Major Customers and Concentrations of Credit Risk - Sales to Major Customers (Detail) - Customer Concentration Risk - Sales Revenue, Net	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Boeing
Revenue, Major Customer [Line Items]
Concentration percentage	17.00%	16.30%	17.30%
Lockheed Martin
Revenue, Major Customer [Line Items]
Concentration percentage	4.40%	5.50%	5.60%
Raytheon
Revenue, Major Customer [Line Items]
Concentration percentage	11.70%	13.50%	8.40%
Spirit
Revenue, Major Customer [Line Items]
Concentration percentage	9.50%	8.20%	8.20%
United Technologies
Revenue, Major Customer [Line Items]
Concentration percentage	4.60%	4.70%	5.30%
Top Ten Customers
Revenue, Major Customer [Line Items]
Concentration percentage	62.90%	62.50%	58.70%