REVENUE - TIMING OF REVENUE RECOGNITION (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Timing of Revenue Recognition [Roll Forward]
Customers' credit, beginning	$ 38,595	$ 44,910
Increase (decrease) for customers' credits	(7,298)	(6,315)
Customers' credit, ending	31,297	38,595
Billed
Timing of Revenue Recognition [Roll Forward]
Billed, beginning	105,531	97,540
Increase (decrease) for customer accounts receivable	3,835	7,991
Billed, end	109,366	105,531
Unbilled
Timing of Revenue Recognition [Roll Forward]
Billed, beginning	20,094	19,100
Increase (decrease) for customer accounts receivable	4,100	994
Billed, end	$ 24,194	$ 20,094