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Securities - Continuous Unrealized Losses (Details) - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022
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Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | $ 125,924 | $ 1,451,466
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | (721) | (104,682)
Available-for-sale debt securities, More than 12 Months, Fair Value | 5,532,528 | 4,332,275
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months | (728,216) | (740,048)
Available-for-sale debt securities, Fair Value, Total | 5,658,452 | 5,783,741
Available-for-sale debt securities, Gross Unrealized Loss, Total | (728,937) | (844,730)
U.S. Treasury securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 0 | 131,843
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | 0 | (8,761)
Available-for-sale debt securities, More than 12 Months, Fair Value | 623,978 | 474,360
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months | (52,313) | (61,342)
Available-for-sale debt securities, Fair Value, Total | 623,978 | 606,203
Available-for-sale debt securities, Gross Unrealized Loss, Total | (52,313) | (70,103)
U.S. government agency and U.S. government-sponsored enterprise debt securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 0 | 97,403
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | 0 | (6,902)
Available-for-sale debt securities, More than 12 Months, Fair Value | 364,446 | 214,136
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months | (47,640) | (49,364)
Available-for-sale debt securities, Fair Value, Total | 364,446 | 311,539
Available-for-sale debt securities, Gross Unrealized Loss, Total | (47,640) | (56,266)
US government agencies And U.S. government-sponsored enterprise mortgage-backed securities - Commercial mortgage-backed securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 0 | 252,144
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | 0 | (30,029)
Available-for-sale debt securities, More than 12 Months, Fair Value | 463,572 | 248,125
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months | (63,276) | (47,094)
Available-for-sale debt securities, Fair Value, Total | 463,572 | 500,269
Available-for-sale debt securities, Gross Unrealized Loss, Total | (63,276) | (77,123)
US government agencies And U.S. government-sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 9,402 | 307,536
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | (558) | (20,346)
Available-for-sale debt securities, More than 12 Months, Fair Value | 1,661,112 | 1,448,658
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months | (229,155) | (228,554)
Available-for-sale debt securities, Fair Value, Total | 1,670,514 | 1,756,194
Available-for-sale debt securities, Gross Unrealized Loss, Total | (229,713) | (248,900)
Municipal securities: |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 2,825 | 95,655
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | (15) | (10,194)
Available-for-sale debt securities, More than 12 Months, Fair Value | 254,773 | 159,439
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months | (36,327) | (36,594)
Available-for-sale debt securities, Fair Value, Total | 257,598 | 255,094
Available-for-sale debt securities, Gross Unrealized Loss, Total | (36,342) | (46,788)
Non-agency commercial mortgage-backed Securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 2,742 | 106,184
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | (4) | (3,309)
Available-for-sale debt securities, More than 12 Months, Fair Value | 364,774 | 282,301
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months | (42,058) | (46,087)
Available-for-sale debt securities, Fair Value, Total | 367,516 | 388,485
Available-for-sale debt securities, Gross Unrealized Loss, Total | (42,062) | (49,396)
Non-agency residential mortgage-backed Securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 0 | 22,715
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | 0 | (1,546)
Available-for-sale debt securities, More than 12 Months, Fair Value | 553,671 | 626,509
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months | (89,664) | (111,432)
Available-for-sale debt securities, Fair Value, Total | 553,671 | 649,224
Available-for-sale debt securities, Gross Unrealized Loss, Total | (89,664) | (112,978)
Corporate debt securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 0 | 173,595
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | 0 | (17,907)
Available-for-sale debt securities, More than 12 Months, Fair Value | 502,425 | 352,679
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months | (151,076) | (129,321)
Available-for-sale debt securities, Fair Value, Total | 502,425 | 526,274
Available-for-sale debt securities, Gross Unrealized Loss, Total | (151,076) | (147,228)
Foreign government bonds |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 110,955 | 107,576
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | (144) | (429)
Available-for-sale debt securities, More than 12 Months, Fair Value | 88,616 | 36,143
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months | (11,384) | (13,857)
Available-for-sale debt securities, Fair Value, Total | 199,571 | 143,719
Available-for-sale debt securities, Gross Unrealized Loss, Total | (11,528) | (14,286)
Asset-backed securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 0 | 12,450
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | 0 | (524)
Available-for-sale debt securities, More than 12 Months, Fair Value | 42,300 | 36,626
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months | (934) | (1,552)
Available-for-sale debt securities, Fair Value, Total | 42,300 | 49,076
Available-for-sale debt securities, Gross Unrealized Loss, Total | (934) | (2,076)
Collateralized loan obligations (“CLOs”) |  |
Debt Securities, Available-for-sale [Line Items] |  |
Available-for-sale debt securities, Less than 12 Months, Fair Value | 0 | 144,365
Available-for-sale debt securities, Gross Unrealized Loss, Less than 12 Months | 0 | (4,735)
Available-for-sale debt securities, More than 12 Months, Fair Value | 612,861 | 453,299
Available-for-sale debt securities, Gross Unrealized Loss, More than 12 Months | (4,389) | (14,851)
Available-for-sale debt securities, Fair Value, Total | 612,861 | 597,664
Available-for-sale debt securities, Gross Unrealized Loss, Total | $ (4,389) | $ (19,586)

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