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Securities - Fair Values and Amortized Costs Securities (Details) - USD ($) $ in Thousands | Jun. 30, 2020 | Dec. 31, 2019
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Debt Securities, Available-for-sale [Line Items] |  |  |
Debt Securities, Available-for-Sale, Amortized Cost | [1] | $ 765,374 | $ 768,427
Debt Securities, Available-for-Sale, Gross Unrealized Gains | [1] | 36,330 | 11,659
Debt Securities, Available-for-Sale, Gross Unrealized Losses | [1] | (1) | (953)
Debt Securities, Available-for-Sale, Fair Value | [1] | 801,703 | 779,133
Marketable equity securities |  | 2,663 | 5,150
Total Securities |  | 804,366 | 784,283
Interest receivable |  | 3,400 | 3,400
U.S. Treasury securities |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Debt Securities, Available-for-Sale, Amortized Cost |  | 9,975 | 9,969
Debt Securities, Available-for-Sale, Gross Unrealized Gains |  | 380 | 71
Debt Securities, Available-for-Sale, Gross Unrealized Losses |  | 0 |
Debt Securities, Available-for-Sale, Fair Value |  | 10,355 | 10,040
Obligations of U.S. government corporations and agencies |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Debt Securities, Available-for-Sale, Amortized Cost |  | 158,869 | 155,969
Debt Securities, Available-for-Sale, Gross Unrealized Gains |  | 4,835 | 1,773
Debt Securities, Available-for-Sale, Gross Unrealized Losses |  | (1) | (45)
Debt Securities, Available-for-Sale, Fair Value |  | 163,703 | 157,697
Collateralized mortgage obligations of U.S. government corporations and agencies |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Debt Securities, Available-for-Sale, Amortized Cost |  | 172,938 | 186,879
Debt Securities, Available-for-Sale, Gross Unrealized Gains |  | 8,224 | 2,773
Debt Securities, Available-for-Sale, Gross Unrealized Losses |  | 0 | (304)
Debt Securities, Available-for-Sale, Fair Value |  | 181,162 | 189,348
Residential mortgage-backed securities of U.S. government corporations and agencies |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Debt Securities, Available-for-Sale, Amortized Cost |  | 18,891 | 22,120
Debt Securities, Available-for-Sale, Gross Unrealized Gains |  | 877 | 321
Debt Securities, Available-for-Sale, Gross Unrealized Losses |  | 0 | (23)
Debt Securities, Available-for-Sale, Fair Value |  | 19,768 | 22,418
Commercial mortgage-backed securities of U.S. government corporations and agencies |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Debt Securities, Available-for-Sale, Amortized Cost |  | 269,673 | 273,771
Debt Securities, Available-for-Sale, Gross Unrealized Gains |  | 14,877 | 2,680
Debt Securities, Available-for-Sale, Gross Unrealized Losses |  | 0 | (581)
Debt Securities, Available-for-Sale, Fair Value |  | 284,550 | 275,870
Corporate obligations |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Debt Securities, Available-for-Sale, Amortized Cost |  | 5,026 | 7,603
Debt Securities, Available-for-Sale, Gross Unrealized Gains |  | 12 | 24
Debt Securities, Available-for-Sale, Gross Unrealized Losses |  | 0 | 0
Debt Securities, Available-for-Sale, Fair Value |  | 5,038 | 7,627
Obligations of states and political subdivisions |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |
Debt Securities, Available-for-Sale, Amortized Cost |  | 130,002 | 112,116
Debt Securities, Available-for-Sale, Gross Unrealized Gains |  | 7,125 | 4,017
Debt Securities, Available-for-Sale, Gross Unrealized Losses |  | 0 | 0
Debt Securities, Available-for-Sale, Fair Value |  | $ 137,127 | $ 116,133
[1] | Excludes interest receivable of $3.4 million at June 30, 2020 and $3.4 million at December 31, 2019. Interest receivable is included in other assets in the consolidated balance sheets.

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