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v3.23.3

Investment Securities - Amortized cost and fair value for available for sale securities (Details) - USD ($) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2023 | Sep. 30, 2022 | Mar. 31, 2022 | Sep. 30, 2023 | Sep. 30, 2022 | Dec. 31, 2022
Investment securities held-to-maturity |  |  |  |  |  |
Amortized cost | $ 2,533,713,000 |  |  | $ 2,533,713,000 |  | $ 2,683,241,000
Gross Unrealized Losses | (521,313,000) |  |  | (521,313,000) |  | (433,073,000)
Fair Value | 2,012,400,000 |  |  | 2,012,400,000 |  | 2,250,168,000
Investment securities available for sale |  |  |  |  |  |
Amortized cost | 5,709,270,000 |  |  | 5,709,270,000 |  | 6,216,141,000
Gross Unrealized Gains | 125,000 |  |  | 125,000 |  | 4,054,000
Gross Unrealized Losses | (1,085,777,000) |  |  | (1,085,777,000) |  | (893,373,000)
Fair Value | 4,623,618,000 |  |  | 4,623,618,000 |  | 5,326,822,000
Gross realized gains |  | $ 103,000 |  | 1,300,000 | $ 103,000 |
Gross realized losses |  | 73,000 |  | 1,300,000 | 73,000 |
Securities gains, net | 0 | $ 30,000 |  | 45,000 | $ 30,000 |
Atlantic Capital |  |  |  |  |  |
Investment securities available for sale |  |  |  |  |  |
Realized gains or losses |  |  | $ 0 |  |  |
Sold securities |  |  | $ 414,400,000 |  |  |
U.S. Treasuries |  |  |  |  |  |
Investment securities available for sale |  |  |  |  |  |
Amortized cost | 174,322,000 |  |  | 174,322,000 |  | 272,416,000
Gross Unrealized Losses | (2,063,000) |  |  | (2,063,000) |  | (6,778,000)
Fair Value | 172,259,000 |  |  | 172,259,000 |  | 265,638,000
U.S. Government agencies |  |  |  |  |  |
Investment securities held-to-maturity |  |  |  |  |  |
Amortized cost | 197,266,000 |  |  | 197,266,000 |  | 197,262,000
Gross Unrealized Losses | (33,016,000) |  |  | (33,016,000) |  | (29,787,000)
Fair Value | 164,250,000 |  |  | 164,250,000 |  | 167,475,000
Investment securities available for sale |  |  |  |  |  |
Amortized cost | 246,059,000 |  |  | 246,059,000 |  | 245,972,000
Gross Unrealized Losses | (29,305,000) |  |  | (29,305,000) |  | (26,884,000)
Fair Value | 216,754,000 |  |  | 216,754,000 |  | 219,088,000
Residential mortgage pass-through securities issued or guaranteed by U.S. government agencies or sponsored enterprises |  |  |  |  |  |
Investment securities held-to-maturity |  |  |  |  |  |
Amortized cost | 1,474,360,000 |  |  | 1,474,360,000 |  | 1,591,646,000
Gross Unrealized Losses | (303,022,000) |  |  | (303,022,000) |  | (255,093,000)
Fair Value | 1,171,338,000 |  |  | 1,171,338,000 |  | 1,336,553,000
Investment securities available for sale |  |  |  |  |  |
Amortized cost | 1,851,803,000 |  |  | 1,851,803,000 |  | 1,996,405,000
Gross Unrealized Losses | (363,097,000) |  |  | (363,097,000) |  | (298,052,000)
Fair Value | 1,488,706,000 |  |  | 1,488,706,000 |  | 1,698,353,000
Residential collateralized mortgage-obligations issued by U.S. government agencies or sponsored enterprises |  |  |  |  |  |
Investment securities held-to-maturity |  |  |  |  |  |
Amortized cost | 451,928,000 |  |  | 451,928,000 |  | 474,660,000
Gross Unrealized Losses | (85,938,000) |  |  | (85,938,000) |  | (69,664,000)
Fair Value | 365,990,000 |  |  | 365,990,000 |  | 404,996,000
Investment securities available for sale |  |  |  |  |  |
Amortized cost | 644,581,000 |  |  | 644,581,000 |  | 708,337,000
Gross Unrealized Losses | (125,154,000) |  |  | (125,154,000) |  | (107,292,000)
Fair Value | 519,427,000 |  |  | 519,427,000 |  | 601,045,000
Commercial mortgage-backed securities issued by U.S. government agencies or sponsored enterprises |  |  |  |  |  |
Investment securities held-to-maturity |  |  |  |  |  |
Amortized cost | 355,664,000 |  |  | 355,664,000 |  | 362,586,000
Gross Unrealized Losses | (85,773,000) |  |  | (85,773,000) |  | (66,304,000)
Fair Value | 269,891,000 |  |  | 269,891,000 |  | 296,282,000
Investment securities available for sale |  |  |  |  |  |
Amortized cost | 1,199,936,000 |  |  | 1,199,936,000 |  | 1,196,700,000
Gross Unrealized Gains | 3,000 |  |  | 3,000 |  | 2,542,000
Gross Unrealized Losses | (250,407,000) |  |  | (250,407,000) |  | (198,844,000)
Fair Value | 949,532,000 |  |  | 949,532,000 |  | 1,000,398,000
State and municipal obligations |  |  |  |  |  |
Investment securities available for sale |  |  |  |  |  |
Amortized cost | 1,132,238,000 |  |  | 1,132,238,000 |  | 1,269,525,000
Gross Unrealized Gains | 1,000 |  |  | 1,000 |  | 1,210,000
Gross Unrealized Losses | (259,232,000) |  |  | (259,232,000) |  | (205,883,000)
Fair Value | 873,007,000 |  |  | 873,007,000 |  | 1,064,852,000
Small Business Administration loan-backed securities |  |  |  |  |  |
Investment securities held-to-maturity |  |  |  |  |  |
Amortized cost | 54,495,000 |  |  | 54,495,000 |  | 57,087,000
Gross Unrealized Losses | (13,564,000) |  |  | (13,564,000) |  | (12,225,000)
Fair Value | 40,931,000 |  |  | 40,931,000 |  | 44,862,000
Investment securities available for sale |  |  |  |  |  |
Amortized cost | 429,785,000 |  |  | 429,785,000 |  | 491,203,000
Gross Unrealized Gains | 120,000 |  |  | 120,000 |  | 302,000
Gross Unrealized Losses | (52,435,000) |  |  | (52,435,000) |  | (46,695,000)
Fair Value | 377,470,000 |  |  | 377,470,000 |  | 444,810,000
Corporate securities. |  |  |  |  |  |
Investment securities available for sale |  |  |  |  |  |
Amortized cost | 30,546,000 |  |  | 30,546,000 |  | 35,583,000
Gross Unrealized Gains | 1,000 |  |  | 1,000 |  |
Gross Unrealized Losses | (4,084,000) |  |  | (4,084,000) |  | (2,945,000)
Fair Value | $ 26,463,000 |  |  | $ 26,463,000 |  | $ 32,638,000

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