Revenue from Contracts with Customers - Additional Information (Details) - USD ($)	3 Months Ended
	Dec. 31, 2020	Dec. 28, 2019	Sep. 30, 2020
Revenue from External Customer [Line Items]
Contract with customer, asset, expected to be transferred to receivables within the next 12 months and therefore	$ 7,000,000.0
Contract with customer, asset, reclassified to receivable	5,300,000
Contract with customer, asset, increase in contract assets related to revenue recognized	5,300,000
Impairments of the contract cost asset	0	$ 0
Deferred revenue, revenue recognized	193,400,000
Deferred revenue, additions	201,000,000.0
Short term and long term accounts receivable	529,900,000		$ 511,300,000
Refund liability	37,700,000		34,500,000
Allowance for doubtful accounts receivable	500,000		500,000
Amortization expense related to costs to obtain a contract with a customer	10,400,000	$ 7,700,000
Deferred revenue	434,055,000		426,465,000
Revenue, remaining performance obligation, amount	1,375,500,000
Unrecorded
Revenue from External Customer [Line Items]
Revenue, remaining performance obligation, amount	941,400,000
Other Current Assets
Revenue from External Customer [Line Items]
Capitalized contract cost, net	36,700,000		33,900,000
Other Assets
Revenue from External Customer [Line Items]
Capitalized contract cost, net	$ 74,700,000		$ 72,900,000