Long-Term Debt - Long-Term Debt (Parenthetical) (Detail) (USD $)	3 Months Ended	12 Months Ended		1 Months Ended	3 Months Ended	12 Months Ended			1 Months Ended	12 Months Ended
	Jun. 30, 2011	Sep. 30, 2013	Sep. 30, 2012	Nov. 01, 2012 Senior Secured Term Loan B	Dec. 31, 2012 Senior Secured Term Loan B	Sep. 30, 2013 Senior Secured Term Loan B	Sep. 30, 2011 Senior Secured Term Loan B	Sep. 30, 2012 Senior Secured Term Loan B	Apr. 03, 2013 Industrial revenue bond	Sep. 30, 2013 Industrial revenue bond	Sep. 30, 2012 Industrial revenue bond
Debt Instrument [Line Items]
Senior secured term loan B, variable interest								4.25%			0.45%
Minimum quarterly repayment amount					$ 225,000	$ 225,000	$ 0
Remaining Term Loan B balance prepaid				$ 13,427,000					$ 1,830,000
Line of credit maturity date	Mar. 13, 2012	Nov. 01, 2017	Jan. 13, 2013							Sep. 01, 2020