| r0.c0 | Number of rental agreements regarding housing facilities/Current | bzk-dvi-i:NumberOfRentalAgreements | xbrli:nonNegativeIntegerItemType | instant | $BasisOfPreparationParam | bzk-ww-dm:DAEBActivitiesMember | $FinancialReportingPeriodCurrentEndDateParam |
| r1.c0 | Number of rental agreements of yearly household income lower than € 36.798/Current | bzk-dvi-i:NumberOfRentalAgreementslHouseholdIncomeTillThirtySixThousandSevenHundredNinetyEight | xbrli:nonNegativeIntegerItemType | instant | $BasisOfPreparationParam | bzk-ww-dm:DAEBActivitiesMember | $FinancialReportingPeriodCurrentEndDateParam |
| r2.c0 | Number of rental agreements of yearly household income higher than € 36.798 but lower than € 41.056/Current | bzk-dvi-i:NumberOfRentalAgreementslHouseholdIncomeFromThirtySixThousandSevenHundredNinetyEightToFourtyOneThousandFiftySix | xbrli:nonNegativeIntegerItemType | instant | $BasisOfPreparationParam | bzk-ww-dm:DAEBActivitiesMember | $FinancialReportingPeriodCurrentEndDateParam |
| r3.c0 | Number of rental agreements of yearly household income higher than € 41.056/Current | bzk-dvi-i:NumberOfRentalAgreementslHouseholdIncomeFromFourtyOneThousandFiftySix | xbrli:nonNegativeIntegerItemType | instant | $BasisOfPreparationParam | bzk-ww-dm:DAEBActivitiesMember | $FinancialReportingPeriodCurrentEndDateParam |