Summary of Significant Accounting Policies - Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 147,309	$ 180,495	$ 320,784	$ 353,061
Military and space
Disaggregation of Revenue [Line Items]
Revenue	94,597	77,189	194,088	150,886
Commercial Aerospace
Disaggregation of Revenue [Line Items]
Revenue	40,418	91,988	104,268	180,456
Industrial
Disaggregation of Revenue [Line Items]
Revenue	12,294	11,318	22,428	21,719
Electronic Systems
Disaggregation of Revenue [Line Items]
Revenue	91,950	89,260	190,070	173,457
Electronic Systems | Military and space
Disaggregation of Revenue [Line Items]
Revenue	68,021	60,272	141,150	117,704
Electronic Systems | Commercial Aerospace
Disaggregation of Revenue [Line Items]
Revenue	11,635	17,670	26,492	34,034
Electronic Systems | Industrial
Disaggregation of Revenue [Line Items]
Revenue	12,294	11,318	22,428	21,719
Structural Systems
Disaggregation of Revenue [Line Items]
Revenue	55,359	91,235	130,714	179,604
Structural Systems | Military and space
Disaggregation of Revenue [Line Items]
Revenue	26,576	16,917	52,938	33,182
Structural Systems | Commercial Aerospace
Disaggregation of Revenue [Line Items]
Revenue	$ 28,783	$ 74,318	$ 77,776	$ 146,422