Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net income	$ 156,697	$ 158,350
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	69,775	56,060
Amortization of debt issuance costs and bond premium, net	2,328	2,073
Amortization of deferred items	2,185	1,448
Provision for doubtful accounts	679	1,871
Provision for inventory obsolescence	860	360
Deferred income tax benefit	(649)	(466)
Share-based compensation expense	7,725	6,813
Gain on sale of assets	(34,079)	0
Other, net	2,118	(13)
Changes in assets and liabilities:
Accounts receivable	(39,559)	24,563
Income tax receivable	(1,543)	(199)
Inventory	(8,097)	(14,106)
Prepaid expenses	9,524	10,109
Deferred costs and other assets	(26,568)	(8,084)
Accounts payable	(8,617)	(43,864)
Accrued liabilities	(1,276)	(5,282)
Income tax payable	3,091	6,582
Deferred credits and other liabilities	33,910	8,247
Net cash provided by operating activities	168,504	204,462
Cash flows from investing activities:
Capital expenditures	(497,634)	(372,957)
Proceeds from sale of assets	56,517	61
Net cash used in investing activities	(441,117)	(372,896)
Cash flows from financing activities:
Proceeds from bank credit facilities	340,000	310,000
Principal payments on bank credit facilities	(90,000)	(100,000)
Principal payments on notes payable	(8,071)	(5,148)
Proceeds from exercise of stock options	1,651	3,418
Debt issuance costs paid	(102)	0
Net cash provided by financing activities	243,478	208,270
Net increase (decrease) in cash and cash equivalents	(29,135)	39,836
Cash and cash equivalents, at beginning of period	88,770	77,871
Cash and cash equivalents, at end of period	59,635	117,707
Non-cash activities:
Changes in accounts payable and accrued liabilities related to capital expenditures	$ 1,375	$ 34,046