Supplemental Cash Flow Information - Supplemental Disclosure of Non-cash Activity (Details) - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2018
Supplemental disclosure of cash activity:
Interest payments	$ 64,648	$ 60,025
Income tax payments	568	495
Tax refunds received	12	39
Reconciliation of cash, cash equivalents, and restricted cash:
Cash and cash equivalents	68,491	136,298	$ 139,805
Restricted cash	16,293	12,167	$ 13,443
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows	$ 84,784	$ 148,465