Summary of Significant Accounting Policies - COGS (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Selling, general and administrative expenses
Cost of Goods Sold
Storage and other warehousing costs	$ 37.3	$ 25.3	$ 20.1