XML 100 R87.htm IDEA: XBRL DOCUMENT
v3.21.1

Subsequent Events - Additional Information (Detail) - USD ($) shares in Thousands, $ in Thousands |  | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | ---
Jun. 01, 2021 | Mar. 31, 2020 | Dec. 02, 2020 | Oct. 08, 2020 | May 01, 2020
HSBC Bank USA [Member] | Letter of Credit [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Line of credit |  | $ 10,000 |  | $ 15,000 | $ 14,000
Letter of Credit [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Line of credit |  |  | $ 7,000 |  |
Revolving Credit Facility [Member] | HSBC Bank USA [Member] | Letter of Credit [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Debt instrument, basis spread on variable rate |  | 3.00% |  |  |
Annual facility fee |  | $ 5 |  |  |
Maximum [Member] | Revolving Credit Facility [Member] | HSBC Bank USA [Member] | Letter of Credit [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Fee for outstanding letters of credit |  | 0.85% |  |  |
Minimum [Member] | Revolving Credit Facility [Member] | HSBC Bank USA [Member] | Letter of Credit [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Fee for outstanding letters of credit |  | 0.75% |  |  |
Subsequent Event [Member] | Revolving Credit Facility [Member] | Letter of Credit [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Debt instrument, basis spread on variable rate | 3.00% |  |  |  |
Annual facility fee | $ 5 |  |  |  |
Subsequent Event [Member] | Maximum [Member] | HSBC Bank USA [Member] | Letter of Credit [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Line of credit | $ 15,000 |  |  |  |
Subsequent Event [Member] | Maximum [Member] | Revolving Credit Facility [Member] | Letter of Credit [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Fee for outstanding letters of credit | 0.85% |  |  |  |
Subsequent Event [Member] | Minimum [Member] | HSBC Bank USA [Member] | Letter of Credit [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Line of credit | $ 7,500 |  |  |  |
Subsequent Event [Member] | Minimum [Member] | Revolving Credit Facility [Member] | Letter of Credit [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Fee for outstanding letters of credit | 0.75% |  |  |  |
Barber-Nichols, Inc. [Member] | Subsequent Event [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Business combination, purchase price | $ 70,113 |  |  |  |
Business combination, common stock, shares | 610 |  |  |  |
Business combination, common stock value | $ 8,963 |  |  |  |
Business combination, cash consideration | 61,150 |  |  |  |
Term loan payment | $ 20,000 |  |  |  |
Term loan payment period | 5 years |  |  |  |
Term loan principal payment frequency | monthly |  |  |  |
Term loan principal payment | $ 167 |  |  |  |
Remaining principal amount maturity date | Jun. 01, 2026 |  |  |  |
Percentage of upfront fees | 0.20% |  |  |  |
Unused commitment fee for borrowing | 0.25% |  |  |  |
Maximum leverage ratio | 3.0 |  |  |  |
Minimum fixed charge coverage ratio | 1.20 |  |  |  |
Percentage of minimum margined assets on outstanding facility | 100.00% |  |  |  |
Barber-Nichols, Inc. [Member] | Subsequent Event [Member] | Line of Credit [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Line of credit | $ 30,000 |  |  |  |
Maximum limit of credit facility | $ 40,000 |  |  |  |
Barber-Nichols, Inc. [Member] | Subsequent Event [Member] | Letter of Credit [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Fee for outstanding letters of credit | 1.50% |  |  |  |
Barber-Nichols, Inc. [Member] | Subsequent Event [Member] | BSBY [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Debt instrument, basis spread on variable rate | 1.50% |  |  |  |
Barber-Nichols, Inc. [Member] | Subsequent Event [Member] | BSBY [Member] | Line of Credit [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Debt instrument, basis spread on variable rate | 1.50% |  |  |  |
Barber-Nichols, Inc. [Member] | Subsequent Event [Member] | Floor Rate [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Debt instrument, basis spread on variable rate | 0.00% |  |  |  |
Barber-Nichols, Inc. [Member] | Subsequent Event [Member] | Floor Rate [Member] | Line of Credit [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Debt instrument, basis spread on variable rate | 0.00% |  |  |  |
Barber-Nichols, Inc. [Member] | Subsequent Event [Member] | Maximum [Member] |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Business combination contingent earn-out eligible to receive, additional cash consideration | $ 14,000 |  |  |  |

X
- Definition The fee, expressed as a percentage of the standby letter of credit amount, incurred for the issuance of a standby letter of credit. + References No definition available. + Details
Name: | ghm_LetterOfCreditCommitmentFeePercentage
Namespace Prefix: | ghm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of the flat fee for the line of credit facility. + References No definition available. + Details
Name: | ghm_LineOfCreditFee
Namespace Prefix: | ghm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Maximum leverage ratio. + References No definition available. + Details
Name: | ghm_MaximumLeverageRatio
Namespace Prefix: | ghm_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition Minimum fixed charge coverage ratio. + References No definition available. + Details
Name: | ghm_MinimumFixedChargeCoverageRatio
Namespace Prefix: | ghm_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of minimum margined assets on outstanding facility. + References No definition available. + Details
Name: | ghm_PercentageOfMinimumMarginedAssetsOnOutstandingFacility
Namespace Prefix: | ghm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Remaining principal amount maturity date. + References No definition available. + Details
Name: | ghm_RemainingPrincipalAmountMaturityDate
Namespace Prefix: | ghm_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares of equity interests issued or issuable to acquire entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b)(4) -URI http://asc.fasb.org/extlink&oid=120321790&loc=d3e6927-128479 + Details
Name: | us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=116859721&loc=d3e6613-128477 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=120321790&loc=d3e6927-128479 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=116859721&loc=d3e6578-128477 + Details
Name: | us-gaap_BusinessCombinationConsiderationTransferred1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=116859721&loc=d3e6613-128477 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=116859721&loc=d3e6578-128477 + Details
Name: | us-gaap_BusinessCombinationConsiderationTransferredEquityInterestsIssuedAndIssuable
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=120321790&loc=d3e6927-128479 + Details
Name: | us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Description of the frequency of periodic payments (monthly, quarterly, annual). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823 + Details
Name: | us-gaap_DebtInstrumentFrequencyOfPeriodicPayment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of the required periodic payments applied to principal. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentPeriodicPaymentPrincipal
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentTerm
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used. + References No definition available. + Details
Name: | us-gaap_LineOfCreditFacilityCommitmentFeePercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility. + References No definition available. + Details
Name: | us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=120321790&loc=d3e6927-128479 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3213-108585 + Details
Name: | us-gaap_PaymentsToAcquireBusinessesGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References No definition available. + Details
Name: | us-gaap_SubsequentEventLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_LineOfCreditFacilityAxis=ghm_HSBCBankUSAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortTermDebtTypeAxis=us-gaap_LetterOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
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: |

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

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=ghm_BarberNicholsIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=us-gaap_LineOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=ghm_BloombergShortTermBankYieldIndexMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=ghm_FloorRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |