| Advances received 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 advances received by the entity before the related work is performed on construction contracts. | en | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |