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Investment Securities (Amortized Cost and Fair Value of Investment Securities) (Details) - USD ($) $ in Thousands | Sep. 30, 2021 | Dec. 31, 2020
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Schedule of Debt Securities Available For Sale and Held To Maturity Securities [Line Item] |  |
Securities available for sale, Amortized Cost | $ 1,098,976 | $ 607,665
Securities available for sale, Unrealized Gains | 11,337 | 20,462
Securities available for sale, Unrealized Losses | 12,363 | 68
Securities available for sale | 1,097,950 | 628,059
Securities held to maturity, Amortized Cost | 218,140 | 271,973
Securities held to maturity, Unrealized Gains | 6,352 | 10,062
Securities held to maturity, Unrealized Losses | 328 |
Securities held to maturity, fair value | 224,164 | 282,035
Allowance for credit losses, Amortized Cost | (5) | (7)
Held-to-maturity securities, net , Amortized Cost | 218,135 | 271,966
U.S. Government Agency And Government Sponsored Enterprises [Member] |  |
Schedule of Debt Securities Available For Sale and Held To Maturity Securities [Line Item] |  |
Securities available for sale, Amortized Cost | 6,253 | 6,239
Securities available for sale, Unrealized Gains | 278 | 396
Securities available for sale | 6,531 | 6,635
State And Political Subdivisions [Member] |  |
Schedule of Debt Securities Available For Sale and Held To Maturity Securities [Line Item] |  |
Securities held to maturity, Amortized Cost | 116,812 | 144,506
Securities held to maturity, Unrealized Gains | 2,897 | 4,478
Securities held to maturity, Unrealized Losses | 196 |
Securities held to maturity, fair value | 119,513 | 148,984
Collateralized Mortgage Obligations [Member] | Federal National Mortgage Association [Member] |  |
Schedule of Debt Securities Available For Sale and Held To Maturity Securities [Line Item] |  |
Securities available for sale, Amortized Cost | 17,689 | 3,047
Securities available for sale, Unrealized Gains | 67 | 97
Securities available for sale, Unrealized Losses | 132 |
Securities available for sale | 17,624 | 3,144
Securities held to maturity, Amortized Cost | 21,668 | 29,988
Securities held to maturity, Unrealized Gains | 644 | 1,075
Securities held to maturity, fair value | 22,312 | 31,063
Collateralized Mortgage Obligations [Member] | Federal Home Loan Mortgage Corporation [Member] |  |
Schedule of Debt Securities Available For Sale and Held To Maturity Securities [Line Item] |  |
Securities available for sale, Amortized Cost | 16,318 |
Securities available for sale, Unrealized Losses | 128 |
Securities available for sale | 16,190 |
Securities held to maturity, Amortized Cost | 26,125 | 35,897
Securities held to maturity, Unrealized Gains | 894 | 1,581
Securities held to maturity, fair value | 27,019 | 37,478
Collateralized Mortgage Obligations [Member] | Government National Mortgage Association [Member] |  |
Schedule of Debt Securities Available For Sale and Held To Maturity Securities [Line Item] |  |
Securities held to maturity, Amortized Cost | 5,993 | 7,864
Securities held to maturity, Unrealized Gains | 166 | 265
Securities held to maturity, fair value | 6,159 | 8,129
Collateralized Mortgage Obligations [Member] | Privately Issued [Member] |  |
Schedule of Debt Securities Available For Sale and Held To Maturity Securities [Line Item] |  |
Securities available for sale, Unrealized Gains | 420 | 435
Securities available for sale | 420 | 435
Mortgage-Backed Securities [Member] |  |
Schedule of Debt Securities Available For Sale and Held To Maturity Securities [Line Item] |  |
Securities available for sale, Amortized Cost | 1,092,723 | 601,426
Securities available for sale, Unrealized Gains | 11,059 | 20,066
Securities available for sale, Unrealized Losses | 12,363 | 68
Securities available for sale | 1,091,419 | 621,424
Securities held to maturity, Amortized Cost | 101,328 | 127,467
Securities held to maturity, Unrealized Gains | 3,455 | 5,584
Securities held to maturity, Unrealized Losses | 132 |
Securities held to maturity, fair value | 104,651 | 133,051
Mortgage-Backed Securities [Member] | Federal National Mortgage Association [Member] |  |
Schedule of Debt Securities Available For Sale and Held To Maturity Securities [Line Item] |  |
Securities available for sale, Amortized Cost | 575,861 | 350,627
Securities available for sale, Unrealized Gains | 8,847 | 15,549
Securities available for sale, Unrealized Losses | 4,973 | 44
Securities available for sale | 579,735 | 366,132
Securities held to maturity, Amortized Cost | 9,535 | 10,776
Securities held to maturity, Unrealized Gains | 539 | 703
Securities held to maturity, fair value | 10,074 | 11,479
Mortgage-Backed Securities [Member] | Federal Home Loan Mortgage Corporation [Member] |  |
Schedule of Debt Securities Available For Sale and Held To Maturity Securities [Line Item] |  |
Securities available for sale, Amortized Cost | 390,062 | 225,645
Securities available for sale, Unrealized Gains | 1,257 | 3,155
Securities available for sale, Unrealized Losses | 6,195 | 24
Securities available for sale | 385,124 | 228,776
Securities held to maturity, Amortized Cost | 8,835 | 5,858
Securities held to maturity, Unrealized Gains | 203 | 382
Securities held to maturity, Unrealized Losses | 132 |
Securities held to maturity, fair value | 8,906 | 6,240
Mortgage-Backed Securities [Member] | Government National Mortgage Association [Member] |  |
Schedule of Debt Securities Available For Sale and Held To Maturity Securities [Line Item] |  |
Securities available for sale, Amortized Cost | 92,793 | 22,107
Securities available for sale, Unrealized Gains | 468 | 830
Securities available for sale, Unrealized Losses | 935 |
Securities available for sale | 92,326 | 22,937
Securities held to maturity, Amortized Cost | 29,172 | 37,084
Securities held to maturity, Unrealized Gains | 1,009 | 1,578
Securities held to maturity, fair value | $ 30,181 | $ 38,662

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