Line of Credit - Additional Information (Detail) (USD $)	1 Months Ended		3 Months Ended	12 Months Ended			15 Months Ended
	Nov. 01, 2012 Y	Jul. 31, 2011	Jun. 30, 2011	Sep. 30, 2013 Tranches	Sep. 30, 2012	Sep. 30, 2011	Nov. 01, 2012 Y
Line Of Credit Facility [Line Items]
Senior secured revolving credit facility			$ 65,000,000	$ 61,000,000	$ 55,000,000
Line of credit maturity date			Mar. 13, 2012	Nov. 01, 2017	Jan. 13, 2013
Additional permitted borrowings under Tranche A				15,000,000
Increments of additional permitted borrowings under Tranche A				2,500,000
Credit Facility extended maximum limit	70,000,000
Credit Facility Tranches				2
Revolving credit facility period	5						5
Minimum excess availability on borrowing base				10.00%
Applicable margin for Base rate borrowings using LIBOR		1.00%					1.75%
Unused line fee under the Credit Facility				0.25%
Credit Facility Description of Variable Rate Basis				The interest rate on outstanding borrowings is equal to, at the Company’s election, either (1) the lender’s base rate plus the applicable margin, or (2) a LIBOR rate plus the applicable margin. The applicable margin for base rate borrowings is 0.50% for Tranche A borrowings and 2.00% for Tranche A-1 borrowings. The applicable margin for LIBOR rate borrowings is 1.50% for Tranche A borrowings and 3.00% for Tranche A-1 borrowings. Tranche A-1 borrowings are deemed to be the first loans made and the last loans repaid.
Deferred financing costs				988,000
Payments of Financing Costs				927,000	61,000	26,000
Increase in effective interest rate on borrowings			0.75%
Letters of credit				5,695,000	7,084,000
Line of credit availability				55,305,000	47,916,000
Line of credit, outstanding borrowings				205,000	0	0
Line of credit borrowings during period				6,200,000
Tranche A
Line Of Credit Facility [Line Items]
Senior secured revolving credit facility				55,000,000
Excess interest rate over prime rate				0.50%
Applicable margin for Base rate borrowings using LIBOR				1.50%
Tranche A | Minimum
Line Of Credit Facility [Line Items]
Prior Credit Facility borrowings interest rate				1.68%
Tranche A | Maximum
Line Of Credit Facility [Line Items]
Prior Credit Facility borrowings interest rate				3.75%
Tranche A-1
Line Of Credit Facility [Line Items]
Senior secured revolving credit facility				$ 6,000,000
Excess interest rate over prime rate				2.00%
Applicable margin for Base rate borrowings using LIBOR				3.00%
Tranche A-1 | Minimum
Line Of Credit Facility [Line Items]
Prior Credit Facility borrowings interest rate				3.18%
Tranche A-1 | Maximum
Line Of Credit Facility [Line Items]
Prior Credit Facility borrowings interest rate				5.25%
Prior Credit Facility
Line Of Credit Facility [Line Items]
Excess interest rate over prime rate		0.00%					0.75%