Graham Corporation Annual report pursuant to Section 13 and 15(d)

Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Mar. 31, 2012
Summary of intangible asset
Finite-Lived Intangible Assets, Gross Carrying Amount	$ 2,870	$ 2,870
Finite-Lived Intangible Assets, Accumulated Amortization	582	402
Finite-Lived Intangible Assets, Net Carrying Amount	2,288	2,468
Indefinite-lived Intangible Assets [Line Items]
Indefinite Lived Intangible Assets, Gross Carrying Amount	12,800	12,800
Indefinite Lived Intangible Assets, Net Carrying Amount	12,800	12,800
Permits [Member]
Indefinite-lived Intangible Assets [Line Items]
Indefinite Lived Intangible Assets, Gross Carrying Amount	10,300	10,300
Indefinite Lived Intangible Assets, Net Carrying Amount	10,300	10,300
Tradename [Member]
Indefinite-lived Intangible Assets [Line Items]
Indefinite Lived Intangible Assets, Gross Carrying Amount	2,500	2,500
Indefinite Lived Intangible Assets, Net Carrying Amount	2,500	2,500
Backlog [Member]
Summary of intangible asset
Finite-Lived Intangible Assets, Gross Carrying Amount	170	170
Finite-Lived Intangible Assets, Accumulated Amortization	170	170
Customer relationships [Member]
Summary of intangible asset
Finite-Lived Intangible Assets, Gross Carrying Amount	2,700	2,700
Finite-Lived Intangible Assets, Accumulated Amortization	412	232
Finite-Lived Intangible Assets, Net Carrying Amount	$ 2,288	$ 2,468