Revenue from Contracts with Customers - Contract Assets and Liabilities (Details) $ in Thousands	9 Months Ended
	Jun. 30, 2020 USD ($)
Change in Contract with Customer, Asset [Roll Forward]
Beginning Balance	$ 132,492
Revenue recognized during period but not yet billed	22,213
Contract asset additions	80,243
Contract assets acquired through the purchase of Shape	6,045
Contract assets reclassified to accounts receivable	(62,523)
Ending Balance	178,470
Change in Contract with Customer, Liability [Roll Forward]
Beginning Balance	1,198,116
Amounts billed but not recognized as revenues	740,050
Amounts acquired through the purchase of Shape	39,000
Revenues recognized related to the opening balance of deferred revenue	(702,114)
Ending Balance	$ 1,275,052