Summary of Significant Accounting Policies - Disaggregated Revenue (Details) - 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
Disaggregation of Revenue [Line Items]
Change in revenue for the period									$ 71,124
Revenues	$ 164,183	$ 159,842	$ 154,827	$ 150,455	$ 142,258	$ 138,690	$ 140,938	$ 136,297	$ 629,307	$ 558,183	$ 550,642
Percentage of revenues									100.00%	100.00%
Electronic Systems
Disaggregation of Revenue [Line Items]
Change in revenue for the period									$ 21,145
Revenues									$ 337,868	$ 316,723
Percentage of revenues									100.00%	100.00%
Structural Systems
Disaggregation of Revenue [Line Items]
Change in revenue for the period									$ 49,979
Revenues									$ 291,439	$ 241,460
Percentage of revenues									100.00%	100.00%
Military and space
Disaggregation of Revenue [Line Items]
Change in revenue for the period									$ 8,901
Revenues									$ 276,659	$ 267,758
Percentage of revenues									44.00%	48.00%
Military and space | Electronic Systems
Disaggregation of Revenue [Line Items]
Change in revenue for the period									$ 3,684
Revenues									$ 214,786	$ 211,102
Percentage of revenues									63.60%	66.60%
Military and space | Structural Systems
Disaggregation of Revenue [Line Items]
Change in revenue for the period									$ 5,217
Revenues									$ 61,873	$ 56,656
Percentage of revenues									21.20%	23.50%
Commercial aerospace
Disaggregation of Revenue [Line Items]
Change in revenue for the period									$ 68,101
Revenues									$ 304,455	$ 236,354
Percentage of revenues									48.40%	42.30%
Commercial aerospace | Electronic Systems
Disaggregation of Revenue [Line Items]
Change in revenue for the period									$ 23,339
Revenues									$ 74,889	$ 51,550
Percentage of revenues									22.20%	16.30%
Commercial aerospace | Structural Systems
Disaggregation of Revenue [Line Items]
Change in revenue for the period									$ 44,762
Revenues									$ 229,566	$ 184,804
Percentage of revenues									78.80%	76.50%
Industrial
Disaggregation of Revenue [Line Items]
Change in revenue for the period									$ (5,878)
Revenues									$ 48,193	$ 54,071
Percentage of revenues									7.60%	9.70%
Industrial | Electronic Systems
Disaggregation of Revenue [Line Items]
Change in revenue for the period									$ (5,878)
Revenues									$ 48,193	$ 54,071
Percentage of revenues									14.20%	17.10%