Contract Costs - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012 Project	Jun. 30, 2011 Project
Long-term Contracts or Programs Disclosure [Line Items]
Percentage of pass-through costs included in revenue	42.10%	50.40%	39.10%	46.40%
Total revenue recorded in relation to orders change in projects			$ 2,100,000	$ 784,000
Number of projects orders changed			2	2
Recognized contract losses	$ 673,000	$ 688,000	$ 762,000	$ 1,100,000