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Accumulated Other Comprehensive Income (Loss) (Components of unrealized holding gains on AFS securities) (Details) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2020 | Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Unrealized gains (losses) on AFS securities arising during the period | $ 6,311 | $ 5,954
Reclassification adjustment for net (gains) losses included in net income | (71) | 0
Tax effect | (1,393) | (1,195)
Unrealized gains (losses), net of tax | 4,739 | 4,695
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 | 6,311 | 5,954
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 | 6,240 | 5,954
Tax effect | (1,393) | (1,195)
Unrealized gains (losses), net of tax | 4,847 | 4,759
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 | (393) | 265
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 | (393) | 265
Tax effect | 0 | 0
Unrealized gains (losses), net of tax | (393) | 265
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 | 6,704 | 5,689
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 | 6,633 | 5,689
Tax effect | (1,393) | (1,195)
Unrealized gains (losses), net of tax | 5,240 | 4,494
Accumulated Defined Benefit Plans Adjustment [Member] |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Unrealized gains (losses), net of tax | $ 0 | $ 0

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