Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net income	$ 83,397	$ 72,831
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	32,544	27,578
Amortization of debt issuance costs and bond premium, net	1,176	1,036
Amortization of deferred items	(4)	(32)
Provision for doubtful accounts	0	1,871
Provision for inventory obsolescence	430	181
Deferred income tax expense/(benefit)	196	(220)
Share-based compensation expense	3,354	3,048
Other, net	392	7
Changes in assets and liabilities:
Accounts receivable	26,868	22,388
Income tax receivable	(859)	141
Inventory	10,842	(257)
Prepaid expenses	6,458	5,470
Deferred costs and other assets	(8,167)	(4,039)
Accounts payable	(13,556)	(27,978)
Accrued liabilities	11,195	4,937
Income tax payable	(3,767)	3,603
Deferred credits and other liabilities	9,695	6,354
Net cash provided by operating activities	160,194	116,919
Cash flows from investing activities:
Capital expenditures	(462,620)	(321,995)
Installment proceeds from pending sale of asset	11,200	0
Proceeds from sale of assets	77	41
Net cash used in investing activities	(451,343)	(321,954)
Cash flows from financing activities:
Proceeds from bank credit facilities	340,000	240,000
Principal payments on notes payable	(6,046)	(5,148)
Proceeds from exercise of stock options	823	653
Debt issuance costs paid	(72)	0
Net cash provided by financing activities	334,705	235,505
Net increase in cash and cash equivalents	43,556	30,470
Cash and cash equivalents, at beginning of period	88,770	77,871
Cash and cash equivalents, at end of period	$ 132,326	$ 108,341