REPORTING SEGMENT AND OTHER OPERATIONS DATA - NET FINANCIAL EARNINGS (LOSS) RECONCILIATION (Details) - USD ($) $ in Thousands		3 Months Ended						6 Months Ended
		Mar. 31, 2019		Dec. 31, 2018	Mar. 31, 2018		Dec. 31, 2017	Mar. 31, 2019		Mar. 31, 2018
Segment Reporting [Abstract]
Net financial earnings	[1]	$ 112,417			$ 142,062			$ 166,510		$ 277,395
Less:
Unrealized (gain) loss on derivative instruments and related transactions		10,226			(11,608)			(707)		23,246
Tax effect		(2,435)			4,716			149		(3,343)
Effects of economic hedging related to natural gas inventory		22,367			6,125			756		(19,262)
Tax effect		(5,316)			(1,715)			(180)		6,529
Net income to NFE tax adjustment		14,002			4,278			6,671		6,260
NET INCOME		$ 73,573	[1]	$ 86,248	140,266	[1]	$ 123,699	$ 159,821	[1]	263,965	[1]
Tax Cuts And Jobs Act Of 2017, income tax benefit					$ (967)					$ (58,500)

[1] Includes income tax benefit related to the Tax Act of $967,000 and $58.5 million, for the three and six months ended March 31, 2018, respectively.