Supplemental Financial Information (Schedule of Condensed Consolidating Statements of Cash Flows) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Schedule Of Supplemental Financial Information [Line Items]
Net cash provided by (used in) operating activities	$ 101,245	$ 44,488
Cash Flows from Investing Activities
Cash paid for acquisitions	(2,314)	(140,620)
Net proceeds from sale of property and equipment	249	26,392
Purchases of property, plant, and equipment	(7,600)	(6,822)
Net proceeds from sale of business	8,250	0
Other, net	1,118	1,154
Net cash used in investing activities	(297)	(119,896)
Cash Flows from Financing Activities
Purchase of treasury stock at market prices	(1,178)	(568)
Long-term debt payments	400	47,592
Proceeds from long-term debt	0	58,192
Net proceeds from issuance of common stock	2,892	237
Payment of debt issuance costs	(54)	0
Inter Company Financing	0	0
Excess tax benefit from stock compensation	941	0
Net cash used in financing activities	2,201	10,269
Effect of exchange rate changes on cash	1,055	(2,140)
Net increase (decrease) in cash and cash equivalents	104,204	(67,279)
Cash and cash equivalents at beginning of year	68,858	110,610
Cash and cash equivalents at end of period	173,062	43,331
Reportable Legal Entities | Gibraltar Industries, Inc.
Schedule Of Supplemental Financial Information [Line Items]
Net cash provided by (used in) operating activities	(34,186)	(13,231)
Cash Flows from Investing Activities
Cash paid for acquisitions	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	0
Net cash used in investing activities	0	0
Cash Flows from Financing Activities
Purchase of treasury stock at market prices	(1,178)	(568)
Long-term debt payments	0	0
Proceeds from long-term debt		0
Net proceeds from issuance of common stock	2,892	237
Payment of debt issuance costs	0
Inter Company Financing	31,531	13,562
Excess tax benefit from stock compensation	941
Net cash used in financing activities	34,186	13,231
Effect of exchange rate changes on cash	0	0
Net increase (decrease) 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	118,849	52,060
Cash Flows from Investing Activities
Cash paid for acquisitions	(2,314)	(113,828)
Net proceeds from sale of property and equipment	220	26,392
Purchases of property, plant, and equipment	(7,177)	(6,458)
Net proceeds from sale of business	0
Other, net	1,118	1,154
Net cash used in investing activities	(8,153)	(92,740)
Cash Flows from Financing Activities
Purchase of treasury stock at market prices	0	0
Long-term debt payments	400	47,592
Proceeds from long-term debt		58,192
Net proceeds from issuance of common stock	0	0
Payment of debt issuance costs	(54)
Inter Company Financing	(55)	(42,500)
Excess tax benefit from stock compensation	0
Net cash used in financing activities	(509)	(31,900)
Effect of exchange rate changes on cash	0	0
Net increase (decrease) in cash and cash equivalents	110,187	(72,580)
Cash and cash equivalents at beginning of year	39,597	91,466
Cash and cash equivalents at end of period	149,784	18,886
Reportable Legal Entities | Non-Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Net cash provided by (used in) operating activities	16,582	5,659
Cash Flows from Investing Activities
Cash paid for acquisitions	0	(26,792)
Net proceeds from sale of property and equipment	29	0
Purchases of property, plant, and equipment	(423)	(364)
Net proceeds from sale of business	8,250
Other, net	0	0
Net cash used in investing activities	7,856	(27,156)
Cash Flows from Financing Activities
Purchase of treasury stock at market prices	0	0
Long-term debt payments	0	0
Proceeds from long-term debt		0
Net proceeds from issuance of common stock	0	0
Payment of debt issuance costs	0
Inter Company Financing	(31,476)	28,938
Excess tax benefit from stock compensation	0
Net cash used in financing activities	(31,476)	28,938
Effect of exchange rate changes on cash	1,055	(2,140)
Net increase (decrease) in cash and cash equivalents	(5,983)	5,301
Cash and cash equivalents at beginning of year	29,261	19,144
Cash and cash equivalents at end of period	23,278	24,445
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	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	0
Net cash used in investing activities	0	0
Cash Flows from Financing Activities
Purchase of treasury stock at market prices	0	0
Long-term debt payments	0	0
Proceeds from long-term debt		0
Net proceeds from issuance of common stock	0	0
Payment of debt issuance costs	0
Inter Company Financing	0	0
Excess tax benefit from stock compensation	0
Net cash used in financing activities	0	0
Effect of exchange rate changes on cash	0	0
Net increase (decrease) 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