Restructuring Costs (Details) - USD ($) $ in Thousands	3 Months Ended		19 Months Ended
	Mar. 29, 2019	Mar. 30, 2018	Mar. 29, 2019
Restructuring Reserve [Roll Forward]
Restructuring costs	$ 266	$ 1,693
Aerospace
Restructuring Reserve [Roll Forward]
Severance costs		900
2017 Announced Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	9,500		$ 9,500
Total cost savings	4,000
Restructuring Reserve [Roll Forward]
Restructuring accrual balance, beginning of period	1,580
Provision	177
Cash payments	(888)
Changes in foreign currency exchange rates	(12)
Restructuring accrual balance, end of period	857		857
Restructuring costs			8,900
2017 Announced Restructuring Plan [Member] | Aerospace
Restructuring Reserve [Roll Forward]
Provision	300	$ 800
2017 Announced Restructuring Plan [Member] | Severance
Restructuring Reserve [Roll Forward]
Restructuring accrual balance, beginning of period	1,022
Provision	28
Cash payments	(606)
Changes in foreign currency exchange rates	(8)
Restructuring accrual balance, end of period	436		436
2017 Announced Restructuring Plan [Member] | Other
Restructuring Reserve [Roll Forward]
Restructuring accrual balance, beginning of period	558
Provision	149
Cash payments	(282)
Changes in foreign currency exchange rates	(4)
Restructuring accrual balance, end of period	421		$ 421
Write-off of inventory	$ 100