Supporting Financial Information - Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Sep. 30, 2022
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 163,858		$ 65,854
Total accumulated amortization	(27,129)		(24,970)
Intangible assets, net	$ 136,729		40,884
Estimated useful live of intangible assets	10 years
Amortization expense of intangible assets	$ 2,200	$ 1,600
Customer contracts and related customer relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	150,187		62,281
Total accumulated amortization	(25,622)		(23,606)
Covenants not to compete
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	637		522
Total accumulated amortization	(330)		(316)
Trade name
Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	13,034		3,051
Total accumulated amortization	$ (1,177)		$ (1,048)