Annual report pursuant to Section 13 and 15(d)

Long-Term Debt - Summary of Long-Term Debt (Detail)

v2.4.1.9
Long-Term Debt - Summary of Long-Term Debt (Detail) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Successor [Member]    
Debt Instrument [Line Items]    
Long-term debt gross $ 877,857hlm_LongTermDebtAndCapitalLeaseObligationCurrentAndNonCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
 
Less: amounts due in one year 5,707us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
 
Long-term debt 872,150us-gaap_LongTermDebtAndCapitalLeaseObligations
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
 
Long-term debt gross 877,857hlm_LongTermDebtAndCapitalLeaseObligationCurrentAndNonCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
 
Successor [Member] | Term Loan B [Member]    
Debt Instrument [Line Items]    
Long-term debt gross 547,250hlm_LongTermDebtAndCapitalLeaseObligationCurrentAndNonCurrent
/ us-gaap_LongtermDebtTypeAxis
= hlm_TermBLoanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
 
Long-term debt gross 547,250hlm_LongTermDebtAndCapitalLeaseObligationCurrentAndNonCurrent
/ us-gaap_LongtermDebtTypeAxis
= hlm_TermBLoanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
 
Successor [Member] | 6.375% Senior Notes [Member]    
Debt Instrument [Line Items]    
Long-term debt gross 330,000hlm_LongTermDebtAndCapitalLeaseObligationCurrentAndNonCurrent
/ us-gaap_LongtermDebtTypeAxis
= hlm_SixPointThreeSevenFivePercentSeniorNotesMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
 
Long-term debt gross 330,000hlm_LongTermDebtAndCapitalLeaseObligationCurrentAndNonCurrent
/ us-gaap_LongtermDebtTypeAxis
= hlm_SixPointThreeSevenFivePercentSeniorNotesMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
 
Successor [Member] | Capital Leases and Other Obligations [Member]    
Debt Instrument [Line Items]    
Long-term debt gross 607us-gaap_ContractualObligation
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_CapitalLeaseObligationsMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
 
Predecessor [Member]    
Debt Instrument [Line Items]    
Long-term debt gross   653,915hlm_LongTermDebtAndCapitalLeaseObligationCurrentAndNonCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Less: amounts due in one year   4,187us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Long-term debt   649,728us-gaap_LongTermDebtAndCapitalLeaseObligations
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Long-term debt gross   653,915hlm_LongTermDebtAndCapitalLeaseObligationCurrentAndNonCurrent
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Predecessor [Member] | Term Loan B [Member]    
Debt Instrument [Line Items]    
Long-term debt gross   381,609hlm_LongTermDebtAndCapitalLeaseObligationCurrentAndNonCurrent
/ us-gaap_LongtermDebtTypeAxis
= hlm_TermBLoanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Long-term debt gross   381,609hlm_LongTermDebtAndCapitalLeaseObligationCurrentAndNonCurrent
/ us-gaap_LongtermDebtTypeAxis
= hlm_TermBLoanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Predecessor [Member] | 10.875% Senior Notes [Member]    
Debt Instrument [Line Items]    
Long-term debt gross   271,750hlm_LongTermDebtAndCapitalLeaseObligationCurrentAndNonCurrent
/ us-gaap_LongtermDebtTypeAxis
= hlm_TenPointEightSevenFivePercentageSeniorNotesMember
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Long-term debt gross   271,750hlm_LongTermDebtAndCapitalLeaseObligationCurrentAndNonCurrent
/ us-gaap_LongtermDebtTypeAxis
= hlm_TenPointEightSevenFivePercentageSeniorNotesMember
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember
Predecessor [Member] | Capital Leases and Other Obligations [Member]    
Debt Instrument [Line Items]    
Long-term debt gross   $ 556us-gaap_ContractualObligation
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_CapitalLeaseObligationsMember
/ us-gaap_StatementScenarioAxis
= us-gaap_PredecessorMember