CONSOLIDATED CONDENSED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
OPERATING ACTIVITIES:
Net income	$ 159,603	$ 144,286
Adjustment for loss from discontinued operations	8	11
Income from continuing operations	159,611	144,297
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	106,599	86,288
Provision for bad debt	2	2
Stock-based compensation	6,028	3,922
Other	1
Gain on sale of investment securities	(8,752)
Income from asset sales	(5,219)	(4,683)
Deferred income tax expense	11,638	57,585
Change in assets and liabilities:
Accounts receivable	40,314	(34,851)
Inventories	(1,973)	(4,500)
Prepaid expenses and other	29,459	(24,440)
Accounts payable	(54,316)	18,383
Accrued liabilities	64,251	791
Deferred income taxes	(654)	113
Other noncurrent liabilities	(5,059)	(6,258)
Net cash provided by operating activities from continuing operations	341,930	236,649
Net cash used in operating activities from discontinued operations	(8)	(11)
Net cash provided by operating activities	341,922	236,638
INVESTING ACTIVITIES:
Capital expenditures	(219,444)	(256,943)
Proceeds from sale of investment securities	18,102
Proceeds from asset sales	7,414	10,155
Net cash used in investing activities	(193,928)	(246,788)
FINANCING ACTIVITIES:
Dividends paid	(7,432)	(7,522)
Exercise of stock options	473	373
Tax withholdings related to net share settlements of restricted stock	(1,677)	(1,514)
Excess tax benefit from stock-based compensation	5,693	2,426
Net cash used in financing activities	(2,943)	(6,237)
Net increase (decrease) in cash and cash equivalents	145,051	(16,387)
Cash and cash equivalents, beginning of period	96,095	364,246
Cash and cash equivalents, end of period	$ 241,146	$ 347,859