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Securities - Unrealized Loss Positions (Details) $ in Thousands | Dec. 31, 2017 USD ($) security | Dec. 31, 2016 USD ($) security
--- | --- | ---
Securities Available-for-Sale, Number of Securities |  |
Less than 12 months in an unrealized loss position | security | 26 | 44
Greater than 12 months in an unrealized loss position | security | 22 | 34
Total | security | 48 | 78
Securities Available-for-Sale, Unrealized Losses |  |
Less than 12 months in an unrealized loss position | $ 1,457 | $ 5,143
Greater than 12 months in an unrealized loss position | 3,216 | 9,463
Total | 4,673 | 14,606
Securities Available-for-Sale, Fair Value |  |
Less than 12 months in an unrealized loss position | 102,830 | 216,050
Greater than 12 months in an unrealized loss position | 108,651 | 213,060
Total | $ 211,481 | $ 429,110
U.S. Treasury |  |
Securities Available-for-Sale, Number of Securities |  |
Less than 12 months in an unrealized loss position | security | 1 |
Total | security | 1 |
Securities Available-for-Sale, Unrealized Losses |  |
Less than 12 months in an unrealized loss position | $ 55 |
Total | 55 |
Securities Available-for-Sale, Fair Value |  |
Less than 12 months in an unrealized loss position | 3,947 |
Total | $ 3,947 |
U.S. government agencies |  |
Securities Available-for-Sale, Number of Securities |  |
Less than 12 months in an unrealized loss position | security | 2 | 11
Greater than 12 months in an unrealized loss position | security |  | 1
Total | security | 2 | 12
Securities Available-for-Sale, Unrealized Losses |  |
Less than 12 months in an unrealized loss position | $ 9 | $ 957
Greater than 12 months in an unrealized loss position |  | 20
Total | 9 | 977
Securities Available-for-Sale, Fair Value |  |
Less than 12 months in an unrealized loss position | 6,550 | 40,636
Greater than 12 months in an unrealized loss position |  | 898
Total | $ 6,550 | $ 41,534
U.S. government agency mortgage-backed |  |
Securities Available-for-Sale, Number of Securities |  |
Less than 12 months in an unrealized loss position | security | 4 |
Greater than 12 months in an unrealized loss position | security | 5 |
Total | security | 9 |
Securities Available-for-Sale, Unrealized Losses |  |
Less than 12 months in an unrealized loss position | $ 24 |
Greater than 12 months in an unrealized loss position | 141 |
Total | 165 |
Securities Available-for-Sale, Fair Value |  |
Less than 12 months in an unrealized loss position | 5,501 |
Greater than 12 months in an unrealized loss position | 4,843 |
Total | $ 10,344 |
States and political subdivisions |  |
Securities Available-for-Sale, Number of Securities |  |
Less than 12 months in an unrealized loss position | security | 13 | 12
Greater than 12 months in an unrealized loss position | security | 1 |
Total | security | 14 | 12
Securities Available-for-Sale, Unrealized Losses |  |
Less than 12 months in an unrealized loss position | $ 1,237 | $ 273
Greater than 12 months in an unrealized loss position | 27 |
Total | 1,264 | 273
Securities Available-for-Sale, Fair Value |  |
Less than 12 months in an unrealized loss position | 45,985 | 35,241
Greater than 12 months in an unrealized loss position | 1,512 |
Total | $ 47,497 | $ 35,241
Corporate bonds |  |
Securities Available-for-Sale, Number of Securities |  |
Less than 12 months in an unrealized loss position | security |  | 1
Greater than 12 months in an unrealized loss position | security | 1 | 2
Total | security | 1 | 3
Securities Available-for-Sale, Unrealized Losses |  |
Less than 12 months in an unrealized loss position |  | $ 183
Greater than 12 months in an unrealized loss position | $ 11 | 153
Total | 11 | 336
Securities Available-for-Sale, Fair Value |  |
Less than 12 months in an unrealized loss position |  | 4,817
Greater than 12 months in an unrealized loss position | 332 | 5,328
Total | $ 332 | $ 10,145
Collateralized mortgage obligations |  |
Securities Available-for-Sale, Number of Securities |  |
Less than 12 months in an unrealized loss position | security | 3 | 16
Greater than 12 months in an unrealized loss position | security | 8 | 7
Total | security | 11 | 23
Securities Available-for-Sale, Unrealized Losses |  |
Less than 12 months in an unrealized loss position | $ 31 | $ 3,402
Greater than 12 months in an unrealized loss position | 1,124 | 397
Total | 1,155 | 3,799
Securities Available-for-Sale, Fair Value |  |
Less than 12 months in an unrealized loss position | 11,534 | 117,752
Greater than 12 months in an unrealized loss position | 40,219 | 18,109
Total | $ 51,753 | $ 135,861
Asset-backed securities |  |
Securities Available-for-Sale, Number of Securities |  |
Less than 12 months in an unrealized loss position | security |  | 4
Greater than 12 months in an unrealized loss position | security | 7 | 12
Total | security | 7 | 16
Securities Available-for-Sale, Unrealized Losses |  |
Less than 12 months in an unrealized loss position |  | $ 328
Greater than 12 months in an unrealized loss position | $ 1,913 | 7,997
Total | 1,913 | 8,325
Securities Available-for-Sale, Fair Value |  |
Less than 12 months in an unrealized loss position |  | 17,604
Greater than 12 months in an unrealized loss position | 61,745 | 107,112
Total | $ 61,745 | $ 124,716
Collateralized loan obligations |  |
Securities Available-for-Sale, Number of Securities |  |
Less than 12 months in an unrealized loss position | security | 3 |
Greater than 12 months in an unrealized loss position | security |  | 12
Total | security | 3 | 12
Securities Available-for-Sale, Unrealized Losses |  |
Less than 12 months in an unrealized loss position | $ 101 |
Greater than 12 months in an unrealized loss position |  | $ 896
Total | 101 | 896
Securities Available-for-Sale, Fair Value |  |
Less than 12 months in an unrealized loss position | 29,313 |
Greater than 12 months in an unrealized loss position |  | 81,613
Total | $ 29,313 | $ 81,613

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