Accounts Receivable - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Receivables [Abstract]
Amount billed but not received under retainage provisions in contracts	$ 2,300,000	$ 500,000
Retainage receivables on contracts period	1 year
Provision for doubtful accounts	$ 700,000	300,000	$ 100,000
Charge-offs (recoveries)	$ 200,000	$ 300,000	$ (35,000)