Segment Information - Schedule of Revenues and Long-Lived Assets by Geographic Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 1,274,280	$ 1,161,602	$ 1,049,041
Property and equipment, net	75,331	65,973
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	912,492	836,083	761,921
Property and equipment, net	37,130	35,634
Mexico
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	267,300	247,613	223,765
Property and equipment, net	27,184	21,839
Other Latin America
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	94,488	77,871	63,300
Property and equipment, net	11,017	8,500
Other Investments
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 0	$ 35	$ 55