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