XML 73 R63.htm IDEA: XBRL DOCUMENT
v3.24.1.1.u2

Leases - Additional Information (Detail) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Mar. 31, 2024 | Mar. 31, 2023 | Mar. 31, 2022
Leases [Line Items] |  |  |
Lessee, option to renew or terminate leases, description | Certain leases include options to renew or terminate. Renewal options are exercisable per the discretion of the Company and vary based on the nature of each lease. |  |
Operating Lease Payments | $ 952 | $ 843 | $ 707
Future fixed minimum lease payments | 5,785 |  |
ROU assets obtained in exchange for operating lease liability | $ 149 | $ 1,169 |
Minimum [Member] |  |  |
Leases [Line Items] |  |  |
Remaining term of contract | 1 year |  |
Maximum [Member] |  |  |
Leases [Line Items] |  |  |
Remaining term of contract | 5 years |  |

X
- Definition Future fixed minimum lease payments. + References No definition available. + Details
Name: | ghm_FutureFixedMinimumLeasePayments
Namespace Prefix: | ghm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Leases. + References No definition available. + Details
Name: | ghm_LeasesLineItems
Namespace Prefix: | ghm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Lessee operating and finance lease remaining term of contract. + References No definition available. + Details
Name: | ghm_LesseeOperatingAndFinanceLeaseRemainingTermOfContract
Namespace Prefix: | ghm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Lessee operating lease and finance lease option to renew or terminate. + References No definition available. + Details
Name: | ghm_LesseeOperatingLeaseAndFinanceLeaseOptionToRenewOrTerminate
Namespace Prefix: | ghm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 5 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479041/842-20-45-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (g)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147478964/842-20-50-4 + Details
Name: | us-gaap_OperatingLeasePayments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of increase in right-of-use asset obtained in exchange for operating lease liability. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 53 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479589/842-20-55-53 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Subparagraph (g)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147478964/842-20-50-4 + Details
Name: | us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |