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Investment Securities Available for Sale - Summary Of Available For Sale Investment Securities (Details) - USD ($) $ in Thousands | Mar. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | $ 11,152,743 | $ 11,091,254
Gross Unrealized Gains | 7,464 | 31,540
Gross Unrealized Losses | (1,465,692) | (1,334,132)
Fair Value | 9,694,515 | 9,788,662
Accrued interest receivable on investment securities available for sale | $ 28,700 | $ 26,600
Debt securities, available-for-sale, accrued interest, after allowance for credit loss, noncurrent, statement of financial position [extensible enumeration] | Other assets | Other assets
U.S. Treasury securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | $ 616,037 | $ 588,082
Gross Unrealized Gains | 505 | 9,547
Gross Unrealized Losses | (1,133) | 0
Fair Value | 615,409 | 597,629
U.S. Government agency securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 29,993 | 29,993
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (1,210) | (1,053)
Fair Value | 28,783 | 28,940
Mortgage-backed securities issued by U.S. Government agencies |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 1,022,881 | 1,021,612
Gross Unrealized Gains | 1,119 | 2,037
Gross Unrealized Losses | (112,082) | (97,985)
Fair Value | 911,918 | 925,664
Mortgage-backed securities issued by U.S. Government sponsored enterprises |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 7,383,405 | 7,523,399
Gross Unrealized Gains | 328 | 1,192
Gross Unrealized Losses | (1,200,822) | (1,094,212)
Fair Value | 6,182,911 | 6,430,379
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 676,772 | 692,487
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (111,832) | (104,892)
Fair Value | 564,940 | 587,595
Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 1,414,621 | 1,226,672
Gross Unrealized Gains | 5,512 | 18,764
Gross Unrealized Losses | (38,403) | (35,653)
Fair Value | 1,381,730 | 1,209,783
Corporate debt securities and other debt securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Amortized Cost | 9,034 | 9,009
Gross Unrealized Gains | 0 | 0
Gross Unrealized Losses | (210) | (337)
Fair Value | $ 8,824 | $ 8,672

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