Annual report pursuant to Section 13 and 15(d)

Goodwill and Other Intangible Assets - Summary of Goodwill Amounts by Reporting Unit (Detail)

v2.4.1.9
Goodwill and Other Intangible Assets - Summary of Goodwill Amounts by Reporting Unit (Detail) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Goodwill [Line Items]  
Goodwill, Beginning balance $ 466,227us-gaap_Goodwill
Acquisitions 158,643us-gaap_GoodwillAcquiredDuringPeriod
Dispositions 0us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit
Other (3,310)us-gaap_GoodwillTranslationAdjustments
Goodwill, Ending balance 621,560us-gaap_Goodwill
United States, Excluding All Points [Member]  
Goodwill [Line Items]  
Goodwill, Beginning balance 446,382us-gaap_Goodwill
/ us-gaap_StatementGeographicalAxis
= hlm_UnitedStatesExcludingAllPointsSegmentMember
Acquisitions 134,038us-gaap_GoodwillAcquiredDuringPeriod
/ us-gaap_StatementGeographicalAxis
= hlm_UnitedStatesExcludingAllPointsSegmentMember
Dispositions 0us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit
/ us-gaap_StatementGeographicalAxis
= hlm_UnitedStatesExcludingAllPointsSegmentMember
Goodwill, Ending balance 580,420us-gaap_Goodwill
/ us-gaap_StatementGeographicalAxis
= hlm_UnitedStatesExcludingAllPointsSegmentMember
All Points [Member]  
Goodwill [Line Items]  
Goodwill, Beginning balance 58us-gaap_Goodwill
/ us-gaap_StatementGeographicalAxis
= hlm_AllPointsSegmentMember
Acquisitions 3,302us-gaap_GoodwillAcquiredDuringPeriod
/ us-gaap_StatementGeographicalAxis
= hlm_AllPointsSegmentMember
Dispositions 0us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit
/ us-gaap_StatementGeographicalAxis
= hlm_AllPointsSegmentMember
Goodwill, Ending balance 3,360us-gaap_Goodwill
/ us-gaap_StatementGeographicalAxis
= hlm_AllPointsSegmentMember
Canada [Member]  
Goodwill [Line Items]  
Goodwill, Beginning balance 12,785us-gaap_Goodwill
/ us-gaap_StatementGeographicalAxis
= country_CA
Acquisitions 22,695us-gaap_GoodwillAcquiredDuringPeriod
/ us-gaap_StatementGeographicalAxis
= country_CA
Dispositions 0us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit
/ us-gaap_StatementGeographicalAxis
= country_CA
Other (2,636)us-gaap_GoodwillTranslationAdjustments
/ us-gaap_StatementGeographicalAxis
= country_CA
Goodwill, Ending balance 32,844us-gaap_Goodwill
/ us-gaap_StatementGeographicalAxis
= country_CA
Mexico [Member]  
Goodwill [Line Items]  
Goodwill, Beginning balance 7,002us-gaap_Goodwill
/ us-gaap_StatementGeographicalAxis
= country_MX
Acquisitions (1,392)us-gaap_GoodwillAcquiredDuringPeriod
/ us-gaap_StatementGeographicalAxis
= country_MX
Dispositions 0us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit
/ us-gaap_StatementGeographicalAxis
= country_MX
Other (674)us-gaap_GoodwillTranslationAdjustments
/ us-gaap_StatementGeographicalAxis
= country_MX
Goodwill, Ending balance 4,936us-gaap_Goodwill
/ us-gaap_StatementGeographicalAxis
= country_MX
Australia [Member]  
Goodwill [Line Items]  
Dispositions $ 0us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit
/ us-gaap_StatementGeographicalAxis
= country_AU