XML 46 R35.htm IDEA: XBRL DOCUMENT
v3.21.1

Municipal Bond Guarantee Insurance (Tables) | 3 Months Ended
--- | ---
Mar. 31, 2021
Guarantees [Abstract] |
Schedule of Municipal Bond Guarantee Insured Obligations | The following table presents a schedule of BAM’s insured obligations as of March 31, 2021 and December 31, 2020:
|  | March 31, 2021 |  | December 31, 2020
Contracts outstanding |  | 11,252 |  |  | 10,997 |
Remaining weighted average contract period outstanding (in years) |  | 10.6 |  | 10.7
Contractual debt service outstanding (in millions): |  |  |  |
Principal |  | $ | 77,689.3 |  |  | $ | 75,287.7 |
Interest |  | 36,710.5 |  |  | 36,448.8 |
Total debt service outstanding |  | $ | 114,399.8 |  |  | $ | 111,736.5 |
Gross unearned insurance premiums (in millions) |  | $ | 243.7 |  |  | $ | 237.5 |
Financial Guarantee Insurance Contracts, Premium Received over Contract Period | The following table presents a schedule of BAM’s future premium revenues as of March 31, 2021:
Millions |  | March 31, 2021
April 1, 2021 - December 31, 2021 |  | $ | 17.6 |
January 1, 2022 - March 31, 2022 |  | 5.7 |
April 1, 2022 - June 30, 2022 |  | 5.6 |
July 1, 2022 - September 30, 2022 |  | 5.6 |
October 1, 2022 - December 31, 2022 |  | 5.4 |
Total 2022 |  | 22.3 |
2023 |  | 21.0 |
2024 |  | 19.4 |
2025 |  | 18.0 |
2026 |  | 16.6 |
2027 and thereafter |  | 128.8 |
Total gross unearned insurance premiums |  | $ | 243.7 |
Schedule of Net Written Premiums | The following table presents a schedule of written premiums and earned premiums included in White Mountains’s HG Global/BAM segment for the three months ended March 31, 2021 and 2020:
|  | Three Months Ended March 31, |  |  |  |
Millions |  | 2021 |  | 2020 |  |  |  |  |  |  |  |
Written premiums: |  |  |  |  |  |  |  |  |  |  |  |
Direct |  | $ | 8.0 |  |  | $ | 9.7 |  |  |  |  |  |  |  |  |
Assumed |  | 4.5 |  |  | — |  |  |  |  |  |  |  |  |
Gross written premiums |  | $ | 12.5 |  |  | $ | 9.7 |  |  |  |  |  |  |  |  |
Earned premiums: |  |  |  |  |  |  |  |  |  |  |  |
Direct |  | $ | 5.3 |  |  | $ | 4.5 |  |  |  |  |  |  |  |  |
Assumed |  | 1.1 |  |  | .9 |  |  |  |  |  |  |  |  |
Gross earned premiums |  | $ | 6.4 |  |  | $ | 5.4 |  |  |  |  |  |  |  |  |

X
- Definition Tabular disclosure of financial guarantee insurance contracts in which premiums are received over the contract period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 310 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6933075&loc=SL5748726-161290 + Details
Name: | us-gaap_FinancialGuaranteeInsuranceContractsPremiumReceivedOverContractPeriodTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition [Table Text Block] for Schedule of Municipal Guarantee Insured Obligations [Table] + References No definition available. + Details
Name: | wtm_ScheduleOfMunicipalGuaranteeInsuredObligationsTableTextBlock
Namespace Prefix: | wtm_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Schedule of Net Written Premiums [Table Text Block] + References No definition available. + Details
Name: | wtm_ScheduleofNetWrittenPremiumsTableTextBlock
Namespace Prefix: | wtm_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration