Income Taxes (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Provision for income taxes attributable to continuing operations
Income taxes at the federal statutory rate	$ 25,369	$ 31,959	$ 77,789
Non-deductible expense related to incentive stock options	0	0	(633)
State income tax, net of federal benefit	765	1,093	349
Change in valuation allowance	164	659	2,242
Federal tax credits	(124)	(314)	(922)
Foreign tax credit	(2,174)	(3,263)	(4,342)
Effect of permanently reinvesting foreign earnings	(3,322)	(606)	(3,820)
Other	128	54	502
Total income tax expense	$ 20,806	$ 29,582	$ 71,165
Effective tax rate	29.00%	29.00%	31.00%