Business Segment Information - Financial Information by Reportable Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 30, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Net Revenues	$ 172,566	$ 150,455
Operating Income	12,848	5,256
Total Depreciation and Amortization Expenses	7,388	5,981
Capital Expenditures	4,525	4,263
Structural Systems
Segment Reporting Information [Line Items]
Net Revenues	88,369	68,046
Electronic Systems
Segment Reporting Information [Line Items]
Net Revenues	84,197	82,409
Operating Segments
Segment Reporting Information [Line Items]
Operating Income	19,730	10,135
Operating Segments | Structural Systems
Segment Reporting Information [Line Items]
Net Revenues	88,369	68,046
Operating Income	10,549	4,391
Total Depreciation and Amortization Expenses	3,250	2,316
Capital Expenditures	3,689	1,529
Operating Segments | Electronic Systems
Segment Reporting Information [Line Items]
Net Revenues	84,197	82,409
Operating Income	9,181	5,744
Total Depreciation and Amortization Expenses	3,844	3,632
Capital Expenditures	836	2,734
Segment Reconciling Items
Segment Reporting Information [Line Items]
Corporate General and Administrative Expenses	(6,882)	(4,879)
Corporate Administration
Segment Reporting Information [Line Items]
Total Depreciation and Amortization Expenses	$ 294	$ 33