Net Income Per Share Data - Denominator for Computation of Basic and Diluted Net Income Per Share (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Earnings Per Share [Abstract]
Net income available to common shareholders	$ 825	$ 3,051	$ 3,338	$ 6,665
Basic weighted average shares outstanding	12,969	12,944	12,956	13,092
Dilutive effect of outstanding stock options, non-vested restricted stock, restricted stock units, deferred stock units and performance shares	221	263	231	273
Diluted weighted average shares outstanding	13,190	13,207	13,187	13,365