Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net loss	$ (435,534)	$ (74,833)
Adjustment for (income) loss from discontinued operations	(212)	433
Loss from continuing operations	(435,746)	(74,400)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	372,298	427,917
Asset impairment charge	563,234	224,327
Restructuring charges	3,536	0
Amortization of debt discount and debt issuance costs	1,358	1,176
Provision for bad debt	4,151	544
Stock-based compensation	32,059	25,467
Loss on investment securities	7,325	50,228
Gain on sale of assets	(18,790)	(27,050)
Gain on sale of subsidiary	(14,963)	0
Deferred income tax benefit	(122,366)	(25,503)
Other	(2,891)	5,356
Change in assets and liabilities:
Accounts receivable	189,280	63,002
Inventories of materials and supplies	(1,657)	1,473
Prepaid expenses and other	3,051	(9,556)
Other noncurrent assets	5,343	(5,899)
Accounts payable	(16,170)	276
Accrued liabilities	(118,178)	8,110
Deferred income tax liability	892	11
Other noncurrent liabilities	(5,475)	(6,052)
Net cash provided by operating activities from continuing operations	446,291	659,427
Net cash used in operating activities from discontinued operations	(38)	(56)
Net cash provided by operating activities	446,253	659,371
Cash flows from investing activities:
Capital expenditures	(120,960)	(403,570)
Purchase of short-term investments	(78,303)	(71,852)
Payment for acquisition of business, net of cash acquired	0	(2,781)
Proceeds from sale of short-term investments	66,033	68,015
Proceeds from sale of subsidiary	15,056	0
Proceeds from asset sales	31,200	36,227
Other	(50)	0
Net cash used in investing activities	(87,024)	(373,961)
Cash flows from financing activities:
Dividends paid	(233,124)	(235,058)
Debt issuance costs paid	0	(3,912)
Proceeds from stock option exercises	4,100	2,901
Payments for employee taxes on net settlement of equity awards	(3,752)	(6,420)
Payment of contingent consideration from acquisition of business	(4,250)	0
Share repurchases	(28,504)	0
Other	(446)	0
Net cash used in financing activities	(265,976)	(242,489)
Net increase in cash and cash equivalents and restricted cash	93,253	42,921
Cash and cash equivalents and restricted cash, beginning of period	382,971	326,185
Cash and cash equivalents and restricted cash, end of period	476,224	369,106
Cash paid during the period:
Interest paid	11,511	12,794
Income tax paid, net	43,629	11,213
Payments for operating leases	13,945	0
Changes in accounts payable and accrued liabilities related to purchases of property, plant and equipment	$ 2,251	$ 16,279