Consolidated Statement of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income [Member]	Retained Earnings [Member]
Beginning balance at Sep. 30, 2014	$ 98,751	$ 680	$ 2,662	$ 1,528	$ 93,881
Beginning balance, shares at Sep. 30, 2014		13,607,000
Net income	11,947				11,947
Other comprehensive income (loss), net of tax	(1,523)			(1,523)
Issuance of common stock	279	$ 7	272
Issuance of common stock, shares		139,000
Common stock repurchased	(20,000)	$ (42)	(2,485)		(17,473)
Common stock repurchased, shares		(848,000)
Common stock options exercised, net	$ 431	$ 2	429
Common stock options exercised, net, shares	166,422	47,000
Purchase of common stock to pay employee taxes	$ (825)		(631)		(194)
Excess tax benefit from stock-based compensation plans	432		432
Stock-based compensation	2,381		2,381
Ending balance at Sep. 30, 2015	91,873	$ 647	3,060	5	88,161
Ending balance, shares at Sep. 30, 2015		12,945,000
Net income	9,985				9,985
Other comprehensive income (loss), net of tax	1,268			1,268
Issuance of common stock	270	$ 4	266
Issuance of common stock, shares		74,000
Common stock options exercised, net	$ 1,546	$ 10	1,536
Common stock options exercised, net, shares	437,850	196,000
Purchase of common stock to pay employee taxes	$ (1,953)	$ (1)	(1,952)
Purchase of common stock to pay employee taxes, shares		(7,000)
Stock-based compensation	3,844		3,844
Ending balance at Sep. 30, 2016	106,833	$ 660	6,754	1,273	98,146
Ending balance, shares at Sep. 30, 2016		13,208,000
Net income	3,926				3,926
Other comprehensive income (loss), net of tax	2,144			2,144
Issuance of common stock	348	$ 5	343
Issuance of common stock, shares		99,000
Common stock repurchased	$ (4,702)	$ (10)	(4,692)
Common stock repurchased, shares	(196,190)	(196,000)
Common stock options exercised, net	$ 96	$ 1	95
Common stock options exercised, net, shares	6,819	7,000
Purchase of common stock to pay employee taxes	$ (560)	$ (1)	(559)
Purchase of common stock to pay employee taxes, shares		(23,000)
Stock-based compensation	3,472		3,472
Ending balance at Sep. 30, 2017	$ 111,557	$ 655	$ 5,413	$ 3,417	$ 102,072
Ending balance, shares at Sep. 30, 2017		13,095,000