Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Supplemental disclosure of non-cash activity:
Increase in operating leases right-of-use assets	$ 11,309	$ 4,114	$ 10,829
Increase in operating leases liabilities	11,309	4,114	11,276
Supplemental disclosure of cash activity:
Interest payments	82,172	75,226	67,342
Income tax payments	11,751	11,359	1,956
Tax refunds received	0	0	9,987
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	214,705	203,907	345,590
Restricted cash	3,866	38,703	40,699
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows	$ 218,571	$ 242,610	$ 386,289	$ 251,828