Segment and Geographic Information - Classification of Revenue by Major Geographic Areas (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Total segment revenues	$ 321,435	$ 345,753
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total segment revenues	259,776	272,598
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Total segment revenues	$ 61,659	$ 73,155