| Other comprehensive income, net of tax, exchange differences on translation | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Other comprehensive income, net of tax, exchange differences on translation | en | http://www.xbrl.org/2003/role/totalLabel | http://www.xbrl.org/2003/role/link |
| The amount of other comprehensive income, net of tax, related to exchange differences when financial statements of foreign operations are translated. [Refer: Other comprehensive income] | en | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |