Accounts Receivable - Summary of Accounts Receivable (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contract receivables	$ 66,180	$ 72,835
Allowance for doubtful accounts	(1,713)	(1,749)
Accounts receivable, Total	76,726	83,062
Trade Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade receivables	$ 12,259	$ 11,976