Business Segment Information - Financial Information by Reportable Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 29, 2019	Jun. 30, 2018	Jun. 29, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Net Revenues	$ 180,495	$ 154,827	$ 353,061	$ 305,282
Operating Income	13,604	5,596	26,452	10,851
Total Depreciation and Amortization Expenses	6,963	6,334	13,759	12,315
Capital Expenditures	5,888	2,769	10,413	7,032
Electronic Systems
Segment Reporting Information [Line Items]
Net Revenues	89,260	84,502	173,457	166,910
Structural Systems
Segment Reporting Information [Line Items]
Net Revenues	91,235	70,325	179,604	138,372
Operating Segments
Segment Reporting Information [Line Items]
Operating Income	21,685	13,694	41,415	23,829
Operating Segments | Electronic Systems
Segment Reporting Information [Line Items]
Net Revenues	89,260	84,502	173,457	166,910
Operating Income	9,912	8,668	19,093	14,412
Total Depreciation and Amortization Expenses	3,531	3,683	7,033	7,315
Capital Expenditures	2,216	1,478	3,052	4,212
Operating Segments | Structural Systems
Segment Reporting Information [Line Items]
Net Revenues	91,235	70,325	179,604	138,372
Operating Income	11,773	5,026	22,322	9,417
Total Depreciation and Amortization Expenses	3,400	2,618	6,400	4,934
Capital Expenditures	3,672	1,101	7,361	2,630
Segment Reconciling Items
Segment Reporting Information [Line Items]
Corporate General and Administrative Expenses	(8,081)	(8,098)	(14,963)	(12,978)
Corporate Administration
Segment Reporting Information [Line Items]
Total Depreciation and Amortization Expenses	32	33	326	66
Capital Expenditures	$ 0	$ 190	$ 0	$ 190