Supplemental Financial Information (Schedule of Consolidating Statements of Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Schedule Of Supplemental Financial Information [Line Items]
Net income (loss)	$ 5,509	$ (2,086)
Other comprehensive (loss) income:
Foreign currency translation adjustment	(3,800)	(904)
Change in unrealized loss on cash flow hedges, net of tax	143	0
Adjustment to retirement benefit liability, net of tax	2	2
Adjustment to post-retirement health care liability, net of tax	37	19
Other comprehensive loss	(3,618)	(883)
Total comprehensive income (loss)	1,891	(2,969)
Gibraltar Industries, Inc.
Schedule Of Supplemental Financial Information [Line Items]
Net income (loss)	5,612	(1,905)
Other comprehensive (loss) income:
Foreign currency translation adjustment	0	0
Change in unrealized 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 loss	0	0
Total comprehensive income (loss)	5,612	(1,905)
Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Net income (loss)	7,851	315
Other comprehensive (loss) income:
Foreign currency translation adjustment	0	0
Change in unrealized loss on cash flow hedges, net of tax	143
Adjustment to retirement benefit liability, net of tax	2	2
Adjustment to post-retirement health care liability, net of tax	37	19
Other comprehensive loss	182	21
Total comprehensive income (loss)	8,033	336
Non-Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Net income (loss)	820	568
Other comprehensive (loss) income:
Foreign currency translation adjustment	(3,800)	(904)
Change in unrealized 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 loss	(3,800)	(904)
Total comprehensive income (loss)	(2,980)	(336)
Eliminations
Schedule Of Supplemental Financial Information [Line Items]
Net income (loss)	(8,774)	(1,064)
Other comprehensive (loss) income:
Foreign currency translation adjustment	0	0
Change in unrealized 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 loss	0	0
Total comprehensive income (loss)	$ (8,774)	$ (1,064)