| Retention for contracts in progress | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Concept not required due to removal of IAS 11 | en | http://www.xbrl.org/2009/role/deprecatedLabel | http://www.xbrl.org/2003/role/link |
| 2018-01-01 | en | http://www.xbrl.org/2009/role/deprecatedDateLabel | http://www.xbrl.org/2003/role/link |
| The amount of progress billings on construction contracts that are not paid until the conditions specified in the contract for the payment of such amounts have been satisfied or until defects have been rectified. [Refer: Progress billings] | en | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |