Note 13 - Net Income Per Share - Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Net income (loss) attributable to SPAR Group, Inc.	$ (1,779)	$ 3,367
Shares used in basic net income per share calculation (in shares)	21,266	21,110
Stock options and unvested restricted shares (in shares)	0	45
Shares used in diluted net income per share calculations (in shares)	21,266	21,155
Basic net income per common share: (in dollars per share)	$ (0.08)	$ 0.16
Diluted net income per common share: (in dollars per share)	$ (0.08)	$ 0.16