Quarterly report pursuant to Section 13 or 15(d)

Document and Entity Information

Document and Entity Information - shares
3 Months Ended
Jun. 30, 2019
Jul. 25, 2019
Document And Entity Information [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Jun. 30, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q1  
Trading Symbol GHM  
Entity Registrant Name GRAHAM CORP  
Entity Central Index Key 0000716314  
Current Fiscal Year End Date --03-31  
Entity Filer Category Accelerated Filer  
Entity Current Reporting Status Yes  
Entity Shell Company false  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity File Number 1-8462  
Entity Tax Identification Number 161194720  
Entity Address, Address Line One 20 Florence Avenue  
Entity Address, City or Town Batavia  
Entity Address, State or Province New York  
Entity Address, Postal Zip Code 14020  
City Area Code 585  
Local Phone Number 343-2216  
Entity Common Stock, Shares Outstanding   9,880,798