XML 52 R1.htm IDEA: XBRL DOCUMENT v3.19.3
Document And Entity Information - shares
 9 Months Ended
Sep. 30, 2019
Nov. 11, 2019
Document Information [Line Items]    
Entity Registrant Name BOSTON OMAHA Corp  
Entity Central Index Key 0001494582  
Trading Symbol bomn  
Current Fiscal Year End Date --12-31  
Entity Filer Category Accelerated Filer  
Entity Current Reporting Status Yes  
Entity Emerging Growth Company false  
Entity Small Business true  
Entity Shell Company false  
Document Type 10-Q  
Document Period End Date Sep. 30, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q3  
Amendment Flag false  
Title of 12(b) Security Common Stock ($0.001 par value)  
Common Class B [Member]    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding (in shares)   1,055,560
Common Class A [Member]    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding (in shares)   22,323,772