| r0.c0 | Inventories/Current | venj-bw2-i:Inventories | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r0.c1 | Inventories/Previous | venj-bw2-i:Inventories | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r1.c0 | Inventories [title]/Current | venj-bw2-abstr:BW2InventoriesTitle | xbrli:stringItemType | duration | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r1.c1 | Inventories [title]/Previous | venj-bw2-abstr:BW2InventoriesTitle | xbrli:stringItemType | duration | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r2.c0 | Trade receivables/Current | venj-bw2-i:TradeReceivables | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r2.c1 | Trade receivables/Previous | venj-bw2-i:TradeReceivables | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r3.c0 | Receivables from OCW and EZ (current)/Current | ocw-i:ReceivablesOCWAndEZCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r3.c1 | Receivables from OCW and EZ (current)/Previous | ocw-i:ReceivablesOCWAndEZCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r4.c0 | Receivables from local government and common regulations (current)/Current | ocw-i:ReceivablesLocalGovernmentCommonRegulationsCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r4.c1 | Receivables from local government and common regulations (current)/Previous | ocw-i:ReceivablesLocalGovernmentCommonRegulationsCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r5.c0 | Current receivables from group companies/Current | venj-bw2-i:ReceivablesGroupCompaniesCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r5.c1 | Current receivables from group companies/Previous | venj-bw2-i:ReceivablesGroupCompaniesCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r6.c0 | Receivables from other participating interests (current)/Current | ocw-i:ReceivablesOtherParticipatingInterestsCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r6.c1 | Receivables from other participating interests (current)/Previous | ocw-i:ReceivablesOtherParticipatingInterestsCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r7.c0 | Receivables from personnel (current)/Current | ocw-i:ReceivablesEmployeesCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r7.c1 | Receivables from personnel (current)/Previous | ocw-i:ReceivablesEmployeesCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r8.c0 | Receivables from parents, students and course participants (current)/Current | ocw-i:ReceivablesParentsStudentsAndCourseParticipantsCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r8.c1 | Receivables from parents, students and course participants (current)/Previous | ocw-i:ReceivablesParentsStudentsAndCourseParticipantsCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r9.c0 | Receivables from other government institutions (current)/Current | ocw-i:ReceivablesGovernmentOtherCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r9.c1 | Receivables from other government institutions (current)/Previous | ocw-i:ReceivablesGovernmentOtherCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r10.c0 | Construction contracts (assets)/Current | rj-i:ConstructionContractsAssets | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r10.c1 | Construction contracts (assets)/Previous | rj-i:ConstructionContractsAssets | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r11.c0 | Current other receivables/Current | venj-bw2-i:ReceivablesOtherCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r11.c1 | Current other receivables/Previous | venj-bw2-i:ReceivablesOtherCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r12.c0 | Receivables, provision bad debts/Current | ocw-i:ReceivablesProvisionBadDebts | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r12.c1 | Receivables, provision bad debts/Previous | ocw-i:ReceivablesProvisionBadDebts | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r13.c0 | Receivables current excluding accrued income, subtotal/Current | ocw-i:ReceivablesCurrentExcludingAccruedIncomeSubtotal | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r13.c1 | Receivables current excluding accrued income, subtotal/Previous | ocw-i:ReceivablesCurrentExcludingAccruedIncomeSubtotal | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r14.c0 | Receivables from taxes and social security contributions (current)/Current | ocw-i:TaxesSocialSecurityContributionsReceivableCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r14.c1 | Receivables from taxes and social security contributions (current)/Previous | ocw-i:TaxesSocialSecurityContributionsReceivableCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r15.c0 | Prepayments/Current | ocw-i:AdvancesPaidPrepayments | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r15.c1 | Prepayments/Previous | ocw-i:AdvancesPaidPrepayments | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r16.c0 | Periodic