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Investments (Fair Value and Gross Pre-Tax Net Unrealized Loss of Securities By Length of Time) (Details) - USD ($) $ in Thousands | Sep. 30, 2020 | Dec. 31, 2019
--- | --- | ---
Available-for-sale Securities |  |
AFS Fair Value, Less than 12 Months | $ 559,701 | $ 516,259
AFS Unrealized Losses, Less than 12 months | (17,078) | (3,379)
AFS Fair Value, 12 months or longer | 169,246 | 230,770
AFS Unrealized Losses, 12 months or longer | (7,337) | (4,359)
AFS Fair Value | 728,947 | 747,029
AFS Unrealized Losses | (24,415) | (7,738)
Available-for-sale Securities | U.S. Government and Government Agencies [Member] |  |
AFS Fair Value, Less than 12 Months | 4,855 |
AFS Unrealized Losses, Less than 12 months | (46) |
AFS Fair Value, 12 months or longer | 0 |
AFS Unrealized Losses, 12 months or longer | 0 |
AFS Fair Value | 4,855 |
AFS Unrealized Losses | (46) |
Available-for-sale Securities | Foreign Government [Member] |  |
AFS Fair Value, Less than 12 Months |  | 1,416
AFS Unrealized Losses, Less than 12 months |  | (2)
AFS Fair Value, 12 months or longer |  | 0
AFS Unrealized Losses, 12 months or longer |  | 0
AFS Fair Value |  | 1,416
AFS Unrealized Losses |  | (2)
Available-for-sale Securities | Obligations of States and Political Subdivisions [Member] |  |
AFS Fair Value, Less than 12 Months | 15,929 | 35,838
AFS Unrealized Losses, Less than 12 months | (164) | (270)
AFS Fair Value, 12 months or longer | 0 | 0
AFS Unrealized Losses, 12 months or longer | 0 | 0
AFS Fair Value | 15,929 | 35,838
AFS Unrealized Losses | (164) | (270)
Available-for-sale Securities | Corporate Securities [Member] |  |
AFS Fair Value, Less than 12 Months | 100,989 | 84,832
AFS Unrealized Losses, Less than 12 months | (7,444) | (480)
AFS Fair Value, 12 months or longer | 2,695 | 20,182
AFS Unrealized Losses, 12 months or longer | (358) | (830)
AFS Fair Value | 103,684 | 105,014
AFS Unrealized Losses | (7,802) | (1,310)
Available-for-sale Securities | Collateralized Loan Obligations and Other Asset Backed Securities [Member] |  |
AFS Fair Value, Less than 12 Months | 302,492 | 205,191
AFS Unrealized Losses, Less than 12 months | (7,804) | (1,938)
AFS Fair Value, 12 months or longer | 149,893 | 204,385
AFS Unrealized Losses, 12 months or longer | (6,394) | (3,496)
AFS Fair Value | 452,385 | 409,576
AFS Unrealized Losses | (14,198) | (5,434)
Available-for-sale Securities | Residential Mortgage Backed Securities [Member] |  |
AFS Fair Value, Less than 12 Months | 55,128 | 126,089
AFS Unrealized Losses, Less than 12 months | (300) | (425)
AFS Fair Value, 12 months or longer | 2,316 | 5,375
AFS Unrealized Losses, 12 months or longer | (33) | (30)
AFS Fair Value | 57,444 | 131,464
AFS Unrealized Losses | (333) | (455)
Available-for-sale Securities | Commercial Mortgage Backed Securities [Member] |  |
AFS Fair Value, Less than 12 Months | 80,308 | 62,893
AFS Unrealized Losses, Less than 12 months | (1,320) | (264)
AFS Fair Value, 12 months or longer | 14,342 | 828
AFS Unrealized Losses, 12 months or longer | (552) | (3)
AFS Fair Value | 94,650 | 63,721
AFS Unrealized Losses | (1,872) | (267)
Available-for-sale Securities [Member] |  |
AFS Unrealized Losses | $ (24,400) | $ (7,700)

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