| Immobilieninvestitionen: Zeitwert [Titel] | de | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Investment properties: Fair value [title] | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Immeubles de placement: Valeur réelle [titre] | fr | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Vastgoedbeleggingen: Reële waarde [titel] | nl | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Immobilieninvestitionen: Zeitwert | de | http://www.xbrl.org/2003/role/terseLabel | http://www.xbrl.org/2003/role/link |
| Investment properties: Fair value | en | http://www.xbrl.org/2003/role/terseLabel | http://www.xbrl.org/2003/role/link |
| Immeubles de placement: Valeur réelle | fr | http://www.xbrl.org/2003/role/terseLabel | http://www.xbrl.org/2003/role/link |
| Vastgoedbeleggingen: Reële waarde | nl | http://www.xbrl.org/2003/role/terseLabel | http://www.xbrl.org/2003/role/link |
| Immobilieninvestitionen: Zeitwert | de | http://www.xbrl.org/2008/role/terseLabel | http://www.xbrl.org/2008/role/link |
| Investment properties: Fair value | en | http://www.xbrl.org/2008/role/terseLabel | http://www.xbrl.org/2008/role/link |
| Immeubles de placement: Valeur réelle | fr | http://www.xbrl.org/2008/role/terseLabel | http://www.xbrl.org/2008/role/link |
| Vastgoedbeleggingen: Reële waarde | nl | http://www.xbrl.org/2008/role/terseLabel | http://www.xbrl.org/2008/role/link |