Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Mar. 31, 2026	Mar. 31, 2025	Sep. 30, 2025
Related Party Transaction [Line Items]
Total revenues	$ 442,293	$ 483,521	$ 822,854	$ 859,335
Accounts receivable, net	60,661		60,661		$ 60,885
Accounts payable	40,457		40,457		43,758
Tax receivable agreement liability	37,500		37,500		37,500
Affiliated Entities and Individuals
Related Party Transaction [Line Items]
Total revenues	300	600	800	2,800
Affiliated Entity
Related Party Transaction [Line Items]
Purchase of inventories	35,700	38,000	76,400	90,400
Expenses incurred	800	$ 600	1,600	$ 2,100
Accounts receivable, net	100		100		0
Accounts payable	1,600		1,600		4,900
Tax receivable agreement liability	$ 33,500		$ 33,500		$ 33,500