Segment and Geographic Information - Revenue By Geographic Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	$ 1,933,347	$ 1,807,159	$ 1,458,415
Operating Segments
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	1,933,347	1,807,159	1,458,415
Americas | Operating Segments
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	895,095	766,021	649,383
Europe | Operating Segments
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	714,216	722,977	543,779
Asia Pacific | Operating Segments
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	$ 324,036	$ 318,161	$ 265,253