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Securities - Amortized Cost and Estimated Fair Value of Securities (Details) - USD ($) $ in Thousands | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
--- | --- | --- | ---
Available for sale: |  |  |
Available for sale, amortized cost | $ 1,497,458 | $ 971,595 |
Available for sale, gross unrealized gains | 21,896 | 33,972 |
Available for sale, gross unrealized losses | (14,626) | (893) |
Available for sale, fair value | 1,504,728 | 1,004,674 |
Available for sale, allowance for credit losses | 0 | 0 |
Available-for-sale, net carrying amount | 1,504,728 | 1,004,674 |
Held to maturity: |  |  |
Held to maturity, fair value | 25,117 | 41,205 |
Held to maturity, allowance for credit losses | (167) | (66) | $ 0
Held to maturity, net carrying amount | 22,767 | 38,128 |
Securities carried at fair value through income: |  |  |
Securities carried at fair value through income, fair value | 7,497 | 11,554 |
State and municipal securities |  |  |
Available for sale: |  |  |
Available for sale, amortized cost | 394,046 | 420,559 |
Available for sale, gross unrealized gains | 14,095 | 21,884 |
Available for sale, gross unrealized losses | (2,323) | (258) |
Available for sale, fair value | 405,818 | 442,185 |
Available for sale, allowance for credit losses | 0 | 0 |
Available-for-sale, net carrying amount | 405,818 | 442,185 |
Held to maturity: |  |  |
Held to maturity, amortized cost | 22,934 | 38,194 |
Held to maturity, gross unrealized gains | 2,183 | 3,011 |
Held to maturity, gross unrealized losses | 0 | 0 |
Held to maturity, fair value | 25,117 | 41,205 |
Held to maturity, allowance for credit losses | (167) | (66) |
Held to maturity, net carrying amount | 22,767 | 38,128 |
Securities carried at fair value through income: |  |  |
Securities carried at fair value through income, amortized cost | 7,375 | 10,618 |
Securities carried at fair value through income, fair value | 7,497 | 11,554 |
Securities carried at fair value through income, net carrying amount | 7,497 | 11,554 |
Corporate bonds |  |  |
Available for sale: |  |  |
Available for sale, amortized cost | 80,498 | 64,313 |
Available for sale, gross unrealized gains | 2,509 | 1,762 |
Available for sale, gross unrealized losses | (273) | (137) |
Available for sale, fair value | 82,734 | 65,938 |
Available for sale, allowance for credit losses | 0 | 0 |
Available-for-sale, net carrying amount | 82,734 | 65,938 |
U.S. government and agency securities |  |  |
Available for sale: |  |  |
Available for sale, amortized cost | 98,892 | 851 |
Available for sale, gross unrealized gains | 2 | 3 |
Available for sale, gross unrealized losses | (1,236) | (5) |
Available for sale, fair value | 97,658 | 849 |
Available for sale, allowance for credit losses | 0 | 0 |
Available-for-sale, net carrying amount | 97,658 | 849 |
Commercial mortgage-backed securities |  |  |
Available for sale: |  |  |
Available for sale, amortized cost | 65,691 | 10,814 |
Available for sale, gross unrealized gains | 0 | 266 |
Available for sale, gross unrealized losses | (1,448) | 0 |
Available for sale, fair value | 64,243 | 11,080 |
Available for sale, allowance for credit losses | 0 | 0 |
Available-for-sale, net carrying amount | 64,243 | 11,080 |
Residential mortgage-backed securities |  |  |
Available for sale: |  |  |
Available for sale, amortized cost | 559,655 | 207,742 |
Available for sale, gross unrealized gains | 3,751 | 7,441 |
Available for sale, gross unrealized losses | (5,605) | (232) |
Available for sale, fair value | 557,801 | 214,951 |
Available for sale, allowance for credit losses | 0 | 0 |
Available-for-sale, net carrying amount | 557,801 | 214,951 |
Commercial collateralized mortgage obligations |  |  |
Available for sale: |  |  |
Available for sale, amortized cost | 20,000 |  |
Available for sale, gross unrealized gains | 2 |  |
Available for sale, gross unrealized losses | (330) |  |
Available for sale, fair value | 19,672 |  |
Available for sale, allowance for credit losses | 0 |  |
Available-for-sale, net carrying amount | 19,672 |  |
Residential collateralized mortgage obligations |  |  |
Available for sale: |  |  |
Available for sale, amortized cost | 196,691 | 193,865 |
Available for sale, gross unrealized gains | 460 | 1,739 |
Available for sale, gross unrealized losses | (3,411) | (261) |
Available for sale, fair value | 193,740 | 195,343 |
Available for sale, allowance for credit losses | 0 | 0 |
Available-for-sale, net carrying amount | 193,740 | 195,343 |
Asset-backed securities |  |  |
Available for sale: |  |  |
Available for sale, amortized cost | 81,985 | 73,451 |
Available for sale, gross unrealized gains | 1,077 | 877 |
Available for sale, gross unrealized losses | 0 | 0 |
Available for sale, fair value | 83,062 | 74,328 |
Available for sale, allowance for credit losses | 0 | 0 |
Available-for-sale, net carrying amount | $ 83,062 | $ 74,328 |

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