XML 42 R30.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Goodwill and Related Intangible Assets (Tables) | 3 Months Ended
--- | ---
Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract] |
Schedule Of Changes In Carrying Amount Of Goodwill | The changes in the carrying amount of goodwill for the three months ended March 31, 2018 are as follows (in thousands):
| Residential Products |  | Industrial and Infrastructure Products |  | Renewable Energy & Conservation |  | Total
Balance at December 31, 2017 | $ | 198,075 |  |  | $ | 54,280 |  |  | $ | 68,719 |  |  | $ | 321,074 |
Foreign currency translation | — |  |  | (163 | ) |  | 861 |  |  | 698 |
Balance at March 31, 2018 | $ | 198,075 |  |  | $ | 54,117 |  |  | $ | 69,580 |  |  | $ | 321,772 |
Schedule Of Acquired Intangible Assets | Acquired intangible assets consist of the following (in thousands):
| March 31, 2018 |  | December 31, 2017 |  |
| Gross Carrying Amount |  | Accumulated Amortization |  | Gross Carrying Amount |  | Accumulated Amortization |  | Estimated Life
Indefinite-lived intangible assets: |  |  |  |  |  |  |  |  |
Trademarks | $ | 45,159 |  |  | $ | — |  |  | $ | 45,107 |  |  | $ | — |  |  | Indefinite
Finite-lived intangible assets: |  |  |  |  |  |  |  |  |
Trademarks | 5,848 |  |  | 3,166 |  |  | 5,876 |  |  | 3,062 |  |  | 5 to 15 Years
Unpatented technology | 28,107 |  |  | 12,490 |  |  | 28,107 |  |  | 12,033 |  |  | 5 to 20 Years
Customer relationships | 81,174 |  |  | 41,215 |  |  | 80,707 |  |  | 39,652 |  |  | 5 to 17 Years
Non-compete agreements | 1,649 |  |  | 1,007 |  |  | 1,649 |  |  | 931 |  |  | 4 to 10 Years
| 116,778 |  |  | 57,878 |  |  | 116,339 |  |  | 55,678 |  |  |
Total acquired intangible assets | $ | 161,937 |  |  | $ | 57,878 |  |  | $ | 161,446 |  |  | $ | 55,678 |  |  |
Schedule of Acquired Intangible Asset Amortization Expense | The following table summarizes the acquired intangible asset amortization expense for the three months ended March 31 (in thousands):
| 2018 |  | 2017
Amortization expense | $ | 2,139 |  |  | $ | 2,162 |
Schedule Of Amortization Expense | Amortization expense related to acquired intangible assets for the remainder of fiscal 2018 and the next five years thereafter is estimated as follows (in thousands):
| 2018 |  | 2019 |  | 2020 |  | 2021 |  | 2022 |  | 2023
Amortization expense | $ | 6,087 |  |  | $ | 7,654 |  |  | $ | 7,142 |  |  | $ | 6,539 |  |  | $ | 6,127 |  |  | $ | 5,588 |

X
- Definition Schedule of Acquired Intangible Asset Amortization Expense [Table Text Block] + References No definition available. + Details
Name: | rock_ScheduleofAcquiredIntangibleAssetAmortizationExpenseTableTextBlock
Namespace Prefix: | rock_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the characteristics, including initial carrying value, residual amount, weighted average useful life, of finite-lived intangible assets acquired during the period by major class. A major class is composed of intangible assets that can be grouped together because they are similar, either by nature or by their use in the operations of the company. + 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) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275 + Details
Name: | us-gaap_ScheduleOfAcquiredFiniteLivedIntangibleAssetsByMajorClassTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of goodwill by reportable segment and in total which includes a rollforward schedule. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13854-109267 + Details
Name: | us-gaap_ScheduleOfGoodwillTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the amount of amortization expense expected to be recorded in succeeding fiscal years for finite-lived intangible assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
Name: | us-gaap_ScheduleofFiniteLivedIntangibleAssetsFutureAmortizationExpenseTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration