Quarterly report pursuant to Section 13 or 15(d)

Document and Entity Information

v3.20.2
Document and Entity Information - shares
 6 Months Ended
Sep. 30, 2020
Oct. 27, 2020
Cover [Abstract]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Sep. 30, 2020  
Document Fiscal Year Focus 2020  
Document Fiscal Period Focus Q2  
Trading Symbol GHM  
Entity Registrant Name GRAHAM CORPORATION  
Entity Central Index Key 0000716314  
Current Fiscal Year End Date --03-31  
Entity Filer Category Non-accelerated Filer  
Entity Current Reporting Status Yes  
Entity Shell Company false  
Entity Small Business true  
Entity Emerging Growth Company false  
Title of 12(b) Security Common Stock, Par Value $0.10 Per Share  
Security Exchange Name NYSE  
Entity File Number 1-08462  
Entity Tax Identification Number 16-1194720  
Entity Incorporation, State or Country Code DE  
Entity Address, Address Line One 20 Florence Avenue  
Entity Address, City or Town Batavia  
Entity Address, State or Province NY  
Entity Address, Postal Zip Code 14020  
City Area Code 585  
Local Phone Number 343-2216  
Entity Interactive Data Current Yes  
Entity Common Stock, Shares Outstanding   9,976,893
Document Quarterly Report true  
Document Transition Report false