Business Segment Information - Segment Assets (Detail) - USD ($) $ in Thousands	Jul. 01, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Total Assets	$ 535,772	$ 515,429
Total Goodwill and Intangibles	179,709	184,127
Operating Segments | Structural Systems
Segment Reporting Information [Line Items]
Total Assets	203,297	175,580
Total Goodwill and Intangibles	3,290	3,745
Operating Segments | Electronic Systems
Segment Reporting Information [Line Items]
Total Assets	318,243	325,780
Total Goodwill and Intangibles	176,419	180,382
Corporate Administration
Segment Reporting Information [Line Items]
Total Assets	$ 14,232	$ 14,069