Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net income	$ 72,831	$ 65,468
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	27,578	15,363
Amortization of debt issuance costs	1,036	681
Amortization of deferred items	(32)	393
Provision for doubtful accounts	1,871	0
Provision for inventory obsolescence	181	255
Deferred income tax benefit	(220)	(186)
Share-based compensation expense	3,048	1,790
Other, net	7	0
Changes in assets and liabilities:
(Increase) decrease in accounts receivable	22,388	(32,511)
Decrease in income tax receivable	141	1,640
(Increase) decrease in inventory	(257)	6,106
Decrease in prepaid expenses	5,470	1,378
Increase in deferred costs and other assets	(4,039)	(1,040)
Increase (decrease) in accounts payable	(27,978)	3,463
Increase (decrease) in accrued liabilities	4,937	(9,143)
Increase in income tax payable	3,603	3,249
Increase in deferred credits and other liabilities	6,354	843
Increase in Operating Capital	44,088	(7,719)
Net cash provided by operating activities	116,919	57,749
Cash flows from investing activities:
Capital expenditures	(321,995)	(257,446)
Proceeds from sale of assets	41	0
Net cash used by investing activities	(321,954)	(257,446)
Cash flows from financing activities:
Proceeds from bank credit facilities	240,000	0
Principal payments on notes payable	(5,148)	(5,461)
Proceeds from exercise of stock options	653	79
Net cash provided (used) by financing activities	235,505	(5,382)
Net increase (decrease) in cash and cash equivalents	30,470	(205,079)
Cash and cash equivalents, at beginning of period	77,871	295,002
Cash and cash equivalents, at end of period	108,341	89,923
Non-cash activities
Increase (decrease) in accounts payable and accrued liabilities related to capital expenditures	$ 22,806	$ (83,190)