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Consolidated Statements of Comprehensive Income - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Consolidated Statements of Comprehensive Income [Abstract] |  |  |
Net income | $ 160.2 | $ 106.5 | $ 95.7
Investment securities available-for-sale: |  |  |
Change in net unrealized gains (losses) during the period | (13.9) | (6.5) | (19.4)
Reclassification adjustment for net losses (gains) included in income | 0.1 | (0.7) | (0.3)
Change in unamortized loss on available-for-sale investment securities transferred into held-to-maturity | 1.6 | 1.9 | 1.9
Change in net unrealized gain (loss) on derivatives | 0.0 | (1.1) | (0.2)
Reclassification adjustment for derivative net (gains) losses included in net income | 0.0 | 1.1 | 0.0
Defined benefit post-retirement benefit plans: |  |  |
Change in net actuarial loss | (0.6) | (1.3) | 3.9
Other comprehensive income (loss), before tax | (12.8) | (6.6) | (14.1)
Deferred tax benefit (expense) related to other comprehensive income (loss) | 3.3 | 2.8 | 5.5
Other comprehensive income (loss), net of tax | (9.5) | (3.8) | (8.6)
Comprehensive income | $ 150.7 | $ 102.7 | $ 87.1

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