Supporting Financial Information - Estimated Amortization Expense and Weighted-Average Remaining Amortization Period of Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
2026	$ 15,720
2027	14,694
2028	14,694
2029	13,734
2030	11,637
Thereafter	21,386
Intangible assets, net	$ 91,865	$ 108,321
Finite-Lived Intangible Assets [Line Items]
Weighted-average remaining amortization period	6 years 6 months
Customer contracts and related customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted-average remaining amortization period	6 years 6 months
Backlog
Finite-Lived Intangible Assets [Line Items]
Weighted-average remaining amortization period	6 years 4 months 24 days
Trade names
Finite-Lived Intangible Assets [Line Items]
Weighted-average remaining amortization period	6 years 9 months 18 days
Covenants-not-to-compete
Finite-Lived Intangible Assets [Line Items]
Weighted-average remaining amortization period	5 years 4 months 24 days