Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

v3.19.1
Document and Entity Information - USD ($)
12 Months Ended
Mar. 31, 2019
May 23, 2019
Sep. 30, 2018
Document And Entity Information [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Mar. 31, 2019    
Document Fiscal Year Focus 2019    
Document Fiscal Period Focus FY    
Trading Symbol GHM    
Entity Registrant Name GRAHAM CORP    
Entity Central Index Key 0000716314    
Current Fiscal Year End Date --03-31    
Entity Well-known Seasoned Issuer No    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Entity Filer Category Accelerated Filer    
Entity Shell Company false    
Entity Emerging Growth Company false    
Entity Small Business false    
Entity Common Stock, Shares Outstanding   9,842,803  
Entity Public Float     $ 268,295,644