|
Income Taxes - Reconciliation of the Provision for Income Taxes (Detail) (USD $)
In Thousands, unless otherwise specified |
12 Months Ended | ||
|---|---|---|---|
|
Mar. 31, 2015
|
Mar. 31, 2014
|
Mar. 31, 2013
|
|
| Effective Income Tax Rate Reconciliation, Amount [Abstract] | |||
| Provision for income taxes at federal rate | $ 7,613us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate | $ 5,149us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate | $ 5,452us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate |
| State taxes | (103)us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes | (139)us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes | (173)us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes |
| Charges not deductible for income tax purposes | 79us-gaap_IncomeTaxReconciliationNondeductibleExpense | 59us-gaap_IncomeTaxReconciliationNondeductibleExpense | 78us-gaap_IncomeTaxReconciliationNondeductibleExpense |
| Recognition of tax benefit generated by qualified production activities deduction | (382)us-gaap_IncomeTaxReconciliationDeductionsQualifiedProductionActivities | (403)us-gaap_IncomeTaxReconciliationDeductionsQualifiedProductionActivities | (417)us-gaap_IncomeTaxReconciliationDeductionsQualifiedProductionActivities |
| Research and development tax credits | (180)us-gaap_IncomeTaxReconciliationTaxCreditsResearch | (80)us-gaap_IncomeTaxReconciliationTaxCreditsResearch | (307)us-gaap_IncomeTaxReconciliationTaxCreditsResearch |
| Valuation allowance | 214us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance | 174us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance | 144us-gaap_IncomeTaxReconciliationChangeInDeferredTaxAssetsValuationAllowance |
| Uncertain tax positions | (134)us-gaap_IncomeTaxReconciliationTaxContingencies | 90us-gaap_IncomeTaxReconciliationTaxContingencies | |
| Contingent earn-out | (326)ghm_IncomeTaxReconciliationContingentEarnout | ||
| Other | (224)us-gaap_IncomeTaxReconciliationOtherAdjustments | (61)us-gaap_IncomeTaxReconciliationOtherAdjustments | (112)us-gaap_IncomeTaxReconciliationOtherAdjustments |
| Total provision for income taxes | $ 7,017us-gaap_IncomeTaxExpenseBenefit | $ 4,565us-gaap_IncomeTaxExpenseBenefit | $ 4,429us-gaap_IncomeTaxExpenseBenefit |
| X | ||||||||||
|
- Definition
The portion of the difference between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to the income from the reversal of the contingent earn out under enacted tax laws. No definition available.
|
| X | ||||||||||
|
- Definition
Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Details
|
| X | ||||||||||
|
- Definition
Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in the valuation allowance for deferred tax assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
Amount of the difference between reported income tax expense (benefit) and the expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to deduction for qualified production activity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to nondeductible expenses. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other adjustments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to state and local income tax expense (benefit). Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in income tax contingencies. Including, but not limited to, domestic tax contingency, foreign tax contingency, state and local tax contingency, and other contingencies. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to research tax credit. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|