Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 9,985	$ 11,947	$ 12,031
Other comprehensive income (loss):
Unrealized holding (losses) gains on available-for-sale securities, net of tax	(68)	(1,208)	1,559
Reclassification adjustment for realized gains included in net income, net of tax		(315)	(89)
Foreign currency translation adjustments	1,336
Other comprehensive income (loss)	1,268	(1,523)	1,470
Comprehensive income	$ 11,253	$ 10,424	$ 13,501