SEGMENT AND GEOGRAPHIC INFORMATION - Geographic Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022	Sep. 30, 2022
SEGMENT INFORMATION
Revenues	$ 151,463	$ 140,313	$ 274,217	$ 224,524	$ 547,656
Long-Lived Assets	188,496		188,496		186,199
United States
SEGMENT INFORMATION
Revenues	129,980	117,890	228,989	190,335
Long-Lived Assets	173,540		173,540		173,417
Netherlands
SEGMENT INFORMATION
Revenues	11,522	12,119	26,744	18,655
Long-Lived Assets	6,436		6,436		5,824
Other
SEGMENT INFORMATION
Revenues	9,961	$ 10,304	18,484	$ 15,534
Long-Lived Assets	$ 8,520		$ 8,520		$ 6,958