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Consolidation Statements of Comprehensive Income - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Net income | $ 168,826 | $ 158,495 | $ 165,861
Unrealized holding gains (losses) arising during year | 43,015 | (5,977) | (26,143)
Non-credit portion of other-than-temporary impairments recognized in other comprehensive income | 23 | (6) | 0
Amounts reclassified into net income: Held-to-maturity securities | (116) | (92) | (377)
Amounts reclassified into net income: Non-credit other-than-temporary impairment | 68 | 138 | 232
Amounts reclassified into net income: Realized losses (gains) on available for sale securities | (4,537) | 3,064 | (9,110)
Total unrealized gains (losses) on investment securities | 38,453 | (2,873) | (35,398)
Net actuarial (loss) gain | (3,700) | (7,852) | 1,585
Amounts reclassified into net income: Net actuarial loss | 1,367 | 4,200 | 4,600
Total defined benefit pension and post-retirement plans | (2,333) | (3,652) | 6,185
Other comprehensive income (loss) | 36,120 | (6,525) | (29,213)
Comprehensive income | $ 204,946 | $ 151,970 | $ 136,648

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