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Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2018 | Sep. 30, 2018 | Jun. 30, 2018 | Mar. 31, 2018 | Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Tax Reform Deferred Tax Asset Impact |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 0 | $ 20,205 | $ 0
Net premiums earned | $ 625,288 | [1] | $ 614,277 |  | $ 604,836 |  | $ 591,828 |  | $ 590,088 | [1] | $ 572,055 |  | $ 568,030 |  | $ 560,854 |  | 2,436,229 | 2,291,027 | 2,149,572
Net investment income earned | 54,109 | [1] | 52,443 |  | 45,553 |  | 43,231 |  | 42,587 | [1] | 40,446 |  | 41,430 |  | 37,419 |  | 195,336 | 161,882 | 130,754
Net realized and unrealized (losses) gains2 | (37,935) | [1],[2] | (4,787) | [2] | (1,652) | [2] | (10,549) | [2] | (1,128) | [1],[2] | 6,798 | [2] | 1,734 | [2] | (1,045) | [2] | (54,923) | 6,359 | (4,937)
Other income | 1,542 | [1] | 2,538 |  | 3,179 |  | 2,179 |  | 2,190 | [1] | 1,994 |  | 3,291 |  | 3,241 |  | 9,438 | 10,716 | 8,881
Total revenues | 643,004 | [1] | 664,471 |  | 651,916 |  | 626,689 |  | 633,737 | [1] | 621,293 |  | 614,485 |  | 600,469 |  | 2,586,080 | 2,469,984 | 2,284,270
Income before federal income tax | 52,135 |  | 67,130 |  | 72,525 |  | 19,931 |  | 68,150 |  | 67,315 |  | 58,929 |  | 67,574 |  | 211,721 | 261,968 | 219,955
Net income | $ 45,760 | [1] | $ 55,435 |  | $ 58,819 |  | $ 18,925 |  | $ 30,242 | [1] | $ 46,718 |  | $ 41,426 |  | $ 50,440 |  | $ 178,939 | $ 168,826 | $ 158,495
Basic net income per share | $ 0.77 | [1] | $ 0.94 |  | $ 1.00 |  | $ 0.32 |  | $ 0.52 | [1] | $ 0.80 |  | $ 0.71 |  | $ 0.87 |  | $ 3.04 | $ 2.89 | $ 2.74
Diluted net income per share | $ 0.76 | [1] | $ 0.93 |  | $ 0.99 |  | $ 0.32 |  | $ 0.51 | [1] | $ 0.79 |  | $ 0.70 |  | $ 0.85 |  | $ 3.00 | $ 2.84 | $ 2.70
[1] | Results for the fourth quarter of 2017 include the impact of the $20.2 million write off of deferred tax assets required with the implementation of Tax Reform. See Note 13. "Federal Income Taxes" above for additional information.
[2] | Effective January 1, 2018, changes in unrealized gains and losses on our equity portfolio are recognized in income through "Net unrealized losses on equity securities" on our Consolidated Statements of Income, as a result of our adoption of ASU 2016-01. See Note 3. "Adoption of Accounting Pronouncements" above.

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