Basis of Presentation and Accounting Policies - Narrative (Details) - USD ($) shares in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021
Accounting Policies [Abstract]
Allowance for doubtful accounts	$ 14,000,000		$ 14,000,000		$ 13,200,000
Allowance for certain customer returns, rebates and incentives	$ 9,200,000		$ 9,200,000		$ 6,700,000
Antidilutive share-based compensation awards (in shares)	0.3	0.2	0.3	0.2
Capital expenditures in accounts payable or other current liabilities at period end			$ 8,100,000	$ 15,500,000
Outstanding purchase of common stock recorded in accounts payable			$ 0	$ 2,800,000