$WTM
WHITE MOUNTAINS INSURANCE GROUP LTD Stock $wtm

$wtm Overview Financials Valuation SEC Filings Company Website

2021 Q1 Form 10-Q Financial Statement

#000077686721000008 Filed on May 10, 2021

Income Statement

Concept	2021 Q1	2020 Q1
Revenue	$178.2M	-$59.20M
YoY Change	-401.01%	-113.65%
Cost Of Revenue	$4.000M	$2.000M
YoY Change	100.0%
Gross Profit	$174.2M	-$61.20M
YoY Change	-384.64%
Gross Profit Margin	97.76%
Selling, General & Admin	$150.1M	$94.60M
YoY Change	58.67%	-31.84%
% of Gross Profit	86.17%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$12.80M	$7.100M
YoY Change	80.28%	-14.46%
% of Gross Profit	7.35%
Operating Expenses	$275.1M	$101.4M
YoY Change	171.3%	-30.88%
Operating Profit	-$100.9M	-$162.6M
YoY Change	-37.95%
Interest Expense	-$13.10M	-$5.400M
YoY Change	142.59%	3.85%
% of Operating Profit
Other Income/Expense, Net
YoY Change
Pretax Income	-$138.7M	-$166.0M
YoY Change	-16.45%	-158.93%
Income Tax	-$9.500M	-$25.50M
% Of Pretax Income
Net Earnings	-$75.30M	-$128.8M
YoY Change	-41.54%	-147.32%
Net Earnings / Revenue	-42.26%
Basic Earnings Per Share	-$24.30	-$40.54
Diluted Earnings Per Share	-$24.30	-$40.54
COMMON SHARES
Basic Shares Outstanding	3.068M shares	3.144M shares
Diluted Shares Outstanding	3.068M shares	3.144M shares

Balance Sheet

Concept	2021 Q1	2020 Q1
SHORT-TERM ASSETS
Cash & Short-Term Investments
YoY Change
Cash & Equivalents	$488.5M	$136.4M
Short-Term Investments
Other Short-Term Assets
YoY Change
Inventory
Prepaid Expenses
Receivables
Other Receivables
Total Short-Term Assets	$4.000M	$58.00M
YoY Change	-93.1%
LONG-TERM ASSETS
Property, Plant & Equipment	$40.00M	$23.00M
YoY Change	73.91%	4.55%
Goodwill	$613.4M	$392.4M
YoY Change	56.32%	12.21%
Intangibles
YoY Change
Long-Term Investments	$3.858B	$2.679B
YoY Change	44.01%	-4.46%
Other Assets	$1.000M	$3.000M
YoY Change	-66.67%	0.0%
Total Long-Term Assets	$6.897B	$3.682B
YoY Change	87.32%
TOTAL ASSETS
Total Short-Term Assets	$4.000M	$58.00M
Total Long-Term Assets	$6.897B	$3.682B
Total Assets	$6.901B	$3.740B
YoY Change	84.53%	3.03%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable
YoY Change
Accrued Expenses	$92.00M	$45.00M
YoY Change	104.44%	-22.41%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00
YoY Change
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$154.0M	$46.00M
YoY Change	234.78%	-28.13%
LONG-TERM LIABILITIES
Long-Term Debt	$430.0M	$295.0M
YoY Change	45.76%	51.28%
Other Long-Term Liabilities	$217.0M	$127.0M
YoY Change	70.87%	6.72%
Total Long-Term Liabilities	$647.0M	$422.0M
YoY Change	53.32%	34.39%
TOTAL LIABILITIES
Total Short-Term Liabilities	$154.0M	$46.00M
Total Long-Term Liabilities	$647.0M	$422.0M
Total Liabilities	$2.965B	$780.6M
YoY Change	279.81%	19.83%
SHAREHOLDERS EQUITY
Retained Earnings	$3.227B	$2.498B
YoY Change	29.17%	-1.74%
Common Stock	$3.100M	$589.3M
YoY Change	-99.47%	0.6%
Preferred Stock
YoY Change
Treasury Stock (at cost)
YoY Change
Treasury Stock Shares
Shareholders Equity	$3.826B	$3.077B
YoY Change
Total Liabilities & Shareholders Equity	$6.901B	$3.740B
YoY Change	84.53%	3.03%

