Note 11 - Earnings Per Share - Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Net income attributable to SPAR Group, Inc.	$ 6,627	$ 866
Weighted-average common shares outstanding – basic (in shares)	23,817	23,114
Stock options and unvested restricted shares (in shares)	196	165
Weighted-average common shares outstanding – diluted (in shares)	24,013	23,279
Basic income per common share attributable to SPAR Group, Inc. (in dollars per share)	$ 0.28	$ 0.04
Diluted income per common share attributable to SPAR Group, Inc. (in dollars per share)	$ 0.28	$ 0.04