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Securities (Details 2) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2017 USD ($) security | Sep. 30, 2016 USD ($) | Sep. 30, 2017 USD ($) security | Sep. 30, 2016 USD ($) | Dec. 31, 2016 USD ($) security
Fair Value |  |  |  |  |
Less Than 12 Months | $ 1,128,863,000 |  | $ 1,128,863,000 |  | $ 2,162,896,000
12 Months or More | 976,729,000 |  | 976,729,000 |  | 253,038,000
Total | 2,105,592,000 |  | 2,105,592,000 |  | 2,415,934,000
Gross Unrealized Losses |  |  |  |  |
Less Than 12 Months | (10,521,000) |  | (10,521,000) |  | (51,760,000)
12 Months or More | (31,816,000) |  | (31,816,000) |  | (4,581,000)
Total | (42,337,000) |  | (42,337,000) |  | $ (56,341,000)
Impairment loss | $ 0 | $ 0 | $ 0 | $ 0 |
Number of securities in an unrealized loss position | security | 146 |  | 146 |  | 170
Gross Unrealized Losses |  |  |  |  |
Carrying amount of investment security held-to-maturity transferred to available-for-sale | $ 115,600,000 |  | $ 115,600,000 |  |
Fair Value |  |  |  |  |
Less Than 12 Months | 1,128,863,000 |  | 1,128,863,000 |  | $ 2,162,896,000
12 Months or More | 976,729,000 |  | 976,729,000 |  | 253,038,000
Total | 2,105,592,000 |  | 2,105,592,000 |  | 2,415,934,000
Gross Unrealized Losses |  |  |  |  |
Less Than 12 Months | (10,521,000) |  | (10,521,000) |  | (51,760,000)
12 Months or More | (31,816,000) |  | (31,816,000) |  | (4,581,000)
Total | (42,337,000) |  | (42,337,000) |  | (56,341,000)
U.S. Treasury securities |  |  |  |  |
Fair Value |  |  |  |  |
Less Than 12 Months | 415,507,000 |  | 415,507,000 |  | 670,268,000
12 Months or More | 110,825,000 |  | 110,825,000 |  | 0
Total | 526,332,000 |  | 526,332,000 |  | 670,268,000
Gross Unrealized Losses |  |  |  |  |
Less Than 12 Months | (4,615,000) |  | (4,615,000) |  | (9,829,000)
12 Months or More | (2,088,000) |  | (2,088,000) |  | 0
Total | $ (6,703,000) |  | $ (6,703,000) |  | $ (9,829,000)
Number of securities in an unrealized loss position | security | 22 |  | 22 |  | 26
U.S. government agency and U.S. government sponsored enterprise debt securities |  |  |  |  |
Fair Value |  |  |  |  |
Less Than 12 Months | $ 96,681,000 |  | $ 96,681,000 |  | $ 203,901,000
12 Months or More | 54,512,000 |  | 54,512,000 |  | 0
Total | 151,193,000 |  | 151,193,000 |  | 203,901,000
Gross Unrealized Losses |  |  |  |  |
Less Than 12 Months | (367,000) |  | (367,000) |  | (3,249,000)
12 Months or More | (2,256,000) |  | (2,256,000) |  | 0
Total | $ (2,623,000) |  | $ (2,623,000) |  | $ (3,249,000)
U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities |  |  |  |  |
Gross Unrealized Losses |  |  |  |  |
Number of securities in an unrealized loss position | security | 79 |  | 79 |  | 82
U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Commercial mortgage-backed securities |  |  |  |  |
Fair Value |  |  |  |  |
Less Than 12 Months | $ 120,070,000 |  | $ 120,070,000 |  | $ 202,106,000
12 Months or More | 155,128,000 |  | 155,128,000 |  | 29,201,000
Total | 275,198,000 |  | 275,198,000 |  | 231,307,000
Gross Unrealized Losses |  |  |  |  |
Less Than 12 Months | (1,721,000) |  | (1,721,000) |  | (5,452,000)
12 Months or More | (5,376,000) |  | (5,376,000) |  | (766,000)
Total | (7,097,000) |  | (7,097,000) |  | (6,218,000)
U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities |  |  |  |  |
Fair Value |  |  |  |  |
Less Than 12 Months | 365,038,000 |  | 365,038,000 |  | 629,324,000
