CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Income Statement [Abstract]
Net sales	$ 232,988	$ 216,479	$ 214,474
Cost of sales	114,939	110,255	108,169
Gross profit	118,049	106,224	106,305
Operating expenses:
Selling, general and administrative	84,945	77,256	76,874
Amortization of intangible assets	3,927	2,869	2,667
Impairment of intangible assets	0	1,810	267
Total operating expenses	88,872	81,935	79,808
Income from operations	29,177	24,289	26,497
Interest and other expense, net	1,252	1,051	1,421
Income before provision for income taxes	27,925	23,238	25,076
Provision for income taxes	9,267	7,967	9,187
Net income	18,658	15,271	15,889
Other comprehensive loss:
Foreign currency translation adjustment, net of tax	(51)	(458)	(122)
Comprehensive income	$ 18,607	$ 14,813	$ 15,767
Net income per common share:
Basic (in dollars per share)	$ 2.00	$ 1.59	$ 1.62
Diluted (in dollars per share)	$ 2.00	$ 1.59	$ 1.62
Weighted average common shares outstanding:
Basic (in shares)	9,345,754	9,588,838	9,792,276
Dilutive effect of stock options (in shares)	0	3,896	8,804
Diluted (in shares)	9,345,754	9,592,734	9,801,080