Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 4,003	$ 3,924	$ 7,341	$ 10,590
Other comprehensive income (loss), net of tax:
Unrealized holding losses on available-for-sale securities arising during the period	(34)	(59)	(36)	(1,216)
Reclassification adjustment for realized gains included in net income		26		(315)
Foreign currency translation adjustments	(809)		919
Other comprehensive (loss) income	(843)	(33)	883	(1,531)
Comprehensive income	$ 3,160	$ 3,891	$ 8,224	$ 9,059