Supplemental Financial Information (Schedule of Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Schedule Of Supplemental Financial Information [Line Items]
Cash and cash equivalents	$ 182,379	$ 170,177	$ 124,114	$ 68,858
Accounts receivable, net	138,871	124,072
Intercompany balances	0	0
Inventories	86,065	89,612
Other current assets	8,351	7,336
Total current assets	415,666	391,197
Property, plant, and equipment, net	95,869	108,304
Goodwill	320,848	304,032
Acquired intangibles	110,325	110,790
Other assets	4,750	3,922
Investment in subsidiaries	0	0
Total assets	947,458	918,245
Accounts payable	88,007	69,944
Accrued expenses	69,389	70,392
Billings in excess of cost	13,963	11,352
Current maturities of long-term debt	400	400
Total current liabilities	171,759	152,088
Long-term debt	209,229	209,237
Deferred income taxes	38,203	38,002
Other non-current liabilities	46,364	58,038
Total shareholders’ equity	481,903	460,880
Total liabilities and shareholders' equity	947,458	918,245
Reportable Legal Entities | Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Cash and cash equivalents	158,843	143,826	100,762	39,597
Accounts receivable, net	131,513	117,526
Intercompany balances	15,604	6,152
Inventories	81,927	85,483
Other current assets	1,498	(10,070)
Total current assets	389,385	342,917
Property, plant, and equipment, net	92,450	104,642
Goodwill	298,399	282,300
Acquired intangibles	101,232	101,520
Other assets	4,750	3,922
Investment in subsidiaries	58,978	58,477
Total assets	945,194	893,778
Accounts payable	84,230	66,363
Accrued expenses	60,533	60,004
Billings in excess of cost	11,524	9,301
Current maturities of long-term debt	400	400
Total current liabilities	156,687	136,068
Long-term debt	950	1,200
Deferred income taxes	35,583	35,354
Other non-current liabilities	46,364	58,038
Total shareholders’ equity	705,610	663,118
Total liabilities and shareholders' equity	945,194	893,778
Reportable Legal Entities | Non-Guarantor Subsidiaries
Schedule Of Supplemental Financial Information [Line Items]
Cash and cash equivalents	23,536	26,351	23,352	29,261
Accounts receivable, net	7,358	6,546
Intercompany balances	(4,815)	(5,537)
Inventories	4,138	4,129
Other current assets	4,123	3,623
Total current assets	34,340	35,112
Property, plant, and equipment, net	3,419	3,662
Goodwill	22,449	21,732
Acquired intangibles	9,093	9,270
Other assets	0	0
Investment in subsidiaries	0	0
Total assets	69,301	69,776
Accounts payable	3,777	3,581
Accrued expenses	1,487	3,019
Billings in excess of cost	2,439	2,051
Current maturities of long-term debt	0	0
Total current liabilities	7,703	8,651
Long-term debt	0	0
Deferred income taxes	2,620	2,648
Other non-current liabilities	0	0
Total shareholders’ equity	58,978	58,477
Total liabilities and shareholders' equity	69,301	69,776
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	(10,789)	(615)
Inventories	0	0
Other current assets	2,730	13,783
Total current assets	(8,059)	13,168
Property, plant, and equipment, net	0	0
Goodwill	0	0
Acquired intangibles	0	0
Other assets	0	0
Investment in subsidiaries	705,610	663,118
Total assets	697,551	676,286
Accounts payable	0	0
Accrued expenses	7,369	7,369
Billings in excess of cost	0	0
Current maturities of long-term debt	0	0
Total current liabilities	7,369	7,369
Long-term debt	208,279	208,037
Deferred income taxes	0	0
Other non-current liabilities	0	0
Total shareholders’ equity	481,903	460,880
Total liabilities and shareholders' equity	697,551	676,286
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	(764,588)	(721,595)
Total assets	(764,588)	(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	(764,588)	(721,595)
Total liabilities and shareholders' equity	$ (764,588)	$ (721,595)