| Adjustments for increase (decrease) in deferred income | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Concept not required as a result of 2020 general improvements | en | http://www.xbrl.org/2009/role/deprecatedLabel | http://www.xbrl.org/2003/role/link |
| 2021-01-01 | en | http://www.xbrl.org/2009/role/deprecatedDateLabel | http://www.xbrl.org/2003/role/link |
| Adjustments for increase (decrease) in deferred income to reconcile profit (loss) to net cash flow from (used in) operating activities. [Refer: Deferred income; Profit (loss)] | en | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |