GOODWILL AND INTANGIBLE ASSETS - Intangible Assets (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Mar. 31, 2024	Sep. 30, 2023
Indefinite Lived Intangible Assets By Major Class [Line Items]
Cost	$ 128,617	$ 128,617
Accumulated Amortization	69,766	63,943
Total	$ 58,851	$ 64,674
Completed technologies
Indefinite Lived Intangible Assets By Major Class [Line Items]
Weighted Average Amortization Period (in years)	6 years 10 months 24 days	6 years 10 months 24 days
Cost	$ 95,761	$ 95,761
Accumulated Amortization	43,715	39,254
Total	$ 52,046	$ 56,507
Customer relationships
Indefinite Lived Intangible Assets By Major Class [Line Items]
Weighted Average Amortization Period (in years)	4 years 8 months 12 days	4 years 8 months 12 days
Cost	$ 25,168	$ 25,168
Accumulated Amortization	22,187	21,396
Total	$ 2,981	$ 3,772
Trade names
Indefinite Lived Intangible Assets By Major Class [Line Items]
Weighted Average Amortization Period (in years)	5 years	5 years
Cost	$ 7,088	$ 7,088
Accumulated Amortization	3,452	2,967
Total	$ 3,636	$ 4,121
Covenants not to compete
Indefinite Lived Intangible Assets By Major Class [Line Items]
Weighted Average Amortization Period (in years)	3 years	3 years
Cost	$ 600	$ 600
Accumulated Amortization	412	326
Total	$ 188	$ 274