Annual report pursuant to Section 13 and 15(d)

Acquisitions - Additional Information (Detail)

v2.4.1.9
Acquisitions - Additional Information (Detail) (Paulin [Member], USD $)
In Thousands, unless otherwise specified
0 Months Ended 12 Months Ended
Feb. 19, 2013
Dec. 31, 2014
Dec. 31, 2013
Paulin [Member]
     
Business Acquisition [Line Items]      
Aggregate purchase price, cash paid $ 103,416us-gaap_PaymentsToAcquireBusinessesGross
/ us-gaap_BusinessAcquisitionAxis
= hlm_PaulinMember
   
Date of acquisition   Feb. 19, 2013  
Post-acquisition revenues     130,459us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual
/ us-gaap_BusinessAcquisitionAxis
= hlm_PaulinMember
Post-acquisition net income     $ 3,009us-gaap_BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual
/ us-gaap_BusinessAcquisitionAxis
= hlm_PaulinMember