CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net income	$ 340,822	$ 350,224	$ 272,171
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	147,358	117,510	70,599
Amortization	8,634	5,224	(712)
Provision for doubtful accounts and inventory obsolescence	2,826	5,582	765
Deferred income tax benefit	(1,270)	(816)	(989)
Share-based compensation expense	14,691	14,231	10,402
(Gain) loss on sale of equipment	(34,139)	971	457
Change in assets and liabilities:
Accounts receivable	(43,965)	(36,330)	(80,013)
Income tax receivable	(1,588)	1,078	(119)
Inventories of materials and supplies	(17,220)	(43,254)	(23,395)
Prepaid expenses, deferred costs and other current assets	15,463	(712)	(6,386)
Deferred costs and other assets	(11,682)	(19,700)	(32,597)
Accounts payable	1,932	11,440	27,536
Accrued liabilities	1,647	1,430	(7,096)
Premium on Senior Notes	0	8,500	0
Income tax payable	(2,320)	5,863	1,250
Deferred credits and other liabilities	21,431	10,869	23,730
Net cash provided by operating activities	442,620	432,110	255,603
Cash flows from investing activities:
Capital expenditures	(975,731)	(745,223)	(785,083)
Proceeds from sale of assets	61,516	147	7,646
Net cash used by investing activities	(914,215)	(745,076)	(777,437)
Cash flows from financing activities:
Proceeds from issuance of long-term debt	700,000	600,000	760,000
Principal payments on long-term debt	(220,000)	(175,000)	(450,000)
Proceeds (repayments) on short-term debt, net	(13,979)	2,923	(313)
Repurchase and retirement of common shares	0	(107,260)	0
Proceeds from exercise of stock options	3,688	9,224	5,546
Debt issuance costs paid	(6,804)	(6,022)	(10,530)
Net cash provided by financing activities	462,905	323,865	304,703
Net increase (decrease) in cash and cash equivalents	(8,690)	10,899	(217,131)
Cash at beginning of period	88,770	77,871	295,002
Cash at end of period	80,080	88,770	77,871
Cash paid during the period for:
Domestic and foreign income taxes	55,777	49,105	49,636
Interest, net of amounts capitalized	35,265	21,200	1,849
Non-cash activities:
Increase (decrease) in accrued liabilities related to capital expenditures	(2,804)	795	(56,965)
Dividends payable	16,090	0	0
Increase in short-term debt related to funding of insurance policies	$ 17,793	$ 0	$ 0