Nature of Business and Summary of Significant Accounting Policies - New Accounting Pronouncements (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Oct. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Document Period End Date	Sep. 30, 2020
Total reported lease liability	$ 95,994
Operating lease, right-of-use asset	$ 57,656
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total reported lease liability		$ 98,900
Operating lease, right-of-use asset		$ 89,800