Document and Entity Information - shares	6 Months Ended
	Sep. 30, 2017	Oct. 24, 2017
Document And Entity Information
Entity Registrant Name	RBC Bearings INC
Entity Central Index Key	0001324948
Document Type	10-Q
Trading Symbol	ROLL
Document Period End Date	Sep. 30, 2017
Amendment Flag	false
Current Fiscal Year End Date	--03-31
Entity a Well-known Seasoned Issuer	No
Entity a Voluntary Filer	No
Entity's Reporting Status Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		24,245,194
Document Fiscal Period Focus	Q2
Document Fiscal Year Focus	2018