Supplemental Cash Flow Information - Supplemental Disclosure of Non-cash Activity (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Supplemental disclosure of cash activity:
Interest payments	$ 25,261	$ 24,524
Income tax payments	380	0
Tax refunds received	0	59
Reconciliation of cash, cash equivalents, and restricted cash:
Cash and cash equivalents	104,226	120,746	$ 345,590
Restricted cash	34,098	35,899	40,699
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows	$ 138,324	$ 156,645	$ 386,289	$ 251,828