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Securities (Continuous Unrealized Losses) (Details) - USD ($) $ in Thousands | Sep. 30, 2021 | Dec. 31, 2020
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Schedule of Available-for-sale Debt Securities |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | $ 5,715,518 | $ 1,519,603
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | (106,241) | (15,456)
Available-for-sale debt securities, 12 Months or More, Fair Value | 873,339 | 342,859
Available-for-sale debt securities, Gross Unrealized Loss, 12 Months or More | (27,437) | (7,005)
Available-for-sale debt securities fair value, Total | 6,588,857 | 1,862,462
Available-for-sale debt securities, Gross Unrealized Loss, Total | (133,678) | (22,461)
U.S. Treasury securities |  |
Schedule of Available-for-sale Debt Securities |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 768,909 | 352,521
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | (8,769) | (1,260)
Available-for-sale debt securities, 12 Months or More, Fair Value | 0 | 0
Available-for-sale debt securities, Gross Unrealized Loss, 12 Months or More | 0 | 0
Available-for-sale debt securities fair value, Total | 768,909 | 352,521
Available-for-sale debt securities, Gross Unrealized Loss, Total | (8,769) | (1,260)
U.S. government agency and U.S. government-sponsored enterprise debt securities |  |
Schedule of Available-for-sale Debt Securities |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 1,008,979 |
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | (21,747) |
Available-for-sale debt securities, 12 Months or More, Fair Value | 144,196 |
Available-for-sale debt securities, Gross Unrealized Loss, 12 Months or More | (5,781) |
Available-for-sale debt securities fair value, Total | 1,153,175 |
Available-for-sale debt securities, Gross Unrealized Loss, Total | (27,528) |
U.S. government agency and U.S. government-sponsored enterprise mortgage-backed securities - Commercial mortgage-backed securities |  |
Schedule of Available-for-sale Debt Securities |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 603,554 | 292,596
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | (17,164) | (5,656)
Available-for-sale debt securities, 12 Months or More, Fair Value | 107,752 | 3,543
Available-for-sale debt securities, Gross Unrealized Loss, 12 Months or More | (5,421) | (54)
Available-for-sale debt securities fair value, Total | 711,306 | 296,139
Available-for-sale debt securities, Gross Unrealized Loss, Total | (22,585) | (5,710)
U.S. government agency and U.S. government-sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities |  |
Schedule of Available-for-sale Debt Securities |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 1,904,559 | 342,561
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | (35,792) | (1,611)
Available-for-sale debt securities, 12 Months or More, Fair Value | 17,591 | 0
Available-for-sale debt securities, Gross Unrealized Loss, 12 Months or More | (1,130) | 0
Available-for-sale debt securities fair value, Total | 1,922,150 | 342,561
Available-for-sale debt securities, Gross Unrealized Loss, Total | (36,922) | (1,611)
Municipal securities |  |
Schedule of Available-for-sale Debt Securities |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 249,055 | 24,529
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | (7,612) | (88)
Available-for-sale debt securities, 12 Months or More, Fair Value | 0 | 0
Available-for-sale debt securities, Gross Unrealized Loss, 12 Months or More | 0 | 0
Available-for-sale debt securities fair value, Total | 249,055 | 24,529
Available-for-sale debt securities, Gross Unrealized Loss, Total | (7,612) | (88)
Non-agency commercial mortgage-backed securities |  |
Schedule of Available-for-sale Debt Securities |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 151,915 | 58,738
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | (2,158) | (1,230)
Available-for-sale debt securities, 12 Months or More, Fair Value | 40,233 | 7,920
Available-for-sale debt securities, Gross Unrealized Loss, 12 Months or More | (1,134) | 0
Available-for-sale debt securities fair value, Total | 192,148 | 66,658
Available-for-sale debt securities, Gross Unrealized Loss, Total | (3,292) | (1,230)
Non-agency residential mortgage-backed securities |  |
Schedule of Available-for-sale Debt Securities |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 561,635 | 90,156
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | (3,233) | (506)
Available-for-sale debt securities, 12 Months or More, Fair Value | 8,145 | 0
Available-for-sale debt securities, Gross Unrealized Loss, 12 Months or More | (3) | 0
Available-for-sale debt securities fair value, Total | 569,780 | 90,156
Available-for-sale debt securities, Gross Unrealized Loss, Total | (3,236) | (506)
Corporate debt securities |  |
Schedule of Available-for-sale Debt Securities |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 207,861 | 251,674
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | (6,139) | (3,645)
Available-for-sale debt securities, 12 Months or More, Fair Value | 178,833 | 9,798
Available-for-sale debt securities, Gross Unrealized Loss, 12 Months or More | (11,166) | (203)
Available-for-sale debt securities fair value, Total | 386,694 | 261,472
Available-for-sale debt securities, Gross Unrealized Loss, Total | (17,305) | (3,848)
Foreign government bonds |  |
Schedule of Available-for-sale Debt Securities |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 54,228 | 106,828
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | (3,514) | (1,460)
Available-for-sale debt securities, 12 Months or More, Fair Value | 84,977 | 0
Available-for-sale debt securities, Gross Unrealized Loss, 12 Months or More | (414) | 0
Available-for-sale debt securities fair value, Total | 139,205 | 106,828
Available-for-sale debt securities, Gross Unrealized Loss, Total | (3,928) | (1,460)
Asset-backed securities |  |
Schedule of Available-for-sale Debt Securities |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 21,631 | 0
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | (55) | 0
Available-for-sale debt securities, 12 Months or More, Fair Value | 0 | 34,104
Available-for-sale debt securities, Gross Unrealized Loss, 12 Months or More | 0 | (242)
Available-for-sale debt securities fair value, Total | 21,631 | 34,104
Available-for-sale debt securities, Gross Unrealized Loss, Total | (55) | (242)
Collateralized loan obligations (“CLOs”) |  |
Schedule of Available-for-sale Debt Securities |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 183,192 | 0
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | (58) | 0
Available-for-sale debt securities, 12 Months or More, Fair Value | 291,612 | 287,494
Available-for-sale debt securities, Gross Unrealized Loss, 12 Months or More | (2,388) | (6,506)
Available-for-sale debt securities fair value, Total | 474,804 | 287,494
Available-for-sale debt securities, Gross Unrealized Loss, Total | $ (2,446) | $ (6,506)

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