v3.8.0.1
Document and Entity Information - shares
9 Months Ended
Dec. 31, 2017
Jan. 31, 2018
Document and Entity Information [Abstract]    
Entity Registrant Name Booz Allen Hamilton Holding Corp  
Entity Central Index Key 0001443646  
Document Type 10-Q  
Document Period End Date Dec. 31, 2017  
Amendment Flag false  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q3  
Current Fiscal Year End Date --03-31  
Entity Filer Category Large Accelerated Filer  
Common stock, Class A    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   145,062,716
Non-voting common stock, Class B    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   0
Restricted common stock, Class C    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   0
Special voting common stock, Class E    
Entity Listings [Line Items]    
Entity Common Stock, Shares Outstanding   0