Business Segment Information - Financial Information by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 31, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Net Revenues	$ 186,926	$ 181,101	$ 180,495	$ 172,566	$ 164,183	$ 159,842	$ 154,827	$ 150,455	$ 721,088	$ 629,307	$ 558,183
Operating Income									56,233	23,918	15,634
Depreciation and amortization									28,305	25,296	22,845
Capital Expenditures									18,846	16,337	26,473
Electronic Systems
Segment Reporting Information [Line Items]
Net Revenues									360,373	337,868
Structural Systems
Segment Reporting Information [Line Items]
Net Revenues									360,715	291,439
Operating Segments
Segment Reporting Information [Line Items]
Operating Income									85,449	49,979	37,026
Operating Segments | Electronic Systems
Segment Reporting Information [Line Items]
Net Revenues									360,373	337,868	316,723
Operating Income									38,613	30,916	31,236
Depreciation and amortization									14,170	14,223	13,888
Capital Expenditures									5,508	6,719	5,019
Operating Segments | Structural Systems
Segment Reporting Information [Line Items]
Net Revenues									360,715	291,439	241,460
Operating Income									46,836	19,063	5,790
Depreciation and amortization									13,663	10,525	8,860
Capital Expenditures									13,338	9,104	20,679
Corporate Administration
Segment Reporting Information [Line Items]
Corporate General and Administrative Expenses									(29,216)	(26,061)	(21,392)
Depreciation and amortization									472	548	97
Capital Expenditures									$ 0	$ 514	$ 775