Income Taxes (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Deferred tax assets attributable to:
Share-based compensation expense	$ 17,082	$ 22,984
Accrued liabilities	27,949	27,074
Inventory adjustments	3,055	2,450
Foreign loss carryforwards	35,315	31,882
Unrecognized tax benefits	471	370
Other	4,065	3,874
Total deferred tax assets	87,937	88,634
Valuation allowance	(34,965)	(29,926)
Total deferred tax assets, net	52,972	58,708
Deferred tax liabilities attributable to:
Depreciation and amortization	103,697	102,032
Total deferred tax liabilities	103,697	102,032
Net deferred tax liability	50,725	43,324
Domestic earnings before provision for income taxes	362,100	361,800	$ 386,600
Foreign earnings before provision for income taxes	16,400	28,900	$ 26,100
Accumulated undistributed earnings of the Company's foreign operations	233,200	202,900
Total operating loss carry-forward	114,200	103,000
Operating loss carry-forward, subject to valuation allowance	98,400	87,100
Amount of operating loss carry-forwards with an expiration date	19,000
Amount of operating loss carry-forwards without an expiration date	95,200
Total tax credit carryforwards	3,400	$ 2,100
Expiring tax credit carryforwards	2,400
Non-expiring tax credit carryforwards	$ 1,000