Derivative Instruments and Hedging Activity (Details - Not designated as hedges) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 26, 2020	Jun. 26, 2020	Dec. 31, 2019
Derivative Instruments, Gain (Loss)
Gain on foreign currency derivatives recorded in earnings, net	$ 1,700	$ 2,300
Not designated as hedging instrument | Prepaid expenses | Foreign currency forward contract
Derivative Instruments, Gain (Loss)
Notional amount, asset	152,803	152,803	$ 13,734
Fair value, asset	2,198	2,198	95
Not designated as hedging instrument | Other liabilities and accrued items | Foreign currency forward contract
Derivative Instruments, Gain (Loss)
Notional amount, liability	9,786	9,786	5,757
Fair value, liability	$ 63	$ 63	$ 16