Construction Partners, Inc. Quarterly report [Sections 13 or 15(d)]

Quarterly report [Sections 13 or 15(d)]

Debt - Additional Information (Details)

Debt - Additional Information (Details)		3 Months Ended	9 Months Ended
Debt - Additional Information (Details)	Nov. 01, 2024 USD ($)	Dec. 31, 2024 USD ($)	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)	Sep. 30, 2024 USD ($)	Jun. 30, 2022 USD ($)
Debt Instrument [Line Items]
Fixed coverage ratio			6.45		11.32
Leverage ratio			3.17		1.80
Notional amount			$ 300,000,000		$ 300,000,000
Fair value of interest rate swaps			9,400,000		11,600,000
Proceeds from revolving credit facility			218,438,000	$ 149,385,000
Term Loan B
Debt Instrument [Line Items]
Long-term debt			845,800,000		0
Term Loan A
Debt Instrument [Line Items]
Long-term debt			$ 600,000,000		392,200,000
Secured Debt \| Term Loan A/Revolver Credit Agreement \| Revolving Credit Facility \| Minimum
Debt Instrument [Line Items]
Fixed coverage ratio			3.00
Secured Debt \| Term Loan A/Revolver Credit Agreement \| Revolving Credit Facility \| Maximum \| Each fiscal quarter ending on or prior to December 31, 2025
Debt Instrument [Line Items]
Leverage ratio			4.50
Secured Debt \| Term Loan A/Revolver Credit Agreement \| Revolving Credit Facility \| Maximum \| Each fiscal quarter ending March 31, 2026 through and including September 30, 2026
Debt Instrument [Line Items]
Leverage ratio			4.25
Secured Debt \| Term Loan A/Revolver Credit Agreement \| Revolving Credit Facility \| Maximum \| Each fiscal quarter ending December 31, 2026 through and including June 30, 2027
Debt Instrument [Line Items]
Leverage ratio			4.00
Secured Debt \| Term Loan A/Revolver Credit Agreement \| Revolving Credit Facility \| Maximum \| Each fiscal quarter ending September 30, 2027 and thereafter
Debt Instrument [Line Items]
Leverage ratio			3.75
Secured Debt \| Term Loan A \| Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity						$ 600,000,000
Secured Debt \| Term Loan - 11 Quarters \| Revolving Credit Facility
Debt Instrument [Line Items]
Principal repayment rate			1.25%
Secured Debt \| Term Loan B Credit Agreement \| Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity	$ 850,000,000
Principal repayment rate	0.25%
Proceeds from revolving credit facility	$ 850,000,000
Secured Debt \| Term Loan B Credit Agreement \| Revolving Credit Facility \| Term SOFR \| Variable Rate Component One
Debt Instrument [Line Items]
Basis spread	1.00%
Secured Debt \| Term Loan B Credit Agreement \| Revolving Credit Facility \| Term SOFR \| Variable Rate Component Two
Debt Instrument [Line Items]
Basis spread	2.50%
Secured Debt \| Term Loan B Credit Agreement \| Revolving Credit Facility \| Fed Funds Effective Rate Overnight Index Swap Rate
Debt Instrument [Line Items]
Basis spread	0.50%
Secured Debt \| Term Loan B Credit Agreement \| Revolving Credit Facility \| Base Rate \| Variable Rate Component One
Debt Instrument [Line Items]
Basis spread	1.00%
Secured Debt \| Term Loan B Credit Agreement \| Revolving Credit Facility \| Base Rate \| Variable Rate Component Two
Debt Instrument [Line Items]
Basis spread	1.50%
Secured Debt \| Bridge Facility
Debt Instrument [Line Items]
Interest expense		$ 3,100,000
Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity			$ 500,000,000
Long-term debt			0		122,900,000
Remaining borrowing capacity			$ 493,500,000		$ 268,800,000
Revolving Credit Facility \| Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity						$ 500,000,000