Derivative Instruments - Forward Contract Hedges in the Consolidated Condensed Balance Sheets (Details) - Cash Flow Hedging - Designated as hedging instrument - Foreign Exchange Forward - USD ($) $ in Thousands |
Jun. 28, 2019 |
Dec. 31, 2018 |
|---|---|---|
| Other accrued liabilities | ||
| Derivative [Line Items] | ||
| Foreign currency forward designated as cash flow hedge, liability | $ 285 | $ 351 |
| Other non-current assets | ||
| Derivative [Line Items] | ||
| Foreign currency forward designated as cash flow hedge, asset | $ 12 | |
| Other non-current liabilities | ||
| Derivative [Line Items] | ||
| Foreign currency forward designated as cash flow hedge, liability | $ 7 |