Business Segment Information - Financial Information by Reportable Segment (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net Revenues	$ 164,183	$ 159,842	$ 154,827	$ 150,455	$ 142,258	$ 138,690	$ 140,938	$ 136,297	$ 629,307	$ 558,183	$ 550,642
Segment Operating Income (Loss)									49,979	37,026	46,128
Corporate General and Administrative Expenses									(26,061)	(21,392)	(16,912)
Operating Income									23,918	15,634	29,216
Depreciation and amortization									25,296	22,845	22,860
Capital Expenditures									16,337	26,473	18,693
Electronic Systems
Segment Reporting Information [Line Items]
Net Revenues									337,868	316,723
Structural Systems
Segment Reporting Information [Line Items]
Net Revenues									291,439	241,460
Operating Segments | Electronic Systems
Segment Reporting Information [Line Items]
Net Revenues									337,868	316,723	304,177
Segment Operating Income (Loss)									30,916	31,236	29,284
Depreciation and amortization									14,223	13,888	14,087
Capital Expenditures									6,719	5,019	3,032
Operating Segments | Structural Systems
Segment Reporting Information [Line Items]
Net Revenues									291,439	241,460	246,465
Segment Operating Income (Loss)									19,063	5,790	16,844
Depreciation and amortization									10,525	8,860	8,688
Capital Expenditures									9,104	20,679	15,661
Corporate Administration
Segment Reporting Information [Line Items]
Depreciation and amortization									548	97	85
Capital Expenditures									$ 514	$ 775	$ 0