Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019	Oct. 01, 2019
Supplemental disclosure of non-cash activity:
Operating lease right-of-use assets	$ 12,344	$ 13,103
Operating lease liabilities	14,154	15,333
Increase in operating leases right-of-use assets	2,905	3,104	$ 0
Increase in operating leases liabilities	2,905	3,104	0
Supplemental disclosure of cash activity:
Interest payments	74,171	71,888	101,109
Income tax payments	3,462	546	766
Tax refunds received	1,078	315	12
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	246,715	327,693	106,741
Restricted cash	27,428	14,835	16,053
Cash, Cash Equivalents, and Restricted Cash	$ 274,143	342,528	$ 122,794
Accounting Standards Update 2016-02
Supplemental disclosure of non-cash activity:
Operating lease right-of-use assets		13,895		$ 13,900
Operating lease liabilities		$ 16,028		$ 16,000