Supplemental Financial Information (Schedule of Consolidating Statements of Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Schedule Of Supplemental Financial Information [Line Items]
Net income	$ 3,996	$ 9,029
Other comprehensive income (loss):
Foreign currency translation adjustment	679	3,078
Adjustment to retirement benefit liability, net of tax	(3)	(1)
Adjustment to post employment health care benefit liability, net of tax	29	38
Other comprehensive income	705	3,115
Total comprehensive income	4,701	12,144
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	0
Total comprehensive income	4,242
Guarantor Subsidiaries
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	26
Total comprehensive income	6,369
Non-Guarantor Subsidiaries
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	679
Total comprehensive income	(13)
Reportable Legal Entities | Gibraltar Industries, Inc.
Schedule Of Supplemental Financial Information [Line Items]
Net income	4,242	9,306
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		0
Total comprehensive income		9,306
Reportable Legal Entities | Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Net income	6,343	11,496
Other comprehensive income (loss):
Foreign currency translation adjustment		0
Adjustment to retirement benefit liability, net of tax		(1)
Adjustment to post employment health care benefit liability, net of tax		38
Other comprehensive income		37
Total comprehensive income		11,533
Reportable Legal Entities | Non-Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Net income	(692)	251
Other comprehensive income (loss):
Foreign currency translation adjustment		3,078
Adjustment to retirement benefit liability, net of tax		0
Adjustment to post employment health care benefit liability, net of tax		0
Other comprehensive income		3,078
Total comprehensive income		3,329
Eliminations
Schedule Of Supplemental Financial Information [Line Items]
Net income	(5,897)	(12,024)
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	0	0
Total comprehensive income	$ (5,897)	$ (12,024)