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Reclassification Adjustments Out of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2019 | Mar. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Abstract] |  |
Net securities gains | $ 57 | $ 72
Interest income (expense) | 77,691 | 73,486
Other noninterest expense | 5,126 | 4,415
Income tax expense (benefit) | 8,118 | 7,009
Net income | 29,127 | 25,986
Reclassification out of Accumulated Other Comprehensive Income [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Abstract] |  |
Total reclassifications during the period, net of tax | 92 | 93
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Abstract] |  |
Income tax expense (benefit) | (67) | (47)
Net income | 199 | 141
Losses on AFS Securities [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Abstract] |  |
Net securities gains | 99 | 0
Amortization of Unrealized Gains Related to Securities Transfer [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Abstract] |  |
Interest income (expense) | 167 | 188
Net Unrealized (Gains) on Cash Flow hedges Reclassified to Interest Expense [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Abstract] |  |
Interest income (expense) | (799) | (359)
Income tax expense (benefit) | 200 | 90
Net income | (599) | (269)
Accumulated Defined Benefit Plans Adjustment [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Abstract] |  |
Income tax expense (benefit) | (164) | (74)
Net income | 492 | 221
Amortization of Net Losses [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Abstract] |  |
Other noninterest expense | 634 | 273
Amortization of Prior Service Costs [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Abstract] |  |
Other noninterest expense | $ 22 | $ 22

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