Note 3 - Earnings Per Share - Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Net income attributable to SPAR Group, Inc.	$ (103)	$ 1,523	$ 193	$ 2,139
Shares used in basic net income per share calculation (in shares)	21,108	20,816	21,107	20,796
Stock options and unvested restricted shares (in shares)	17	288	50	284
Shares used in diluted net income per share calculations (in shares)	21,125	21,104	21,157	21,080
Basic net income per common share: (in dollars per share)	$ 0	$ 0.07	$ 0.01	$ 0.10
Diluted net income per common share: (in dollars per share)	$ 0	$ 0.07	$ 0.01	$ 0.10