Supplemental Financial Information (Schedule of Condensed Consolidating Statements of Cash Flows) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Schedule Of Supplemental Financial Information [Line Items]
Net cash provided by (used in) operating activities	$ 21,720	$ 49,441
Cash Flows from Investing Activities
Cash paid for acquisitions, net of cash acquired	(18,494)	(2,314)
Net proceeds from sale of property and equipment	12,778	162
Purchases of property, plant, and equipment	(3,274)	(4,035)
Net proceeds from sale of business	0	8,479
Other, net	0	1,118
Net cash (used in) provided by investing activities	(8,990)	3,410
Cash Flows from Financing Activities
Long-term debt payments	400	400
Payment of debt issuance costs		54
Purchase of treasury stock at market prices	(1,003)	(462)
Net proceeds from issuance of common stock	247	2,057
Payment of debt issuance costs	0	(54)
Intercompany financing	0	0
Net cash used in financing activities	(1,156)	1,141
Effect of exchange rate changes on cash	628	1,264
Net increase in cash and cash equivalents	12,202	55,256
Cash and cash equivalents at beginning of year	170,177	68,858
Cash and cash equivalents at end of period	182,379	124,114
Guarantor Subsidiaries
Cash Flows from Financing Activities
Purchase of treasury stock at market prices		0
Non-Guarantor Subsidiaries
Cash Flows from Financing Activities
Purchase of treasury stock at market prices		0
Reportable Legal Entities | Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Net cash provided by (used in) operating activities	31,687	62,474
Cash Flows from Investing Activities
Cash paid for acquisitions, net of cash acquired	(18,494)	(2,314)
Net proceeds from sale of property and equipment	12,627	133
Purchases of property, plant, and equipment	(3,123)	(3,852)
Net proceeds from sale of business		0
Other, net		1,118
Net cash (used in) provided by investing activities	(8,990)	(4,915)
Cash Flows from Financing Activities
Long-term debt payments	400	400
Payment of debt issuance costs		54
Purchase of treasury stock at market prices	0
Net proceeds from issuance of common stock	0	0
Intercompany financing	(7,280)	4,060
Net cash used in financing activities	(7,680)	3,606
Effect of exchange rate changes on cash	0	0
Net increase in cash and cash equivalents	15,017	61,165
Cash and cash equivalents at beginning of year	143,826	39,597
Cash and cash equivalents at end of period	158,843	100,762
Reportable Legal Entities | Non-Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Net cash provided by (used in) operating activities	(3,327)	14,263
Cash Flows from Investing Activities
Cash paid for acquisitions, net of cash acquired	0	0
Net proceeds from sale of property and equipment	151	29
Purchases of property, plant, and equipment	(151)	(183)
Net proceeds from sale of business		8,479
Other, net		0
Net cash (used in) provided by investing activities	0	8,325
Cash Flows from Financing Activities
Long-term debt payments	0	0
Payment of debt issuance costs		0
Purchase of treasury stock at market prices	0
Net proceeds from issuance of common stock	0	0
Intercompany financing	(116)	(29,761)
Net cash used in financing activities	(116)	(29,761)
Effect of exchange rate changes on cash	628	1,264
Net increase in cash and cash equivalents	(2,815)	(5,909)
Cash and cash equivalents at beginning of year	26,351	29,261
Cash and cash equivalents at end of period	23,536	23,352
Reportable Legal Entities | Gibraltar Industries, Inc.
Schedule Of Supplemental Financial Information [Line Items]
Net cash provided by (used in) operating activities	(6,640)	(27,296)
Cash Flows from Investing Activities
Cash paid for acquisitions, net of cash acquired	0	0
Net proceeds from sale of property and equipment	0	0
Purchases of property, plant, and equipment	0	0
Net proceeds from sale of business		0
Other, net		0
Net cash (used in) provided by investing activities	0	0
Cash Flows from Financing Activities
Long-term debt payments	0	0
Payment of debt issuance costs		0
Purchase of treasury stock at market prices	(1,003)	(462)
Net proceeds from issuance of common stock	247	2,057
Intercompany financing	7,396	25,701
Net cash used in financing activities	6,640	27,296
Effect of exchange rate changes on cash	0	0
Net increase in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of year	0	0
Cash and cash equivalents at end of period	0	0
Eliminations
Schedule Of Supplemental Financial Information [Line Items]
Net cash provided by (used in) operating activities	0	0
Cash Flows from Investing Activities
Cash paid for acquisitions, net of cash acquired	0	0
Net proceeds from sale of property and equipment	0	0
Purchases of property, plant, and equipment	0	0
Net proceeds from sale of business		0
Other, net		0
Net cash (used in) provided by investing activities	0	0
Cash Flows from Financing Activities
Long-term debt payments	0	0
Payment of debt issuance costs		0
Purchase of treasury stock at market prices	0	0
Net proceeds from issuance of common stock	0	0
Intercompany financing	0	0
Net cash used in financing activities	0	0
Effect of exchange rate changes on cash	0	0
Net increase in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of year	0	0
Cash and cash equivalents at end of period	$ 0	$ 0