Construction Partners, Inc. Quarterly report pursuant to Section 13 or 15(d)

Related Parties - Schedule of Related Party Transactions (Details) - Affiliated Entity - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021
Purchaser of Subsidiary
Related Party Transaction [Line Items]
Revenue Earned (Expense Incurred)	$ 0	$ 0	$ 0	$ 0
Accounts Receivable (Payable)	518		518		$ 518
Disposed Entity
Related Party Transaction [Line Items]
Revenue Earned (Expense Incurred)	0	0	0	0
Accounts Receivable (Payable)	330		330		330
Land Development Project
Related Party Transaction [Line Items]
Revenue Earned (Expense Incurred)	0	0	0	0
Accounts Receivable (Payable)	701		701		788
Subcontracting Services
Related Party Transaction [Line Items]
Revenue Earned (Expense Incurred)	(853)	(425)	(3,092)	(2,603)
Accounts Receivable (Payable)	(226)		(226)		(563)
Construction Services
Related Party Transaction [Line Items]
Revenue Earned (Expense Incurred)	0	119	3	119
Accounts Receivable (Payable)	0		0		0
Island Pond
Related Party Transaction [Line Items]
Revenue Earned (Expense Incurred)	(80)	(80)	(160)	(160)
Accounts Receivable (Payable)	0		0		0
Vehicles - Purchases
Related Party Transaction [Line Items]
Revenue Earned (Expense Incurred)	0	(98)	0	(408)
Accounts Receivable (Payable)	0		0		0
Vehicles - Rent Expense
Related Party Transaction [Line Items]
Revenue Earned (Expense Incurred)	0	(49)	0	(127)
Accounts Receivable (Payable)	0		0		0
SunTx
Related Party Transaction [Line Items]
Revenue Earned (Expense Incurred)	(384)	$ (521)	(759)	$ (1,138)
Accounts Receivable (Payable)	$ 0		$ 0		$ 0