REPORTING SEGMENT AND OTHER OPERATIONS DATA - NET FINANCIAL EARNINGS (LOSS) RECONCILIATION (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting [Abstract]
Net financial (loss) earnings	$ (8,899)			$ 9,670			$ 202,121	$ 232,264
Less:
Unrealized loss (gain) on derivative instruments and related transactions	3,803			(12,970)			23,860	(30,502)
Tax effect	(903)			3,083			(5,670)	7,250
Effects of economic hedging related to natural gas inventory	(385)			24,116			(19,458)	36,885
Tax effect	91			(5,731)			4,624	(8,766)
Gain on equity method investment	0			(100)			0	(300)
Tax effect	0			24			0	74
NFE tax adjustment	69			(284)			116	(77)
NET (LOSS) INCOME	$ (11,574)	$ 120,812	$ 89,411	$ 1,532	$ 110,247	$ 115,921	$ 198,649	$ 227,700