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Investment Securities Available for Sale - Summary Of Available For Sale Investment Securities (Details) - USD ($) $ in Thousands | Dec. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | $ 10,991,506 | $ 7,801,864
Gross Unrealized Gains | 66,427 | 177,243
Gross Unrealized Losses | (139,604) | (16,669)
Fair Value | 10,918,329 | 7,962,438
U.S. Treasury securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 120,465 | 20,257
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (2,627) | 0
Fair Value | 117,838 | 20,257
U.S. Government agency securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 53,214 | 79,638
Gross Unrealized Gains | 1,374 | 2,682
Gross Unrealized Losses | (387) | 0
Fair Value | 54,201 | 82,320
Mortgage-backed securities issued by U.S. Government agencies |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 790,329 | 1,216,012
Gross Unrealized Gains | 768 | 7,930
Gross Unrealized Losses | (11,464) | (5,925)
Fair Value | 779,633 | 1,218,017
Mortgage-backed securities issued by U.S. Government sponsored enterprises |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 8,063,890 | 4,865,858
Gross Unrealized Gains | 50,491 | 134,188
Gross Unrealized Losses | (102,080) | 0
Fair Value | 8,012,301 | 5,000,046
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 951,691 | 1,245,644
Gross Unrealized Gains | 4,658 | 15,309
Gross Unrealized Losses | (16,726) | (10,576)
Fair Value | 939,623 | 1,250,377
Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 479,420 | 354,244
Gross Unrealized Gains | 8,644 | 16,677
Gross Unrealized Losses | (6,320) | 0
Fair Value | 481,744 | 370,921
Asset-backed securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 514,188 |
Gross Unrealized Gains | 0 |
Gross Unrealized Losses | 0 |
Fair Value | 514,188 |
Corporate debt securities and other debt securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 18,309 | 20,211
Gross Unrealized Gains | 492 | 457
Gross Unrealized Losses | 0 | (168)
Fair Value | $ 18,801 | $ 20,500

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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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