Supplemental Financial Information (Schedule of Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Schedule Of Supplemental Financial Information [Line Items]
Cash and cash equivalents	$ 124,114	$ 68,858	$ 39,422	$ 110,610	$ 39,422	$ 110,610
Accounts receivable, net	150,170	164,969
Intercompany balances	0	0
Inventories	98,221	107,058
Other current assets	12,119	10,537
Total current assets	384,624	351,422
Property, plant, and equipment, net	108,808	118,932
Goodwill	294,797	292,390
Acquired intangibles	120,435	123,013
Other assets	4,336	4,015
Investment in subsidiaries	0	0
Total assets	913,000	889,772
Accounts payable	82,805	89,204
Accrued expenses	49,331	67,605
Billings in excess of cost	30,358	28,186
Current maturities of long-term debt	400	400
Total current liabilities	162,894	185,395
Long-term debt	208,836	208,882
Deferred income taxes	43,149	42,654
Other non-current liabilities	48,542	42,755
Total shareholders’ equity	449,579	410,086
Total liabilities and shareholders' equity	913,000	889,772
Reportable Legal Entities | Gibraltar Industries, Inc.
Schedule Of Supplemental Financial Information [Line Items]
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	0	0
Intercompany balances	12,719	15,023
Inventories	0	0
Other current assets	11,517	4,535
Total current assets	24,236	19,558
Property, plant, and equipment, net	0	0
Goodwill	0	0
Acquired intangibles	0	0
Other assets	0	0
Investment in subsidiaries	640,535	603,208
Total assets	664,771	622,766
Accounts payable	0	0
Accrued expenses	7,397	5,127
Billings in excess of cost	0	0
Current maturities of long-term debt	0	0
Total current liabilities	7,397	5,127
Long-term debt	207,795	207,553
Deferred income taxes	0	0
Other non-current liabilities	0	0
Total shareholders’ equity	449,579	410,086
Total liabilities and shareholders' equity	664,771	622,766
Reportable Legal Entities | Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Cash and cash equivalents	100,762	39,597	17,160	91,466
Accounts receivable, net	138,630	142,674
Intercompany balances	(5,014)	12,033
Inventories	92,657	99,132
Other current assets	(3,380)	2,957
Total current assets	323,655	296,393
Property, plant, and equipment, net	103,439	106,413
Goodwill	270,017	270,017
Acquired intangibles	107,934	111,734
Other assets	4,336	4,015
Investment in subsidiaries	62,888	54,792
Total assets	872,269	843,364
Accounts payable	78,856	81,551
Accrued expenses	38,600	55,363
Billings in excess of cost	25,486	20,548
Current maturities of long-term debt	400	400
Total current liabilities	143,342	157,862
Long-term debt	1,041	1,329
Deferred income taxes	38,809	38,763
Other non-current liabilities	48,542	42,202
Total shareholders’ equity	640,535	603,208
Total liabilities and shareholders' equity	872,269	843,364
Reportable Legal Entities | Non-Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Cash and cash equivalents	23,352	29,261	22,262	19,144
Accounts receivable, net	11,540	22,295
Intercompany balances	(7,705)	(27,056)
Inventories	5,564	7,926
Other current assets	3,982	3,045
Total current assets	36,733	35,471
Property, plant, and equipment, net	5,369	12,519
Goodwill	24,780	22,373
Acquired intangibles	12,501	11,279
Other assets	0	0
Investment in subsidiaries	0	0
Total assets	79,383	81,642
Accounts payable	3,949	7,653
Accrued expenses	3,334	7,115
Billings in excess of cost	4,872	7,638
Current maturities of long-term debt	0	0
Total current liabilities	12,155	22,406
Long-term debt	0	0
Deferred income taxes	4,340	3,891
Other non-current liabilities	0	553
Total shareholders’ equity	62,888	54,792
Total liabilities and shareholders' equity	79,383	81,642
Eliminations
Schedule Of Supplemental Financial Information [Line Items]
Cash and cash equivalents	0	0	$ 0	$ 0
Accounts receivable, net	0	0
Intercompany balances	0	0
Inventories	0	0
Other current assets	0	0
Total current assets	0	0
Property, plant, and equipment, net	0	0
Goodwill	0	0
Acquired intangibles	0	0
Other assets	0	0
Investment in subsidiaries	(703,423)	(658,000)
Total assets	(703,423)	(658,000)
Accounts payable	0	0
Accrued expenses	0	0
Billings in excess of cost		0
Current maturities of long-term debt	0	0
Total current liabilities	0	0
Long-term debt	0	0
Deferred income taxes	0	0
Other non-current liabilities	0	0
Total shareholders’ equity	(703,423)	(658,000)
Total liabilities and shareholders' equity	$ (703,423)	$ (658,000)