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Income Taxes (Valuation Allowance) (Details) - USD ($) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2015 | Sep. 30, 2015 | Jun. 30, 2015 | Mar. 31, 2015 | Dec. 31, 2014 | Sep. 30, 2014 | Jun. 30, 2014 | Mar. 31, 2014 | Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Valuation Allowance [Line Items] |  |  |  |  |  |  |  |  |  |  |
Valuation allowance | $ 156,800,000 |  |  |  | $ 140,500,000 |  |  |  | $ 156,800,000 | $ 140,500,000 |
Change in valuation allowance |  |  |  |  |  |  |  |  | 18,700,000 | 36,000,000 | $ 49,900,000
Income Tax Expense (Benefit) | (1,500,000) | $ (1,600,000) | $ (2,200,000) | $ 4,600,000 | (26,200,000) | $ (4,700,000) | $ 7,100,000 | $ 9,000,000 | (700,000) | (14,800,000) | $ 32,600,000
Net operating losses in Luxembourg subsidiaries |  |  |  |  |  |  |  |  |  |  |
Valuation Allowance [Line Items] |  |  |  |  |  |  |  |  |  |  |
Valuation allowance | 28,300,000 |  |  |  |  |  |  |  | 28,300,000 |  |
U.S. losses and other federal deferred tax benefits |  |  |  |  |  |  |  |  |  |  |
Valuation Allowance [Line Items] |  |  |  |  |  |  |  |  |  |  |
Valuation allowance | 122,900,000 |  |  |  | 107,500,000 |  |  |  | 122,900,000 | 107,500,000 |
Net Operating Losses in Israel Subsidiaries [Member] |  |  |  |  |  |  |  |  |  |  |
Valuation Allowance [Line Items] |  |  |  |  |  |  |  |  |  |  |
Valuation allowance | 5,500,000 |  |  |  | 1,900,000 |  |  |  | 5,500,000 | 1,900,000 |
Net Operating Losses in Netherlands Subsidiaries [Member] [Member] |  |  |  |  |  |  |  |  |  |  |
Valuation Allowance [Line Items] |  |  |  |  |  |  |  |  |  |  |
Valuation allowance | $ 100,000 |  |  |  |  |  |  |  | 100,000 |  |
Non-US | Net operating losses in Luxembourg subsidiaries |  |  |  |  |  |  |  |  |  |  |
Valuation Allowance [Line Items] |  |  |  |  |  |  |  |  |  |  |
Change in valuation allowance |  |  |  |  |  |  |  |  | 300,000 | 15,700,000 |
Non-US | Net Operating Losses in Israel Subsidiaries [Member] |  |  |  |  |  |  |  |  |  |  |
Valuation Allowance [Line Items] |  |  |  |  |  |  |  |  |  |  |
Change in valuation allowance |  |  |  |  |  |  |  |  | 3,000,000 | 1,200,000 |
Subsidiaries | Luxembourg | Net operating losses in Luxembourg subsidiaries |  |  |  |  |  |  |  |  |  |  |
Valuation Allowance [Line Items] |  |  |  |  |  |  |  |  |  |  |
Valuation allowance |  |  |  |  | 31,000,000 |  |  |  |  | 31,000,000 |
Subsidiaries | NETHERLANDS | Net operating losses in Luxembourg subsidiaries |  |  |  |  |  |  |  |  |  |  |
Valuation Allowance [Line Items] |  |  |  |  |  |  |  |  |  |  |
Valuation allowance |  |  |  |  | $ 100,000 |  |  |  |  | 100,000 |
Guilford Holdings, Inc. | UNITED STATES |  |  |  |  |  |  |  |  |  |  |
Valuation Allowance [Line Items] |  |  |  |  |  |  |  |  |  |  |
Change in valuation allowance |  |  |  |  |  |  |  |  | 8,200,000 | 7,200,000 |
BAM |  |  |  |  |  |  |  |  |  |  |
Valuation Allowance [Line Items] |  |  |  |  |  |  |  |  |  |  |
Change in valuation allowance |  |  |  |  |  |  |  |  | 6,300,000 | 8,500,000 |
Income Tax Expense (Benefit) |  |  |  |  |  |  |  |  | (8,700,000) | 4,900,000 |
Houston General Insurance [Member] |  |  |  |  |  |  |  |  |  |  |
Valuation Allowance [Line Items] |  |  |  |  |  |  |  |  |  |  |
Change in valuation allowance |  |  |  |  |  |  |  |  | (500,000) | 0.1 |
Star & Shield Insurance Exchange [Member] |  |  |  |  |  |  |  |  |  |  |
Valuation Allowance [Line Items] |  |  |  |  |  |  |  |  |  |  |
Change in valuation allowance |  |  |  |  |  |  |  |  | $ (1,200,000) | $ (3,200,000) |

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