SUPPLEMENTAL CASH FLOW INFORMATION (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Cash payments:
Interest paid, net of amounts capitalized	$ 28,011	$ 11,651	$ 5,377
Income taxes paid	15,577	131,128	317,599
Reconciliation of total capital expenditures incurred to total capital expenditures in the consolidated statements of cash flows
Capital expenditures incurred	241,290	1,033,241	1,045,820
Additions incurred prior year but paid for in current period	25,344	123,548	29,264
Additions incurred but not paid for as of the end of the period	(9,465)	(25,344)	(123,548)
Capital expenditures per Consolidated Condensed Statements of Cash Flows	$ 257,169	$ 1,131,445	$ 951,536