LEASES - Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2018
Lease, Cost [Abstract]
Weighted average remaining lease term, Operating leases	22 years
Weighted average remaining lease term, Finance leases	18 years
Weighted average discount rate, Operating leases	8.48%
Weighted average discount rate, Finance leases	4.99%
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member	us-gaap:AccountingStandardsUpdate201409Member
Operating lease expense
Operating lease expense	$ 38,414
Short-term lease expense	27,121
Variable lease expense	12,922
Finance lease expense:
Amortization of ROU assets	2,401
Interest on lease liabilities	1,547
Less: sublease income	(20,791)
Total	$ 61,614