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Earnings (Loss) Per Share (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2011 | Sep. 30, 2010 | Sep. 30, 2011 | Sep. 30, 2010
Basic and diluted earnings per share numerators (in millions): |  |  |  |
Net income (loss) attributable to White Mountains' common shareholders | $ (15.8) | $ 50.7 | $ (32.3) | $ 13.6
Less: net (income) loss from discontinued operations | 30.1 | (3.6) | 28.9 | (1.2)
Net income (loss) attributable to White Mountains' common shareholders from continuing operations | 14.3 | 47.1 | (3.4) | 12.4
Dividends declared on common shares |  |  | (8.0) | (8.8)
Undistributed earnings (loss) | $ 14.3 | $ 47.1 | $ (11.4) | $ 3.6
Basic earnings per share denominators (in thousands): |  |  |  |
Average common shares outstanding during the period (in shares) | 7,845 | 8,332 | 7,902 | 8,547
Average unvested restricted shares (in shares) | 74 | 99 | 68 | 97
Basic earnings (loss) per share denominator (in shares) | 7,919 | 8,431 | 7,970 | 8,644
Diluted earnings per share denominator (in thousands): |  |  |  |
Average common shares outstanding during the period (in shares) | 7,845 | 8,332 | 7,902 | 8,547
Average unvested restricted shares (in shares) | 74 | 99 | 68 | 97
Average outstanding dilutive options to acquire common shares (in shares) |  |  |  | 1
Diluted earnings (loss) per share denominator (in shares) | 7,919 | 8,431 | 7,970 | 8,645
Basic earnings per share (in dollars): |  |  |  |
Net income (loss) from continuing operations attributable to White Mountains' common shareholders (in dollars per share) | $ 1.81 | $ 5.58 | $ (0.43) | $ 1.44
Dividends declared and paid (in dollars per share) |  |  | $ (1.00) | $ (1.00)
Undistributed earnings (loss) per share (in dollars per share) | $ 1.81 | $ 5.58 | $ (1.43) | $ 0.44
Diluted earnings per share (in dollars) |  |  |  |
Net income from continuing operations attributable to White Mountains' common shareholders (in dollars per share) | $ 1.81 | $ 5.58 | $ (0.43) | $ 1.44
Dividends declared and paid (in dollars per share) |  |  | $ (1.00) | $ (1.00)
Undistributed earnings (loss) per share (in dollars per share) | $ 1.81 | $ 5.58 | $ (1.43) | $ 0.44

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- Definition The earnings attributable to each security on the basis that all of the earnings for the period had been distributed (to the extent that each security may share in earnings). This is the earnings amount which reflects the participation rights in undistributed earnings of each security. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 61 -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 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-6 -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. + Details
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