Nature of Operations and Summary of Significant Accounting Policies - Schedule of Changes in Allowance for Slow Move and Obsolete Inventories (Detail) - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Inventory Disclosure [Abstract]
Balance, beginning of year	$ 3,869,000	$ 3,310,000	$ 3,139,000
Charged to cost of sales	77,000	621,000	144,000
Disposal of inventory, net of recoveries	(120,000)	(62,000)	27,000
Balance, end of year	$ 3,826,000	$ 3,869,000	$ 3,310,000