REPORTING SEGMENT AND OTHER OPERATIONS DATA - NET FINANCIAL EARNINGS (LOSS) RECONCILIATION (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting [Abstract]
Net financial earnings (loss)	$ 9,670			$ (3,551)			$ 232,264	$ 192,425
Less:
Unrealized gain on derivative instruments and related transactions	(12,970)			(17,891)			(30,502)	(58,060)
Tax effect	3,083			4,253			7,250	13,809
Effects of economic hedging related to natural gas inventory	24,116			428			36,885	25,160
Tax effect	(5,731)			(102)			(8,766)	(5,979)
Gain on equity method investment	(100)			(4,021)			(300)	(4,021)
Tax effect	24			1,003			74	1,003
NFE tax adjustment	(284)			(274)			(77)	113
NET INCOME	$ 1,532	$ 110,247	$ 115,921	$ 13,053	$ 96,035	$ 111,312	$ 227,700	$ 220,400