v3.10.0.1
Document And Entity Information - shares
9 Months Ended
Sep. 30, 2018
Nov. 14, 2018
Document Information [Line Items]    
Entity Registrant Name SPAR GROUP INC  
Entity Central Index Key 0001004989  
Trading Symbol sgrp  
Current Fiscal Year End Date --12-31  
Entity Filer Category Non-accelerated Filer  
Entity Current Reporting Status Yes  
Entity Emerging Growth Company false  
Entity Small Business true  
Entity Common Stock, Shares Outstanding (in shares)   20,657,919
Document Type 10-Q  
Document Period End Date Sep. 30, 2018  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q3  
Amendment Flag false