LEASES - RIGHT-OF-USE ASSETS AND LEASE LIABILITIES (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Sep. 30, 2020
NONCURRENT ASSETS
Operating lease assets	$ 144,326	$ 131,769
Finance lease assets	61,432	71,085
Total lease assets	205,758	202,854
Current
Operating lease liabilities	4,001	6,724
Finance lease liabilities	5,855	10,416
Noncurrent
Operating lease liabilities	111,034	95,030
Finance lease liabilities	62,334	63,743
Total lease liabilities	$ 183,224	$ 175,913