Supplemental Financial Information (Schedule of Consolidating Statements of Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Schedule Of Supplemental Financial Information [Line Items]
Net income	$ 6,493	$ 5,509
Other comprehensive income:
Foreign currency translation adjustment	3,078	(3,800)
Reclassification of loss on cash flow hedges, net of tax	0	143
Adjustment to retirement benefit liability, net of tax	(1)	2
Adjustment to post-retirement health care liability, net of tax	38	37
Other comprehensive income (loss)	3,115	(3,618)
Total comprehensive income	9,608	1,891
Gibraltar Industries, Inc.
Schedule Of Supplemental Financial Information [Line Items]
Net income	6,770	5,612
Other comprehensive income:
Foreign currency translation adjustment	0	0
Reclassification of loss on cash flow hedges, net of tax		0
Adjustment to retirement benefit liability, net of tax	0	0
Adjustment to post-retirement health care liability, net of tax	0	0
Other comprehensive income (loss)	0	0
Total comprehensive income	6,770	5,612
Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Net income	8,960	7,851
Other comprehensive income:
Foreign currency translation adjustment	0	0
Reclassification of loss on cash flow hedges, net of tax		143
Adjustment to retirement benefit liability, net of tax	(1)	2
Adjustment to post-retirement health care liability, net of tax	38	37
Other comprehensive income (loss)	37	182
Total comprehensive income	8,997	8,033
Non-Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Net income	250	820
Other comprehensive income:
Foreign currency translation adjustment	3,078	(3,800)
Reclassification of loss on cash flow hedges, net of tax		0
Adjustment to retirement benefit liability, net of tax	0	0
Adjustment to post-retirement health care liability, net of tax	0	0
Other comprehensive income (loss)	3,078	(3,800)
Total comprehensive income	3,328	(2,980)
Eliminations
Schedule Of Supplemental Financial Information [Line Items]
Net income	(9,487)	(8,774)
Other comprehensive income:
Foreign currency translation adjustment	0	0
Reclassification of loss on cash flow hedges, net of tax		0
Adjustment to retirement benefit liability, net of tax	0	0
Adjustment to post-retirement health care liability, net of tax	0	0
Other comprehensive income (loss)	0	0
Total comprehensive income	$ (9,487)	$ (8,774)