Accounts Receivable - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Receivables [Abstract]
Amount billed but not received under retainage provisions in contracts	$ 1,700,000		$ 2,300,000
Retainage receivables on contracts period	1 year
Provision for doubtful accounts	$ 100,000	$ 45,000