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Supplemental Financial Information (Schedule of Consolidating Statements of Comprehensive Income) (Details) - USD ($) $ in Thousands | 3 Months Ended |
--- | --- | ---
Mar. 31, 2018 | Mar. 31, 2017 | Dec. 31, 2017
Schedule Of Supplemental Financial Information [Line Items] |  |  |
Net income | $ 8,352 | $ 3,996 |
Other comprehensive income (loss): |  |  |
Foreign currency translation adjustment | 110 | 679 |
Cumulative effect of new accounting principle in period of adoption |  |  | $ 274
Adjustment to retirement benefit liability, net of tax | (5) | (3) |
Adjustment to post employment health care benefit liability, net of tax | 32 | 29 |
Other comprehensive income (loss) | (213) | 705 |
Total comprehensive income | 8,139 | 4,701 |
Guarantor Subsidiaries |  |  |
Other comprehensive income (loss): |  |  |
Foreign currency translation adjustment | 0 |  |
Adjustment to retirement benefit liability, net of tax | (5) |  |
Adjustment to post employment health care benefit liability, net of tax | 32 |  |
Other comprehensive income (loss) | (323) |  |
Total comprehensive income | 10,647 |  |
Non-Guarantor Subsidiaries |  |  |
Other comprehensive income (loss): |  |  |
Foreign currency translation adjustment | 110 |  |
Adjustment to retirement benefit liability, net of tax | 0 |  |
Adjustment to post employment health care benefit liability, net of tax | 0 |  |
Other comprehensive income (loss) | 110 |  |
Total comprehensive income | 1,200 |  |
Gibraltar Industries, Inc. |  |  |
Other comprehensive income (loss): |  |  |
Foreign currency translation adjustment | 0 |  |
Adjustment to retirement benefit liability, net of tax | 0 |  |
Adjustment to post employment health care benefit liability, net of tax | 0 |  |
Other comprehensive income (loss) | 0 |  |
Total comprehensive income | 8,489 |  |
Reportable Legal Entities | Guarantor Subsidiaries |  |  |
Schedule Of Supplemental Financial Information [Line Items] |  |  |
Net income | 10,970 | 6,343 |
Other comprehensive income (loss): |  |  |
Foreign currency translation adjustment |  | 0 |
Adjustment to retirement benefit liability, net of tax |  | (3) |
Adjustment to post employment health care benefit liability, net of tax |  | 29 |
Other comprehensive income (loss) |  | 26 |
Total comprehensive income |  | 6,369 |
Reportable Legal Entities | Non-Guarantor Subsidiaries |  |  |
Schedule Of Supplemental Financial Information [Line Items] |  |  |
Net income | 1,090 | (692) |
Other comprehensive income (loss): |  |  |
Foreign currency translation adjustment |  | 679 |
Adjustment to retirement benefit liability, net of tax |  | 0 |
Adjustment to post employment health care benefit liability, net of tax |  | 0 |
Other comprehensive income (loss) |  | 679 |
Total comprehensive income |  | (13) |
Reportable Legal Entities | Gibraltar Industries, Inc. |  |  |
Schedule Of Supplemental Financial Information [Line Items] |  |  |
Net income | 8,489 | 4,242 |
Other comprehensive income (loss): |  |  |
Foreign currency translation adjustment |  | 0 |
Adjustment to retirement benefit liability, net of tax |  | 0 |
Adjustment to post employment health care benefit liability, net of tax |  | 0 |
Other comprehensive income (loss) |  | 0 |
Total comprehensive income |  | 4,242 |
Eliminations |  |  |
Schedule Of Supplemental Financial Information [Line Items] |  |  |
Net income | (12,197) | (5,897) |
Other comprehensive income (loss): |  |  |
Foreign currency translation adjustment | 0 | 0 |
Adjustment to retirement benefit liability, net of tax | 0 | 0 |
Adjustment to post employment health care benefit liability, net of tax | 0 | 0 |
Other comprehensive income (loss) | 0 | 0 |
Total comprehensive income | $ (12,197) | $ (5,897) |
Accounting Standards Update 2014-09 |  |  |
Other comprehensive income (loss): |  |  |
Cumulative effect of new accounting principle in period of adoption |  |  | (350)
Accounting Standards Update 2014-09 | Guarantor Subsidiaries |  |  |
Other comprehensive income (loss): |  |  |
Cumulative effect of new accounting principle in period of adoption |  |  | $ (350)

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