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Share-based payment (Details) - Schedule non-vested shares activity - $ / shares
6 Months Ended 12 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Dec. 31, 2020
Non-Vested Share [Member]      
Share-based payment (Details) - Schedule non-vested shares activity [Line Items]      
Weighted average grant date fair value per share, outstanding at beginning   $ 182.13 $ 182.13
Weighted average grant date fair value per share, transfer from non-vested shares   182.13  
Weighted average grant date fair value per share, outstanding at ending    
Weighted average grant date fair value per share, Outstanding as of June 30, 2020    
Non-Vested Share [Member] | Non-vested share [Member]      
Share-based payment (Details) - Schedule non-vested shares activity [Line Items]      
Number of non-vested shares, outstanding at beginning   20,523 20,523
Number of non-vested shares, transfer from non-vested shares   (20,523)  
Number of non-vested shares, outstanding at ending    
Number of non-vested shares, Outstanding as of June 30, 2020    
Non-Vested Share Units [Member]      
Share-based payment (Details) - Schedule non-vested shares activity [Line Items]      
Weighted average grant date fair value per share, outstanding at beginning $ 149.10 $ 143.89 $ 143.89
Weighted average grant date fair value per share, forfeited 227.24  
Weighted average grant date fair value per share, transfer from non-vested shares   182.13  
Weighted average grant date fair value per share, outstanding at ending $ 149.10 149.10 $ 149.10
Weighted average grant date fair value per share, Outstanding as of June 30, 2020   $ 149.10  
Non-Vested Share Units [Member] | Non-vested share [Member]      
Share-based payment (Details) - Schedule non-vested shares activity [Line Items]      
Number of non-vested shares, outstanding at beginning 143,652 123,575 123,575
Number of non-vested shares, forfeited (446)  
Number of non-vested shares, transfer from non-vested shares   20,523  
Number of non-vested shares, outstanding at ending 143,652 143,652 143,652
Number of non-vested shares, Outstanding as of June 30, 2020   143,652