Segment Information - Underwriting Margins and Combined Ratios for our Underwriting Operations (Detail) - Underwriting operations |
3 Months Ended | |
|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
|
| Segment Reporting Information [Line Items] | ||
| Under- writing Margin | 13.60% | 14.00% |
| Combined Ratio | 86.40% | 86.00% |
| Operating Segments | Personal Lines | ||
| Segment Reporting Information [Line Items] | ||
| Under- writing Margin | 14.00% | 14.30% |
| Combined Ratio | 86.00% | 85.70% |
| Operating Segments | Commercial Lines | ||
| Segment Reporting Information [Line Items] | ||
| Under- writing Margin | 11.00% | 12.50% |
| Combined Ratio | 89.00% | 87.50% |