Cashflow Statement

Concept	2021 Q1	2020 Q1
OPERATING ACTIVITIES
Net Income	-$75.30M	-$128.8M
YoY Change	-41.54%	-147.32%
Depreciation, Depletion And Amortization	$12.80M	$7.100M
YoY Change	80.28%	-14.46%
Cash From Operating Activities	-$92.80M	-$59.80M
YoY Change	55.18%	45.5%
INVESTING ACTIVITIES
Capital Expenditures
YoY Change
Acquisitions
YoY Change
Other Investing Activities	-$60.90M	$50.90M
YoY Change	-219.65%	192.53%
Cash From Investing Activities	$363.9M	$80.50M
YoY Change	352.05%	-288.08%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net	$0.00	$47.80M
YoY Change	-100.0%
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	$6.500M	-$44.20M
YoY Change	-114.71%	-141.9%
NET CHANGE
Cash From Operating Activities	-$92.80M	-$59.80M
Cash From Investing Activities	$363.9M	$80.50M
Cash From Financing Activities	$6.500M	-$44.20M
Net Change In Cash	$277.3M	-$24.60M
YoY Change	-1227.24%	-213.89%
FREE CASH FLOW
Cash From Operating Activities	-$92.80M	-$59.80M
Capital Expenditures
Free Cash Flow
YoY Change

