Contingencies and Commitments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020	Dec. 29, 2020	Sep. 30, 2020
Operating Leases [Abstract]
Rent expense	$ 3,900	$ 3,100	$ 7,000	$ 6,100
Lease term	1 year		1 year
Acquisition Contingent Consideration [Abstract]
Contingent consideration	$ 5,500		$ 5,500			$ 5,500
Contingent consideration transaction final payout					$ 5,900
Loss on contingent consideration	$ 0	$ 0	$ 377	$ 0