Summary of Significant Accounting Policies (Details) - USD ($)	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Significant Accounting Policies [Line Items]
Foreign currency gain (loss)	$ (1,700,000)	$ 7,700,000	$ 500,000
Cash and cash equivalents	216,400,000	188,700,000
Software amortization	5,000,000.0	4,700,000	4,500,000
Depreciation	55,600,000	55,700,000	60,600,000
Reserve for Sales Returns, Current	53,500,000	47,500,000
Customer advance payments	600,000	1,100,000
Advertising expense	116,000,000.0	$ 125,800,000	$ 142,300,000
Variable rate debt
Significant Accounting Policies [Line Items]
Variable rate debt outstanding	$ 122,000,000.0
Share options
Significant Accounting Policies [Line Items]
Vesting period (in years)	3 years
Minimum
Significant Accounting Policies [Line Items]
Useful life assigned to definite lived trade names	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
Significant Accounting Policies [Line Items]
Useful life assigned to definite lived trade names	25 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