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2021Q1	dei	Entity Central Index Key EntityCentralIndexKey	0000776867
CY2021Q1	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
CY2021Q1	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2021
CY2021Q1	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q1
CY2021Q1	dei	Amendment Flag AmendmentFlag	false
CY2021Q1	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	1.00
CY2020Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	1.00
CY2021Q1	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	50000000	shares
CY2020Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	50000000	shares
CY2021Q1	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	3107267	shares
CY2020Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	3102011	shares
CY2021Q1	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	3107267	shares
CY2020Q4	us-gaap	Common Stock Shares Outstanding CommonStockSharesOutstanding	3102011	shares
CY2020Q1	us-gaap	Revenues Revenues	-59200000	USD
CY2021Q1	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	316900000	USD
CY2020Q4	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	78400000	USD
CY2021Q1	dei	Document Quarterly Report DocumentQuarterlyReport	true
CY2020Q1	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	64900000	USD
CY2021Q1	us-gaap	Cash Acquired From Acquisition CashAcquiredFromAcquisition	52000000.0	USD
CY2019Q4	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	56300000	USD
CY2021Q1	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	83200000	USD
CY2020Q1	us-gaap	Cash Acquired From Acquisition CashAcquiredFromAcquisition	0	USD
CY2021Q1	dei	Document Type DocumentType	10-Q
CY2021Q1	dei	Document Period End Date DocumentPeriodEndDate	2021-03-31
CY2021Q1	dei	Document Transition Report DocumentTransitionReport	false
CY2021Q1	dei	Entity File Number EntityFileNumber	1-8993
CY2021Q1	dei	Entity Registrant Name EntityRegistrantName	WHITE MOUNTAINS INSURANCE GROUP, LTD
CY2021Q1	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	D0
CY2021Q1	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	94-2708455
CY2021Q1	dei	Entity Address Address Line1 EntityAddressAddressLine1	23 South Main Street, Suite 3B
CY2021Q1	dei	Entity Address City Or Town EntityAddressCityOrTown	Hanover,
CY2021Q1	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	03755-2053
CY2021Q1	dei	Entity Address State Or Province EntityAddressStateOrProvince	NH
CY2021Q1	dei	Security Exchange Name SecurityExchangeName	NYSE
CY2021Q1	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2021Q1	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2021Q1	dei	City Area Code CityAreaCode	603
CY2021Q1	dei	Local Phone Number LocalPhoneNumber	640-2200
CY2021Q1	dei	Security12b Title Security12bTitle	Common Shares, par value $1.00
CY2021Q1	dei	Trading Symbol TradingSymbol	WTM
CY2021Q1	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2021Q1	dei	Entity Small Business EntitySmallBusiness	false
CY2021Q1	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2021Q1	dei	Entity Shell Company EntityShellCompany	false
CY2021Q2	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	3107267	shares
CY2021Q1	us-gaap	Assets Assets	6900700000	USD
CY2020Q4	us-gaap	Assets Assets	4831400000	USD
CY2021Q1	us-gaap	Liabilities Liabilities	2964800000	USD
CY2020Q4	us-gaap	Liabilities Liabilities	1013500000	USD
CY2021Q1	us-gaap	Common Stock Value CommonStockValue	3100000	USD
CY2020Q4	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	3311200000	USD
CY2021Q1	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	1300000	USD
CY2020Q4	us-gaap	Accumulated Other Comprehensive Income Loss Net Of Tax AccumulatedOtherComprehensiveIncomeLossNetOfTax	-400000	USD
CY2020Q4	us-gaap	Common Stock Value CommonStockValue	3100000	USD
CY2021Q1	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	594800000	USD
CY2020Q4	us-gaap	Additional Paid In Capital AdditionalPaidInCapital	592100000	USD
CY2021Q1	us-gaap	Retained Earnings Accumulated Deficit RetainedEarningsAccumulatedDeficit	3226700000	USD
CY2021Q1	us-gaap	Stockholders Equity StockholdersEquity	3825900000	USD
CY2020Q4	us-gaap	Stockholders Equity StockholdersEquity	3906000000.0	USD
CY2021Q1	us-gaap	Minority Interest MinorityInterest	110000000.0	USD
CY2020Q4	us-gaap	Minority Interest MinorityInterest	-88100000	USD
CY2021Q1	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	3935900000	USD
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CY2021Q1	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax	18700000	USD
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CY2021Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	1800000	USD
CY2020Q1	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	106800000	USD
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CY2021Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-9500000	USD
CY2020Q1	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-25500000	USD
CY2020Q1	us-gaap	Discontinued Operation Gain Loss On Disposal Of Discontinued Operation Net Of Tax DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax	900000	USD
CY2021Q1	us-gaap	Profit Loss ProfitLoss	-110500000	USD
CY2020Q1	us-gaap	Profit Loss ProfitLoss	-139600000	USD
CY2021Q1	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	-35200000	USD
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CY2021Q1	us-gaap	Net Income Loss NetIncomeLoss	-75300000	USD
CY2020Q1	us-gaap	Net Income Loss NetIncomeLoss	-128800000	USD
CY2021Q1	us-gaap	Net Income Loss NetIncomeLoss	-75300000	USD
CY2021Q1	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	-30.33
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CY2021Q1	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-73500000	USD
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CY2021Q1	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	100000	USD
CY2020Q1	us-gaap	Comprehensive Income Net Of Tax Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	0	USD
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CY2021Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Basic Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare	6.03
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CY2021Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	6.03
CY2020Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Per Diluted Share IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare	0.28
CY2021Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-24.30
CY2020Q1	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	-40.54
CY2021Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.00
CY2020Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.00
CY2021Q1	us-gaap	Profit Loss ProfitLoss	-110500000	USD
CY2020Q1	us-gaap	Profit Loss ProfitLoss	-139600000	USD
CY2021Q1	wtm	Gain Loss On Investments Net Of Tax GainLossOnInvestmentsNetOfTax	1100000	USD
