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Investment Securities Available for Sale (Summary of Available for Sale Investment Securities) (Details) - USD ($) $ in Thousands | Mar. 31, 2022 | Dec. 31, 2021
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | $ 11,157,760 | $ 10,991,506
Gross Unrealized Gains | 7,045 | 66,427
Gross Unrealized Losses | (701,704) | (139,604)
Fair Value | 10,463,101 | 10,918,329
U.S. Treasury securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 414,397 | 120,465
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (19,811) | (2,627)
Fair Value | 394,586 | 117,838
U.S. Government agency securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 52,865 | 53,214
Gross Unrealized Gains | 411 | 1,374
Gross Unrealized Losses | (1,471) | (387)
Fair Value | 51,805 | 54,201
Mortgage-backed securities issued by U.S. Government agencies |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 733,289 | 790,329
Gross Unrealized Gains | 60 | 768
Gross Unrealized Losses | (46,605) | (11,464)
Fair Value | 686,744 | 779,633
Mortgage-backed securities issued by U.S. Government sponsored enterprises |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 8,169,609 | 8,063,890
Gross Unrealized Gains | 4,937 | 50,491
Gross Unrealized Losses | (553,915) | (102,080)
Fair Value | 7,620,631 | 8,012,301
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 877,362 | 951,691
Gross Unrealized Gains | 326 | 4,658
Gross Unrealized Losses | (54,810) | (16,726)
Fair Value | 822,878 | 939,623
Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 554,868 | 479,420
Gross Unrealized Gains | 1,020 | 8,644
Gross Unrealized Losses | (25,092) | (6,320)
Fair Value | 530,796 | 481,744
Asset-backed securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 337,037 | 514,188
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | 0 | 0
Fair Value | 337,037 | 514,188
Corporate debt securities and other debt securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 18,333 | 18,309
Gross Unrealized Gains | 291 | 492
Gross Unrealized Losses | 0 | 0
Fair Value | $ 18,624 | $ 18,801

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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=123581744&loc=d3e27161-111563 + Details
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- Definition Amount, before tax, of unrealized loss 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 (c) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563 + Details
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