Annual report pursuant to Section 13 and 15(d)

Basis of Presentation - Fair Value of Acquired Assets and Assumed Liabilities to Total Purchase Price (Detail)

v2.4.1.9
Basis of Presentation - Fair Value of Acquired Assets and Assumed Liabilities to Total Purchase Price (Detail) (USD $)
In Thousands, unless otherwise specified
0 Months Ended 12 Months Ended
May 16, 2014
Dec. 31, 2014
Business Combination, Separately Recognized Transactions [Abstract]    
Fair value of consideration transferred $ 1,504,498us-gaap_BusinessCombinationConsiderationTransferred1 $ 1,399,055us-gaap_BusinessCombinationConsiderationTransferred1
Cash   28,695us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents
Accounts receivable   113,030us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables
Inventory   187,509us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory
Other current assets   25,224us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther
Property and equipment   117,336us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment
Goodwill   624,870hlm_BusinessCombinationGoodwill
Intangible assets   822,620us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill
Other non-current assets   3,481us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets
Total assets acquired   1,922,765us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets
Accounts payable   (65,009)us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable
Deferred income taxes   (275,957)us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilitiesNoncurrent
Junior subordinated debentures   (105,443)hlm_BusinessAcquisitionPurchasePriceAllocationToJuniorSubordinatedLongTermNotes
Junior subordinated debentures premium   (22,437)hlm_BusinessAcquisitionPurchasePriceAllocationToJuniorSubordinatedLongTermNotesPremium
Other liabilities   (54,864)us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther
Total purchase price   $ 1,399,055us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet