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		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before provision for income taxes	$ 6	$ 39	$ 1,660	$ 5,069
Provision for income taxes	(3)	(56)	364	824
Net income	9	95	1,296	4,245
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)	(747)	(655)
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	(55)	(48)	(164)	(145)
Net income	$ (194)	$ (170)	$ (583)	$ (510)

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