Deferred Revenues (Tables)  | 
12 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||
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Dec. 31, 2018  | ||||||||||||||||||||||||||||||||||||||||||||||
| Revenue from Contract with Customer [Abstract] | ||||||||||||||||||||||||||||||||||||||||||||||
| Schedule of Deferred Revenues | 
 Deferred revenues are comprised of the following: 
 
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- Definition Schedule of Deferred Revenues [Table Text Block] No definition available. 
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- References No definition available. 
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