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Investment Securities - Schedule of Investment Securities (Details) - USD ($) | Mar. 31, 2025 | Dec. 31, 2024 | Mar. 31, 2024
--- | --- | --- | ---
Available-for-sale securities |  |  |
Amortized Cost | $ 4,729,234,000 | $ 4,725,539,000 | $ 4,942,360,000
Gross Unrealized Gains | 3,389,000 | 2,071,000 | 2,001,000
Gross Unrealized Losses | (512,318,000) | (586,128,000) | (556,763,000)
Fair Value | 4,220,305,000 | 4,141,482,000 | 4,387,598,000
Held-to-maturity securities |  |  |
Amortized Cost | 3,564,936,000 | 3,613,720,000 | 3,810,344,000
Gross Unrealized Gains | 2,172,000 | 1,066,000 | 697,000
Gross Unrealized Losses | (644,295,000) | (704,236,000) | (699,087,000)
Fair Value | 2,922,813,000 | 2,910,550,000 | 3,111,954,000
Less: Allowance for credit losses | (446,000) | (457,000) | (329,000)
Held-to-maturity securities, net of allowance for credit losses | 3,564,490,000 | 3,613,263,000 | 3,810,015,000
Equity securities with readily determinable fair value |  |  |
Amortized Cost | 272,400,000 | 220,758,000 | 123,421,000
Gross Unrealized Gains | 5,254,000 | 2,905,000 | 4,480,000
Gross Unrealized Losses | (7,212,000) | (8,251,000) | (8,124,000)
Fair Value | 270,442,000 | 215,412,000 | 119,777,000
U.S. Treasury |  |  |
Available-for-sale securities |  |  |
Amortized Cost | 12,943,000 | 37,858,000 | 61,185,000
Gross Unrealized Gains | 51,000 | 49,000 | 0
Gross Unrealized Losses | 0 | 0 | (10,000)
Fair Value | 12,994,000 | 37,907,000 | 61,175,000
U.S. government agencies |  |  |
Available-for-sale securities |  |  |
Amortized Cost | 50,000,000 | 50,000,000 | 50,000,000
Gross Unrealized Gains | 0 | 0 | 0
Gross Unrealized Losses | (4,056,000) | (5,055,000) | (4,285,000)
Fair Value | 45,944,000 | 44,945,000 | 45,715,000
Held-to-maturity securities |  |  |
Amortized Cost | 313,539,000 | 313,539,000 | 336,463,000
Gross Unrealized Gains | 0 | 0 | 0
Gross Unrealized Losses | (62,627,000) | (69,127,000) | (69,998,000)
Fair Value | 250,912,000 | 244,412,000 | 266,465,000
Municipal |  |  |
Available-for-sale securities |  |  |
Amortized Cost | 190,670,000 | 188,405,000 | 144,752,000
Gross Unrealized Gains | 1,063,000 | 528,000 | 569,000
Gross Unrealized Losses | (3,584,000) | (4,340,000) | (4,731,000)
Fair Value | 188,149,000 | 184,593,000 | 140,590,000
Held-to-maturity securities |  |  |
Amortized Cost | 158,307,000 | 161,016,000 | 168,490,000
Gross Unrealized Gains | 303,000 | 243,000 | 258,000
Gross Unrealized Losses | (4,964,000) | (5,290,000) | (4,709,000)
Fair Value | 153,646,000 | 155,969,000 | 164,039,000
Corporate notes |  |  |
Held-to-maturity securities |  |  |
Amortized Cost | 56,681,000 | 56,851,000 | 57,372,000
Gross Unrealized Gains | 14,000 | 8,000 | 8,000
Gross Unrealized Losses | (1,367,000) | (1,870,000) | (3,358,000)
Fair Value | 55,328,000 | 54,989,000 | 54,022,000
Financial issuers |  |  |
Available-for-sale securities |  |  |
Amortized Cost | 83,997,000 | 83,997,000 | 83,996,000
Gross Unrealized Gains | 0 | 0 | 0
Gross Unrealized Losses | (3,562,000) | (3,828,000) | (8,264,000)
Fair Value | 80,435,000 | 80,169,000 | 75,732,000
Other |  |  |
Available-for-sale securities |  |  |
Amortized Cost | 1,000,000 | 1,000,000 | 1,000,000
Gross Unrealized Gains | 0 | 0 | 0
Gross Unrealized Losses | 0 | (7,000) | (7,000)
Fair Value | 1,000,000 | 993,000 | 993,000
Residential mortgage-backed securities |  |  |
Available-for-sale securities |  |  |
Amortized Cost | 4,067,349,000 | 4,106,641,000 | 4,396,962,000
Gross Unrealized Gains | 907,000 | 284,000 | 480,000
Gross Unrealized Losses | (482,256,000) | (553,287,000) | (520,719,000)
Fair Value | 3,586,000,000 | 3,553,638,000 | 3,876,723,000
Held-to-maturity securities |  |  |
Amortized Cost | 2,825,859,000 | 2,864,927,000 | 3,007,304,000
Gross Unrealized Gains | 1,072,000 | 0 | 0
Gross Unrealized Losses | (555,525,000) | (605,014,000) | (597,758,000)
Fair Value | 2,271,406,000 | 2,259,913,000 | 2,409,546,000
Commercial (multi-family) mortgage-backed securities |  |  |
Available-for-sale securities |  |  |
Amortized Cost | 58,205,000 | 19,064,000 | 16,225,000
Gross Unrealized Gains | 118,000 | 23,000 | 28,000
Gross Unrealized Losses | (1,696,000) | (755,000) | (577,000)
Fair Value | 56,627,000 | 18,332,000 | 15,676,000
Held-to-maturity securities |  |  |
Amortized Cost | 6,351,000 | 6,364,000 | 6,401,000
Gross Unrealized Gains | 20,000 | 0 | 0
Gross Unrealized Losses | (134,000) | (252,000) | (281,000)
Fair Value | 6,237,000 | 6,112,000 | 6,120,000
Collateralized mortgage obligations |  |  |
Available-for-sale securities |  |  |
Amortized Cost | 265,070,000 | 238,574,000 | 188,240,000
Gross Unrealized Gains | 1,250,000 | 1,187,000 | 924,000
Gross Unrealized Losses | (17,164,000) | (18,856,000) | (18,170,000)
Fair Value | 249,156,000 | 220,905,000 | 170,994,000
Held-to-maturity securities |  |  |
Amortized Cost | 204,199,000 | 211,023,000 | 234,314,000
Gross Unrealized Gains | 763,000 | 815,000 | 431,000
Gross Unrealized Losses | (19,678,000) | (22,683,000) | (22,983,000)
Fair Value | 185,284,000 | 189,155,000 | 211,762,000
Mortgage-backed securities, subprime |  |  |
Available-for-sale securities |  |  |
Fair Value | $ 0 | $ 0 | $ 0

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