2.4.0.8154 - Disclosure - Long-term debt - Additional Information (Detail)truefalsefalse1false USDfalsefalseeol_PE376591--1320-F0001_STD_364_20130330_0http://www.sec.gov/CIK0001179821duration2012-04-01T00:00:002013-03-30T00:00:00DStandardhttp://www.xbrl.org/2009/utrDutr0pureStandardhttp://www.xbrl.org/2003/instancepure0iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170$2false CADfalsefalseeol_PE376591--1320-F0001_STD_364_20130330_0http://www.sec.gov/CIK0001179821duration2012-04-01T00:00:002013-03-30T00:00:00DStandardhttp://www.xbrl.org/2009/utrDutr0iso4217_CADStandardhttp://www.xbrl.org/2003/iso4217CADiso421703false USDfalsefalse$eol_PE376591--1320-F0001_STD_0_20121211_0http://www.sec.gov/CIK0001179821instant2012-12-11T00:00:000001-01-01T00:00:00iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$4false CADfalsefalseeol_PE376591--1320-F0001_STD_0_20121211_0http://www.sec.gov/CIK0001179821instant2012-12-11T00:00:000001-01-01T00:00:00iso4217_CADStandardhttp://www.xbrl.org/2003/iso4217CADiso42170CADCAD5false USDfalsefalse$eol_PE376591--1320-F0001_STD_0_20120331_0http://www.sec.gov/CIK0001179821instant2012-03-31T00:00:000001-01-01T00:00:00iso4217_USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1true 1us-gaap_DebtDisclosureAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Debt Disclosure [Abstract]2false 2us-gaap_LettersOfCreditOutstandingAmountus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse17000001700000USD$falsetruefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5truefalsefalse18000001800000USD$falsetruefalsexbrli:monetaryItemTypemonetaryThe total amount of the contingent obligation under letters of credit outstanding as of the reporting date.No definition available.false2Outstanding letters of credit3false 2bmj_CapitalLeasesExpirationPeriodbmj_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse2020falsefalsefalse2truefalsefalse2020falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalsexbrli:integerItemTypeintegerCapital Leases Expiration PeriodNo definition available.false256Lease period4false 2bmj_CapitalLeaseNetAnnualRentalPaymentbmj_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse20000002000000USD$falsetruefalse2truefalsefalse20131382013138CADfalsetruefalse3truefalsefalse18000001800000USD$falsetruefalse4truefalsefalse18301251830125CADfalsetruefalse5falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryCapital Lease Net Annual Rental PaymentNo definition available.false2Annual rent rate5false 2us-gaap_CapitalLeasesOfLesseeContingentRentalsBasisSpreadOnVariableRateus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truetruefalse0.100.10falsefalsefalse2truetruefalse0.100.10falsefalsefalse3falsetruefalse00falsefalsefalse4falsetruefalse00falsefalsefalse5falsetruefalse00falsefalsefalsenum:percentItemTypepureThe percentage points added to the reference rate to compute the variable rate on the lessee's capital lease.No definition available.false0Increase in percentage of annual rent rate6false 2us-gaap_DescriptionOfLesseeLeasingArrangementsCapitalLeasesus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00The Company has four options to renew and extend the term of the lease for four further terms of five years each, except for the last option which is five years less eleven days, terminating on November 30, 2040. Subject to specific terms and conditions, the Company also has two options to purchase the premises, which may be exercised no later than six months prior to the end of the fifteenth year of the term of the lease and the end of the twentieth year of the term of the lease, respectively.falsefalsefalse2falsefalsefalse00The Company has four options to renew and extend the term of the lease for four further terms of five years each, except for the last option which is five years less eleven days, terminating on November 30, 2040. Subject to specific terms and conditions, the Company also has two options to purchase the premises, which may be exercised no later than six months prior to the end of the fifteenth year of the term of the lease and the end of the twentieth year of the term of the lease, respectively.falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringA general description of the lessee's leasing arrangements including, but not limited to, the following: a) the basis on which contingent rental payments are determined; (b) the existence and terms of renewal or purchase options and escalation clauses; (c) restrictions imposed by lease agreements, such as those concerning dividends, additional debt, and further leasing.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6452660&loc=d3e36991-112694 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 440 -SubTopic 10 -Section 25 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6394851&loc=SL2265659-115463 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 15 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=6451445&loc=d3e32400-112679 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 01-8 -Paragraph 7, 8, 10, 14 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 13 -Paragraph 1 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 13 -Paragraph 16 -Subparagraph d -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false0Condition for lease agreementfalseLong-term debt - Additional Information (Detail)NoRoundingUnKnownUnKnownUnKnowntruefalsetrueSheethttp://www.birksandmayors.com/taxonomy/role/DisclosureLongtermDebtAdditionalInformation56