Business Segment Information - Segment Assets (Details) - USD ($) $ in Thousands	Sep. 26, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Total Assets	$ 853,361	$ 790,429
Total Goodwill and Intangibles	298,849	309,279
Operating Segments | Electronic Systems
Segment Reporting Information [Line Items]
Total Assets	441,151	411,981
Total Goodwill and Intangibles	203,399	210,453
Operating Segments | Structural Systems
Segment Reporting Information [Line Items]
Total Assets	322,111	328,718
Total Goodwill and Intangibles	95,450	98,826
Corporate Administration
Segment Reporting Information [Line Items]
Total Assets	$ 90,099	$ 49,730