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, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Segment Reporting Information [Line Items]
Net sales	$ 25,624	$ 22,654	$ 21,126	$ 22,365	$ 22,301	$ 17,323	$ 22,798	$ 27,617	$ 91,769	$ 90,039	$ 135,169
Heat transfer equipment [Member]
Segment Reporting Information [Line Items]
Net sales									27,616	31,479	58,224
Vacuum equipment [Member]
Segment Reporting Information [Line Items]
Net sales									29,672	28,323	28,698
All other [Member]
Segment Reporting Information [Line Items]
Net sales									$ 34,481	$ 30,237	$ 48,247