Supplemental Financial Information (Schedule of Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2014	Dec. 31, 2013
Schedule Of Supplemental Financial Information [Line Items]
Cash and cash equivalents	$ 160,901	$ 170,177	$ 82,627	$ 68,858	$ 82,627	$ 68,858
Accounts receivable, net	128,482	124,072
Intercompany balances	0	0
Inventories	86,943	89,612
Other current assets	5,957	7,336
Total current assets	382,283	391,197
Property, plant, and equipment, net	98,691	108,304
Goodwill	320,411	304,032
Acquired intangibles	112,533	110,790
Other assets	4,548	3,922
Investment in subsidiaries	0	0
Total assets	918,466	918,245
Accounts payable	76,894	69,944
Accrued expenses	66,253	70,392
Billings in excess of cost	14,452	11,352
Current maturities of long-term debt	400	400
Total current liabilities	157,999	152,088
Long-term debt	209,433	209,237
Deferred income taxes	38,089	38,002
Other non-current liabilities	46,640	58,038
Total shareholders’ equity	466,305	460,880
Total liabilities and shareholders' equity	918,466	918,245
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	(11,508)	(615)
Inventories	0	0
Other current assets	1,424	13,783
Total current assets	(10,084)	13,168
Property, plant, and equipment, net	0	0
Goodwill	0	0
Acquired intangibles	0	0
Other assets	0	0
Investment in subsidiaries	688,635	663,118
Total assets	678,551	676,286
Accounts payable	0	0
Accrued expenses	4,088	7,369
Billings in excess of cost	0	0
Current maturities of long-term debt	0	0
Total current liabilities	4,088	7,369
Long-term debt	208,158	208,037
Deferred income taxes	0	0
Other non-current liabilities	0	0
Total shareholders’ equity	466,305	460,880
Total liabilities and shareholders' equity	678,551	676,286
Reportable Legal Entities | Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Cash and cash equivalents	138,763	143,826	53,155	39,597
Accounts receivable, net	121,615	117,526
Intercompany balances	15,414	6,152
Inventories	82,288	85,483
Other current assets	1,262	(10,070)
Total current assets	359,342	342,917
Property, plant, and equipment, net	95,183	104,642
Goodwill	298,179	282,300
Acquired intangibles	103,223	101,520
Other assets	4,548	3,922
Investment in subsidiaries	58,481	58,477
Total assets	918,956	893,778
Accounts payable	73,838	66,363
Accrued expenses	60,307	60,004
Billings in excess of cost	12,491	9,301
Current maturities of long-term debt	400	400
Total current liabilities	147,036	136,068
Long-term debt	1,275	1,200
Deferred income taxes	35,370	35,354
Other non-current liabilities	46,640	58,038
Total shareholders’ equity	688,635	663,118
Total liabilities and shareholders' equity	918,956	893,778
Reportable Legal Entities | Non-Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Cash and cash equivalents	22,138	26,351	29,472	29,261
Accounts receivable, net	6,867	6,546
Intercompany balances	(3,906)	(5,537)
Inventories	4,655	4,129
Other current assets	3,271	3,623
Total current assets	33,025	35,112
Property, plant, and equipment, net	3,508	3,662
Goodwill	22,232	21,732
Acquired intangibles	9,310	9,270
Other assets	0	0
Investment in subsidiaries	0	0
Total assets	68,075	69,776
Accounts payable	3,056	3,581
Accrued expenses	1,858	3,019
Billings in excess of cost	1,961	2,051
Current maturities of long-term debt	0	0
Total current liabilities	6,875	8,651
Long-term debt	0	0
Deferred income taxes	2,719	2,648
Other non-current liabilities	0	0
Total shareholders’ equity	58,481	58,477
Total liabilities and shareholders' equity	68,075	69,776
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	(747,116)	(721,595)
Total assets	(747,116)	(721,595)
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	(747,116)	(721,595)
Total liabilities and shareholders' equity	$ (747,116)	$ (721,595)