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

Stock Compensation Plans - Stock Options Outstanding (Detail)

Stock Compensation Plans - Stock Options Outstanding (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2015
Range 1 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price, Minimum	$ 6.90
Exercise Price, Maximum	$ 7.98
Options Outstanding at March 31, 2014	9
Weighted Average Exercise Price	$ 6.96
Weighted Average Remaining Contractual Life (in years)	2 years 1 month 10 days
Range 2 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price, Minimum	$ 12.52
Exercise Price, Maximum	$ 15.25
Options Outstanding at March 31, 2014	24
Weighted Average Exercise Price	$ 14.68
Weighted Average Remaining Contractual Life (in years)	4 years 2 months 19 days
Range 3 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price, Minimum	$ 18.65
Exercise Price, Maximum	$ 21.19
Options Outstanding at March 31, 2014	45
Weighted Average Exercise Price	$ 18.96
Weighted Average Remaining Contractual Life (in years)	7 years 18 days
Range 4 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price, Minimum	$ 30.88
Exercise Price, Maximum	$ 44.50
Options Outstanding at March 31, 2014	12
Weighted Average Exercise Price	$ 33.04
Weighted Average Remaining Contractual Life (in years)	3 years 2 months 12 days
Range 5 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise Price, Minimum	$ 6.90
Exercise Price, Maximum	$ 44.50
Options Outstanding at March 31, 2014	90
Weighted Average Exercise Price	$ 18.57
Weighted Average Remaining Contractual Life (in years)	5 years 3 months 22 days