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11 Intangible assets and goodwill (Details 2)
 12 Months Ended
Dec. 31, 2020
Education Content [Member]  
Disclosure of detailed information about intangible assets [line items]  
Estimated useful lives of intangible assets 3 years
Customer relationships - medicine [member]  
Disclosure of detailed information about intangible assets [line items]  
Estimated useful lives of intangible assets 6 years
Customer relationships - other courses [member]  
Disclosure of detailed information about intangible assets [line items]  
Estimated useful lives of intangible assets 4 years 6 months
Trademarks [member] | Bottom of Range [Member]  
Disclosure of detailed information about intangible assets [line items]  
Estimated useful lives of intangible assets 19 years
Trademarks [member] | Top of Range [member]  
Disclosure of detailed information about intangible assets [line items]  
Estimated useful lives of intangible assets 20 years
Developed technology [member]  
Disclosure of detailed information about intangible assets [line items]  
Estimated useful lives of intangible assets 5 years
Software [member]  
Disclosure of detailed information about intangible assets [line items]  
Estimated useful lives of intangible assets 5 years