Supplemental Financial Information (Consolidating Statements of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Income Statements, Captions [Line Items]
Net sales	$ 282,093	$ 304,994	$ 253,171	$ 200,615	$ 201,994	$ 234,101	$ 234,960	$ 191,032	$ 1,040,873	$ 862,087	$ 827,567
Cost of sales									853,897	722,042	669,470
Gross profit	51,546	61,396	44,119	29,915	28,480	41,578	40,123	29,864	186,976	140,045	158,097
Selling, general, and administrative expense									134,028	102,492	113,457
Intangible asset impairment									4,863	107,970	23,160
Income (loss) from operations	4,520	23,394	11,201	8,970	(103,872)	18,392	14,730	333	48,085	(70,417)	21,480
Interest expense	3,614	3,878	3,811	3,700	3,433	3,657	3,691	3,640	15,003	14,421	22,489
Other income									(4,018)	(88)	(177)
Income (loss) before taxes									37,100	(84,750)	(832)
Provision for (benefit of) income taxes									13,624	(2,958)	4,797
Income (loss) from continuing operations	220	13,632	4,087	5,537	(95,708)	9,571	6,431	(2,086)	23,476	(81,792)	(5,629)
Loss before taxes									(44)	(51)	(7)
Benefit of income taxes									(16)	(19)	(3)
Loss from discontinued operations	0	0	0	(28)	(1)	(31)	0	0	(28)	(32)	(4)
Equity in earnings from subsidiaries									0	0	0
Net income (loss)	$ 220	$ 13,632	$ 4,087	$ 5,509	$ (95,709)	$ 9,540	$ 6,431	$ (2,086)	23,448	(81,824)	(5,633)
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									133	128	171
Intangible asset impairment									0	0	0
Income (loss) from operations									(133)	(128)	(171)
Interest expense									13,609	13,568	21,214
Other income									50	144	0
Income (loss) before taxes									(13,792)	(13,840)	(21,385)
Provision for (benefit of) income taxes									(4,427)	(4,381)	(7,480)
Income (loss) from continuing operations									(9,365)	(9,459)	(13,905)
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									36,401	(71,191)	9,041
Net income (loss)									27,036	(80,650)	(4,864)
Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Net sales									960,614	792,078	758,790
Cost of sales									785,085	661,041	610,049
Gross profit									175,529	131,037	148,741
Selling, general, and administrative expense									116,529	95,735	105,693
Intangible asset impairment									4,863	107,970	1,000
Income (loss) from operations									54,137	(72,668)	42,048
Interest expense									1,469	995	1,399
Other income									(3,801)	(328)	(177)
Income (loss) before taxes									56,469	(73,335)	40,826
Provision for (benefit of) income taxes									18,827	753	12,430
Income (loss) from continuing operations									37,642	(74,088)	28,396
Loss before taxes									(44)	(51)	(7)
Benefit of income taxes									(16)	(19)	(3)
Loss from discontinued operations									(28)	(32)	(4)
Equity in earnings from subsidiaries									(1,213)	2,929	(19,351)
Net income (loss)									36,401	(71,191)	9,041
Non-Guarantor Subsidiaries
Condensed Income Statements, Captions [Line Items]
Net sales									109,984	88,096	91,198
Cost of sales									94,949	77,914	81,073
Gross profit									15,035	10,182	10,125
Selling, general, and administrative expense									17,366	6,629	7,593
Intangible asset impairment									0	0	22,160
Income (loss) from operations									(2,331)	3,553	(19,628)
Interest expense									(75)	(142)	(124)
Other income									(267)	96	0
Income (loss) before taxes									(1,989)	3,599	(19,504)
Provision for (benefit of) income taxes									(776)	670	(153)
Income (loss) from continuing operations									(1,213)	2,929	(19,351)
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 income (loss)									(1,213)	2,929	(19,351)
Eliminations
Condensed Income Statements, Captions [Line Items]
Net sales									(29,725)	(18,087)	(22,421)
Cost of sales									(26,137)	(16,913)	(21,652)
Gross profit									(3,588)	(1,174)	(769)
Selling, general, and administrative expense									0	0	0
Intangible asset impairment									0	0	0
Income (loss) from operations									(3,588)	(1,174)	(769)
Interest expense									0	0	0
Other income									0	0	0
Income (loss) before taxes									(3,588)	(1,174)	(769)
Provision for (benefit of) income taxes									0	0	0
Income (loss) from continuing operations									(3,588)	(1,174)	(769)
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									(35,188)	68,262	10,310
Net income (loss)									$ (38,776)	$ 67,088	$ 9,541