Foreign Currency Contracts Notional Values (Details) - USD ($) $ in Thousands	Sep. 27, 2019	Dec. 31, 2018
Derivative, Notional Amount	$ 115,860	$ 118,612
Foreign currency contracts related to customer sales contracts | Not Designated As Hedging Instrument [Member]
Derivative, Notional Amount	24,868	43,510
Foreign currency contracts related to supplier purchase contracts | Not Designated As Hedging Instrument [Member]
Derivative, Notional Amount	$ 90,992	$ 75,102