payments/Current | ocw-i:AdvancesPaidPeriodicPayments | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r16.c1 | Periodic payments/Previous | ocw-i:AdvancesPaidPeriodicPayments | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r17.c0 | Interest receivable/Current | ocw-i:InterestReceivable | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r17.c1 | Interest receivable/Previous | ocw-i:InterestReceivable | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r18.c0 | Other accrued income/Current | venj-bw2-i:AccruedIncomeOther | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r18.c1 | Other accrued income/Previous | venj-bw2-i:AccruedIncomeOther | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r19.c0 | Prepayments and accrued income/Current | venj-bw2-i:AccruedIncome | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r19.c1 | Prepayments and accrued income/Previous | venj-bw2-i:AccruedIncome | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r20.c0 | Prepayments and accrued income [title]/Current | venj-bw2-abstr:AccruedIncomeTitle | xbrli:stringItemType | duration | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r20.c1 | Prepayments and accrued income [title]/Previous | venj-bw2-abstr:AccruedIncomeTitle | xbrli:stringItemType | duration | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r21.c0 | Receivables/Current | venj-bw2-i:Receivables | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r21.c1 | Receivables/Previous | venj-bw2-i:Receivables | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r22.c0 | Receivables [title]/Current | venj-bw2-abstr:BW2ReceivablesTitle | xbrli:stringItemType | duration | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r22.c1 | Receivables [title]/Previous | venj-bw2-abstr:BW2ReceivablesTitle | xbrli:stringItemType | duration | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r23.c0 | Current shares and other variable-yield securities/Current | ocw-i:SharesOtherVariableYieldSecuritiesCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r23.c1 | Current shares and other variable-yield securities/Previous | ocw-i:SharesOtherVariableYieldSecuritiesCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r24.c0 | Current bonds and other fixed-income securities/Current | ocw-i:BondsOtherFixedIncomeSecuritiesCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r24.c1 | Current bonds and other fixed-income securities/Previous | ocw-i:BondsOtherFixedIncomeSecuritiesCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r25.c0 | Current securities/Current | venj-bw2-i:SecuritiesCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r25.c1 | Current securities/Previous | venj-bw2-i:SecuritiesCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r26.c0 | Securities [title]/Current | kvk-abstr:SecuritiesTitle | xbrli:stringItemType | duration | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r26.c1 | Securities [title]/Previous | kvk-abstr:SecuritiesTitle | xbrli:stringItemType | duration | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r27.c0 | Cash/Current | ocw-i:Cash | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r27.c1 | Cash/Previous | ocw-i:Cash | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r28.c0 | Bank accounts balance/Current | ocw-i:BankAccountsBalance | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r28.c1 | Bank accounts balance/Previous | ocw-i:BankAccountsBalance | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r29.c0 | Deposits/Current | ocw-i:Deposits | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r29.c1 | Deposits/Previous | ocw-i:Deposits | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r30.c0 | Treasury banking/Current | ocw-i:TreasuryBanking | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r30.c1 | Treasury banking/Previous | ocw-i:TreasuryBanking | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r31.c0 | Cash and cash equivalents/Current | venj-bw2-i:CashAndCashEquivalents | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r31.c1 | Cash and cash equivalents/Previous | venj-bw2-i:CashAndCashEquivalents | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r32.c0 | Cash and cash equivalents [title]/Current | kvk-abstr:CashAndCashEquivalentsTitle | xbrli:stringItemType | duration | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r32.c1 | Cash and cash equivalents [title]/Previous | kvk-abstr:CashAndCashEquivalentsTitle | xbrli:stringItemType | duration | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |
| r33.c0 | Current assets/Current | venj-bw2-i:AssetsCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2017-12-31') | venj-bw2-dm:SeparateMember |
| r33.c1 | Current assets/Previous | venj-bw2-i:AssetsCurrent | nl-types:monetaryNoDecimalsItemType | instant | ocw-dm:ActualsMember | xs:date('2016-12-31') | venj-bw2-dm:SeparateMember |