Segment and Enterprise Wide Disclosures - Operations by Geographic Area (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Net Sales to Unaffiliated Customers
Net sales	$ 128,250	$ 141,886	$ 134,859	$ 135,264	$ 128,487	$ 138,847	$ 137,792	$ 136,350	$ 540,259	$ 541,476	$ 545,394
United States | Reportable Geographical Components
Net Sales to Unaffiliated Customers
Net sales									512,585	514,779	520,023
Long-Lived Assets, Net
Long-Lived Assets	53,992				51,449				53,992	51,449
Foreign | Reportable Geographical Components
Net Sales to Unaffiliated Customers
Net sales									27,674	26,697	25,371
Long-Lived Assets, Net
Long-Lived Assets	$ 1,799				$ 976				$ 1,799	$ 976