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CY2021Q1	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-1400000	USD
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CY2021Q1	wtm	Amortizationof Restricted Sharesand Option Awards AmortizationofRestrictedSharesandOptionAwards	4000000.0	USD
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CY2021Q1	us-gaap	Increase Decrease In Premiums Receivable IncreaseDecreaseInPremiumsReceivable	-199700000	USD
CY2021Q1	wtm	Increase Decrease In Ceded Unearned Premiums IncreaseDecreaseInCededUnearnedPremiums	24800000	USD
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CY2021Q1	wtm	Proceeds From Sale Of Trading Common Equity Securities ProceedsFromSaleOfTradingCommonEquitySecurities	160300000	USD
CY2020Q1	wtm	Proceeds From Sale Of Trading Common Equity Securities ProceedsFromSaleOfTradingCommonEquitySecurities	40300000	USD
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CY2020Q1	wtm	Proceeds From Release Of Cash Placed In Escrow ProceedsFromReleaseOfCashPlacedInEscrow	0	USD
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CY2020Q1	us-gaap	Payments For Proceeds From Businesses And Interest In Affiliates PaymentsForProceedsFromBusinessesAndInterestInAffiliates	0	USD
CY2021Q1	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	101000000.0	USD
CY2020Q1	us-gaap	Payments To Acquire Other Investments PaymentsToAcquireOtherInvestments	10900000	USD
CY2021Q1	wtm	Payments To Acquire Trading Common Equity Securities PaymentsToAcquireTradingCommonEquitySecurities	68800000	USD
CY2020Q1	wtm	Payments To Acquire Trading Common Equity Securities PaymentsToAcquireTradingCommonEquitySecurities	20900000	USD
CY2021Q1	wtm	Payments To Acquire Trading Fixed Maturity And Convertible Fixed Maturity Investments PaymentsToAcquireTradingFixedMaturityAndConvertibleFixedMaturityInvestments	411100000	USD
CY2020Q1	wtm	Payments To Acquire Trading Fixed Maturity And Convertible Fixed Maturity Investments PaymentsToAcquireTradingFixedMaturityAndConvertibleFixedMaturityInvestments	180100000	USD
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CY2020Q1	us-gaap	Payments For Proceeds From Other Investing Activities PaymentsForProceedsFromOtherInvestingActivities	50900000	USD
CY2021Q1	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	363900000	USD
CY2020Q1	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	80500000	USD
CY2021Q1	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	105300000	USD
CY2020Q1	us-gaap	Proceeds From Lines Of Credit ProceedsFromLinesOfCredit	12000000.0	USD
CY2021Q1	us-gaap	Repayments Of Debt RepaymentsOfDebt	93700000	USD
CY2020Q1	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	3200000	USD
CY2020Q1	us-gaap	Repayments Of Debt RepaymentsOfDebt	1000000.0	USD
CY2021Q1	us-gaap	Payments Of Dividends Common Stock PaymentsOfDividendsCommonStock	3100000	USD
CY2021Q1	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	0	USD
CY2020Q1	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	47800000	USD
CY2021Q1	us-gaap	Payments Of Capital Distribution PaymentsOfCapitalDistribution	900000	USD
CY2020Q1	us-gaap	Payments Of Capital Distribution PaymentsOfCapitalDistribution	700000	USD
CY2021Q1	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	6700000	USD
CY2020Q1	us-gaap	Payment For Contingent Consideration Liability Financing Activities PaymentForContingentConsiderationLiabilityFinancingActivities	6400000	USD
CY2021Q1	us-gaap	Proceeds From Payments To Minority Shareholders ProceedsFromPaymentsToMinorityShareholders	-400000	USD
CY2020Q1	us-gaap	Proceeds From Payments To Minority Shareholders ProceedsFromPaymentsToMinorityShareholders	400000	USD
CY2021Q1	wtm	Members Capital Contribution MembersCapitalContribution	13800000	USD
CY2020Q1	wtm	Members Capital Contribution MembersCapitalContribution	10000000.0	USD
CY2021Q1	wtm	Fidus Re Premium Payment FidusRePremiumPayment	3200000	USD
CY2020Q1	wtm	Fidus Re Premium Payment FidusRePremiumPayment	800000	USD
CY2021Q1	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-4600000	USD
CY2020Q1	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-6700000	USD
CY2021Q1	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	6500000	USD
CY2020Q1	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-44200000	USD
CY2021Q1	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-300000	USD
CY2020Q1	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-1100000	USD
CY2021Q1	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	277300000	USD
CY2020Q1	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-24600000	USD
CY2020Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	211200000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	161000000.0	USD
CY2021Q1	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	488500000	USD
CY2020Q1	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	136400000	USD
CY2021Q1	us-gaap	Interest Paid Net InterestPaidNet	7500000	USD
CY2020Q1	us-gaap	Interest Paid Net InterestPaidNet	5200000	USD
CY2021Q1	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	1400000	USD
CY2020Q1	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	0	USD
CY2021Q1	us-gaap	Use Of Estimates UseOfEstimates	<div style="text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Use of Estimates</span></div><div style="text-indent:18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.</span></div>
CY2021Q1	wtm	Disposal Group Held For Sale Remeasurement Loss DisposalGroupHeldForSaleRemeasurementLoss	28700000	USD
CY2021Q1	wtm	Change In Fair Value Of Contingent Earnout Liability Expense Revenue Recognized ChangeInFairValueOfContingentEarnoutLiabilityExpenseRevenueRecognized	0	USD
CY2020Q1	wtm	Change In Fair Value Of Contingent Earnout Liability Expense Revenue Recognized ChangeInFairValueOfContingentEarnoutLiabilityExpenseRevenueRecognized	-600000	USD
CY2021Q1	us-gaap	Schedule Of Liability For Unpaid Claims And Claims Adjustment Expense ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense	<div style="text-indent:18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following table summarizes the loss and LAE reserve activities of Ark’s insurance and reinsurance subsidiaries for the three months ended March 31, 2021:</span></div><div><span><br/></span></div><div style="text-align:center"><table style="border-collapse:collapse;display:inline-table;margin-bottom:5pt;vertical-align:text-bottom;width:79.093%"><tr><td style="width:1.0%"/><td style="width:72.837%"/><td style="width:0.1%"/><td style="width:0.1%"/><td style="width:0.724%"/><td style="width:0.1%"/><td style="width:1.0%"/><td style="width:24.039%"/><td style="width:0.1%"/></tr><tr><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Millions</span></td><td colspan="3" style="border-top:1pt solid #000;padding:0 1pt"/><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:center;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:8pt;font-weight:700;line-height:100%">Three Months Ended