| Investitionen in Hypothekendarlehen [Mitglied] | de | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Investments in mortgage loans [member] | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Placements dans des prêts hypothécaires [membre] | fr | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Beleggingen in hypothecaire leningen [member] | nl | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Investitionen in Hypothekendarlehen | de | http://www.xbrl.org/2003/role/terseLabel | http://www.xbrl.org/2003/role/link |
| Investments in mortgage loans | en | http://www.xbrl.org/2003/role/terseLabel | http://www.xbrl.org/2003/role/link |
| Placements dans des prêts hypothécaires | fr | http://www.xbrl.org/2003/role/terseLabel | http://www.xbrl.org/2003/role/link |
| Beleggingen in hypothecaire leningen | nl | http://www.xbrl.org/2003/role/terseLabel | http://www.xbrl.org/2003/role/link |