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v3.19.1

Investments (Aggregate Values and Unrealized Gains and Losses) (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2019 | Dec. 31, 2018
Investment securities available for sale |  |
Cost | $ 4,611,736 | $ 4,607,117
Gross Unrealized Gains | 9,387 | 6,425
Gross Unrealized Losses | 31,323 | 56,432
Fair Value | 4,589,800 | 4,557,110
Cost | 79,809 | 73,809
Gross unrealized gains | 30,252 | 19,010
Gross unrealized losses | 177 | 220
Fair value | 109,884 | 92,599
Investment securities held to maturity |  |
Cost | 2,214,829 | 2,184,653
Cost | 6,906,374 | 6,865,579
Gross unrealized gains | 80,184 | 42,774
Gross unrealized losses | 31,950 | 57,142
Fair value | 6,954,608 | 6,851,211
U. S. Treasury |  |
Investment securities available for sale |  |
Cost | 1,196,584 | 1,249,243
Gross Unrealized Gains | 1,305 | 633
Gross Unrealized Losses | 847 | 2,166
Fair Value | 1,197,042 | 1,247,710
Agency Securities |  |
Investment securities available for sale |  |
Cost | 351,284 | 257,252
Gross Unrealized Gains | 330 | 222
Gross Unrealized Losses | 1,087 | 639
Fair Value | 350,527 | 256,835
Mortgage Backed Securities |  |
Investment securities available for sale |  |
Cost | 2,917,000 | 2,956,793
Gross Unrealized Gains | 7,373 | 5,309
Gross Unrealized Losses | 28,429 | 52,763
Fair Value | 2,895,944 | 2,909,339
Investment securities held to maturity |  |
Cost | 2,214,829 | 2,184,653
Held To Maturity Securities Accumulated Unrecognized Holding Gain | 40,545 | 17,339
Held To Maturity Securities Accumulated Unrecognized Holding Loss | 450 | 490
Fair Value | 2,254,924 | 2,201,502
Corporate Bonds |  |
Investment securities available for sale |  |
Cost | 142,939 | 139,906
Gross Unrealized Gains | 183 | 59
Gross Unrealized Losses | 960 | 864
Fair Value | 142,162 | 139,101
Other |  |
Investment securities available for sale |  |
Cost | 3,929 | 3,923
Gross Unrealized Gains | 196 | 202
Gross Unrealized Losses | 0 | 0
Fair Value | $ 4,125 | $ 4,125

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