XML 83 R45.htm IDEA: XBRL DOCUMENT
v2.3.0.15

Investment Securities (Details 5) (USD $) In Millions, unless otherwise specified | Sep. 30, 2011 | Dec. 31, 2010
--- | --- | ---
Hedge and private equity funds included in other long-term investments |  |
Other long-term investments |  |
Largest single fund investment | $ 31.4 |
Other long-term investments | 277.6 | 315.5
Unfunded Commitments | 81.6 | 88.7
Hedge funds |  |
Other long-term investments |  |
Number of limited partnership and limited liability corporation investments | 17 |
Other long-term investments | 130.2 | 155.7
Distributions outstanding | 3.2 |
Redemption requests | 2.0 |
Hedge funds | Monthly |  |
Other long-term investments |  |
Other long-term investments | 6.0 |
Hedge funds | Monthly | 120+ days notice |  |
Other long-term investments |  |
Other long-term investments | 6.0 |
Hedge funds | Quarterly |  |
Other long-term investments |  |
Other long-term investments | 75.4 |
Hedge funds | Quarterly | 30-59 days notice |  |
Other long-term investments |  |
Other long-term investments | 26.1 |
Hedge funds | Quarterly | 60-89 days notice |  |
Other long-term investments |  |
Other long-term investments | 29.7 |
Hedge funds | Quarterly | 90-119 days notice |  |
Other long-term investments |  |
Other long-term investments | 19.6 |
Hedge funds | Semi-annual |  |
Other long-term investments |  |
Other long-term investments | 19.8 |
Hedge funds | Semi-annual | 60-89 days notice |  |
Other long-term investments |  |
Other long-term investments | 5.1 |
Hedge funds | Semi-annual | 120+ days notice |  |
Other long-term investments |  |
Other long-term investments | 14.7 |
Hedge funds | Annual |  |
Other long-term investments |  |
Other long-term investments | 29.0 |
Hedge funds | Annual | 30-59 days notice |  |
Other long-term investments |  |
Other long-term investments | 21.9 |
Hedge funds | Annual | 90-119 days notice |  |
Other long-term investments |  |
Other long-term investments | 6.6 |
Hedge funds | Annual | 120+ days notice |  |
Other long-term investments |  |
Other long-term investments | 0.5 |
Hedge funds | 30-59 days notice |  |
Other long-term investments |  |
Other long-term investments | 48.0 |
Hedge funds | 60-89 days notice |  |
Other long-term investments |  |
Other long-term investments | 34.8 |
Hedge funds | 90-119 days notice |  |
Other long-term investments |  |
Other long-term investments | 26.2 |
Hedge funds | 120+ days notice |  |
Other long-term investments |  |
Other long-term investments | 21.2 |
Long/short equity |  |
Other long-term investments |  |
Other long-term investments | 49.0 | 50.4
Long/short credit & distressed |  |
Other long-term investments |  |
Other long-term investments | 32.3 | 34.1
Long diversified strategies |  |
Other long-term investments |  |
Other long-term investments | 22.0 | 24.0
Long/short equity REIT |  |
Other long-term investments |  |
Other long-term investments | 14.7 | 25.2
Long/short equity activist |  |
Other long-term investments |  |
Other long-term investments | 11.7 | 16.9
Long bank loan |  |
Other long-term investments |  |
Other long-term investments | 0.5 | 5.1
Private equity funds |  |
Other long-term investments |  |
Number of limited partnership and limited liability corporation investments | 33 |
Other long-term investments | 147.4 | 159.8
Unfunded Commitments | 81.6 | 88.7
Private equity funds | 1-3 years |  |
Other long-term investments |  |
Other long-term investments | 47.3 |
Private equity funds | 5-10 years |  |
Other long-term investments |  |
Other long-term investments | 83.1 |
Private equity funds | >10 years |  |
Other long-term investments |  |
Other long-term investments | 17.0 |
Distressed residential real estate |  |
Other long-term investments |  |
Other long-term investments | 31.4 | 49.2
Energy infrastructure and services |  |
Other long-term investments |  |
Other long-term investments | 29.5 | 24.2
Unfunded Commitments | 9.9 | 10.8
Multi-sector |  |
Other long-term investments |  |
Other long-term investments | 28.0 | 26.0
Unfunded Commitments | 8.2 | 10.6
Manufacturing/Industrial |  |
Other long-term investments |  |
Other long-term investments | 17.0 | 17.9
Private equity secondaries |  |
Other long-term investments |  |
Other long-term investments | 11.3 | 10.4
Unfunded Commitments | 4.0 | 4.4
Real estate |  |
Other long-term investments |  |
Other long-term investments | 10.2 | 9.1
Unfunded Commitments | 3.3 | 4.6
International multi-sector, Europe |  |
Other long-term investments |  |
Other long-term investments | 8.0 | 10.5
Unfunded Commitments | 4.7 | 5.3
International multi-sector, Asia |  |
Other long-term investments |  |
Other long-term investments | 3.6 | 4.9
Unfunded Commitments | 2.7 | 2.7
Insurance |  |
Other long-term investments |  |
Other long-term investments | 3.6 | 3.9
Unfunded Commitments | 41.3 | 41.3
Venture capital fund |  |
Other long-term investments |  |
Other long-term investments | 2.5 | 2.2
Unfunded Commitments | 0.5 | 1.0
Healthcare |  |
Other long-term investments |  |
Other long-term investments | 2.3 | 1.5
Unfunded Commitments | $ 7.0 | $ 8.0

X
- Definition The amount of unfunded commitments for which the entity is obligated, to those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 6A -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6925170&loc=SL6742756-110258 + Details
Name: | us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments
Namespace Prefix: | us-gaap
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Distributions pending from hedge funds that are no longer active and are in process of disposing their underlying investments. + Details
Name: | wtm_DistributionsFromInactiveHedgeFunds
Namespace Prefix: | wtm
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount of redemption requests submitted for investments for hedge funds. + Details
Name: | wtm_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareRedemptionRequest
Namespace Prefix: | wtm
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number of investments in limited partnership and limited liability corporations held as of the balance sheet date. + Details
Name: | wtm_NumberOfLimitedPartnershipAndLimitedLiabilityCorporationInvestments
Namespace Prefix: | wtm
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | wtm_OtherLongTermInvestmentsAbstract
Namespace Prefix: | wtm
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition This element represents the total fair market value of investments in certain entities that calculate net asset value per share (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments). This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements, but may also be used in both the balance sheet and disclosure in the same submission. This item represents alternative investments as of the balance sheet date which may include investments in certain hedge funds, venture capital funds, private equity funds, real estate partnerships or funds, and any other investment in which investee management calculates net asset value per share as the primary metric for investment value. + Details
Name: | wtm_OtherLongTermInvestmentsFairValueDisclosure
Namespace Prefix: | wtm
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The largest investment which the entity has made in a single fund. + Details
Name: | wtm_OtherLongTermInvestmentsLargestSingleInvestment
Namespace Prefix: | wtm
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant