Line of Credit and Notes Payable (Details) (USD $)			6 Months Ended				1 Months Ended		6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012 Asset-based revolving credit facility	Jun. 30, 2012 Term note	Dec. 14, 2010 Term note	Jun. 30, 2012 Notes payable	Jun. 30, 2011 Credit agreement	Jun. 30, 2012 Credit agreement	Jun. 30, 2012 Credit agreement Prime rate	Jun. 30, 2012 Credit agreement LIBOR
Line of Credit and Notes Payable
Credit limit			$ 160,000,000
Amount of increments to increase the credit limit			5,000,000
Total credit limit			180,000,000				10,900,000
Line fee (as a percent)			0.65%
Unused line fee (as a percent)			0.25%
Remaining excess borrowing capacity not assured			20,000,000
Fixed charge coverage ratio			1.0
Net working capital advances outstanding	71,753,000	91,852,000	71,800,000
Amount available to borrow for working capital advances			62,900,000
Principal balance of debt					2,870,000
Outstanding amount of debt				2,260,000
Maturities of remaining balance of term note
Remainder of 2012				205,000
2013				410,000
2014				410,000
2015				410,000
2016				410,000
2017				410,000
Additional disclosures
Effective weighted average annual interest rate (as a percent)			2.38%	2.38%
Notes payable - current	974,000	1,015,000				100,000
Borrowing term							5 years
Principal repayment amortization period (in years)							25 years
Variable interest rate basis									Prime	LIBOR
Percentage points added to the reference rate									0.375%	2.375%
Amount outstanding under credit agreement								$ 9,900,000