Segment Information - Schedule of Revenues and Long-Lived Assets by Geographic Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 1,161,602	$ 1,049,041	$ 886,225
Property and equipment, net	65,973	68,096
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	836,083	761,921	658,762
Property and equipment, net	35,634	37,695
Mexico
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	247,613	223,765	173,122
Property and equipment, net	21,839	24,033
Other Latin America
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	77,871	63,300	54,230
Property and equipment, net	8,500	6,368
Other Investments
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 35	$ 55	$ 111