XML 59 R38.htm IDEA: XBRL DOCUMENT
v3.25.1

Employee Share-Based Incentive Compensation Plans (Tables) | 3 Months Ended
--- | ---
Mar. 31, 2025
Share-Based Payment Arrangement [Abstract] |
Schedule of performance share activity | The following table presents performance share activity for the three months ended March 31, 2025 and 2024 for performance shares granted under the WTM Incentive Plan:
|  |  |  | Three Months Ended March 31,
|  |  |  |  |  | 2025 |  | 2024
$ in Millions |  |  |  |  |  |  |  |  |  | Target Performance Shares Outstanding |  | Accrued Expense |  | Target Performance Shares Outstanding |  | Accrued Expense
Beginning of period |  |  |  |  |  |  |  |  |  | 34,859 |  |  | $ | 71.1 |  |  | 37,031 |  |  | $ | 69.4 |
Shares paid or expired (1) |  |  |  |  |  |  |  |  |  | (13,150) |  |  | (48.7) |  |  | (13,475) |  |  | (44.9) |
New grants |  |  |  |  |  |  |  |  |  | 10,645 |  |  | — |  |  | 10,405 |  |  | — |
Forfeitures and cancellations (2) |  |  |  |  |  |  |  |  |  | 38 |  |  | .8 |  |  | 46 |  |  | .3 |
Expense recognized |  |  |  |  |  |  |  |  |  | — |  |  | .1 |  |  | — |  |  | 19.4 |
End of period |  |  |  |  |  |  |  |  |  | 32,392 |  |  | $ | 23.3 |  |  | 34,007 |  |  | $ | 44.2 |
(1) WTM performance share payments for the 2022-2024 performance cycle were made in March 2025 at 200% of target. WTM performance share payments for the 2021-2023 performance cycle were made in March 2024 at 188% of target. (2) Amounts include changes in assumed forfeitures, as required under GAAP.
Schedule of performance shares outstanding and accrued expense for performance shares awarded | The following table presents performance shares outstanding and accrued expense for performance shares awarded under the WTM Incentive Plan as of March 31, 2025 for each performance cycle:
|  | March 31, 2025
$ in Millions |  | Target Performance Shares Outstanding |  | Accrued Expense
Performance cycle: |  |  |  |
2023 – 2025 |  | 10,835 |  |  | $ | 15.4 |
2024 – 2026 |  | 11,405 |  |  | 7.6 |
2025 – 2027 |  | 10,645 |  |  | .6 |
Sub-total |  | 32,885 |  |  | 23.6 |
Assumed forfeitures |  | (493) |  |  | (.3) |
Total |  | 32,392 |  |  | $ | 23.3 |
Schedule of unrecognized compensation costs associated with outstanding restricted share awards | The following table presents the unrecognized compensation cost associated with the outstanding restricted share awards under the WTM Incentive Plan for the three months ended March 31, 2025 and 2024:
|  |  |  | Three Months Ended March 31,
|  |  |  |  |  | 2025 |  | 2024
$ in Millions |  |  |  |  |  |  |  |  |  | Restricted Shares |  | Unamortized Issue Date Fair Value |  | Restricted Shares |  | Unamortized Issue Date Fair Value
Non-vested, |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning of period |  |  |  |  |  |  |  |  |  | 35,390 |  |  | $ | 19.9 |  |  | 37,595 |  |  | $ | 16.2 |
Vested |  |  |  |  |  |  |  |  |  | (13,150) |  |  | — |  |  | (13,475) |  |  | — |
Issued |  |  |  |  |  |  |  |  |  | 10,645 |  |  | 19.5 |  |  | 10,405 |  |  | 18.3 |
Forfeited |  |  |  |  |  |  |  |  |  | — |  |  | — |  |  | — |  |  | — |
Expense recognized |  |  |  |  |  |  |  |  |  | — |  |  | (3.8) |  |  | — |  |  | (3.2) |
End of period |  |  |  |  |  |  |  |  |  | 32,885 |  |  | $ | 35.6 |  |  | 34,525 |  |  | $ | 31.3 |

X
- References No definition available. + Details
Name: | us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the changes in outstanding nonvested restricted stock shares. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Subparagraph (c) -Paragraph 2 -SubTopic 10 -Topic 718 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480429/718-10-50-2 + Details
Name: | us-gaap_NonvestedRestrictedStockSharesActivityTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the changes in nonvested performance shares outstanding and the amount accrued for performance shares. + References No definition available. + Details
Name: | wtm_ScheduleOfNonvestedPerformanceShareActivityTableTextBlock
Namespace Prefix: | wtm_
Data Type: | dtr-types1:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of performance shares outstanding and the amount accrued by performance cycle, under the entity's Incentive Plan. + References No definition available. + Details
Name: | wtm_ScheduleOfPerformanceSharesOutstandingAndAccruedExpenseByPerformanceCycleUnderIncentivePlanTableTextBlock
Namespace Prefix: | wtm_
Data Type: | dtr-types1:textBlockItemType
Balance Type: | na
Period Type: | duration