Quarterly report pursuant to Section 13 or 15(d)

Cover Page

v3.20.2
Cover Page - shares
 9 Months Ended
Jun. 30, 2020
Aug. 05, 2020
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2020  
Document Transition Report false  
Entity File Number 001-38479  
Entity Registrant Name Construction Partners, Inc.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 26-0758017  
Entity Address, Address Line One 290 Healthwest Drive, Suite 2  
Entity Address, City or Town Dothan  
Entity Address, State or Province AL  
Entity Address, Postal Zip Code 36303  
City Area Code 334  
Local Phone Number 673-9763  
Title of 12(b) Security Class A common stock, par value $0.001 per share  
Trading Symbol ROAD  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period true  
Entity Shell Company false  
Amendment Flag false  
Document Fiscal Year Focus 2020  
Document Fiscal Period Focus Q3  
Entity Central Index Key 0001718227  
Current Fiscal Year End Date --09-30  
Class A Common Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding (in shares)   33,875,884
Class B Common Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding (in shares)   17,905,861