Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

v2.4.1.9
Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)
6 Months Ended 12 Months Ended
Dec. 31, 2014
Jun. 29, 2014
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Summary Of Significant Accounting Policies [Line Items]          
Foreign bank balance $ 4,597,000hlm_CashAndCashEquivalentsHeldInForeignBankAccounts   $ 4,597,000hlm_CashAndCashEquivalentsHeldInForeignBankAccounts $ 6,701,000hlm_CashAndCashEquivalentsHeldInForeignBankAccounts  
Maturity period     90 days    
Allowance for doubtful accounts 627,000us-gaap_AllowanceForDoubtfulAccountsReceivable   627,000us-gaap_AllowanceForDoubtfulAccountsReceivable 703,000us-gaap_AllowanceForDoubtfulAccountsReceivable  
Period for classifying as non moving inventory     24 months    
Capitalized computer software additions       2,298,000us-gaap_CapitalizedComputerSoftwareAdditions 5,685,000us-gaap_CapitalizedComputerSoftwareAdditions
Estimated useful lives of assets     Generally two to 27 years or over the terms of the related leases, whichever is shorter.    
Impairment charges     0us-gaap_GoodwillImpairmentLoss 0us-gaap_GoodwillImpairmentLoss 0us-gaap_GoodwillImpairmentLoss
Long-lived assets impairment charges 0us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf 0us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf   0us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf 0us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf
Risk cover by third party, maximum 40,000,000hlm_MaximumAmountOfRiskCoveredFromThirdPartyInsurers   40,000,000hlm_MaximumAmountOfRiskCoveredFromThirdPartyInsurers    
Risk cover by third party, minimum 250,000hlm_MinimumAmountOfRiskCoveredFromThirdPartyInsurers   250,000hlm_MinimumAmountOfRiskCoveredFromThirdPartyInsurers    
Loss limit covered under self-insurance     200,000hlm_SelfInsuranceStopLossLimitPerParticipant    
Percentage of coverage under health insurance plan     125.00%hlm_MinimumPercentageOfExpectedClaimsForCoverageUnderGroupHealthInsurance    
Matching contribution for eligible employees, percentage     6.00%us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent    
Maximum matching contribution for eligible employees     50.00%hlm_MaximumPercentageOfMatchingContributionsMadeByEmployer    
Maximum employee contribution percentage     8.00%hlm_MaximumEmployeeContributionToDefinedContributionsPlan    
Percentage of employer required contribution     100.00%us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch    
Defined contribution plan costs       1,843,000us-gaap_DefinedContributionPlanCostRecognized 1,426,000us-gaap_DefinedContributionPlanCostRecognized
Shipping and handling costs       26,095,000us-gaap_ShippingHandlingAndTransportationCosts 23,067,000us-gaap_ShippingHandlingAndTransportationCosts
Research and development costs       1,366,000us-gaap_ResearchAndDevelopmentExpense 1,222,000us-gaap_ResearchAndDevelopmentExpense
Common stock, shares outstanding       51.9us-gaap_TemporaryEquitySharesOutstanding  
Deferred Profit Sharing Plan [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Minimum required contribution     0hlm_MinimumRequiredContribution
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= hlm_DeferredProfitSharingPlanMember
   
Put Options [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Fair value of temporary equity held by management       16,975,000us-gaap_TemporaryEquityValueExcludingAdditionalPaidInCapital
/ us-gaap_OptionIndexedToIssuersEquityTypeAxis
= us-gaap_PutOptionMember
 
Common stock, shares outstanding       161.2us-gaap_TemporaryEquitySharesOutstanding
/ us-gaap_OptionIndexedToIssuersEquityTypeAxis
= us-gaap_PutOptionMember
 
Successor [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Capitalized computer software additions 5,097,000us-gaap_CapitalizedComputerSoftwareAdditions
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
       
Defined contribution plan costs 983,000us-gaap_DefinedContributionPlanCostRecognized
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
       
Shipping and handling costs 15,989,000us-gaap_ShippingHandlingAndTransportationCosts
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
       
Research and development costs 598,000us-gaap_ResearchAndDevelopmentExpense
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
       
Successor [Member] | Put Options [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Common stock, shares outstanding 0.0us-gaap_TemporaryEquitySharesOutstanding
/ us-gaap_OptionIndexedToIssuersEquityTypeAxis
= us-gaap_PutOptionMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
  0.0us-gaap_TemporaryEquitySharesOutstanding
/ us-gaap_OptionIndexedToIssuersEquityTypeAxis
= us-gaap_PutOptionMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
   
Predecessor [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Capitalized computer software additions   704,000us-gaap_CapitalizedComputerSoftwareAdditions
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
     
Defined contribution plan costs   1,003,000us-gaap_DefinedContributionPlanCostRecognized
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
     
Shipping and handling costs   14,890,000us-gaap_ShippingHandlingAndTransportationCosts
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
     
Research and development costs   1,094,000us-gaap_ResearchAndDevelopmentExpense
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
     
Predecessor [Member] | Put Options [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Fair value of temporary equity held by management       16,975,000us-gaap_TemporaryEquityValueExcludingAdditionalPaidInCapital
/ us-gaap_OptionIndexedToIssuersEquityTypeAxis
= us-gaap_PutOptionMember
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
 
Common stock, shares outstanding       161.2us-gaap_TemporaryEquitySharesOutstanding
/ us-gaap_OptionIndexedToIssuersEquityTypeAxis
= us-gaap_PutOptionMember
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
 
Minimum [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Estimated useful lives of assets     2 years    
Percentage of fair value over carrying value       10.00%hlm_PercentageOfFairValueOverCarryingValue
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
10.00%hlm_PercentageOfFairValueOverCarryingValue
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Minimum [Member] | RRSP [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Matching contribution for eligible employees, percentage     1.00%us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= hlm_RegisteredRetirementSavingsPlanMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
   
Employee service period     2 years    
Maximum [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Estimated useful lives of assets     27 years    
Compensation and general liability losses $ 250,000hlm_RiskInsuranceReserveForProductLiabilityAutomotiveWorkersCompensationAndGeneralLiability
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
  $ 250,000hlm_RiskInsuranceReserveForProductLiabilityAutomotiveWorkersCompensationAndGeneralLiability
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
   
Maximum [Member] | RRSP [Member]          
Summary Of Significant Accounting Policies [Line Items]          
Matching contribution for eligible employees, percentage     5.00%us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= hlm_RegisteredRetirementSavingsPlanMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember