Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Total
Balances (in shares) at Sep. 30, 2014	22,485,488
Balances at Sep. 30, 2014	$ 22	$ 54,552	$ 44,280		$ 98,854
Net income			16,204		16,204
Share-based compensation (in shares)	11,140
Share-based compensation		471			471
Tax shortfall related to share-based compensation		(41)			(41)
Balances (in shares) at Sep. 30, 2015	22,496,628
Balances at Sep. 30, 2015	$ 22	54,982	60,484		115,488
Net income			11,471		11,471
Share-based compensation (in shares)	23,951
Share-based compensation	$ 1	609		$ 139	749
Tax shortfall related to share-based compensation		(154)			$ (154)
Repurchase of common stock (in shares)	(67,970)				(67,970)
Repurchase of common stock				(829)	$ (829)
Balances (in shares) at Sep. 30, 2016	22,452,609
Balances at Sep. 30, 2016	$ 23	55,437	71,955	(690)	126,725
Net income			6,891		6,891
Share-based compensation		399		288	687
Tax shortfall related to share-based compensation		(158)			$ (158)
Repurchase of common stock (in shares)	(4,553)				(30,000)
Repurchase of common stock				(262)	$ (262)
Balances (in shares) at Sep. 30, 2017	22,448,056
Balances at Sep. 30, 2017	$ 23	$ 55,678	$ 78,846	$ (664)	$ 133,883