Summary of Significant Accounting Policies - Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 181,101	$ 159,842	$ 534,162	$ 465,124
Military and space
Disaggregation of Revenue [Line Items]
Revenue	80,487	71,459	231,635	208,140
Commercial Aerospace
Disaggregation of Revenue [Line Items]
Revenue	88,922	76,343	269,080	219,019
Industrial
Disaggregation of Revenue [Line Items]
Revenue	11,692	12,040	33,447	37,965
Electronic Systems
Disaggregation of Revenue [Line Items]
Revenue	90,588	85,696	264,045	252,606
Electronic Systems | Military and space
Disaggregation of Revenue [Line Items]
Revenue	59,081	54,068	176,813	160,969
Electronic Systems | Commercial Aerospace
Disaggregation of Revenue [Line Items]
Revenue	19,815	19,588	53,785	53,672
Electronic Systems | Industrial
Disaggregation of Revenue [Line Items]
Revenue	11,692	12,040	33,447	37,965
Structural Systems
Disaggregation of Revenue [Line Items]
Revenue	90,513	74,146	270,117	212,518
Structural Systems | Military and space
Disaggregation of Revenue [Line Items]
Revenue	21,406	17,391	54,822	47,171
Structural Systems | Commercial Aerospace
Disaggregation of Revenue [Line Items]
Revenue	$ 69,107	$ 56,755	$ 215,295	$ 165,347