Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
CASH FLOW FROM OPERATING ACTIVITIES:
Net income	$ 124,934	$ 123,462
Adjustments to reconcile net cash provided by operating activities:
Depreciation	30,769	17,596
Amortization of debt issuance costs	1,562	404
Amortization of deferred items	791	3,941
Provision for inventory obsolescence	435	314
Deferred income tax benefit	(425)	(443)
Share-based compensation expense	4,931	3,316
Other, net	863	(77)
Changes in assets and liabilities:
Increase in accounts receivable	(765)	(5,614)
Decrease in income tax receivable	1,764	8,960
Increase in inventory	(3,003)	(3,378)
Decrease in prepaid expenses	6,285	5,444
Increase in deferred costs and other assets	(14,220)	(7,690)
Increase in accounts payable	10,465	245
Increase (decrease) in accrued liabilities	(7,337)	1,473
Increase (decrease) in income tax payable	4,680	(12,162)
Increase (decrease) in deferred credits and other liabilities	(5,441)	37,842
Net cash provided by operating activities	156,288	173,633
CASH FLOW FROM INVESTING ACTIVITIES:
Capital expenditures	(397,444)	(420,829)
Proceeds from sale of assets		115
Net cash used by investing activities	(397,444)	(420,714)
CASH FLOW FROM FINANCING ACTIVITIES:
Proceeds from issuance of bonds	450,000
Proceeds from credit facilities	80,000	225,000
Principal payments on credit facilities	(450,000)
Principal payments on notes payable	(5,461)
Proceeds from exercise of stock options	3,242	3,559
Net cash provided by financing activities	77,781	228,559
NET DECREASE IN CASH AND CASH EQUIVALENTS	(163,375)	(18,522)
CASH AND CASH EQUIVALENTS, at beginning of period	295,002	180,523
CASH AND CASH EQUIVALENTS, at end of period	131,627	162,001
Non-cash activities
Increase (decrease) in accounts payable and accrued liabilities related to capital expenditures	$ (65,662)	$ 6,676