SUPPLEMENTAL CASH FLOW INFORMATION (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Current assets:
Accounts receivable	$ (13,423)	$ 24,055	$ 8,779
Inventories	(12,839)	5,976	830
Other current assets	(15,618)	(14,803)	10,317
Total change in current assets	(41,880)	15,228	19,926
Current liabilities:
Trade accounts payable	29,621	8,363	3,715
Accrued compensation	10,791	15,512	(8,832)
Accrued income taxes	601	(2,384)	(5,416)
Other current liabilities	13,849	9,648	(21,875)
Total change in current liabilities	54,862	31,139	(32,408)
Net change	$ 12,982	$ 46,367	$ (12,482)