Document and Entity Information - shares
6 Months Ended
Sep. 29, 2018
Oct. 12, 2018
Document and Entity Information [Abstract]    
Entity Registrant Name BLACK BOX CORP  
Entity Central Index Key 0000849547  
Document Type 10-Q  
Document Period End Date Sep. 29, 2018  
Amendment Flag false  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q2  
Current Fiscal Year End Date --03-31  
Entity Filer Category Non-accelerated Filer  
Entity Common Stock, Shares Outstanding   15,237,521