Debt (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Debt [Abstract]
Interest expense	$ 1,130	$ 1,574	$ 1,771
Amount available under the 2012 Credit Facility	22,820
Letters of Credit Outstanding	6,918
Line Of Credit Facility Amount Outstanding	$ 10,234
Revolving Loan [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Initiation Date	Aug. 09, 2012
Line Of Credit Facility, Expiration Date	Aug. 09, 2018
Line of Credit Facility, Description	On August 9, 2012, we entered into a Credit and Security Agreement (the “Credit Agreement”), for a credit facility (as amended, the “2012 Credit Facility”) with Wells Fargo Bank, National Association (“Wells Fargo”). We have subsequently entered into three amendments to the 2012 Credit Facility and entered into an Amended and Restated Credit and Security Agreement (the “Amended Credit Agreement”) as of September 24, 2014, which increased the maximum revolver under the 2012 Credit Facility amount from $30 million to $60 million, and extended the maturity date by one year to August 9, 2018. In addition, under the Amended Credit Agreement, the Company eliminated its term loan facility so that borrowings that would previously have been made under the term loan facility, including borrowings for acquisitions, are now made under the revolving credit facility with terms more favorable than the term loan facility, including a lower interest rate (as described below).
Line Of Credit Facility Covenant Terms	The 2012 Credit Facility contains customary affirmative, negative and financial covenants. At September 30, 2015, we were subject to the financial covenant under the 2012 Credit Facility requiring, at any time that our Liquidity (the aggregate amount of unrestricted cash and cash equivalents on hand plus Excess Availability, as defined in the Amended Credit Agreement) is less than $20 million or our Excess Availability is less than $5 million, that we maintain a Fixed Charge Coverage Ratio of not less than 1.0:1.0. At September 30, 2015, our Liquidity was $72,180 and our Excess Availability was $22,820, and as such, we were not required to maintain a Fixed Charge Coverage Ratio of 1.0:1.0 as of such date. Nonetheless, at September 30, 2015, our Fixed Charge Coverage Ratio was 4.0:1.0. Compliance with our Fixed Charge Coverage Ratio, while not required at September 30, 2015, provides us with the ability to use cash on hand or to draw on our 2012 Credit Facility such that we can fall below the Excess Availability and Liquidity minimum thresholds described above without violating our financial covenant.
Line of Credit Facility, Interest Rate Description	Under the terms of the 2012 Credit Facility, amounts outstanding bear interest at a per annum rate equal to a Daily Three Month LIBOR (as defined in the Credit Agreement), plus an interest rate margin, which is determined quarterly
Revolving credit facility amount	$ 60,000
Unused commitment fee	0.50%
Line Of Credit Facility Collateral Fees	a collateral monitoring fee ranging from $1 thousand to $2 thousand, based on the then-applicable interest rate margin