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Investment Securities (Amortized Cost and Fair Value of Investment Securities) (Details) - USD ($) $ in Thousands | Sep. 30, 2020 | Dec. 31, 2019
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Schedule of Debt Securities Available For Sale and Held To Maturity Securities [Line Item] |  |
Securities available for sale, Amortized Cost | $ 495,618 | $ 415,852
Securities available for sale, Unrealized Gains | 20,559 | 3,696
Securities available for sale, Unrealized Losses | 206 | 1,631
Securities available for sale | 515,971 | 417,917
Securities held to maturity, Amortized Cost | 290,954 | 359,000
Securities held to maturity, Unrealized Gains | 10,924 | 4,882
Securities held to maturity, Unrealized Losses |  | 623
Securities held to maturity, fair value | 301,878 | 363,259
Allowance for credit losses, Amortized Cost | (8) |
Held-to-maturity securities, net , Amortized Cost | 290,946 | 359,000
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 | 6,234 | 26,440
Securities available for sale, Unrealized Gains | 421 | 437
Securities available for sale | 6,655 | 26,877
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 | 151,611 | 192,215
Securities held to maturity, Unrealized Gains | 5,052 | 3,803
Securities held to maturity, fair value | 156,663 | 196,018
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 | 18,104 | 23,834
Securities available for sale, Unrealized Gains | 229 |
Securities available for sale, Unrealized Losses |  | 57
Securities available for sale | 18,333 | 23,777
Securities held to maturity, Amortized Cost | 33,396 | 41,561
Securities held to maturity, Unrealized Gains | 1,236 | 150
Securities held to maturity, Unrealized Losses |  | 256
Securities held to maturity, fair value | 34,632 | 41,455
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 | 4,365 | 4,907
Securities available for sale, Unrealized Gains | 16 |
Securities available for sale, Unrealized Losses |  | 18
Securities available for sale | 4,381 | 4,889
Securities held to maturity, Amortized Cost | 39,905 | 49,389
Securities held to maturity, Unrealized Gains | 1,835 | 307
Securities held to maturity, Unrealized Losses |  | 103
Securities held to maturity, fair value | 41,740 | 49,593
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 | 8,652 | 11,033
Securities held to maturity, Unrealized Gains | 309 | 12
Securities held to maturity, Unrealized Losses |  | 83
Securities held to maturity, fair value | 8,961 | 10,962
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 | 435 | 618
Securities available for sale | 435 | 618
Mortgage-Backed Securities [Member] |  |
Schedule of Debt Securities Available For Sale and Held To Maturity Securities [Line Item] |  |
Securities available for sale, Amortized Cost | 489,384 | 389,412
Securities available for sale, Unrealized Gains | 20,138 | 3,259
Securities available for sale, Unrealized Losses | 206 | 1,631
Securities available for sale | 509,316 | 391,040
Securities held to maturity, Amortized Cost | 139,343 | 166,785
Securities held to maturity, Unrealized Gains | 5,872 | 1,079
Securities held to maturity, Unrealized Losses |  | 623
Securities held to maturity, fair value | 145,215 | 167,241
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 | 303,740 | 293,873
Securities available for sale, Unrealized Gains | 15,923 | 2,263
Securities available for sale, Unrealized Losses | 66 | 1,380
Securities available for sale | 319,597 | 294,756
Securities held to maturity, Amortized Cost | 11,576 | 12,049
Securities held to maturity, Unrealized Gains | 725 | 227
Securities held to maturity, Unrealized Losses |  | 6
Securities held to maturity, fair value | 12,301 | 12,270
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 | 139,875 | 52,733
Securities available for sale, Unrealized Gains | 2,684 | 318
Securities available for sale, Unrealized Losses | 140 | 172
Securities available for sale | 142,419 | 52,879
Securities held to maturity, Amortized Cost | 6,183 | 6,995
Securities held to maturity, Unrealized Gains | 365 | 77
Securities held to maturity, Unrealized Losses |  | 47
Securities held to maturity, fair value | 6,548 | 7,025
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 | 23,300 | 14,065
Securities available for sale, Unrealized Gains | 851 | 60
Securities available for sale, Unrealized Losses |  | 4
Securities available for sale | 24,151 | 14,121
Securities held to maturity, Amortized Cost | 39,631 | 45,758
Securities held to maturity, Unrealized Gains | 1,402 | 306
Securities held to maturity, Unrealized Losses |  | 128
Securities held to maturity, fair value | $ 41,033 | $ 45,936

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