Note 11 - Earnings Per Share - Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Net income (loss) attributable to SPAR Group, Inc.	$ 259	$ (32)	$ 1,764	$ 1,789
Weighted-average common shares outstanding – basic (in shares)	23,237	22,227	23,201	21,873
Stock options and unvested restricted shares (in shares)	139	0	149	137
Weighted-average common shares outstanding – diluted (in shares)	23,376	22,227	23,350	22,010
Basic income per common share attributable to SPAR Group, Inc. (in dollars per share)	$ 0.01	$ (0)	$ 0.08	$ 0.08
Diluted income per common share attributable to SPAR Group, Inc. (in dollars per share)	$ 0.01	$ (0)	$ 0.08	$ 0.08