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Segment Information (Reconciliation of Segment Results to Income Before Federal Income Tax (Details)) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2022 | Jun. 30, 2021 | Jun. 30, 2022 | Jun. 30, 2021
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |  |
Investment income | $ 27,342 | $ 93,788 | $ 59,592 | $ 168,623
Interest expense | (7,252) | (7,366) | (14,420) | (14,725)
Corporate expenses | (7,899) | (9,112) | (18,920) | (18,666)
Income before federal income tax | 49,904 | 153,198 | 119,794 | 288,830
Preferred stock dividends | (2,300) | (2,300) | (4,600) | (4,753)
Income available to common stockholders, before federal income tax | 47,604 | 150,898 | 115,194 | 284,077
Standard Commercial Lines |  |  |  |
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |  |
Underwriting income (loss), before federal income tax | $ 46,708 | $ 67,938 | $ 89,092 | $ 137,437
ROE Contribution | 6.00% | 8.20% | 5.50% | 8.30%
Standard Personal Lines |  |  |  |
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |  |
Underwriting income (loss), before federal income tax | $ (12,367) | $ 5,644 | $ (5,847) | $ 13,339
ROE Contribution | (1.60%) | 0.70% | (0.40%) | 0.80%
E&S Lines |  |  |  |
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |  |
Underwriting income (loss), before federal income tax | $ 3,372 | $ 2,306 | $ 10,297 | $ 2,822
ROE Contribution | 0.40% | 0.30% | 0.60% | 0.20%
Investments |  |  |  |
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |  |
ROE Contribution | 9.10% | 10.30% | 8.90% | 9.50%
Operating Segments |  |  |  |
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] |  |  |  |
Underwriting income (loss), total all segments | $ 65,055 | $ 169,676 | $ 153,134 | $ 322,221

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