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Accumulated Other Comprehensive Income (Loss) (Components of unrealized holding gains on AFS securities) (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2020 | Jun. 30, 2019 | Jun. 30, 2020 | Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Unrealized gains (losses) on AFS securities arising during the period | $ 2,059 | $ 4,876 | $ 8,370 | $ 10,830
Reclassification adjustment for net (gains) losses included in net income | 0 | 0 | (71) | 0
Tax effect | (379) | (1,018) | (1,772) | (2,213)
Unrealized gains (losses), net of tax | 1,657 | 3,757 | 6,396 | 8,452
Unrealized Holding Gains (Losses) on AFS Securities [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Unrealized gains (losses) on AFS securities arising during the period | 2,059 | 4,876 | 8,370 | 10,830
Reclassification adjustment for net (gains) losses included in net income |  |  | (71) | 0
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent |  |  | 8,299 | 10,830
Tax effect | (379) | (1,018) | (1,772) | (2,213)
Unrealized gains (losses), net of tax | 1,680 | 3,858 | 6,527 | 8,617
Unrealized Holding Gains (Losses) on AFS Securities [Member] | Auction Rate Money Market Preferred and Preferred Stocks [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Unrealized gains (losses) on AFS securities arising during the period | 253 | 30 | (140) | 295
Reclassification adjustment for net (gains) losses included in net income |  |  | 0 | 0
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent |  |  | (140) | 295
Tax effect | 0 | 0 | 0 | 0
Unrealized gains (losses), net of tax | 253 | 30 | (140) | 295
Unrealized Holding Gains (Losses) on AFS Securities [Member] | All Other AFS Securities [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Unrealized gains (losses) on AFS securities arising during the period | 1,806 | 4,846 | 8,510 | 10,535
Reclassification adjustment for net (gains) losses included in net income |  |  | (71) | 0
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent |  |  | 8,439 | 10,535
Tax effect | (379) | (1,018) | (1,772) | (2,213)
Unrealized gains (losses), net of tax | 1,427 | 3,828 | 6,667 | 8,322
Accumulated Defined Benefit Plans Adjustment [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Unrealized gains (losses), net of tax | $ 0 | $ 0 | $ 0 | $ 0

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