Inventories, Net - Additional Information (Detail) - USD ($)	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Inventory Disclosure [Abstract]
LIFO reserves of inventories	$ 4,250,000	$ 4,766,000
Slow moving and obsolete inventory reserve	$ 3,826,000	$ 3,869,000	$ 3,310,000	$ 3,139,000

The excess of replacement or current cost over the stated LIFO (last in first out) inventory value when the LIFO inventory method is utilized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.6(c))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_ExcessOfReplacementOrCurrentCostsOverStatedLIFOValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant