Note 28 - Selected Quarterly Financial Information (Unaudited) - Selected Quarterly Financial Information (Unaudited) (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
Interest income	$ 11,639	$ 11,179	$ 10,600	$ 10,187	$ 9,789	$ 9,048	$ 7,898	$ 7,205	$ 7,290	$ 7,745	$ 7,133	$ 7,292	$ 43,605	$ 33,940	$ 29,460
Interest expense	3,091	2,642	2,288	996	684	390	267	253	273	278	289	288	9,017	1,594	1,128
Net interest income	8,548	8,537	8,312	9,191	9,105	8,658	7,631	6,952	7,017	7,467	6,844	7,004	34,588	32,346	28,332
Provision for (recapture of) credit losses	308	290	350	193					(400)	0	0	75	1,141	950	(325)
Net interest income after provision for credit losses	8,240	8,247	7,962	8,998	8,705	8,483	7,431	6,777	7,417	7,467	6,844	6,929	33,447	31,396	28,657
Noninterest income	1,831	1,947	1,863	1,991	1,942	1,873	1,965	2,147	2,291	2,270	2,552	2,438	7,632	7,927	9,551
Noninterest expenses	6,480	6,481	6,666	6,401	6,300	6,559	6,235	5,994	6,357	6,202	6,165	5,807	26,028	25,088	24,531
Income before income taxes	3,591	3,713	3,159	4,588	4,347	3,797	3,161	2,930	3,351	3,535	3,231	3,560	15,051	14,235	13,677
Income tax expense	478	572	429	769	804	669	447	400	529	596	497	618	2,248	2,320	2,240
Net income	3,113	3,141	2,730	3,819	3,543	3,128	2,714	2,530	2,822	2,939	2,734	2,942	12,803	11,915	11,437
Less: net income attributable to noncontrolling interest in subsidiary	3	3	4	3	3	3	4	3	3	3	4	3	13	13	13
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
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
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
Provision for loan losses					$ 400	$ 175	$ 200	$ 175