Document and Entity Information - USD ($)	12 Months Ended
	Mar. 31, 2018	Jun. 29, 2018	Sep. 30, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	BLACK BOX CORP
Entity Central Index Key	0000849547
Document Type	10-K
Document Period End Date	Mar. 31, 2018
Amendment Flag	false
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--03-31
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		15,233,830
Entity Public Float			$ 47,849,997