Contract Balance - Deferred Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Contract with Customer, Liability	$ 103,336	$ 122,789	$ 110,763	$ 122,141
Revenue recognized that was included in the deferred revenues balance at the beginning of the period	(45,942)	(47,793)
Increases due to billings, excluding amounts recognized as revenue during the period	38,515	$ 48,441
Deferred revenue, current portion	98,400		105,400
Deferred revenue, noncurrent	$ 4,900		$ 5,400