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

Changes in Accumulated Other Comprehensive Loss - Reclassifications Out of Accumulated Other Comprehensive Loss by Component (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before provision for income taxes	$ 1,547	$ 2,005	$ 1,654	$ 5,030
Provision for income taxes	342	178	367	880
Net income	1,205	1,827	1,287	4,150
Reclassifications Out of Accumulated Other Comprehensive Loss [Member] \| Amortization of Actuarial Loss [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before provision for income taxes	(249)	(218)	(498)	(437)
Reclassifications Out of Accumulated Other Comprehensive Loss [Member] \| Pension and Other Postretirement Benefits Items [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Provision for income taxes	(54)	(48)	(109)	(97)
Net income	$ (195)	$ (170)	$ (389)	$ (340)

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.