CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
OPERATING ACTIVITIES:
Net income (loss)	$ 480,219	$ (105,680)
Adjustment for income (loss) from discontinued operations	10,616	(472)
(Loss) income from continuing operations	490,835	(106,152)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	433,521	431,667
Amortization of debt discount and debt issuance costs	798	789
Provision for bad debt	598	3,858
Stock-based compensation	23,472	19,247
Pension settlement charge		1,411
Gain from sale of property, plant and equipment	(15,133)	(17,593)
Deferred income tax benefit	(498,491)	(27,798)
Other	3,735	62
Change in assets and liabilities:
Increase in accounts receivable	(87,508)	(62,942)
Increase in inventories	(14,905)	(11,806)
(Increase) decrease in prepaid expenses and other	(5,900)	26,820
Increase in accounts payable	6,513	41,398
Increase (decrease) in accrued liabilities	30,043	(53,456)
Decrease (increase) in deferred income tax liability	(2,511)	3,070
Decrease in other noncurrent liabilities	(6,496)	(8,205)
Net cash provided by operating activities from continuing operations	358,571	240,370
Net cash used in operating activities from discontinued operations	(150)	(115)
Net cash provided by operating activities	358,421	240,255
INVESTING ACTIVITIES:
Capital expenditures	(322,658)	(300,275)
Purchase of short-term investments	(52,159)	(48,958)
Payment for acquisition of business, net of cash acquired	(47,886)	(70,416)
Proceeds from sale of short-term investments	52,470	53,150
Proceeds from asset sales	28,049	17,921
Net cash used in investing activities	(342,184)	(348,578)
FINANCING ACTIVITIES:
Dividends paid	(230,368)	(229,061)
Proceeds from stock option exercises	5,160	10,884
Payments for employee taxes on net settlement of equity awards	(5,978)	(6,274)
Net cash used in financing activities	(231,186)	(224,451)
Net decrease in cash and cash equivalents	(214,949)	(332,774)
Cash and cash equivalents, beginning of period	521,375	905,561
Cash and cash equivalents, end of period	$ 306,426	$ 572,787