Graham Corporation Quarterly report pursuant to Section 13 or 15(d)

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
Income Taxes - Additional Information (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2014
Income Taxes [Line Items]
Liability unrecognized tax benefits	$ 0us-gaap_UnrecognizedTaxBenefits		$ 0us-gaap_UnrecognizedTaxBenefits		$ 0us-gaap_UnrecognizedTaxBenefits
Unrecognized tax benefits, interest expense on income taxes	0	(15,000)	0	(11,000)
Penalties related to uncertain tax positions	$ 0	$ 0	$ 0	$ 0
Earliest Tax Year [Member] \| Federal Tax Jurisdictions [Member]
Income Taxes [Line Items]
Federal and State tax jurisdictions for tax period			2013
Earliest Tax Year [Member] \| State Tax Jurisdictions [Member]
Income Taxes [Line Items]
Federal and State tax jurisdictions for tax period			2010
Earliest Tax Year [Member] \| International Tax Jurisdictions [Member]
Income Taxes [Line Items]
Federal and State tax jurisdictions for tax period			2012
Latest Tax Year [Member] \| Federal Tax Jurisdictions [Member]
Income Taxes [Line Items]
Federal and State tax jurisdictions for tax period			2014
Latest Tax Year [Member] \| State Tax Jurisdictions [Member]
Income Taxes [Line Items]
Federal and State tax jurisdictions for tax period			2014
Latest Tax Year [Member] \| International Tax Jurisdictions [Member]
Income Taxes [Line Items]
Federal and State tax jurisdictions for tax period			2014