Supplemental Financial Information (Schedule of Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2014	Dec. 31, 2013
Schedule Of Supplemental Financial Information [Line Items]
Cash and cash equivalents	$ 82,627	$ 68,858	$ 118,300	$ 110,610
Accounts receivable, net	149,458	164,969
Intercompany balances	0	0
Inventories	106,406	107,058
Other current assets	9,852	10,537
Total current assets	348,343	351,422
Property, plant, and equipment, net	116,681	118,932
Goodwill	293,664	292,390
Acquired intangibles	121,649	123,013
Other assets	4,112	4,015
Investment in subsidiaries	0	0
Total assets	884,449	889,772
Accounts payable	83,994	89,204
Accrued expenses	50,615	67,605
Billings in excess of cost	31,523	28,186
Current maturities of long-term debt	400	400
Total current liabilities	166,532	185,395
Long-term debt	209,032	208,882
Deferred income taxes	42,964	42,654
Other non-current liabilities	44,973	42,755
Total shareholders’ equity	420,948	410,086
Total liabilities and shareholders' equity	884,449	889,772
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	13,943	15,023
Inventories	0	0
Other current assets	1,281	4,535
Total current assets	15,224	19,558
Property, plant, and equipment, net	0	0
Goodwill	0	0
Acquired intangibles	0	0
Other assets	0	0
Investment in subsidiaries	614,945	603,208
Total assets	630,169	622,766
Accounts payable	0	0
Accrued expenses	1,547	5,127
Billings in excess of cost	0
Current maturities of long-term debt	0	0
Total current liabilities	1,547	5,127
Long-term debt	207,674	207,553
Deferred income taxes	0	0
Other non-current liabilities	0	0
Total shareholders’ equity	420,948	410,086
Total liabilities and shareholders' equity	630,169	622,766
Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Cash and cash equivalents	53,155	39,597	100,829	91,466
Accounts receivable, net	131,436	142,674
Intercompany balances	13,634	12,033
Inventories	96,928	99,132
Other current assets	4,571	2,957
Total current assets	299,724	296,393
Property, plant, and equipment, net	104,380	106,413
Goodwill	270,017	270,017
Acquired intangibles	109,837	111,734
Other assets	4,112	4,015
Investment in subsidiaries	58,092	54,792
Total assets	846,162	843,364
Accounts payable	75,413	81,551
Accrued expenses	44,927	55,363
Billings in excess of cost	25,863
Current maturities of long-term debt	400	400
Total current liabilities	146,603	157,862
Long-term debt	1,358	1,329
Deferred income taxes	38,786	38,763
Other non-current liabilities	44,470	42,202
Total shareholders’ equity	614,945	603,208
Total liabilities and shareholders' equity	846,162	843,364
Non-Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Cash and cash equivalents	29,472	29,261	17,471	19,144
Accounts receivable, net	18,022	22,295
Intercompany balances	(27,577)	(27,056)
Inventories	9,478	7,926
Other current assets	4,000	3,045
Total current assets	33,395	35,471
Property, plant, and equipment, net	12,301	12,519
Goodwill	23,647	22,373
Acquired intangibles	11,812	11,279
Other assets	0	0
Investment in subsidiaries	0	0
Total assets	81,155	81,642
Accounts payable	8,581	7,653
Accrued expenses	4,141	7,115
Billings in excess of cost	5,660
Current maturities of long-term debt	0	0
Total current liabilities	18,382	22,406
Long-term debt	0	0
Deferred income taxes	4,178	3,891
Other non-current liabilities	503	553
Total shareholders’ equity	58,092	54,792
Total liabilities and shareholders' equity	81,155	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	(673,037)	(658,000)
Total assets	(673,037)	(658,000)
Accounts payable	0	0
Accrued expenses	0	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	(673,037)	(658,000)
Total liabilities and shareholders' equity	$ (673,037)	$ (658,000)