Supplemental Cash Flow Information - Supplemental Disclosure of Non-cash Activity (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2018
Supplemental disclosure of cash activity:
Interest payments	$ 13,986	$ 10,766
Income tax payments	121	0
Tax refunds received	1,148	39
Reconciliation of cash, cash equivalents, and restricted cash:
Cash and cash equivalents	84,399	177,812	$ 139,805
Restricted cash	12,637	12,082	$ 13,443
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows	$ 97,036	$ 189,894