INCOME TAXES (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Operating Loss Carryforwards
Amount of foreign tax credit carryforwards for income tax purposes	$ 50,300
Deferred tax asset prior to consideration of valuation allowance	39,300
Current:
Federal	(86,010)	$ 84,229	$ 323,386
Foreign	9,987	14,864	17,333
State	(3,742)	10,881	21,197
Total current	(79,765)	109,974	361,916
Deferred:
Federal	58,136	165,491	28,183
Foreign	408	(34,410)	(4,257)
State	1,544	350	2,206
Total deferred	60,088	131,431	26,132
Total provision	(19,677)	241,405	388,048
Amounts of domestic and foreign income before income taxes
Domestic	(49,636)	675,425	1,061,019
Foreign	(23,031)	(13,546)	33,639
Income (loss) from continuing operations before income taxes	(72,667)	661,879	$ 1,094,658
Deferred tax liabilities:
Property, plant and equipment	1,411,139	1,335,680
Available-for-sale securities	25,470	33,187
Other	2,326	3,929
Total deferred tax liabilities	1,438,935	1,372,796
Deferred tax assets:
Pension reserves	8,330	3,405
Self-insurance reserves	15,282	14,317
Net operating loss and foreign tax credit carryforwards	71,778	56,494
Financial accruals	67,594	63,558
Other	4,952	12,283
Total deferred tax assets	167,936	150,057
Valuation allowance	(71,457)	(55,971)
Net deferred tax assets	96,479	94,086
Net deferred tax liabilities	$ 1,342,456	$ 1,278,710
Effective income tax rates as compared to the U.S. Federal income tax rate
U.S. Federal income tax rate (as a percent)	35.00%	35.00%	35.00%
Effect of foreign taxes (as a percent)	(13.80%)	(3.20%)	1.30%
State income taxes, net of federal tax benefit (as a percent)	3.20%	0.80%	1.40%
U.S. domestic production activities (as a percent)	10.40%	1.20%	2.60%
Other impact of foreign operations	14.70%	4.50%	0.60%
Other (as a percent)	(1.60%)	0.60%	(0.20%)
Effective income tax rate (as a percent)	27.10%	36.50%	35.50%
Accrued interest and penalties related to unrecognized tax benefits	$ 6,800	$ 11,100
Reconciliation of the change in gross unrecognized tax benefits
Unrecognized tax benefits at the beginning of the period	11,211	11,211	$ 10,747
Gross decreases - tax positions in prior periods		(706)
Gross increases - tax positions in prior periods		3,278
Gross decreases - current period effect of tax positions	(1,173)	(821)
Gross increases - current period effect of tax positions	969
Expiration of statute of limitations for assessments	(679)	(956)
Settlements	(777)	(331)
Unrecognized tax benefits at the end of the period	9,551	11,211	$ 11,211
Unrecognized tax benefits related to discontinued operations	3,800	$ 2,900
State and Local jurisdiction
Operating Loss Carryforwards
Amount of net operating loss carryforwards for income tax purposes	11,600
Net operating loss carryforward, valuation allowance	1,000
Foreign jurisdiction
Operating Loss Carryforwards
Amount of net operating loss carryforwards for income tax purposes	94,000
Net operating loss carryforward, valuation allowance	31,100
Foreign tax carryforwards which more likely than not will not be utilized	$ 39,300