XML 83 R99.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Fair Value Measurements (Narrative) (Details) (USD $) In Thousands, unless otherwise specified | 12 Months Ended |
--- | --- | ---
Dec. 31, 2014 trail | Dec. 31, 2013 business | Jan. 31, 2013
Extinguishment of Debt [Line Items] |  |  |
Number of completed acquisitions |  | 1 us-gaap_NumberOfBusinessesAcquired |
Carrying value of outstanding debt | $ 213,600 us-gaap_LongTermDebt | $ 214,007 us-gaap_LongTermDebt |
Triangular distribution, number of trails | 500,000 rock_DiscountedCashFlowAnalysisTriangularDistributionNumberOfTrails |  |
Senior Subordinated 6.25% Notes |  |  |
Extinguishment of Debt [Line Items] |  |  |
Carrying value of outstanding debt | $ 210,000 us-gaap_LongTermDebt / us-gaap_DebtInstrumentAxis = rock_SeniorSubordinatedSixPointTwoFivePercentNotesDueFebruaryOneTwoThousandTwentyOneMember | $ 210,000 us-gaap_LongTermDebt / us-gaap_DebtInstrumentAxis = rock_SeniorSubordinatedSixPointTwoFivePercentNotesDueFebruaryOneTwoThousandTwentyOneMember |
Senior Subordinated Notes, interest rate | 6.25%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = rock_SeniorSubordinatedSixPointTwoFivePercentNotesDueFebruaryOneTwoThousandTwentyOneMember | 6.25%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = rock_SeniorSubordinatedSixPointTwoFivePercentNotesDueFebruaryOneTwoThousandTwentyOneMember | 6.25%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = rock_SeniorSubordinatedSixPointTwoFivePercentNotesDueFebruaryOneTwoThousandTwentyOneMember

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- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 7 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 9 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 20, 22 -Article 5 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
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