| In millions, except per share items | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 | Dec-31-14 | Dec-31-13 |
| | 20-F | 20-F | 20-F | 20-F | 20-F | 20-F | 20-F | 20-F |
| Statement [Table] | | | | | | | | |
| US Dollars [Member] | | | | | | | | |
| Statement Line Items [Line Items] | | | | | | | | |
| Revenue | | | | | | | | |
| Cost of sales | | | | | | | | |
| Gross profit | | | | | | | | |
| Operating costs and expenses | | | | | | | | |
| Selling expenses | | | | | | | | |
| General and administrative expenses | | | | | | | | |
| Other Income | | | | | | | | |
| Operating costs and expenses | 27.3 | 76.6 | 60.4 | 57.6 | 53.9 | | | |
| |
| Operating profit | | | | | | | | |
| Finance Income | 3.5 | 21.0 | -7.2 | 17.9 | -3.4 | | | |
| Finance expense | 0.4 | 3.0 | -2.3 | 3.8 | 3.1 | | | |
| |
| Profit before taxes on Income | | | | | | | | |
| Taxes on Income | | | | | | | | |
| Net Income | | | | | | | | |
| Earnings per share: | | | | | | | | |
| Basic earnings per share | | | | | | | | |
| Diluted earnings per share | | | | | | | | |
| Shares used in computation of basic/ diluted EPS | shares | | | | | | | | |
| Actual number of shares | shares | | | | | | | | |