12 Months or More | 288,768,000 |  | 288,768,000 |  | 119,603,000
Total | 653,806,000 |  | 653,806,000 |  | 748,927,000
Gross Unrealized Losses |  |  |  |  |
Less Than 12 Months | (2,344,000) |  | (2,344,000) |  | (9,594,000)
12 Months or More | (5,538,000) |  | (5,538,000) |  | (1,955,000)
Total | (7,882,000) |  | (7,882,000) |  | (11,549,000)
Municipal securities |  |  |  |  |
Fair Value |  |  |  |  |
Less Than 12 Months | 22,010,000 |  | 22,010,000 |  | 57,655,000
12 Months or More | 11,256,000 |  | 11,256,000 |  | 2,692,000
Total | 33,266,000 |  | 33,266,000 |  | 60,347,000
Gross Unrealized Losses |  |  |  |  |
Less Than 12 Months | (222,000) |  | (222,000) |  | (1,699,000)
12 Months or More | (234,000) |  | (234,000) |  | (201,000)
Total | (456,000) |  | (456,000) |  | (1,900,000)
Non-agency residential mortgage-backed securities | Investment grade |  |  |  |  |
Fair Value |  |  |  |  |
Less Than 12 Months | 4,715,000 |  | 4,715,000 |  | 5,033,000
12 Months or More | 0 |  | 0 |  | 6,444,000
Total | 4,715,000 |  | 4,715,000 |  | 11,477,000
Gross Unrealized Losses |  |  |  |  |
Less Than 12 Months | (7,000) |  | (7,000) |  | (101,000)
12 Months or More | 0 |  | 0 |  | (14,000)
Total | (7,000) |  | (7,000) |  | (115,000)
Corporate debt securities | Investment grade |  |  |  |  |
Fair Value |  |  |  |  |
Less Than 12 Months | 0 |  | 0 |  | 0
12 Months or More | 2,327,000 |  | 2,327,000 |  | 71,667,000
Total | 2,327,000 |  | 2,327,000 |  | 71,667,000
Gross Unrealized Losses |  |  |  |  |
Less Than 12 Months | 0 |  | 0 |  | 0
12 Months or More | (137,000) |  | (137,000) |  | (375,000)
Total | (137,000) |  | (137,000) |  | (375,000)
Corporate debt securities | Non-investment grade |  |  |  |  |
Fair Value |  |  |  |  |
Less Than 12 Months | 0 |  | 0 |  | 0
12 Months or More | 9,615,000 |  | 9,615,000 |  | 9,173,000
Total | 9,615,000 |  | 9,615,000 |  | 9,173,000
Gross Unrealized Losses |  |  |  |  |
Less Than 12 Months | 0 |  | 0 |  | 0
12 Months or More | (576,000) |  | (576,000) |  | (1,018,000)
Total | (576,000) |  | (576,000) |  | (1,018,000)
Foreign bonds | Investment grade |  |  |  |  |
Fair Value |  |  |  |  |
Less Than 12 Months | 73,619,000 |  | 73,619,000 |  | 363,618,000
12 Months or More | 344,298,000 |  | 344,298,000 |  | 14,258,000
Total | 417,917,000 |  | 417,917,000 |  | 377,876,000
Gross Unrealized Losses |  |  |  |  |
Less Than 12 Months | (873,000) |  | (873,000) |  | (21,327,000)
12 Months or More | (15,611,000) |  | (15,611,000) |  | (252,000)
Total | $ (16,484,000) |  | $ (16,484,000) |  | $ (21,579,000)
Number of securities in an unrealized loss position | security | 14 |  | 14 |  | 13
Other securities |  |  |  |  |
Fair Value |  |  |  |  |
Less Than 12 Months | $ 31,223,000 |  | $ 31,223,000 |  | $ 30,991,000
12 Months or More | 0 |  | 0 |  | 0
Total | 31,223,000 |  | 31,223,000 |  | 30,991,000
Gross Unrealized Losses |  |  |  |  |
Less Than 12 Months | (372,000) |  | (372,000) |  | (509,000)
12 Months or More | 0 |  | 0 |  | 0
Total | (372,000) |  | (372,000) |  | (509,000)
Non-agency commercial mortgage-backed security |  |  |  |  |
Fair Value |  |  |  |  |
Less Than 12 Months | 0 |  | 0 |  | 0
12 Months or More | 0 |  | 0 |  | 0
Total | 0 |  | 0 |  | 0
Gross Unrealized Losses |  |  |  |  |
Less Than 12 Months | 0 |  | 0 |  | 0
12 Months or More | 0 |  | 0 |  | 0
Total | $ 0 |  | $ 0 |  | $ 0

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