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Securities (Schedule of Available-for-sale Debt Securities) (Details) - USD ($) $ in Thousands | Sep. 30, 2020 | Dec. 31, 2019
--- | --- | ---
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | $ 4,471,694 | $ 3,320,648
Gross Unrealized Gains | 92,913 | 19,805
Gross Unrealized Losses | (25,447) | (23,239)
AFS debt securities, Fair Value | 4,539,160 | 3,317,214
U.S. Treasury securities |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 50,410 | 177,215
Gross Unrealized Gains | 588 | 0
Gross Unrealized Losses | 0 | (793)
AFS debt securities, Fair Value | 50,998 | 176,422
U.S. government agency and U.S. government-sponsored enterprise debt securities |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 718,907 | 584,275
Gross Unrealized Gains | 10,565 | 1,377
Gross Unrealized Losses | (2,410) | (4,407)
AFS debt securities, Fair Value | 727,062 | 581,245
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 | 937,078 | 599,814
Gross Unrealized Gains | 34,292 | 8,551
Gross Unrealized Losses | (4,261) | (4,894)
AFS debt securities, Fair Value | 967,109 | 603,471
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 | 1,206,488 | 998,447
Gross Unrealized Gains | 32,578 | 6,927
Gross Unrealized Losses | (1,057) | (1,477)
AFS debt securities, Fair Value | 1,238,009 | 1,003,897
Municipal securities |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 327,422 | 101,621
Gross Unrealized Gains | 7,199 | 790
Gross Unrealized Losses | (1,346) | (109)
AFS debt securities, Fair Value | 333,275 | 102,302
Non-agency commercial mortgage-backed securities |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 210,343 | 86,609
Gross Unrealized Gains | 5,556 | 1,947
Gross Unrealized Losses | (1,223) | (6)
AFS debt securities, Fair Value | 214,676 | 88,550
Non-agency residential mortgage-backed securities |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 277,306 | 46,830
Gross Unrealized Gains | 782 | 3
Gross Unrealized Losses | (475) | (285)
AFS debt securities, Fair Value | 277,613 | 46,548
Corporate debt securities |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 251,253 | 11,250
Gross Unrealized Gains | 1,327 | 12
Gross Unrealized Losses | (1,403) | (113)
AFS debt securities, Fair Value | 251,177 | 11,149
Foreign government bonds |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 134,179 | 354,481
Gross Unrealized Gains | 26 | 198
Gross Unrealized Losses | (1,534) | (507)
AFS debt securities, Fair Value | 132,671 | 354,172
Asset-backed securities |  |
Schedule of Available-for-sale Debt Securities |  |
Amortized Cost | 64,308 | 66,106
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (1,160) | (1,354)
AFS debt securities, Fair Value | 63,148 | 64,752
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 | (10,578) | (9,294)
AFS debt securities, Fair Value | $ 283,422 | $ 284,706

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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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