XML 50 R37.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Employee Benefit Plans (Tables) | 12 Months Ended
--- | ---
Mar. 31, 2018
Pension Plans, Defined Benefit [Member] |
Components of Postretirement Benefit Expense (Income) and Pension Cost (Benefit) | The components of pension cost (benefit) are:
|  | Year ended March 31, |
|  | 2018 |  |  | 2017 |  |  | 2016 |
Service cost during the period |  | $ | 598 |  |  | $ | 600 |  |  | $ | 521 |
Interest cost on projected benefit obligation |  |  | 1,423 |  |  |  | 1,450 |  |  |  | 1,437 |
Expected return on assets |  |  | (2,977 | ) |  |  | (2,873 | ) |  |  | (3,181 | )
Amortization of: |  |  |  |  |  |  |  |  |  |  |  |
Actuarial loss |  |  | 1,013 |  |  |  | 1,351 |  |  |  | 1,174 |
Net pension cost (benefit) |  | $ | 57 |  |  | $ | 528 |  |  | $ | (49 | )
Weighted Average Actuarial Assumptions Used to Determine and Develop Net Pension Cost | The weighted average actuarial assumptions used to determine net pension cost are:
|  | Year ended March 31, |
|  | 2018 |  |  | 2017 |  |  | 2016 |
Discount rate |  |  | 4.08 | % |  |  | 3.93 | % |  |  | 3.74 | %
Rate of increase in compensation levels |  |  | 3.00 | % |  |  | 3.00 | % |  |  | 3.00 | %
Long-term rate of return on plan assets |  |  | 8.00 | % |  |  | 8.00 | % |  |  | 8.00 | %
Changes in Company's Benefit Obligation, Plan Assets and Funded Status for Plan | Changes in the Company's benefit obligation, plan assets and funded status for the pension plan are presented below:
|  | Year ended March 31, |
|  | 2018 |  |  | 2017 |
Change in the benefit obligation |  |  |  |  |  |  |  |
Projected benefit obligation at beginning of year |  | $ | 35,460 |  |  | $ | 37,444 |
Service cost |  |  | 494 |  |  |  | 496 |
Interest cost |  |  | 1,423 |  |  |  | 1,450 |
Actuarial gain |  |  | (44 | ) |  |  | (994 | )
Benefit payments |  |  | (2,002 | ) |  |  | (1,818 | )
Liability released through annuity purchase |  |  | (890 | ) |  |  | (1,118 | )
Projected benefit obligation at end of year |  | $ | 34,441 |  |  | $ | 35,460 |
Change in fair value of plan assets |  |  |  |  |  |  |  |
Fair value of plan assets at beginning of year |  | $ | 37,800 |  |  | $ | 36,471 |
Employer contribution |  |  | 52 |  |  |  | — |
Actual return on plan assets |  |  | 3,958 |  |  |  | 4,393 |
Benefit and administrative expense payments |  |  | (2,002 | ) |  |  | (1,818 | )
Annuities purchased |  |  | (998 | ) |  |  | (1,246 | )
Fair value of plan assets at end of year |  | $ | 38,810 |  |  | $ | 37,800 |
Funded status |  |  |  |  |  |  |  |
Funded status at end of year |  | $ | 4,369 |  |  | $ | 2,340 |
Amount recognized in the Consolidated Balance Sheets |  | $ | 4,369 |  |  | $ | 2,340 |
Weighted Average Actuarial Assumptions Used to Determine and Develop Net Pension Cost | The weighted average actuarial assumptions used to determine the benefit obligation are:
|  | March 31, |
|  | 2018 |  |  | 2017 |
Discount rate |  |  | 3.95 | % |  |  | 4.08 | %
Rate of increase in compensation levels |  |  | 3.00 | % |  |  | 3.00 | %
Schedule of Defined Benefit Plan Amounts in Accumulated Other Comprehensive Income Loss [Table Text Block] | Amounts recognized in accumulated other comprehensive loss, net of income tax, consist of:
|  | March 31, |
|  | 2018 |  |  | 2017 |
Net actuarial loss |  | $ | 8,369 |  |  | $ | 8,180 |
Summary of Increase (Decrease) in Accumulated Other Comprehensive Loss, Net of Income Tax | The increase (decrease) in accumulated other comprehensive loss, net of income tax, consists of:
|  | March 31, |
|  | 2018 |  |  | 2017 |
Net actuarial gain arising during the year |  | $ | (794 | ) |  | $ | (1,609 | )
Reclassification of stranded tax effects related to the Tax Act |  |  | 1,771 |  |  |  | — |
Amortization of actuarial loss |  |  | (788 | ) |  |  | (873 | )
|  | $ | 189 |  |  | $ | (2,482 | )
Summary of Benefit Payments, Which Reflect Future Service, are Expected to be Paid | The following benefit payments, which reflect future service, are expected to be paid:
2019 |  | $ | 1,206 |
2020 |  |  | 1,338 |
2021 |  |  | 1,428 |
2022 |  |  | 1,471 |
2023 |  |  | 1,490 |
2024-2028 |  |  | 8,369 |
Total |  | $ | 15,302 |
Summary of Weighted Average Asset Allocation of Plan Assets by Asset Category | The weighted average asset allocation of the plan assets by asset category is as follows:
|  |  |  | March 31, |
