Accumulated Other Comprehensive Income Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Beginning Balance	$ 289,624	$ 329,258	$ 289,058
Other comprehensive income (loss)	(2,996)	(10,449)	(1,432)
Ending Balance	244,467	289,624	329,258
Unrealized Gains (Losses) on Available-for-Sale Securities
Beginning Balance	(3)	(26)
Other comprehensive income (loss)	(12)	23	(26)
Ending Balance	(15)	(3)	(26)
Foreign Currency Translation Adjustments
Beginning Balance	(12,942)	(2,470)	(1,064)
Other comprehensive income (loss)	(2,984)	(10,472)	(1,406)
Ending Balance	(15,926)	(12,942)	(2,470)
Accumulated Other Comprehensive Loss
Beginning Balance	(12,945)	(2,496)	(1,064)
Other comprehensive income (loss)	(2,996)	(10,449)	(1,432)
Ending Balance	$ (15,941)	$ (12,945)	$ (2,496)