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Securities - Amortized Cost and Fair Value (Details) $ in Thousands | 9 Months Ended |
--- | --- | ---
Sep. 30, 2016 USD ($) | Dec. 31, 2015 USD ($)
Securities Available-for-Sale |  |
Amortized Cost | $ 538,539 | $ 470,719
Gross Unrealized Gains | 4,498 | 383
Gross Unrealized Losses | (11,980) | (15,036)
Fair Value | 531,057 | 456,066
Securities Held-to-Maturity |  |
Amortized Cost |  | 247,746
Gross Unrealized Gains |  | 4,894
Gross Unrealized Losses |  | (965)
Fair Value |  | 251,675
U.S. Treasury |  |
Securities Available-for-Sale |  |
Amortized Cost |  | 1,509
Fair Value |  | 1,509
U.S. government agencies |  |
Securities Available-for-Sale |  |
Amortized Cost | 1,661 | 1,683
Gross Unrealized Losses | (158) | (127)
Fair Value | 1,503 | 1,556
States and political subdivisions |  |
Securities Available-for-Sale |  |
Amortized Cost | 21,489 | 30,341
Gross Unrealized Gains | 765 | 285
Gross Unrealized Losses |  | (100)
Fair Value | 22,254 | 30,526
Corporate bonds |  |
Securities Available-for-Sale |  |
Amortized Cost | 10,958 | 30,157
Gross Unrealized Losses | (228) | (757)
Fair Value | 10,730 | 29,400
Collateralized mortgage obligations |  |
Securities Available-for-Sale |  |
Amortized Cost | 202,670 | 68,743
Gross Unrealized Gains | 2,478 | 24
Gross Unrealized Losses | (758) | (1,847)
Fair Value | 204,390 | 66,920
Securities Held-to-Maturity |  |
Amortized Cost |  | 211,241
Gross Unrealized Gains |  | 3,302
Gross Unrealized Losses |  | (965)
Fair Value |  | 213,578
Asset-backed securities |  |
Securities Available-for-Sale |  |
Amortized Cost | 149,394 | 241,872
Gross Unrealized Gains | 431 | 74
Gross Unrealized Losses | (9,652) | (10,038)
Fair Value | 140,173 | 231,908
FFEL |  |
Other disclosures |  |
Asset-backed securities | $ 118,900 |
Percentage of outstanding principal amount of loans guaranteed by US Department of Education | 97.00 |
Total added credit enhancement in the form of overcollaterization and/or subordination of outstanding principal | $ 12,800 |
Percentage of total added credit enhancement in the form of overcollaterization and/or subordination of outstanding principal | 9.62 |
Collateralized loan obligations |  |
Securities Available-for-Sale |  |
Amortized Cost | $ 109,468 | 94,374
Gross Unrealized Losses | (1,184) | (2,123)
Fair Value | 108,284 | 92,251
U.S. government agency mortgage-backed |  |
Securities Available-for-Sale |  |
Amortized Cost | 42,899 | 2,040
Gross Unrealized Gains | 824 |
Gross Unrealized Losses |  | (44)
Fair Value | $ 43,723 | 1,996
Securities Held-to-Maturity |  |
Amortized Cost |  | 36,505
Gross Unrealized Gains |  | 1,592
Fair Value |  | $ 38,097

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