INCOME TAXES (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Current:
Federal	$ (36,260)	$ (86,010)	$ 84,229
Foreign	4,108	9,987	14,864
State	(472)	(3,742)	10,881
Total current	(32,624)	(79,765)	109,974
Deferred:
Federal	(14,953)	58,136	165,491
Foreign	(7,827)	408	(34,410)
State	(1,331)	1,544	350
Total deferred	(24,111)	60,088	131,431
Total provision (benefit)	(56,735)	(19,677)	241,405
Amounts of domestic and foreign income before income taxes
Domestic	(173,157)	(49,636)	675,425
Foreign	(11,441)	(23,031)	(13,546)
Income (loss) from continuing operations before income taxes	(184,598)	(72,667)	$ 661,879
Deferred tax liabilities:
Property, plant and equipment	1,386,512	1,411,139
Available-for-sale securities	24,940	25,470
Other	21,609	2,326
Total deferred tax liabilities	1,433,061	1,438,935
Deferred tax assets:
Pension reserves	7,614	8,330
Self-insurance reserves	19,461	15,282
Net operating loss, foreign tax credit, and other federal tax credit carryforwards	62,478	71,778
Financial accruals	62,971	67,594
Other	6,003	4,952
Total deferred tax assets	158,527	167,936
Valuation allowance	(58,155)	(71,457)
Net deferred tax assets	100,372	96,479
Net deferred tax liabilities	$ 1,332,689	$ 1,342,456