Asset Category |  | Target Allocation |  | 2018 |  |  | 2017 |
Equity securities |  | 50-70% |  |  | 67 | % |  |  | 68 | %
Debt securities |  | 20-50% |  |  | 33 | % |  |  | 32 | %
|  |  |  |  | 100 | % |  |  | 100 | %
Fair Values of Company's Pension Plan Assets by Asset Category | The fair values of the Company's pension plan assets at March 31, 2018 and 2017, by asset category, are as follows:
|  |  |  |  |  | Fair Value Measurements Using |
Asset Category |  | At March 31, 2018 |  |  | Quoted prices in active markets for identical assets (Level 1) |  |  | Significant other observable inputs (Level 2) |  |  | Significant unobservable inputs (Level 3) |
Cash |  | $ | 98 |  |  | $ | 98 |  |  | $ | — |  |  | $ | — |
Equity securities: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
U.S. companies |  |  | 20,663 |  |  |  | 20,663 |  |  |  | — |  |  |  | — |
International companies |  |  | 5,181 |  |  |  | 5,181 |  |  |  | — |  |  |  | — |
Fixed income: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Corporate bond funds |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Intermediate-term |  |  | 10,283 |  |  |  | 10,283 |  |  |  | — |  |  |  | — |
Short-term |  |  | 2,585 |  |  |  | 2,585 |  |  |  | — |  |  |  | — |
|  | $ | 38,810 |  |  | $ | 38,810 |  |  | $ | — |  |  | $ | — |
|  |  |  |  |  | Fair Value Measurements Using |
Asset Category |  | At March 31, 2017 |  |  | Quoted prices in active markets for identical assets (Level 1) |  |  | Significant other observable inputs (Level 2) |  |  | Significant unobservable inputs (Level 3) |
Cash |  | $ | 154 |  |  | $ | 154 |  |  | $ | — |  |  | $ | — |
Equity securities: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
U.S. companies |  |  | 20,570 |  |  |  | 20,570 |  |  |  | — |  |  |  | — |
International companies |  |  | 5,071 |  |  |  | 5,071 |  |  |  | — |  |  |  | — |
Fixed income: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Corporate bond funds |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Intermediate-term |  |  | 9,585 |  |  |  | 9,585 |  |  |  | — |  |  |  | — |
Short-term |  |  | 2,420 |  |  |  | 2,420 |  |  |  | — |  |  |  | — |
|  | $ | 37,800 |  |  | $ | 37,800 |  |  | $ | — |  |  | $ | — |
Other Postretirement Benefit Plans [Member] |
Components of Postretirement Benefit Expense (Income) and Pension Cost (Benefit) | The components of postretirement benefit expense are:
|  | Year ended March 31, |
|  | 2018 |  |  | 2017 |  |  | 2016 |
Interest cost on accumulated benefit obligation |  | $ | 26 |  |  | $ | 26 |  |  | $ | 29 |
Amortization of actuarial loss |  |  | 37 |  |  |  | 36 |  |  |  | 40 |
Net postretirement benefit expense |  | $ | 63 |  |  | $ | 62 |  |  | $ | 69 |
Changes in Company's Benefit Obligation, Plan Assets and Funded Status for Plan | Changes in the Company's benefit obligation, plan assets and funded status for the plan are as follows:
|  | Year ended March 31, |
|  | 2018 |  |  | 2017 |
Change in the benefit obligation |  |  |  |  |  |  |  |
Projected benefit obligation at beginning of year |  | $ | 844 |  |  | $ | 875 |
Interest cost |  |  | 26 |  |  |  | 26 |
Actuarial loss (gain) |  |  | (73 | ) |  |  | 20 |
Benefit payments |  |  | (74 | ) |  |  | (77 | )
Projected benefit obligation at end of year |  | $ | 723 |  |  | $ | 844 |
Change in fair value of plan assets |  |  |  |  |  |  |  |
Fair value of plan assets at beginning of year |  | $ | — |  |  | $ | — |
Employer contribution |  |  | 74 |  |  |  | 77 |
Benefit payments |  |  | (74 | ) |  |  | (77 | )
Fair value of plan assets at end of year |  | $ | — |  |  | $ | — |
Funded status |  |  |  |  |  |  |  |
Funded status at end of year |  | $ | (723 | ) |  | $ | (844 | )
Amount recognized in the Consolidated Balance Sheets |  | $ | (723 | ) |  | $ | (844 | )
Weighted Average Actuarial Assumptions Used to Determine and Develop Net Pension Cost | The weighted average actuarial assumptions used to develop the accrued postretirement benefit obligation were:
|  | March 31, |
|  | 2018 |  |  | 2017 |
Discount rate |  |  | 3.63 | % |  |  | 3.23 | %
Medical care cost trend rate |  |  | 8.00 | % |  |  | 8.00 | %
Schedule of Defined Benefit Plan Amounts in Accumulated Other Comprehensive Income Loss [Table Text Block] | Amounts recognized in accumulated other comprehensive loss, net of income tax, consist of:
|  | March 31, |
|  | 2018 |  |  | 2017 |
Net actuarial loss |  | $ | 230 |  |  | $ | 259 |
