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Securities (Schedule of Available-for-sale Debt Securities) (Details) - USD ($) $ in Thousands | Mar. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | $ 7,904,546 | $ 5,470,523
Gross Unrealized Gains | 57,453 | 96,596
Gross Unrealized Losses | (172,786) | (22,461)
Fair Value | 7,789,213 | 5,544,658
U.S. Treasury securities |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 841,711 | 50,310
Gross Unrealized Gains | 328 | 451
Gross Unrealized Losses | (15,697) | 0
Fair Value | 826,342 | 50,761
U.S. government agency and U.S. government-sponsored enterprise debt securities |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 1,236,446 | 806,814
Gross Unrealized Gains | 5,145 | 8,765
Gross Unrealized Losses | (47,586) | (1,260)
Fair Value | 1,194,005 | 814,319
U.S. government agency and U.S. government-sponsored enterprise mortgage-backed securities - Commercial mortgage-backed securities |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 1,178,238 | 1,125,174
Gross Unrealized Gains | 16,407 | 34,306
Gross Unrealized Losses | (25,254) | (5,710)
Fair Value | 1,169,391 | 1,153,770
U.S. government agency and U.S. government-sponsored enterprise mortgage-backed securities - Residential mortgage-backed securities |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 2,271,645 | 1,634,553
Gross Unrealized Gains | 17,026 | 27,952
Gross Unrealized Losses | (41,265) | (1,611)
Fair Value | 2,247,406 | 1,660,894
Municipal securities |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 417,676 | 382,573
Gross Unrealized Gains | 7,348 | 13,588
Gross Unrealized Losses | (4,959) | (88)
Fair Value | 420,065 | 396,073
Non-agency commercial mortgage-backed securities |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 281,099 | 234,965
Gross Unrealized Gains | 4,311 | 6,107
Gross Unrealized Losses | (4,383) | (1,230)
Fair Value | 281,027 | 239,842
Non-agency residential mortgage-backed securities |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 525,560 | 288,520
Gross Unrealized Gains | 1,599 | 1,761
Gross Unrealized Losses | (3,659) | (506)
Fair Value | 523,500 | 289,775
Corporate debt securities |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 517,309 | 406,323
Gross Unrealized Gains | 4,677 | 3,493
Gross Unrealized Losses | (25,343) | (3,848)
Fair Value | 496,643 | 405,968
Foreign government bonds |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 278,100 | 183,828
Gross Unrealized Gains | 320 | 163
Gross Unrealized Losses | (2,092) | (1,460)
Fair Value | 276,328 | 182,531
Asset-backed securities |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 62,762 | 63,463
Gross Unrealized Gains | 292 | 10
Gross Unrealized Losses | (14) | (242)
Fair Value | 63,040 | 63,231
Collateralized loan obligations (“CLOs”) |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 294,000 | 294,000
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (2,534) | (6,506)
Fair Value | $ 291,466 | $ 287,494

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- Definition Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563 + Details
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