Revenue from Contracts with Customers - Disaggregated By Geographic Location (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 220,350	$ 203,880	$ 651,077	$ 581,637
North America
Disaggregation of Revenue [Line Items]
Total revenue	79,882	88,744	246,000	240,796
Asia/Pacific/Other
Disaggregation of Revenue [Line Items]
Total revenue	99,415	77,275	307,969	234,388
United Kingdom
Disaggregation of Revenue [Line Items]
Total revenue	15,441	13,879	35,745	38,497
Rest of Europe
Disaggregation of Revenue [Line Items]
Total revenue	$ 25,612	$ 23,982	$ 61,363	$ 67,956