Supplemental Financial Information (Consolidating Statements of Operations) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Income Statements, Captions [Line Items]
Net sales	$ 201,994	$ 234,101	$ 234,960	$ 191,032	$ 188,835	$ 217,412	$ 224,519	$ 196,801	$ 862,087	$ 827,567	$ 790,058
Cost of sales									722,042	669,470	640,498
Gross profit	28,480	41,578	40,123	29,864	35,452	41,762	44,706	36,177	140,045	158,097	149,560
Selling, general, and administrative expense									102,492	113,457	104,671
Intangible asset impairment									107,970	23,160	4,628
(Loss) income from operations	(103,872)	18,392	14,730	333	6,153	(6,152)	16,283	5,196	(70,417)	21,480	40,261
Interest expense	3,433	3,657	3,691	3,640	3,811	3,828	3,690	11,160	14,421	22,489	18,582
Other income									(88)	(177)	(488)
(Loss) income before taxes									(84,750)	(832)	22,167
(Benefit of) provision for income taxes									(2,958)	4,797	9,517
(Loss) income from continuing operations	(95,708)	9,571	6,431	(2,086)	4,009	(13,727)	7,732	(3,643)	(81,792)	(5,629)	12,650
Loss before taxes									(51)	(7)	(289)
Benefit of income taxes									(19)	(3)	(284)
Loss from discontinued operations	(1)	(31)	0	0	0	0	0	(4)	(32)	(4)	(5)
Equity in earnings from subsidiaries									0	0	0
Net (loss) income	(95,709)	9,540	6,431	(2,086)	4,009	(13,727)	7,732	(3,647)	(81,824)	(5,633)	12,645
Gibraltar Industries, Inc.
Condensed Income Statements, Captions [Line Items]
Net sales									0	0	0
Cost of sales									0	0	0
Gross profit									0	0	0
Selling, general, and administrative expense									128	171	23
Intangible asset impairment									0	0	0
(Loss) income from operations									(128)	(171)	(23)
Interest expense									13,568	21,214	17,422
Other income									144	0	0
(Loss) income before taxes									(13,840)	(21,385)	(17,445)
(Benefit of) provision for income taxes									(4,381)	(7,480)	(6,524)
(Loss) income from continuing operations									(9,459)	(13,905)	(10,921)
Loss before taxes									0	0	0
Benefit of income taxes									0	0	0
Loss from discontinued operations									0	0	0
Equity in earnings from subsidiaries									(71,191)	9,041	24,535
Net (loss) income									(80,650)	(4,864)	13,614
Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Net sales									792,078	758,790	712,279
Cost of sales									661,041	610,049	574,647
Gross profit									131,037	148,741	137,632
Selling, general, and administrative expense									95,735	105,693	96,499
Intangible asset impairment									107,970	1,000	4,628
(Loss) income from operations									(72,668)	42,048	36,505
Interest expense									995	1,399	1,285
Other income									(328)	(177)	(480)
(Loss) income before taxes									(73,335)	40,826	35,700
(Benefit of) provision for income taxes									753	12,430	15,120
(Loss) income from continuing operations									(74,088)	28,396	20,580
Loss before taxes									(51)	(7)	(289)
Benefit of income taxes									(19)	(3)	(284)
Loss from discontinued operations									(32)	(4)	(5)
Equity in earnings from subsidiaries									2,929	(19,351)	3,960
Net (loss) income									(71,191)	9,041	24,535
Non-Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Net sales									88,096	91,198	98,304
Cost of sales									77,914	81,073	85,407
Gross profit									10,182	10,125	12,897
Selling, general, and administrative expense									6,629	7,593	8,149
Intangible asset impairment									0	22,160	0
(Loss) income from operations									3,553	(19,628)	4,748
Interest expense									(142)	(124)	(125)
Other income									96	0	(8)
(Loss) income before taxes									3,599	(19,504)	4,881
(Benefit of) provision for income taxes									670	(153)	921
(Loss) income from continuing operations									2,929	(19,351)	3,960
Loss before taxes									0	0	0
Benefit of income taxes									0	0	0
Loss from discontinued operations									0	0	0
Equity in earnings from subsidiaries									0	0	0
Net (loss) income									2,929	(19,351)	3,960
Eliminations
Condensed Income Statements, Captions [Line Items]
Net sales									(18,087)	(22,421)	(20,525)
Cost of sales									(16,913)	(21,652)	(19,556)
Gross profit									(1,174)	(769)	(969)
Selling, general, and administrative expense									0	0	0
Intangible asset impairment									0	0	0
(Loss) income from operations									(1,174)	(769)	(969)
Interest expense									0	0	0
Other income									0	0	0
(Loss) income before taxes									(1,174)	(769)	(969)
(Benefit of) provision for income taxes									0	0	0
(Loss) income from continuing operations									(1,174)	(769)	(969)
Loss before taxes									0	0	0
Benefit of income taxes									0	0	0
Loss from discontinued operations									0	0	0
Equity in earnings from subsidiaries									68,262	10,310	(28,495)
Net (loss) income									$ 67,088	$ 9,541	$ (29,464)