Contract Receivables (Details) (USD $)	1 Months Ended	3 Months Ended
	Apr. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
Contract Receivables [Abstract]
Maximum term of contract receivables (in months)		12 months
Components of contract receivables [Abstract]
Billed receivables		$ 10,970,000	$ 12,403,000
Recoverable costs and accrued profit not billed		11,879,000	11,315,000
Allowance for doubtful accounts		(2,000)	(2,000)
Total contract receivables, net		22,847,000	23,716,000
Unbilled Contract Receivables Billed during April 2013	$ 3,700,000
Benchmark to disclose customers of total accounts receivable, minimum percentage (in hundredths)		10.00%
Contract Receivable [Member] | Slovenske elektrarne, a.s. [Member]
Percentage of contract receivable by major customer [Abstract]
Percentage of contract receivables accounted by major customers (in hundredths)		24.40%	17.40%
Contract Receivable [Member] | Shandong Nuclear Power Co. Ltd. [Member]
Percentage of contract receivable by major customer [Abstract]
Percentage of contract receivables accounted by major customers (in hundredths)		11.40%	13.80%