Graham Corporation Annual report [Section 13 and 15(d), not S-K Item 405]

Annual report [Section 13 and 15(d), not S-K Item 405]

Cover
- Document and Entity Information
Financial Statements
Notes to Financial Statements
Accounting Policies
- The Company and Its Accounting Policies (Policies)
Notes Tables
Notes Details

Segment Information - Additional Information (Detail)

v3.25.1

Segment Information - Additional Information (Detail)	12 Months Ended
Segment Information - Additional Information (Detail)	Mar. 31, 2025 Customer Segment	Mar. 31, 2024 Customer	Mar. 31, 2023 Customer
Segment Reporting Information [Line Items]
Number of reportable operating segments \| Segment	1
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]	srt:ChiefExecutiveOfficerMember
Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description	The Company's chief operating decision maker ("CODM") has been identified as its Chief Executive Officer who evaluates performance on an operating segment bases, as well as a consolidated basis, based on Adjusted EBITDA, which is a non-GAAP measure. This measure is used by our CODM, management, our Board of Directors, investors, lenders and other external users of our financial statements to assess our operating performance and to compare operating performance to other companies in our industry.
Customer Concentration Risk [Member] \| Net Sales [Member] \| Customer One [Member]
Segment Reporting Information [Line Items]
Number of customers	1	1	1
Concentration risk percentage	17.00%	16.00%	15.00%
Customer Concentration Risk [Member] \| Net Sales [Member] \| Customer Two [Member]
Segment Reporting Information [Line Items]
Number of customers	2	2	2
Concentration risk percentage	13.00%	15.00%	12.00%

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