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Operating Segment Information - Operating Results by Segment (Details) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2026 | Mar. 31, 2025
Revenue |  |
Net premiums earned | $ 411,386 | $ 398,345
Net investment income | 42,321 | 36,726
Net realized gains | 9,559 | 14,912
Net unrealized gains (losses) on equity securities | (39,396) | (42,318)
Consolidated revenue | 423,870 | 407,665
Less: Expenses |  |
Losses and settlement expenses | 193,244 | 177,238
Insurance operating expenses | 28,280 | 26,874
Earnings before income taxes | 67,341 | 78,631
Casualty Segment |  |
Revenue |  |
Net premiums earned | 248,566 | 229,048
Property Segment |  |
Revenue |  |
Net premiums earned | 126,378 | 132,544
Surety Segment |  |
Revenue |  |
Net premiums earned | 36,442 | 36,753
Operating Segments |  |
Revenue |  |
Net premiums earned | 411,386 | 398,345
Net investment income | 42,321 | 36,726
Net realized gains | 9,559 | 14,912
Net unrealized gains (losses) on equity securities | (39,396) | (42,318)
Consolidated revenue | 423,870 | 407,665
Less: Expenses |  |
Earnings before income taxes | 57,787 | 70,546
Operating Segments | Casualty Segment |  |
Revenue |  |
Net premiums earned | 248,566 | 229,048
Consolidated revenue | 248,566 | 229,048
Less: Expenses |  |
Losses and settlement expenses | 152,832 | 145,835
Amortization of deferred acquisition costs | 47,482 | 42,903
Other policy acquisition costs | 24,232 | 22,669
Insurance operating expenses | 16,727 | 15,570
Earnings before income taxes | 7,293 | 2,071
Depreciation and amortization expense | 1,597 | 1,505
Operating Segments | Property Segment |  |
Revenue |  |
Net premiums earned | 126,378 | 132,544
Consolidated revenue | 126,378 | 132,544
Less: Expenses |  |
Losses and settlement expenses | 33,854 | 32,725
Amortization of deferred acquisition costs | 25,342 | 26,976
Other policy acquisition costs | 10,813 | 7,957
Insurance operating expenses | 8,184 | 7,971
Earnings before income taxes | 48,185 | 56,915
Depreciation and amortization expense | 538 | 498
Operating Segments | Surety Segment |  |
Revenue |  |
Net premiums earned | 36,442 | 36,753
Consolidated revenue | 36,442 | 36,753
Less: Expenses |  |
Losses and settlement expenses | 6,558 | (1,322)
Amortization of deferred acquisition costs | 12,735 | 12,602
Other policy acquisition costs | 11,471 | 10,580
Insurance operating expenses | 3,369 | 3,333
Earnings before income taxes | 2,309 | 11,560
Depreciation and amortization expense | 365 | 310
Corporate |  |
Revenue |  |
Net investment income | 42,321 | 36,726
Net realized gains | 9,559 | 14,912
Net unrealized gains (losses) on equity securities | $ (39,396) | $ (42,318)

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