XML 54 R46.htm IDEA: XBRL DOCUMENT ﻿
v2.3.0.11

Investment Securities (Details 8) (USD $) In Millions, unless otherwise specified |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 6 Months Ended |  | 6 Months Ended |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Jun. 30, 2011 Mortgage-backed and asset-backed securities Fair Value | Dec. 31, 2010 Mortgage-backed and asset-backed securities Fair Value | Jun. 30, 2011 Mortgage-backed and asset-backed securities Level 3 Inputs | Dec. 31, 2010 Mortgage-backed and asset-backed securities Level 3 Inputs | Jun. 30, 2011 Mortgage-backed and asset-backed securities Level 2 Inputs | Dec. 31, 2010 Mortgage-backed and asset-backed securities Level 2 Inputs | Jun. 30, 2011 Mortgage-backed securities Fair Value | Dec. 31, 2010 Mortgage-backed securities Fair Value | Jun. 30, 2011 Mortgage-backed securities Level 2 Inputs | Dec. 31, 2010 Mortgage-backed securities Level 2 Inputs | Jun. 30, 2011 Level 3 Inputs Mortgage-backed securities | Dec. 31, 2010 Level 3 Inputs Mortgage-backed securities | Jun. 30, 2011 Agency mortgage-backed securities Fair Value | Dec. 31, 2010 Agency mortgage-backed securities Fair Value | Jun. 30, 2011 Agency mortgage-backed securities Level 2 Inputs | Dec. 31, 2010 Agency mortgage-backed securities Level 2 Inputs | Jun. 30, 2011 Level 3 Inputs Agency mortgage-backed securities | Dec. 31, 2010 Level 3 Inputs Agency mortgage-backed securities | Jun. 30, 2011 GNMA Fair Value | Dec. 31, 2010 GNMA Fair Value | Jun. 30, 2011 GNMA Level 2 Inputs | Dec. 31, 2010 GNMA Level 2 Inputs | Jun. 30, 2011 Level 3 Inputs GNMA | Dec. 31, 2010 Level 3 Inputs GNMA | Jun. 30, 2011 FNMA Fair Value | Dec. 31, 2010 FNMA Fair Value | Jun. 30, 2011 FNMA Level 2 Inputs | Dec. 31, 2010 FNMA Level 2 Inputs | Jun. 30, 2011 Level 3 Inputs FNMA | Jun. 30, 2011 FHLMC Fair Value | Dec. 31, 2010 FHLMC Fair Value | Jun. 30, 2011 FHLMC Level 2 Inputs | Dec. 31, 2010 FHLMC Level 2 Inputs | Jun. 30, 2011 Non-agency mortgage-backed securities 2003 | Jun. 30, 2011 Non-agency mortgage-backed securities 2005 | Jun. 30, 2011 Non-agency mortgage-backed securities 2006 | Jun. 30, 2011 Non-agency mortgage-backed securities 2007 | Jun. 30, 2011 Non-agency mortgage-backed securities 2010 | Jun. 30, 2011 Non-agency mortgage-backed securities 2011 | Jun. 30, 2011 Non-agency mortgage-backed securities Fair Value | Dec. 31, 2010 Non-agency mortgage-backed securities Fair Value | Jun. 30, 2011 Non-agency mortgage-backed securities Level 2 Inputs | Dec. 31, 2010 Non-agency mortgage-backed securities Level 2 Inputs | Dec. 31, 2010 Level 3 Inputs Non-agency mortgage-backed securities | Jun. 30, 2011 Non-agency residential mortgage-backed securities (RMBS) 2003 | Jun. 30, 2011 Non-agency residential mortgage-backed securities (RMBS) 2006 | Jun. 30, 2011 Non-agency residential mortgage-backed securities (RMBS) 2007 | Jun. 30, 2011 Non-agency residential mortgage-backed securities (RMBS) 2010 | Jun. 30, 2011 Non-agency residential mortgage-backed securities (RMBS) 2011 | Jun. 30, 2011 Non-agency residential mortgage-backed securities (RMBS) Fair Value | Dec. 31, 2010 Non-agency residential mortgage-backed securities (RMBS) Fair Value | Jun. 30, 2011 Non-agency residential mortgage-backed securities (RMBS) Fair Value Prime | Jun. 30, 2011 Non-agency residential mortgage-backed securities (RMBS) Fair Value Non-prime | Jun. 30, 2011 Non-agency residential mortgage-backed securities (RMBS) Level 2 Inputs | Dec. 31, 2010 Non-agency residential mortgage-backed securities (RMBS) Level 2 Inputs | Jun. 30, 2011 Non-agency residential mortgage-backed securities (RMBS) Super Senior | Jun. 30, 2011 Non-agency residential mortgage-backed securities (RMBS) Super Senior Prime | Jun. 30, 2011 Non-agency residential mortgage-backed securities (RMBS) Super Senior Non-prime | Jun. 30, 2011 Non-agency residential mortgage-backed securities (RMBS) Senior | Jun. 30, 2011 Non-agency residential mortgage-backed securities (RMBS) Senior Prime | Jun. 30, 2011 Non-agency residential mortgage-backed securities (RMBS) Senior Non-prime | Dec. 31, 2010 Level 3 Inputs Non-agency residential mortgage-backed securities (RMBS) | Jun. 30, 2011 Non-agency commercial mortgage-backed securities (CMBS) | Jun. 30, 2011 Non-agency commercial mortgage-backed securities (CMBS) 2003 | Jun. 30, 2011 Non-agency commercial mortgage-backed securities (CMBS) 2005 | Jun. 30, 2011 Non-agency commercial mortgage-backed securities (CMBS) 2007 | Jun. 30, 2011 Non-agency