Note 5 - Supplemental Disclosure for Earnings Per Share - Supplemental Disclosure for Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Net income attributable to First Capital, Inc.	$ 2,939	$ 2,094
Weighted average common shares outstanding (in shares)	3,342,492	3,336,459
Net income attributable to First Capital, Inc. per common share, basic (in dollars per share)	$ 0.88	$ 0.63
Net income attributable to First Capital, Inc.	$ 2,939	$ 2,094
Weighted average common shares outstanding (in shares)	3,342,492	3,336,459
Add: Dilutive effect of restricted stock (in shares)	5,275	13,257
Weighted average common shares outstanding, as adjusted (in shares)	3,347,767	3,349,716
Net income attributable to First Capital, Inc. per common share, diluted (in dollars per share)	$ 0.88	$ 0.63