Note 8 - Earnings Per Share - Summary of Earnings and Weighted Average Number of Common Shares Used in Calculation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Basic:
Weighted average common shares outstanding (in shares)	15,393,782	15,310,142	15,410,222
Net income attributable to common stockholders of National Healthcare Corporation	$ 101,927	$ 66,798	$ 22,445
Earnings per common share, basic (in dollars per share)	$ 6.62	$ 4.36	$ 1.46
Diluted:
Weighted average common shares outstanding (in shares)	15,393,782	15,310,142	15,410,222
Dilutive effect of stock options (in shares)	204,746	67,201	36,989
Assumed average common shares outstanding (in shares)	15,598,528	15,377,343	15,447,211
Net income attributable to common stockholders of National Healthcare Corporation	$ 101,927	$ 66,798	$ 22,445
Earnings per common share, diluted (in dollars per share)	$ 6.53	$ 4.34	$ 1.45