Annual report pursuant to Section 13 and 15(d)

Income Taxes - Reconciliation of Statutory Income Tax Rates to Effective Income Tax Rates (Detail)

v2.4.1.9
Income Taxes - Reconciliation of Statutory Income Tax Rates to Effective Income Tax Rates (Detail)
6 Months Ended 12 Months Ended
Dec. 31, 2014
Jun. 29, 2014
Dec. 31, 2013
Dec. 31, 2012
Successor [Member]        
Income Taxes [Line Items]        
Statutory federal income tax rate 35.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
     
Non-U.S. taxes and the impact of non-U.S. losses for which a current tax benefit is not available (11.00%)us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
     
State and local income taxes, net of U.S. federal income tax benefit 2.50%us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
     
Adjustment of reserve for change in valuation allowance and other items 0.50%hlm_EffectiveIncomeTaxRateReconciliationAdjustmentOfReserveForChangeInValuationAllowanceAndOtherItems
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
     
Adjustment for change in tax law 3.10%us-gaap_EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
     
Adjustment of unrecognized tax benefits 0.00%hlm_EffectiveIncomeTaxRateReconciliationAdjustmentOfUnrecognizedTaxBenefits
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
     
Permanent differences:        
Acquisition and related transaction costs (8.20%)hlm_EffectiveIncomeTaxRateReconciliationAcquisitionTransactionCosts
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
     
Meals and entertainment expense (0.20%)us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseMealsAndEntertainment
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
     
Foreign tax credit 2.40%us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsForeign
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
     
Reconciliation of tax provision to return 0.00%us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
     
Reconciliation of other adjustments 0.50%us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
     
Effective income tax rate 24.60%us-gaap_EffectiveIncomeTaxRateContinuingOperations
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
     
Predecessor [Member]        
Income Taxes [Line Items]        
Statutory federal income tax rate   35.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
35.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
35.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Non-U.S. taxes and the impact of non-U.S. losses for which a current tax benefit is not available   1.50%us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
(19.60%)us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
(6.10%)us-gaap_EffectiveIncomeTaxRateReconciliationForeignIncomeTaxRateDifferential
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
State and local income taxes, net of U.S. federal income tax benefit   3.00%us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
(0.10%)us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
1.90%us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Adjustment of reserve for change in valuation allowance and other items   (0.30%)hlm_EffectiveIncomeTaxRateReconciliationAdjustmentOfReserveForChangeInValuationAllowanceAndOtherItems
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
15.00%hlm_EffectiveIncomeTaxRateReconciliationAdjustmentOfReserveForChangeInValuationAllowanceAndOtherItems
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
1.20%hlm_EffectiveIncomeTaxRateReconciliationAdjustmentOfReserveForChangeInValuationAllowanceAndOtherItems
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Adjustment for change in tax law   0.50%us-gaap_EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
8.90%us-gaap_EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
(0.40%)us-gaap_EffectiveIncomeTaxRateReconciliationChangeInEnactedTaxRate
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Adjustment of unrecognized tax benefits   0.00%hlm_EffectiveIncomeTaxRateReconciliationAdjustmentOfUnrecognizedTaxBenefits
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
36.60%hlm_EffectiveIncomeTaxRateReconciliationAdjustmentOfUnrecognizedTaxBenefits
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
11.60%hlm_EffectiveIncomeTaxRateReconciliationAdjustmentOfUnrecognizedTaxBenefits
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Permanent differences:        
Acquisition and related transaction costs   (4.00%)hlm_EffectiveIncomeTaxRateReconciliationAcquisitionTransactionCosts
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
(4.00%)hlm_EffectiveIncomeTaxRateReconciliationAcquisitionTransactionCosts
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
(0.90%)hlm_EffectiveIncomeTaxRateReconciliationAcquisitionTransactionCosts
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Meals and entertainment expense   (0.10%)us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseMealsAndEntertainment
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
(3.50%)us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseMealsAndEntertainment
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
(1.10%)us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseMealsAndEntertainment
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Foreign tax credit   0.00%us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsForeign
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
1.30%us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsForeign
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
0.00%us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsForeign
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Reconciliation of tax provision to return   0.00%us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
2.00%us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
0.50%us-gaap_EffectiveIncomeTaxRateReconciliationTaxExemptIncome
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Reconciliation of other adjustments   (0.50%)us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
(0.80%)us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
0.00%us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Effective income tax rate   35.10%us-gaap_EffectiveIncomeTaxRateContinuingOperations
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
70.80%us-gaap_EffectiveIncomeTaxRateContinuingOperations
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
41.70%us-gaap_EffectiveIncomeTaxRateContinuingOperations
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember