LEASES - Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
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	8.45%
Weighted average discount rate, Finance leases	4.99%
Operating lease cost
Operating lease expense	$ 11,355	$ 9,601
Short-term lease expense	6,555	9,956
Variable lease expense	3,956	3,609
Finance lease expense:
Amortization of right-of-use assets	573	607
Interest on lease liabilities	387	397
Less: sublease income	(3,923)	(9,604)
Total	$ 18,903	$ 14,566