commercial mortgage-backed securities (CMBS) 2011 | Jun. 30, 2011 Non-agency commercial mortgage-backed securities (CMBS) Fair Value | Dec. 31, 2010 Non-agency commercial mortgage-backed securities (CMBS) Fair Value | Jun. 30, 2011 Non-agency commercial mortgage-backed securities (CMBS) Level 2 Inputs | Dec. 31, 2010 Non-agency commercial mortgage-backed securities (CMBS) Level 2 Inputs | Jun. 30, 2011 Non-agency commercial mortgage-backed securities (CMBS) Super Senior | Jun. 30, 2011 Non-agency commercial mortgage-backed securities (CMBS) Senior | Jun. 30, 2011 Fixed Rate CMBS | Jun. 30, 2011 Fixed Rate CMBS Fair Value | Jun. 30, 2011 Fixed Rate CMBS Super Senior | Jun. 30, 2011 Fixed Rate CMBS Senior | Jun. 30, 2011 Floating Rate CMBS | Jun. 30, 2011 Floating Rate CMBS Fair Value | Jun. 30, 2011 Floating Rate CMBS Super Senior | Jun. 30, 2011 Other asset-backed securities Fair Value | Dec. 31, 2010 Other asset-backed securities Fair Value | Jun. 30, 2011 Other asset-backed securities Level 2 Inputs | Dec. 31, 2010 Other asset-backed securities Level 2 Inputs | Jun. 30, 2011 Credit card receivables Fair Value | Dec. 31, 2010 Credit card receivables Fair Value | Jun. 30, 2011 Credit card receivables Level 2 Inputs | Dec. 31, 2010 Credit card receivables Level 2 Inputs | Jun. 30, 2011 Vehicle receivables Fair Value | Dec. 31, 2010 Vehicle receivables Fair Value | Jun. 30, 2011 Vehicle receivables Level 2 Inputs | Dec. 31, 2010 Vehicle receivables Level 2 Inputs | Jun. 30, 2011 Other Fair Value | Dec. 31, 2010 Other Fair Value | Jun. 30, 2011 Other Level 2 Inputs | Dec. 31, 2010 Other Level 2 Inputs | Jun. 30, 2011 Fair Value | Dec. 31, 2010 Fair Value | Jun. 30, 2011 Level 2 Inputs | Dec. 31, 2010 Level 2 Inputs
Mortgage-backed, Asset-backed Securities Abstract |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Average basis points of subordination (as a percent) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 20 |  |  |  | 60 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of underlying loans reported as non-performing (as a percent) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair value investments | $ 2,308.0 | $ 2,071.7 | $ 52.8 | $ 57.0 | $ 2,255.2 | $ 2,014.7 | $ 1,774.2 | $ 1,595.2 | $ 1,721.4 | $ 1,538.2 | $ 52.8 | $ 57.0 | $ 1,554.7 | $ 1,417.6 | $ 1,501.9 | $ 1,376.7 | $ 52.8 | $ 40.9 | $ 1,222.8 | $ 1,143.6 | $ 1,170.7 | $ 1,102.7 | $ 52.1 | $ 40.9 | $ 264.4 | $ 234.9 | $ 263.7 | $ 234.9 | $ 0.7 | $ 67.5 | $ 39.1 | $ 67.5 | $ 39.1 | $ 6.8 | $ 22.8 | $ 42.6 | $ 46.0 | $ 10.5 | $ 90.8 | $ 219.5 | $ 177.6 | $ 219.5 | $ 161.5 | $ 16.1 | $ 3.8 | $ 42.6 | $ 29.6 | $ 10.5 | $ 21.6 | $ 108.1 | $ 90.6 | $ 90.1 | $ 18.0 | $ 108.1 | $ 74.5 | $ 44.3 | $ 27.2 | $ 17.1 | $ 63.8 | $ 62.9 | $ 0.9 | $ 16.1 |  | $ 3.0 | $ 22.8 | $ 16.4 | $ 69.2 | $ 111.4 | $ 87.0 | $ 111.4 | $ 87.0 | $ 39.3 | $ 72.1 |  | $ 80.5 | $ 8.4 | $ 72.1 |  | $ 30.9 | $ 30.9 | $ 533.8 | $ 476.5 | $ 533.8 | $ 476.5 | $ 223.7 | $ 248.3 | $ 223.7 | $ 248.3 | $ 285.8 | $ 228.1 | $ 285.8 | $ 228.1 | $ 24.3 | $ 0.1 | $ 24.3 | $ 0.1 | $ 7,493.9 | $ 7,901.6 | $ 5,330.6 | $ 5,477.4

X
- Definition This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents investment securities as of the balance sheet date which may include marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Available-for-Sale Securities -URI http://asc.fasb.org/extlink&oid=6505594 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6379932&loc=d3e22054-111558 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 13 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 12 -Subparagraph a -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 7 -Section 03 -Paragraph 1 -Subparagraph a, f, g Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 35 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6956420&loc=d3e24584-111560 + Details
Name: | us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix: | us-gaap
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Reflects the percentage derived from dividing impaired loans on which interest has ceased to be accrued by total loans. + Details
Name: | us-gaap_LoansAndLeasesReceivableRatioOfNonperformingLoansToAllLoans
Namespace Prefix: | us-gaap
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Basis points of subordination on average. + Details
Name: | wtm_AverageBasisPointsOfSubordination
Namespace Prefix: | wtm
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

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