| Plan assets, at fair value | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Plan assets, at fair value at beginning of period | en | http://www.xbrl.org/2003/role/periodStartLabel | http://www.xbrl.org/2003/role/link |
| Plan assets, at fair value at end of period | en | http://www.xbrl.org/2003/role/periodEndLabel | http://www.xbrl.org/2003/role/link |
| The fair value of defined benefit plan assets. Plan assets comprise assets held by a long-term employee benefit fund and qualifying insurance policies. [Refer: At fair value [member]] | en | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |