Related Party Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Sep. 30, 2024
Related Party Transaction [Line Items]
Total revenues	$ 552,864	$ 542,441	$ 1,412,199	$ 1,394,775
Accounts receivable, net	79,472		79,472		$ 73,269
Accounts payable	32,452		32,452		32,106
Tax receivable agreement liability	40,800		40,800		40,600
Affiliated Entities and Individuals
Related Party Transaction [Line Items]
Total revenues	500	100	3,300	1,400
Costs and expenses, related party	0	100	200	100
Affiliated Entity
Related Party Transaction [Line Items]
Purchase of inventories	28,400	32,300	118,800	103,800
Expenses incurred	800	$ 600	2,800	$ 1,800
Accounts receivable, net	2,500		2,500		0
Accounts payable	200		200		6,000
Tax receivable agreement liability	$ 36,400		$ 36,400		$ 36,200