Basis of Presentation and Summary of Significant Accounting Policies - Schedule of Contract Assets and Liabilities (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Contract assets	$ 36,500,000	$ 51,500,000
Contract liabilities	32,800,000	29,200,000
Net contract assets	3,700,000	$ 22,300,000
$ Change
Contract assets	(15,000,000)
Contract liabilities	3,600,000
Net contract assets	$ (18,600,000)
% Change
Contract assets	(29.10%)
Contract liabilities	12.30%
Net contract assets	(83.40%)
Percent of contract liabilities		70.00%
Impairment losses on contract assets	$ 0