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

Changes in Accumulated Other Comprehensive Loss - Reclassifications Out of Accumulated Other Comprehensive Loss by Component (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before provision for income taxes									$ (145)	$ (12,854)	$ 7,049
Provision for income taxes									163	(3,010)	2,026
Net income	$ (4,553)	$ 95	$ 1,827	$ 2,323	$ 833	$ (11,622)	$ 10	$ 935	(308)	(9,844)	$ 5,023
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									(875)	(1,050)
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]
Income before provision for income taxes									(875)	(1,050)
Provision for income taxes									(142)	(233)
Net income									$ (733)	$ (817)

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