Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation - Summary of Stock Option Activity (Detail)

v2.4.1.9
Stock-Based Compensation - Summary of Stock Option Activity (Detail) (2014 Equity Incentive Plan [Member], USD $)
In Thousands, except Share data, unless otherwise specified
12 Months Ended 6 Months Ended
Dec. 31, 2014
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Granted, Number of Shares 35,817us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod  
Successor [Member]
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Granted, Number of Shares   35,817us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
/ us-gaap_PlanNameAxis
= hlm_TwoThousandFourteenEquityIncentivePlanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
Exercised or converted, Number of Shares   0us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
/ us-gaap_PlanNameAxis
= hlm_TwoThousandFourteenEquityIncentivePlanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
Forfeited or expired, Number of Shares   0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod
/ us-gaap_PlanNameAxis
= hlm_TwoThousandFourteenEquityIncentivePlanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
Outstanding at December 31, 2014, Number of Shares 35,817us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_PlanNameAxis
= hlm_TwoThousandFourteenEquityIncentivePlanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
35,817us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_PlanNameAxis
= hlm_TwoThousandFourteenEquityIncentivePlanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
Exercisable at December 31, 2014, Number of Shares 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
/ us-gaap_PlanNameAxis
= hlm_TwoThousandFourteenEquityIncentivePlanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
/ us-gaap_PlanNameAxis
= hlm_TwoThousandFourteenEquityIncentivePlanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
Granted, Weighted Average Exercise Price Per Share   $ 1,000us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
/ us-gaap_PlanNameAxis
= hlm_TwoThousandFourteenEquityIncentivePlanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
Exercised or converted, Weighted Average Exercise Price Per Share   $ 0us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice
/ us-gaap_PlanNameAxis
= hlm_TwoThousandFourteenEquityIncentivePlanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
Forfeited or expired, Weighted Average Exercise Price Per Share   $ 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice
/ us-gaap_PlanNameAxis
= hlm_TwoThousandFourteenEquityIncentivePlanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
Outstanding at December 31, 2014, Weighted Average Exercise Price Per Share 1,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_PlanNameAxis
= hlm_TwoThousandFourteenEquityIncentivePlanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
$ 1,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
/ us-gaap_PlanNameAxis
= hlm_TwoThousandFourteenEquityIncentivePlanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
Exercisable at December 31, 2014, Weighted Average Exercise Price Per Share 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
/ us-gaap_PlanNameAxis
= hlm_TwoThousandFourteenEquityIncentivePlanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
$ 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
/ us-gaap_PlanNameAxis
= hlm_TwoThousandFourteenEquityIncentivePlanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
Outstanding, Weighted Average Remaining Contractual Term (Years)   9 years 6 months
Outstanding at December 31, 2014, Aggregate Intrinsic Value 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
/ us-gaap_PlanNameAxis
= hlm_TwoThousandFourteenEquityIncentivePlanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember
$ 0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
/ us-gaap_PlanNameAxis
= hlm_TwoThousandFourteenEquityIncentivePlanMember
/ us-gaap_StatementScenarioAxis
= us-gaap_SuccessorMember