Contract Balances and Performance Obligation - Contract Balances (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Contract With Customer, Liability [Roll Forward]
Beginning balance	$ 116,320	$ 108,118
Revenue recognized that was included in the deferred revenues balance at the beginning of the period	(47,934)	(53,339)
Increases due to billings, excluding amounts recognized as revenue during the period	51,291	53,388
Ending balance	119,677	108,167
Deferred revenue and other liabilities, current portion	114,700	103,600
Deferred revenue and other liabilities, noncurrent	$ 5,000	$ 4,600