CONSOLIDATED CONDENSED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
OPERATING ACTIVITIES:
Net income	$ 310,683	$ 274,005
Adjustment for (income) loss from discontinued operations	(5)	55
Income from continuing operations	310,678	274,060
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	219,032	177,222
Provision for bad debt	3,792	2
Stock-based compensation	11,726	8,758
Other	772	2
Gain on sale of investment securities	(8,752)
Income from asset sales	(10,532)	(12,503)
Deferred income tax expense	20,127	100,143
Change in assets and liabilities:
Accounts receivable	13,459	(50,665)
Inventories	(6,148)	(7,003)
Prepaid expenses and other	31,046	(22,719)
Accounts payable	(70,000)	(12,253)
Accrued liabilities	(7,826)	(14,083)
Deferred income taxes	(1,211)	205
Other noncurrent liabilities	(11,855)	(2,289)
Net cash provided by operating activities from continuing operations	494,308	438,877
Net cash provided by (used in) operating activities from discontinued operations	5	(55)
Net cash provided by operating activities	494,313	438,822
INVESTING ACTIVITIES:
Capital expenditures	(438,473)	(492,701)
Proceeds from sale of investment securities	18,102
Proceeds from asset sales	16,151	25,543
Net cash used in investing activities	(404,220)	(467,158)
FINANCING ACTIVITIES:
Dividends paid	(23,469)	(15,070)
Exercise of stock options	4,906	1,895
Tax withholdings related to net share settlements of restricted stock	(1,677)	(1,514)
Excess tax benefit from stock-based compensation	7,045	3,164
Net cash used in financing activities	(13,195)	(11,525)
Net increase (decrease) in cash and cash equivalents	76,898	(39,861)
Cash and cash equivalents, beginning of period	96,095	364,246
Cash and cash equivalents, end of period	$ 172,993	$ 324,385