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

Segment Information - Net Sales by Product Line (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Net sales	$ 22,301	$ 17,323	$ 22,798	$ 27,617	$ 37,455	$ 33,646	$ 35,566	$ 28,502	$ 90,039	$ 135,169	$ 102,218
Heat transfer equipment [Member]
Segment Reporting Information [Line Items]
Net sales									31,479	58,224	37,086
Vacuum equipment [Member]
Segment Reporting Information [Line Items]
Net sales									28,323	28,698	27,236
All other [Member]
Segment Reporting Information [Line Items]
Net sales									$ 30,237	$ 48,247	$ 37,896