Annual report pursuant to Section 13 and 15(d)

Contingencies (Details)

v2.4.1.9
Contingencies (Details) (USD $)
In Millions, unless otherwise specified
0 Months Ended 1 Months Ended 0 Months Ended
May 08, 2014
item
Sep. 15, 2011
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Jan. 31, 2015
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Feb. 10, 2011
item
Dec. 03, 2013
item
Mar. 18, 2014
item
Jan. 31, 2014
item
Commitments and Contingencies              
Aggregate estimate of possible loss     17us-gaap_LossContingencyEstimateOfPossibleLoss        
Rea claims              
Commitments and Contingencies              
Number of plaintiffs 50us-gaap_LossContingencyNumberOfPlaintiffs
/ us-gaap_LossContingenciesByNatureOfContingencyAxis
= mik_ReaClaimMember
4us-gaap_LossContingencyNumberOfPlaintiffs
/ us-gaap_LossContingenciesByNatureOfContingencyAxis
= mik_ReaClaimMember
         
Number of certified members         200mik_LossContingencyNumberOfCertifiedMembers
/ us-gaap_LossContingenciesByNatureOfContingencyAxis
= mik_ReaClaimMember
   
Graham claim              
Commitments and Contingencies              
Number of new claims filed     4us-gaap_LossContingencyNewClaimsFiledNumber
/ us-gaap_LossContingenciesByNatureOfContingencyAxis
= mik_GrahamClaimMember
       
Data security incident              
Commitments and Contingencies              
Number of pending claims           5us-gaap_LossContingencyPendingClaimsNumber
/ us-gaap_LossContingenciesByNatureOfContingencyAxis
= mik_DataSecurityIncidentMember
4us-gaap_LossContingencyPendingClaimsNumber
/ us-gaap_LossContingenciesByNatureOfContingencyAxis
= mik_DataSecurityIncidentMember
California zip code claims              
Commitments and Contingencies              
Number of cases consolidated       3mik_LossContingencyNumberOfCasesConsolidated
/ us-gaap_LossContingenciesByNatureOfContingencyAxis
= mik_CaliforniaZipCodeClaimsMember