Derivative Instruments and Hedging Activity (Details - Designated as hedges) - Designated as hedging instrument - USD ($) $ in Thousands	Mar. 27, 2020	Dec. 31, 2019
Derivative [Line Items]
Notional amount total	$ 35,742	$ 34,205
Fair value total	1,762	657
Prepaid expenses
Derivative [Line Items]
Notional amount, asset	13,241	7,558
Fair value, asset	172	188
Prepaid expenses | Foreign currency forward contract | Yen
Derivative [Line Items]
Notional amount, asset	807	1,025
Fair value, asset	16	10
Prepaid expenses | Foreign currency forward contract | Euro
Derivative [Line Items]
Notional amount, asset	12,434	3,466
Fair value, asset	156	83
Prepaid expenses | Precious metal swaps
Derivative [Line Items]
Notional amount, asset	0	1,116
Fair value, asset	0	34
Prepaid expenses | Copper swaps
Derivative [Line Items]
Notional amount, asset	0	1,951
Fair value, asset	0	61
Other assets | Precious metal swaps
Derivative [Line Items]
Notional amount, asset	0	157
Fair value, asset	0	1
Other liabilities and accrued items
Derivative [Line Items]
Notional amount, liability	21,317	26,341
Fair value, liability	1,877	841
Other liabilities and accrued items | Foreign currency forward contract | Yen
Derivative [Line Items]
Notional amount, liability	2,780	2,355
Fair value, liability	32	12
Other liabilities and accrued items | Foreign currency forward contract | Euro
Derivative [Line Items]
Notional amount, liability	6,956	15,686
Fair value, liability	328	183
Other liabilities and accrued items | Precious metal swaps
Derivative [Line Items]
Notional amount, liability	8,441	7,034
Fair value, liability	1,093	618
Other liabilities and accrued items | Copper swaps
Derivative [Line Items]
Notional amount, liability	3,140	1,266
Fair value, liability	424	28
Other long-term liabilities
Derivative [Line Items]
Notional amount, liability	1,184	149
Fair value, liability	57	5
Other long-term liabilities | Foreign currency forward contract | Yen
Derivative [Line Items]
Notional amount, liability	109	0
Fair value, liability	4	0
Other long-term liabilities | Foreign currency forward contract | Euro
Derivative [Line Items]
Notional amount, liability	1,075	0
Fair value, liability	53	0
Other long-term liabilities | Precious metal swaps
Derivative [Line Items]
Notional amount, liability	0	149
Fair value, liability	$ 0	$ 5