XML 54 R61.htm IDEA: XBRL DOCUMENT v2.4.1.9

Acquisitions (Schedule of Acquired Intangible Assets) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
2013 Acquisitions
Business Acquisition [Line Items]
Fair Value	$ 2,170us-gaap_FinitelivedIntangibleAssetsAcquired1 / us-gaap_BusinessAcquisitionAxis = rock_AcquisitionsDuring2013Member
2013 Acquisitions | Trademarks
Business Acquisition [Line Items]
Fair Value	640us-gaap_FinitelivedIntangibleAssetsAcquired1 / us-gaap_BusinessAcquisitionAxis = rock_AcquisitionsDuring2013Member / us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_TrademarksMember
2013 Acquisitions | Customer relationships
Business Acquisition [Line Items]
Fair Value	1,130us-gaap_FinitelivedIntangibleAssetsAcquired1 / us-gaap_BusinessAcquisitionAxis = rock_AcquisitionsDuring2013Member / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_CustomerRelationshipsMember
Estimated Useful Life	15 years
2013 Acquisitions | Technology
Business Acquisition [Line Items]
Fair Value	260us-gaap_FinitelivedIntangibleAssetsAcquired1 / us-gaap_BusinessAcquisitionAxis = rock_AcquisitionsDuring2013Member / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_TechnologyEquipmentMember
Estimated Useful Life	15 years
2013 Acquisitions | Non-compete agreements
Business Acquisition [Line Items]
Fair Value	140us-gaap_FinitelivedIntangibleAssetsAcquired1 / us-gaap_BusinessAcquisitionAxis = rock_AcquisitionsDuring2013Member / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_NoncompeteAgreementsMember
Estimated Useful Life	5 years
2012 Acquisitions
Business Acquisition [Line Items]
Fair Value		10,183us-gaap_FinitelivedIntangibleAssetsAcquired1 / us-gaap_BusinessAcquisitionAxis = rock_AcquisitionsDuring2012Member
2012 Acquisitions | Trademarks
Business Acquisition [Line Items]
Fair Value		2,130us-gaap_FinitelivedIntangibleAssetsAcquired1 / us-gaap_BusinessAcquisitionAxis = rock_AcquisitionsDuring2012Member / us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_TrademarksMember
2012 Acquisitions | Customer relationships
Business Acquisition [Line Items]
Fair Value		4,470us-gaap_FinitelivedIntangibleAssetsAcquired1 / us-gaap_BusinessAcquisitionAxis = rock_AcquisitionsDuring2012Member / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_CustomerRelationshipsMember
2012 Acquisitions | Unpatented technology and patents
Business Acquisition [Line Items]
Fair Value		2,313us-gaap_FinitelivedIntangibleAssetsAcquired1 / us-gaap_BusinessAcquisitionAxis = rock_AcquisitionsDuring2012Member / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_UnpatentedTechnologyMember
Estimated Useful Life		15 years
2012 Acquisitions | Trademarks
Business Acquisition [Line Items]
Fair Value		800us-gaap_FinitelivedIntangibleAssetsAcquired1 / us-gaap_BusinessAcquisitionAxis = rock_AcquisitionsDuring2012Member / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_TrademarksMember
Estimated Useful Life		5 years
2012 Acquisitions | Non-compete agreements
Business Acquisition [Line Items]
Fair Value		340us-gaap_FinitelivedIntangibleAssetsAcquired1 / us-gaap_BusinessAcquisitionAxis = rock_AcquisitionsDuring2012Member / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_NoncompeteAgreementsMember
2012 Acquisitions | Backlog
Business Acquisition [Line Items]
Fair Value		$ 130us-gaap_FinitelivedIntangibleAssetsAcquired1 / us-gaap_BusinessAcquisitionAxis = rock_AcquisitionsDuring2012Member / us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis = us-gaap_OrderOrProductionBacklogMember
Estimated Useful Life		0 years 6 months
2012 Acquisitions | Maximum | Customer relationships
Business Acquisition [Line Items]
Estimated Useful Life	15 years
2012 Acquisitions | Maximum | Non-compete agreements
Business Acquisition [Line Items]
Estimated Useful Life	10 years
2012 Acquisitions | Minimum | Customer relationships
Business Acquisition [Line Items]
Estimated Useful Life	5 years
2012 Acquisitions | Minimum | Non-compete agreements
Business Acquisition [Line Items]
Estimated Useful Life	5 years

X

- Definition

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16265-109275

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- Definition

Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, resulting from a business combination.

+ References

No definition available.

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