Fair Value of Financial Instruments (Details) (USD $)	Dec. 31, 2013 Letter Bond Contract	Dec. 31, 2012
Assets and liabilities measured at fair value [Abstract]
Money market funds	$ 10,553,000	$ 18,082,000
Certificates of deposit	0	890,000
Foreign exchange contracts - Assets	142,000	316,000
Total assets	10,695,000	19,288,000
Foreign exchange contracts - Liabilities	(655,000)	(339,000)
Total liabilities	(655,000)	(339,000)
Unrestricted cash	9,500,000	16,400,000
Standby letters of credit and surety bonds	4,900,000
Number of standby letters of credit	10
Number of surety bonds	2
Number of bid bonds contract	11
Number of stand by letters of credit deposited in certificates of deposit	4
Restricted cash and investments	1,100,000
Number of additional letters of credit collateralized using the line of credit	6
Issuances of stand-by letters of credit and advances as of period end	3,600,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets and liabilities measured at fair value [Abstract]
Money market funds	10,553,000	18,082,000
Certificates of deposit	0	890,000
Foreign exchange contracts - Assets	0	0
Total assets	10,553,000	18,972,000
Foreign exchange contracts - Liabilities	0	0
Total liabilities	0	0
Significant Other Observable Inputs (Level 2) [Member]
Assets and liabilities measured at fair value [Abstract]
Money market funds	0	0
Certificates of deposit	0	0
Foreign exchange contracts - Assets	142,000	316,000
Total assets	142,000	316,000
Foreign exchange contracts - Liabilities	(655,000)	(339,000)
Total liabilities	(655,000)	(339,000)
Significant Unobservable Inputs (Level 3) [Member]
Assets and liabilities measured at fair value [Abstract]
Money market funds	0	0
Certificates of deposit	0	0
Foreign exchange contracts - Assets	0	0
Total assets	0	0
Foreign exchange contracts - Liabilities	0	0
Total liabilities	$ 0	$ 0