REPORTING SEGMENT AND OTHER OPERATIONS DATA - NET FINANCIAL EARNINGS (LOSS) RECONCILIATION (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting [Abstract]
Net financial earnings	$ 142,062	$ 104,106	$ 277,395	$ 144,489
Less:
Unrealized (gain) loss on derivative instruments and related transactions	(11,608)	(54,855)	(23,246)	(26,553)
Tax effect	4,716	19,679	(3,343)	9,922
Effects of economic hedging related to natural gas inventory	6,125	34,328	(19,262)	16,389
Tax effect	(1,715)	(12,334)	(6,529)	(6,130)
Net income to NFE tax adjustment	4,278	2,586	6,260	1,230
NET INCOME	140,266	$ 114,702	263,965	$ 149,631
Tax Cuts And Jobs Act Of 2017, income tax benefit	$ (967)		$ (58,532)