LEASES - RIGHT-OF-USE ASSETS AND LEASE LIABILITIES (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 30, 2020
NONCURRENT ASSETS
Operating lease assets	$ 138,633	$ 131,769
Finance lease assets	69,839	71,085
Total lease assets	208,472	202,854
Current
Operating lease liabilities	4,397	6,724
Finance lease liabilities	10,164	10,416
Noncurrent
Operating lease liabilities	104,970	95,030
Finance lease liabilities	59,345	63,743
Total lease liabilities	$ 178,876	$ 175,913