Summary of Increase (Decrease) in Accumulated Other Comprehensive Loss, Net of Income Tax | The decrease in accumulated other comprehensive loss, net of income tax, consists of:
|  | March 31, |
|  | 2018 |  |  | 2017 |
Net actuarial loss (gain) arising during the year |  | $ | (57 | ) |  | $ | 13 |
Reclassification of stranded tax effects related to the Tax Act |  |  | 57 |  |  |  | — |
Amortization of actuarial loss |  |  | (29 | ) |  |  | (24 | )
|  | $ | (29 | ) |  | $ | (11 | )
Summary of Benefit Payments, Which Reflect Future Service, are Expected to be Paid | The following benefit payments are expected to be paid during the fiscal years ending March 31:
2019 |  | $ | 81 |
2020 |  |  | 77 |
2021 |  |  | 73 |
2022 |  |  | 69 |
2023 |  |  | 64 |
2024-2028 |  |  | 257 |
Total |  | $ | 621 |

X
- Definition Tabular disclosure of the assumptions used to determine the defined benefit pension plan or other postretirement plan benefit obligation, including assumed discount rates, rate increase in compensation levels and medical care cost trend rate. + References No definition available. + Details
Name: | ghm_ScheduleOfAssumptionsUsedBenefitObligationTableTextBlock
Namespace Prefix: | ghm_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the assumptions used to determine for the pension plan net benefit cost, including assumed discount rates, rate increase in compensation levels, and expected long-term rates of return on plan assets. + References No definition available. + Details
Name: | ghm_ScheduleOfAssumptionsUsedNetPensionCostTableTextBlock
Namespace Prefix: | ghm_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Aggregate amount in accumulated other comprehensive income or loss related to defined benefit pension plans or other postretirement plans that will be recognized as a component of net periodic benefit cost in future periods. + References No definition available. + Details
Name: | ghm_ScheduleOfDefinedBenefitPlanAmountsInAccumulatedOtherComprehensiveIncomeLossTableTextBlock
Namespace Prefix: | ghm_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Schedule of weighted average asset allocation of plan assets. + References No definition available. + Details
Name: | ghm_ScheduleOfWeightedAverageAssetAllocationOfPlanAssetsTableTextBlock
Namespace Prefix: | ghm_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the major categories of plan assets of pension plans and/or other employee benefit plans. This information may include, but is not limited to, the target allocation of plan assets, the fair value of each major category of plan assets, and the level within the fair value hierarchy in which the fair value measurements fall. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(5) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the net gain (loss) and net prior service cost or credit recognized in other comprehensive income (loss) for the period for pension plans and/or other employee benefit plans, and reclassification adjustments of other comprehensive income (loss) for the period, as those amounts, including amortization of the net transition asset or obligation, are recognized as components of net periodic benefit cost. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (i) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfAmountsRecognizedInOtherComprehensiveIncomeLossTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the change in the benefit obligation of pension plans and/or other employee benefit plans from the beginning to the end of the period, showing separately, if applicable, the effects of the following: service cost, interest cost, contributions by plan participants, actuarial gains and losses, foreign currency exchange rate changes, benefits paid, plan amendments, business combinations, divestitures, curtailments, settlements, and special and contractual termination benefits. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfChangesInProjectedBenefitObligationsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of benefits expected to be paid by pension plans and/or other employee benefit plans in each of the next five fiscal years and in the aggregate for the five fiscal years thereafter. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920 + Details
Name: | us-gaap_ScheduleOfNetBenefitCostsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |