Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating Leases, Future Minimum Payments Due [Abstract]
2013	$ 979,000
2014	653,000
2015	657,000
2016	763,000
2017	772,000
Thereafter	646,000
Total	4,470,000
Rent Expense [Abstract]
Rent expense	1,000,000	1,100,000	942,000
Standby Letters of Credit, Bank Guarantees, Surety Bonds and Performance Bonds [Abstract]
Standby letters of credit and surety bonds	6,000,000
Number of standby letters of credit	14
Number of surety bonds	5
Number of bid bonds contract	15
Number of stand by letters of credit deposited in certificates of deposit	6
Restricted cash and investments	$ 1,800,000
Number of additional letters of credit collateralized using the line of credit	7