Supplemental Financial Information (Schedule of Condensed Consolidating Statements of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Schedule Of Supplemental Financial Information [Line Items]
Net cash provided by (used in) operating activities	$ 2,343	$ 15,541
Cash Flows from Investing Activities
Cash paid for acquisitions, net of cash acquired	(18,561)	(2,314)
Net proceeds from sale of property and equipment	9,233	57
Purchases of property, plant, and equipment	(1,453)	(1,501)
Other, net	0	1,118
Net cash used in investing activities	(10,781)	(2,640)
Cash Flows from Financing Activities
Payment of debt issuance costs		54
Purchase of treasury stock at market prices	(922)	(414)
Net proceeds from issuance of common stock	11	133
Payment of debt issuance costs	0	(54)
Inter Company Financing	0	0
Net cash used in financing activities	(911)	(335)
Effect of exchange rate changes on cash	73	1,203
Net (decrease) increase in cash and cash equivalents	(9,276)	13,769
Cash and cash equivalents at beginning of year	170,177	68,858
Cash and cash equivalents at end of period	160,901	82,627
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 | Gibraltar Industries, Inc.
Schedule Of Supplemental Financial Information [Line Items]
Net cash provided by (used in) operating activities	(6,605)	(6,371)
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
Other, net		0
Net cash used in investing activities	0	0
Cash Flows from Financing Activities
Payment of debt issuance costs		0
Purchase of treasury stock at market prices	(922)	(414)
Net proceeds from issuance of common stock	11	133
Inter Company Financing	7,516	6,652
Net cash used in financing activities	6,605	6,371
Effect of exchange rate changes on cash	0	0
Net (decrease) 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
Reportable Legal Entities | Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Net cash provided by (used in) operating activities	12,141	23,251
Cash Flows from Investing Activities
Cash paid for acquisitions, net of cash acquired	(18,561)	(2,314)
Net proceeds from sale of property and equipment	9,081	57
Purchases of property, plant, and equipment	(1,326)	(1,356)
Other, net		1,118
Net cash used in investing activities	(10,806)	(2,495)
Cash Flows from Financing Activities
Payment of debt issuance costs		54
Purchase of treasury stock at market prices	0
Net proceeds from issuance of common stock	0	0
Inter Company Financing	(6,398)	(7,144)
Net cash used in financing activities	(6,398)	(7,198)
Effect of exchange rate changes on cash	0	0
Net (decrease) increase in cash and cash equivalents	(5,063)	13,558
Cash and cash equivalents at beginning of year	143,826	39,597
Cash and cash equivalents at end of period	138,763	53,155
Reportable Legal Entities | Non-Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Net cash provided by (used in) operating activities	(3,193)	(1,339)
Cash Flows from Investing Activities
Cash paid for acquisitions, net of cash acquired	0	0
Net proceeds from sale of property and equipment	152	0
Purchases of property, plant, and equipment	(127)	(145)
Other, net		0
Net cash used in investing activities	25	(145)
Cash Flows from Financing Activities
Payment of debt issuance costs		0
Purchase of treasury stock at market prices	0
Net proceeds from issuance of common stock	0	0
Inter Company Financing	(1,118)	492
Net cash used in financing activities	(1,118)	492
Effect of exchange rate changes on cash	73	1,203
Net (decrease) increase in cash and cash equivalents	(4,213)	211
Cash and cash equivalents at beginning of year	26,351	29,261
Cash and cash equivalents at end of period	22,138	29,472
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
Other, net		0
Net cash used in investing activities	0	0
Cash Flows from Financing Activities
Payment of debt issuance costs		0
Purchase of treasury stock at market prices	0	0
Net proceeds from issuance of common stock	0	0
Inter Company Financing	0	0
Net cash used in financing activities	0	0
Effect of exchange rate changes on cash	0	0
Net (decrease) 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