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Investment Securities - Expected Maturities of Investment Securities Portfolio (Detail) - USD ($) $ in Thousands | Dec. 31, 2020 | Dec. 31, 2019
--- | --- | ---
Available-for-sale, Amortized Cost |  |
Within one year | $ 353,414 |
One to five years | 2,828,719 |
Five to ten years | 1,029,340 |
Beyond ten years | 1,573,281 |
Total | 5,784,754 | $ 5,313,209
Available-for-sale, Fair Value |  |
Within one year | 358,852 |
One to five years | 2,922,695 |
Five to ten years | 1,049,684 |
Beyond ten years | 1,638,884 |
Total | $ 5,970,115 | $ 5,385,091
Available-for-sale, Weighted Average Yield |  |
Within one year | 2.61% |
One to five years | 2.27% |
Five to ten years | 1.98% |
Beyond ten years | 2.90% |
Total | 2.41% |

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