Income Taxes (Details 2) (USD $)	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Deferred tax assets attributable to:
Share-based compensation expense	$ 18,771,000	$ 19,683,000
Accrued liabilities	33,495,000	28,711,000
Inventory adjustments	5,208,000	3,432,000
Foreign loss carryforwards	23,405,000	18,315,000
Unrecognized tax benefits	605,000	651,000
Interest rate swaps		2,503,000
Other	2,011,000	2,673,000
Total deferred tax assets	83,495,000	75,968,000
Valuation allowance	(21,681,000)	(17,100,000)
Total deferred tax assets, net	61,814,000	58,868,000
Deferred tax liabilities attributable to:
Depreciation and amortization	92,292,000	81,644,000
Total deferred tax liabilities	92,292,000	81,644,000
Net deferred tax liability	30,478,000	22,776,000
Domestic earnings before provision for income taxes	334,500,000	300,100,000	215,900,000
Foreign earnings before provision for income taxes	26,400,000	35,800,000	12,000,000
Retained earnings attributable to foreign subsidiaries considered to be indefinitely invested	140,800,000	110,600,000
Total operating loss carry-forward	80,100,000	62,500,000
Operating loss carry-forward, subject to valuation allowance	65,100,000	50,100,000
Amount of operating loss carry-forwards with an expiration date	26,300,000
Amount of operating loss carry-forwards without an expiration date	53,800,000
Tax credit carryforwards	1,100,000	1,100,000
Tax credit carryforwards without an expiration date, subject to a valuation allowance	$ 500,000	$ 500,000