ 1.06	$ 0.93	$ 0.81	$ 0.75	$ 0.83	$ 0.88	$ 0.82	$ 0.88	$ 3.82	$ 3.55	$ 3.41
Net income attributable to First Capital, Inc.													$ 12,790	$ 11,902	$ 11,424
Weighted average common shares outstanding (in shares)													3,347,341	3,355,023	3,346,038
Add: Dilutive effect of restricted stock (in shares)													0	0	457
Weighted average common shares outstanding, as adjusted (in shares)													3,347,341	3,355,023	3,346,495
Net income attributable to First Capital, Inc. per common share, diluted (in dollars per share)	$ 0.93	$ 0.94	$ 0.82	$ 1.14	$ 1.06	$ 0.93	$ 0.81	$ 0.75	$ 0.83	$ 0.88	$ 0.82	$ 0.88	$ 3.82	$ 3.55	$ 3.41