Prepaid Expenses and Other Assets - Summary of Prepaid Expenses and Other Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Prepaid Expense and Other Assets [Abstract]
Prepaid expenses	$ 5,582	$ 7,494
Revenues in excess of billings	5,873	4,841
Contract retainage	2,185	1,449
Income tax receivable	1,080	2,230
Other	890	864
Total prepaid expenses and other assets	$ 15,610	$ 16,878