Revenue from Contracts with Customers - Revenue By Geographic Segment (Parenthetical) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Total revenue	$ 2,739,226	$ 2,298,472	$ 2,097,053
United States
Total revenue	1,287,500	1,057,300	993,800
Germany
Total revenue	$ 368,800	$ 330,500	$ 292,000