Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
NET LOSS	$ (56,338)	$ (191,434)
Adjustment for (income) loss from discontinued operations	383	(9,786)
Loss from continuing operations	(55,955)	(201,220)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	203,374	213,278
Asset impairment charge	4,363	54,284
Amortization of debt discount and debt issuance costs	559	920
Loss on extinguishment of debt	60,083	0
Provision for credit loss	669	(227)
Provision for obsolete inventory	(761)	423
Stock-based compensation	14,163	14,277
Gain on investment securities	(69,994)	(5,444)
Gain on reimbursement of drilling equipment	(11,702)	(5,939)
Other loss on sale of assets	313	12,118
Deferred income tax benefit	(11,597)	(46,068)
Other	(3,526)	3,646
Change in assets and liabilities:
Accounts receivable	(103,751)	(8,498)
Inventories of materials and supplies	158	7,159
Prepaid expenses and other	(4,068)	(7,951)
Other noncurrent assets	10,375	(3,696)
Accounts payable	32,138	25,277
Accrued liabilities	(29,322)	(451)
Deferred income tax liability	196	27
Other noncurrent liabilities	(16,777)	6,912
Net cash provided by operating activities from continuing operations	18,938	58,827
Net cash used in operating activities from discontinued operations	(42)	(25)
Net cash provided by operating activities	18,896	58,802
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(104,482)	(30,745)
Other capital expenditures related to assets held-for-sale	(10,550)	0
Purchase of short-term investments	(68,565)	(105,662)
Purchase of long-term investments	(14,124)	(1,069)
Proceeds from sale of short-term investments	117,456	63,742
Proceeds from asset sales	34,944	13,419
Net cash used in investing activities	(45,321)	(60,315)
CASH FLOWS FROM FINANCING ACTIVITIES:
Dividends paid	(54,007)	(54,230)
Payments for employee taxes on net settlement of equity awards	(5,503)	(2,119)
Payment of contingent consideration from acquisition of business	(250)	(250)
Payments for early extinguishment of long-term debt	(487,148)	0
Make-whole premium payment	(56,421)	0
Share repurchases	(76,999)	0
Other	(587)	0
Net cash used in financing activities	(680,915)	(56,599)
Net decrease in cash and cash equivalents and restricted cash	(707,340)	(58,112)
Cash and cash equivalents and restricted cash, beginning of period	936,716	536,747
Cash and cash equivalents and restricted cash, end of period	229,376	478,635
Cash paid during the period:
Interest paid	10,798	11,473
Income tax paid (received), net	633	(31,965)
Payments for operating leases	6,069	8,970
Non-cash operating and investing activities:
Changes in accounts payable and accrued liabilities related to purchases of property, plant and equipment	(2,431)	(1,296)
Changes in accounts receivable, property, plant and equipment and other noncurrent assets related to the sale of equipment	0	9,290
Cumulative effect adjustment for adoption of ASU No. 2016-13	$ 0	$ (1,251)