Summary of Significant Accounting Policies (Details) - USD ($)	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Significant Accounting Policies [Line Items]
Foreign currency gain (loss)	$ 1,900,000	$ 1,700,000	$ (7,700,000)
Cash and cash equivalents	209,100,000	216,400,000
Software amortization	4,300,000	5,000,000.0	4,700,000
Depreciation	52,700,000	55,600,000	55,700,000
Reserve for Sales Returns, Current	50,300,000	53,500,000
Customer advance payments	1,100,000	600,000
Advertising expense	$ 127,100,000	$ 116,000,000.0	$ 125,800,000
Supplier Finance Program, Obligation, Statement of Financial Position [Extensible Enumeration]	Accounts payable	Accounts payable
Variable rate debt
Significant Accounting Policies [Line Items]
Variable rate debt outstanding	$ 34,000,000.0
Share options
Significant Accounting Policies [Line Items]
Vesting period (in years)	3 years
Minimum | Capitalized software costs
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	3 years
Minimum | Machinery and equipment
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	2 years
Minimum | Buildings and building improvements
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	3 years
Minimum | RSE awards
Significant Accounting Policies [Line Items]
Vesting period (in years)	2 years
Maximum | Capitalized software costs
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life		7 years
Maximum | Machinery and equipment
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	10 years
Maximum | Buildings and building improvements
Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life		30 years
Maximum | RSE awards
Significant Accounting Policies [Line Items]
Vesting period (in years)	4 years