Supplemental Financial Information (Schedule of Consolidating Statements of Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Schedule Of Supplemental Financial Information [Line Items]
Net income	$ 16,989	$ 4,087	$ 23,482	$ 9,596
Other comprehensive income:
Foreign currency translation adjustment	7,753	2,138	10,831	(1,662)
Reclassification of loss on cash flow hedges, net of tax	0	0	0	143
Adjustment to retirement benefit liability, net of tax	(1)	2	(2)	4
Adjustment to post-retirement health care liability, net of tax	38	37	76	74
Other comprehensive income (loss)	7,790	2,177	10,905	(1,441)
Total comprehensive income	24,779	6,264	34,387	8,155
Gibraltar Industries, Inc.
Other comprehensive income:
Foreign currency translation adjustment	0
Adjustment to retirement benefit liability, net of tax	0
Adjustment to post-retirement health care liability, net of tax	0
Other comprehensive income (loss)	0
Total comprehensive income	17,348
Guarantor Subsidiaries
Other comprehensive income:
Foreign currency translation adjustment	0
Adjustment to retirement benefit liability, net of tax	(1)
Adjustment to post-retirement health care liability, net of tax	38
Other comprehensive income (loss)	37
Total comprehensive income	35,178
Non-Guarantor Subsidiaries
Other comprehensive income:
Foreign currency translation adjustment	7,753
Adjustment to retirement benefit liability, net of tax	0
Adjustment to post-retirement health care liability, net of tax	0
Other comprehensive income (loss)	7,753
Total comprehensive income	15,172
Reportable Legal Entities | Gibraltar Industries, Inc.
Schedule Of Supplemental Financial Information [Line Items]
Net income	17,348	4,438	24,118	10,050
Other comprehensive income:
Foreign currency translation adjustment		0	0	0
Reclassification of loss on cash flow hedges, net of tax				0
Adjustment to retirement benefit liability, net of tax		0	0	0
Adjustment to post-retirement health care liability, net of tax		0	0	0
Other comprehensive income (loss)		0	0	0
Total comprehensive income		4,438	24,118	10,050
Reportable Legal Entities | Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Net income	35,141	6,655	44,101	14,506
Other comprehensive income:
Foreign currency translation adjustment		0	0	0
Reclassification of loss on cash flow hedges, net of tax				143
Adjustment to retirement benefit liability, net of tax		2	(2)	4
Adjustment to post-retirement health care liability, net of tax		37	76	74
Other comprehensive income (loss)		39	74	221
Total comprehensive income		6,694	44,175	14,727
Reportable Legal Entities | Non-Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Net income	7,419	(272)	7,669	548
Other comprehensive income:
Foreign currency translation adjustment		2,138	10,831	(1,662)
Reclassification of loss on cash flow hedges, net of tax				0
Adjustment to retirement benefit liability, net of tax		0	0	0
Adjustment to post-retirement health care liability, net of tax		0	0	0
Other comprehensive income (loss)		2,138	10,831	(1,662)
Total comprehensive income		1,866	18,500	(1,114)
Eliminations
Schedule Of Supplemental Financial Information [Line Items]
Net income	(42,919)	(6,734)	(52,406)	(15,508)
Other comprehensive income:
Foreign currency translation adjustment	0	0	0	0
Reclassification of loss on cash flow hedges, net of tax				0
Adjustment to retirement benefit liability, net of tax	0	0	0	0
Adjustment to post-retirement health care liability, net of tax	0	0	0	0
Other comprehensive income (loss)	0	0	0	0
Total comprehensive income	$ (42,919)	$ (6,734)	$ (52,406)	$ (15,508)