Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Fair Value of Company's Fixed Rate Senior Notes and Junior Subordinated Debentures (Detail)

v2.4.1.9
Fair Value Measurements - Fair Value of Company's Fixed Rate Senior Notes and Junior Subordinated Debentures (Detail) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
6.375% Senior Notes [Member] | Estimated Fair Value [Member]    
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]    
Debt $ 315,563us-gaap_DebtInstrumentFairValue
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_LongtermDebtTypeAxis
= hlm_SixPointThreeSevenFivePercentSeniorNotesMember
 
6.375% Senior Notes [Member] | Carrying Amount [Member]    
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]    
Debt 330,000us-gaap_DebtInstrumentFairValue
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember
/ us-gaap_LongtermDebtTypeAxis
= hlm_SixPointThreeSevenFivePercentSeniorNotesMember
 
10.875% Senior Notes [Member] | Estimated Fair Value [Member]    
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]    
Debt   285,538us-gaap_DebtInstrumentFairValue
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_LongtermDebtTypeAxis
= hlm_TenPointEightSevenFivePercentageSeniorNotesMember
10.875% Senior Notes [Member] | Carrying Amount [Member]    
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]    
Debt   271,750us-gaap_DebtInstrumentFairValue
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember
/ us-gaap_LongtermDebtTypeAxis
= hlm_TenPointEightSevenFivePercentageSeniorNotesMember
Junior Subordinated Debentures [Member] | Estimated Fair Value [Member]    
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]    
Debt 137,764us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= hlm_JuniorSubordinatedDebenturesMember
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
131,480us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= hlm_JuniorSubordinatedDebenturesMember
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
Junior Subordinated Debentures [Member] | Carrying Amount [Member]    
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]    
Debt $ 130,685us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= hlm_JuniorSubordinatedDebenturesMember
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember
$ 114,941us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= hlm_JuniorSubordinatedDebenturesMember
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_CarryingReportedAmountFairValueDisclosureMember