Supplemental Financial Information (Schedule of Consolidating Statements of Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Schedule Of Supplemental Financial Information [Line Items]
Net Sales	$ 247,627	$ 265,738	$ 454,232	$ 503,409
Cost of sales	185,802	196,895	343,152	380,416
Gross profit	61,825	68,843	111,080	122,993
Selling, general, and administrative expense	36,895	40,267	76,471	76,656
Income from operations	24,930	28,576	34,609	46,337
Interest expense	3,550	3,666	7,126	7,357
Other expense	353	8,195	407	8,160
Income before taxes	21,027	16,715	27,076	30,820
Provision for (benefit of) income taxes	7,853	(1,897)	9,906	3,179
Income from continuing operations	13,174	18,612	17,170	27,641
Loss from discontinued operations before taxes	(644)	0	(644)	0
Benefit of income taxes	(239)	0	(239)	0
Loss from discontinued operations	(405)	0	(405)	0
Equity in earnings from subsidiaries	0	0	0	0
Net income	12,769	18,612	16,765	27,641
Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Loss from discontinued operations before taxes	(644)
Benefit of income taxes	(239)
Loss from discontinued operations	(405)
Non-Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Loss from discontinued operations before taxes	0
Benefit of income taxes	0
Loss from discontinued operations	0
Gibraltar Industries, Inc.
Schedule Of Supplemental Financial Information [Line Items]
Loss from discontinued operations before taxes	0
Benefit of income taxes	0
Loss from discontinued operations	0
Reportable Legal Entities | Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Net Sales	238,652	247,912	436,400	463,125
Cost of sales	178,779	183,557	329,286	348,996
Gross profit	59,873	64,355	107,114	114,129
Selling, general, and administrative expense	33,681	29,206	70,187	61,117
Income from operations	26,192	35,149	36,927	53,012
Interest expense	162	285	354	595
Other expense	115	225	245	441
Income before taxes	25,915	34,639	36,328	51,976
Provision for (benefit of) income taxes	9,360	5,293	12,738	11,385
Income from continuing operations	16,555		23,590
Loss from discontinued operations before taxes			(644)
Benefit of income taxes			(239)
Loss from discontinued operations			(405)
Equity in earnings from subsidiaries	(1,348)	7,418	(2,040)	7,669
Net income	14,802	36,764	21,145	48,260
Reportable Legal Entities | Non-Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Net Sales	10,627	19,922	21,869	47,215
Cost of sales	8,739	15,075	17,721	37,715
Gross profit	1,888	4,847	4,148	9,500
Selling, general, and administrative expense	3,180	(3,073)	6,207	1,365
Income from operations	(1,292)	7,920	(2,059)	8,135
Interest expense	(15)	(20)	(33)	(42)
Other expense	238	(563)	162	(768)
Income before taxes	(1,515)	8,503	(2,188)	8,945
Provision for (benefit of) income taxes	(167)	1,085	(148)	1,276
Income from continuing operations	(1,348)		(2,040)
Loss from discontinued operations before taxes			0
Benefit of income taxes			0
Loss from discontinued operations			0
Equity in earnings from subsidiaries	0	0	0	0
Net income	(1,348)	7,418	(2,040)	7,669
Reportable Legal Entities | Gibraltar Industries, Inc.
Schedule Of Supplemental Financial Information [Line Items]
Net Sales	0	0	0	0
Cost of sales	0	0	0	0
Gross profit	0	0	0	0
Selling, general, and administrative expense	34	14,134	77	14,174
Income from operations	(34)	(14,134)	(77)	(14,174)
Interest expense	3,403	3,401	6,805	6,804
Other expense	0	8,533	0	8,487
Income before taxes	(3,437)	(26,068)	(6,882)	(29,465)
Provision for (benefit of) income taxes	(1,340)	(8,275)	(2,684)	(9,482)
Income from continuing operations	(2,097)		(4,198)
Loss from discontinued operations before taxes			0
Benefit of income taxes			0
Loss from discontinued operations			0
Equity in earnings from subsidiaries	14,802	36,764	21,145	48,260
Net income	12,705	18,971	16,947	28,277
Eliminations
Schedule Of Supplemental Financial Information [Line Items]
Net Sales	(1,652)	(2,096)	(4,037)	(6,931)
Cost of sales	(1,716)	(1,737)	(3,855)	(6,295)
Gross profit	64	(359)	(182)	(636)
Selling, general, and administrative expense	0	0	0	0
Income from operations	64	(359)	(182)	(636)
Interest expense	0	0	0	0
Other expense	0	0	0	0
Income before taxes	64	(359)	(182)	(636)
Provision for (benefit of) income taxes	0	0	0	0
Income from continuing operations	64		(182)
Loss from discontinued operations before taxes	0		0
Benefit of income taxes	0		0
Loss from discontinued operations	0		0
Equity in earnings from subsidiaries	(13,454)	(44,182)	(19,105)	(55,929)
Net income	$ (13,390)	$ (44,541)	$ (19,287)	$ (56,565)