Supporting Financial Information - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Finite-Lived Intangible Assets [Line Items]
Amortization expense of intangible assets	$ 4.1	$ 4.1	$ 12.3	$ 12.3
Intangible assets, remaining amortization period	6 years 8 months 12 days		6 years 8 months 12 days
Depreciation	$ 0.2	$ 0.2	$ 0.5	$ 0.4
Disposition of equipment and improvements	3.9
Cash proceeds from disposition of assets	$ 0.0
Customer contracts and related customer relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets, remaining amortization period	6 years 8 months 12 days		6 years 8 months 12 days
Backlog
Finite-Lived Intangible Assets [Line Items]
Intangible assets, remaining amortization period	6 years 7 months 6 days		6 years 7 months 6 days
Trade name
Finite-Lived Intangible Assets [Line Items]
Intangible assets, remaining amortization period	7 years		7 years
Covenants-not-to-compete
Finite-Lived Intangible Assets [Line Items]
Intangible assets, remaining amortization period	5 years 3 months 18 days		5 years 3 months 18 days