Income Taxes (Details 5) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Income Taxes
Undistributed international earnings	$ 241,547
Change in the valuation allowance
Beginning balance	(9,543)	$ (14,116)	$ (14,867)
Balance at the end of the period	(7,984)	(9,543)	(14,116)
New York State (NYS) | Investment tax credit
Change in the valuation allowance
NYS investment tax credit carryforwards expired/(generated)	636	1,269	(321)
Foreign
Change in the valuation allowance
Foreign net operating losses utilized/(generated)	$ 923	$ 3,304	1,580
Foreign net operating losses acquired			$ (508)