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Investment Securities (Details) - USD ($) | Dec. 31, 2018 | Dec. 31, 2017
--- | --- | ---
Held-to-maturity securities |  |
Amortized cost | $ 1,200,000 | $ 2,400,000
Estimated fair value | 1,200,000 | 2,400,000
Carrying Value | 1,200,000 | 2,400,000
Available-for-sale securities |  |
Amortized cost, Available-for-sale securities | 3,481,165,000 | 4,196,263,000
Gross Unrealized Gains | 9,459,000 |
Gross Unrealized Losses | (79,274,000) |
Available for sale debt securities | 3,411,350,000 | 4,124,184,000
Equity Securities | 5,937,000 | 27,886,000
Total Amortized cost | 3,481,165,000 | 4,196,263,000
Total Gross unrealized gains |  | 22,274,000
Total Gross unrealized losses |  | 66,467,000
Available for sale debt securities and equity securities | 3,411,350,000 |
Assets/liabilities measured at fair value |  |
Available-for-sale securities |  |
Total Amortized cost |  | 4,152,070,000
Available for sale debt securities and equity securities | 3,411,350,000 |
Carrying Value |  |
Available-for-sale securities |  |
Available for sale debt securities and equity securities | 3,411,350,000 | 4,152,070,000
Residential mortgage-backed securities |  |
Available-for-sale securities |  |
Amortized cost, Available-for-sale securities | 3,295,366,000 | 3,943,092,000
Gross Unrealized Gains | 6,813,000 | 14,110,000
Gross Unrealized Losses | (79,169,000) | (65,969,000)
Residential mortgage-backed securities | Assets/liabilities measured at fair value |  |
Available-for-sale securities |  |
Available for sale debt securities | 3,223,010,000 | 3,891,233,000
Residential mortgage-backed securities | Carrying Value |  |
Available-for-sale securities |  |
Available for sale debt securities | 3,223,010,000 | 3,891,233,000
Mortgage-backed securities by Ginnie Mae |  |
Available-for-sale securities |  |
Available for sale debt securities | 501,293,000 | 654,063,000
Mortgage-backed securities by Fannie Mae and Freddie Mac |  |
Available-for-sale securities |  |
Available for sale debt securities | 2,721,717,000 | 32,371,700
Obligations of states and political subdivisions |  |
Available-for-sale securities |  |
Amortized cost, Available-for-sale securities | 185,799,000 | 225,096,000
Gross Unrealized Gains | 2,646,000 | 7,871,000
Gross Unrealized Losses | (105,000) | (16,000)
Obligations of states and political subdivisions | Assets/liabilities measured at fair value |  |
Available-for-sale securities |  |
Available for sale debt securities | 188,340,000 | 232,951,000
Obligations of states and political subdivisions | Carrying Value |  |
Available-for-sale securities |  |
Available for sale debt securities | 188,340,000 | 232,951,000
Other securities |  |
Held-to-maturity securities |  |
Amortized cost | 1,200,000 | 2,400,000
Estimated fair value | 1,200,000 | 2,400,000
Carrying Value | $ 1,200,000 | 2,400,000
Equity securities with readily determinable fair values |  |
Available-for-sale securities |  |
Amortized Cost, Equity securities |  | 28,075,000
Gross Unrealized Gains, Equity securities |  | 293,000
Gross Unrealized Losses, Equity securities |  | (482,000)
Equity securities with readily determinable fair values | Assets/liabilities measured at fair value |  |
Available-for-sale securities |  |
Equity Securities |  | 27,886,000
Equity securities with readily determinable fair values | Carrying Value |  |
Available-for-sale securities |  |
Equity Securities |  | $ 27,886,000

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