Prepaid Expenses and Other Assets - Summary of Prepaid Expenses and Other Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Prepaid Expense and Other Assets [Abstract]
Revenues in excess of billings	$ 7,140	$ 7,987
Prepaid expenses	3,647	3,390
Contract retainage	2,586	2,469
Income tax receivable	0	471
Other	504	1,245
Total prepaid expenses and other assets	$ 13,877	$ 15,562