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Supplemental Financial Information (Schedule of Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands | Sep. 30, 2015 | Dec. 31, 2014 | Mar. 31, 2014 | Dec. 31, 2013
--- | --- | --- | --- | ---
Schedule Of Supplemental Financial Information [Line Items] |  |  |  |
Cash and cash equivalents | $ 43,331 | $ 110,610 | $ 101,013 | $ 97,039
Accounts receivable, net | 177,117 | 101,141 |  |
Intercompany balances | 0 | 0 |  |
Inventories | 126,006 | 128,743 |  |
Other current assets | 24,514 | 19,937 |  |
Total current assets | 370,968 | 360,431 |  |
Property, plant, and equipment, net | 121,218 | 129,575 |  |
Goodwill | 291,940 | 236,044 |  |
Acquired intangibles | 131,872 | 82,215 |  |
Other assets | 4,199 | 2,206 |  |
Investment in subsidiaries | 0 | 0 |  |
Total assets | 920,197 | 810,471 |  |
Accounts payable | 104,244 | 81,246 |  |
Accrued expenses | 69,576 | 52,439 |  |
Billings in excess of cost | 22,206 | 0 |  |
Current maturities of long-term debt | 400 | 400 |  |
Total current liabilities | 196,426 | 134,085 |  |
Long-term debt | 220,814 | 209,511 |  |
Deferred income taxes | 54,880 | 49,772 |  |
Other non-current liabilities | 39,696 | 29,874 |  |
Total shareholders’ equity | 408,381 | 387,229 |  |
Total liabilities and shareholders' equity | 920,197 | 810,471 |  |
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 | (126,295) | 21,619 |  |
Inventories | 0 | 0 |  |
Other current assets | 3,627 | 4,484 |  |
Total current assets | (122,668) | 26,103 |  |
Property, plant, and equipment, net | 0 | 0 |  |
Goodwill | 0 | 0 |  |
Acquired intangibles | 0 | 0 |  |
Other assets | 0 | 0 |  |
Investment in subsidiaries | 739,878 | 573,664 |  |
Total assets | 617,210 | 599,767 |  |
Accounts payable | 0 | 0 |  |
Accrued expenses | 1,397 | 5,469 |  |
Billings in excess of cost | 0 |  |  |
Current maturities of long-term debt | 0 | 0 |  |
Total current liabilities | 1,397 | 5,469 |  |
Long-term debt | 207,432 | 207,069 |  |
Deferred income taxes | 0 | 0 |  |
Other non-current liabilities | 0 | 0 |  |
Total shareholders’ equity | 408,381 | 387,229 |  |
Total liabilities and shareholders' equity | 617,210 | 599,767 |  |
Guarantor Subsidiaries |  |  |  |
Schedule Of Supplemental Financial Information [Line Items] |  |  |  |
Cash and cash equivalents | 18,886 | 91,466 | 80,085 | 75,856
Accounts receivable, net | 158,386 | 91,713 |  |
Intercompany balances | 150,946 | (1,850) |  |
Inventories | 116,553 | 120,091 |  |
Other current assets | 17,676 | 14,488 |  |
Total current assets | 462,447 | 315,908 |  |
Property, plant, and equipment, net | 107,979 | 116,628 |  |
Goodwill | 271,246 | 229,558 |  |
Acquired intangibles | 116,371 | 77,259 |  |
Other assets | 4,199 | 2,206 |  |
Investment in subsidiaries | 56,282 | 32,404 |  |
Total assets | 1,018,524 | 773,963 |  |
Accounts payable | 95,579 | 74,751 |  |
Accrued expenses | 63,125 | 45,561 |  |
Billings in excess of cost | 18,038 |  |  |
Current maturities of long-term debt | 400 | 400 |  |
Total current liabilities | 177,142 | 120,712 |  |
Long-term debt | 13,382 | 2,442 |  |
Deferred income taxes | 48,891 | 47,717 |  |
Other non-current liabilities | 39,231 | 29,428 |  |
Total shareholders’ equity | 739,878 | 573,664 |  |
Total liabilities and shareholders' equity | 1,018,524 | 773,963 |  |
Non-Guarantor Subsidiaries |  |  |  |
Schedule Of Supplemental Financial Information [Line Items] |  |  |  |
Cash and cash equivalents | 24,445 | 19,144 | 20,928 | 21,183
Accounts receivable, net | 18,731 | 9,428 |  |
Intercompany balances | (24,651) | (19,769) |  |
Inventories | 9,453 | 8,652 |  |
Other current assets | 3,211 | 965 |  |
Total current assets | 31,189 | 18,420 |  |
Property, plant, and equipment, net | 13,239 | 12,947 |  |
Goodwill | 20,694 | 6,486 |  |
Acquired intangibles | 15,501 | 4,956 |  |
Other assets | 0 | 0 |  |
Investment in subsidiaries | 0 | 0 |  |
Total assets | 80,623 | 42,809 |  |
Accounts payable | 8,665 | 6,495 |  |
Accrued expenses | 5,054 | 1,409 |  |
Billings in excess of cost | 4,168 |  |  |
Current maturities of long-term debt | 0 | 0 |  |
Total current liabilities | 17,887 | 7,904 |  |
Long-term debt | 0 | 0 |  |
Deferred income taxes | 5,989 | 2,055 |  |
Other non-current liabilities | 465 | 446 |  |
Total shareholders’ equity | 56,282 | 32,404 |  |
Total liabilities and shareholders' equity | 80,623 | 42,809 |  |
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 | (796,160) | (606,068) |  |
Total assets | (796,160) | (606,068) |  |
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 | (796,160) | (606,068) |  |
Total liabilities and shareholders' equity | $ (796,160) | $ (606,068) |  |

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