CONSOLIDATED CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
OPERATING ACTIVITIES:
Net income (loss)	$ (35,063)	$ 16,002
Adjustment for (income) loss from discontinued operations	509	(104)
Income (loss) from continuing operations	(34,554)	15,898
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	133,847	142,129
Amortization of debt discount and debt issuance costs	263	255
Provision for bad debt	2,350	6
Stock-based compensation	5,901	7,921
Other	10	233
Income from asset sales	(842)	(4,589)
Deferred income tax expense	(17,073)	20,169
Change in assets and liabilities:
Accounts receivable	46,048	72,083
Inventories	(1,721)	1,299
Prepaid expenses and other	7,288	(3,657)
Accounts payable	15,883	(10,554)
Accrued liabilities	(69,733)	74,170
Deferred income taxes	(1,153)	3,487
Other noncurrent liabilities	(15,827)	(10,758)
Net cash provided by operating activities from continuing operations	70,687	308,092
Net cash provided by (used in) operating activities from discontinued operations	(19)	104
Net cash provided by operating activities	70,668	308,196
INVESTING ACTIVITIES:
Capital expenditures	(82,127)	(114,470)
Purchase of short-term investments	(15,025)	(6,918)
Proceeds from sales of short-term investments	13,900	4,600
Proceeds from asset sales	1,209	6,058
Net cash used in investing activities	(82,043)	(110,730)
FINANCING ACTIVITIES:
Debt issuance costs		(32)
Dividends paid	(76,176)	(74,560)
Exercise of stock options, net of tax withholding	9,827	(59)
Tax withholdings related to net share settlements of restricted stock	(5,647)	(3,617)
Excess tax benefit from stock-based compensation	3,703	(352)
Net cash used in financing activities	(68,293)	(78,620)
Net increase (decrease) in cash and cash equivalents	(79,668)	118,846
Cash and cash equivalents, beginning of period	905,561	729,384
Cash and cash equivalents, end of period	$ 825,893	$ 848,230