XML 50 R42.htm IDEA: XBRL DOCUMENT v3.22.2
Currency conversion (Detail)
 6 Months Ended
Jun. 30, 2022
Jun. 30, 2021
Dec. 31, 2021
US dollar to Pound sterling      
Disclosure Of Foreign Currency Translation [line items]      
Average exchange rate 1.30 1.39  
Closing exchange rate 1.22   1.35
Euro to Pound sterling      
Disclosure Of Foreign Currency Translation [line items]      
Average exchange rate 1.19 1.15  
Closing exchange rate 1.16   1.19