Revenue from Contracts with Customers - Revenue By Geographic Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	$ 636,366	$ 603,072	$ 1,201,494	$ 1,153,286
Operating Segments
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	636,366	603,072	1,201,494	1,153,286
Americas | Operating Segments
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	292,823	260,622	570,792	527,889
Europe | Operating Segments
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	251,148	257,309	447,172	454,262
Asia-Pacific | Operating Segments
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue	$ 92,395	$ 85,141	$ 183,530	$ 171,135