March 31, 2021</span></td></tr><tr><td colspan="3" style="border-top:1pt solid #000;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Gross beginning balance as of January 1, 2021</span></td><td colspan="3" style="padding:0 1pt"/><td style="border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">$</span></td><td style="border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">696.0</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Less: beginning reinsurance recoverable on unpaid losses</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">(433.4)</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt 2px 13pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net loss and LAE reserves</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">262.6</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr style="height:8pt"><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Loss and LAE incurred relating to:</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Current year losses</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">65.5</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Prior year losses</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">.5</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt 2px 13pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total incurred losses and LAE</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">66.0</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr style="height:8pt"><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Foreign currency translation adjustment to loss and LAE reserves</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">.7</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr style="height:6pt"><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Loss and LAE paid relating to:</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Current year losses</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">(5.2)</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Prior year losses</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">(19.7)</span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt 2px 13pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Total loss and LAE payments</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">(24.9)</span></td><td style="border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr style="height:6pt"><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/><td colspan="3" style="padding:0 1pt"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Net ending balance</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">304.4</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Plus: ending reinsurance recoverable on unpaid losses</span></td><td colspan="3" style="padding:0 1pt"/><td colspan="2" style="padding:2px 0 2px 1pt;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">447.5</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr><tr><td colspan="3" style="border-bottom:3pt double #000;padding:2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%">Gross ending balance as of March 31, 2021</span></td><td colspan="3" style="border-bottom:3pt double #000;padding:0 1pt"/><td style="border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0 2px 1pt;text-align:left;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">$</span></td><td style="border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 0;text-align:right;vertical-align:bottom"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:100%">751.9</span><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:100%"> </span></td><td style="border-bottom:3pt double #000;border-top:1pt solid #000;padding:2px 1pt 2px 0;text-align:right;vertical-align:bottom"/></tr></table></div>
CY2020Q4	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	696000000.0	USD
CY2020Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Opening Balance Adjustments LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseOpeningBalanceAdjustments	433400000	USD
CY2020Q4	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	262600000	USD
CY2021Q1	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Current Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersCurrentYearClaimsAndClaimsAdjustmentExpense	65500000	USD
CY2021Q1	us-gaap	Supplemental Information For Property Casualty Insurance Underwriters Prior Year Claims And Claims Adjustment Expense SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense	500000	USD
CY2021Q1	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Incurred Claims1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1	66000000.0	USD
CY2021Q1	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Foreign Currency Translation Gain Loss LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseForeignCurrencyTranslationGainLoss	700000	USD
CY2021Q1	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Current Year1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidCurrentYear1	5200000	USD
CY2021Q1	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Claims Paid Prior Years1 LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseClaimsPaidPriorYears1	19700000	USD
CY2021Q1	us-gaap	Payments For Losses And Loss Adjustment Expense PaymentsForLossesAndLossAdjustmentExpense	24900000	USD
CY2021Q1	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Net LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseNet	304400000	USD
CY2021Q1	us-gaap	Liability For Unpaid Claims And Claims Adjustment Expense Opening Balance Adjustments LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseOpeningBalanceAdjustments	447500000	USD
CY2021Q1	us-gaap	Liability For Claims And Claims Adjustment Expense LiabilityForClaimsAndClaimsAdjustmentExpense	751900000	USD
CY2021Q1	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	21000000.0	USD
CY2021Q1	us-gaap	Reinsurance Recoverables On Unpaid Losses Gross ReinsuranceRecoverablesOnUnpaidLossesGross	447500000	USD
CY2021Q1	us-gaap	Reinsurance Recoverables On Paid Losses Gross ReinsuranceRecoverablesOnPaidLossesGross	1500000	USD
CY2021Q1	us-gaap	Reinsurance Recoverables On Unpaid Losses Gross ReinsuranceRecoverablesOnUnpaidLossesGross	447500000	USD
CY2021Q1	wtm	Percentage Of Reinsurance Recoverables From Insurers With A Excellent Of Higher Credit Ratings PercentageOfReinsuranceRecoverablesFromInsurersWithAExcellentOfHigherCreditRatings	0.90
CY2020Q1	us-gaap	Interest And Dividend Income Operating InterestAndDividendIncomeOperating	23200000	USD
CY2021Q1	us-gaap	Investment Income Investment Expense InvestmentIncomeInvestmentExpense	400000	USD
CY2020Q1	us-gaap	Investment Income Investment Expense InvestmentIncomeInvestmentExpense	300000	USD
CY2021Q1	us-gaap	Net Investment Income NetInvestmentIncome	20600000	USD
CY2020Q1	us-gaap	Net Investment Income NetInvestmentIncome	22900000	USD
CY2021Q1	us-gaap	Gain Loss On Investments GainLossOnInvestments	-40600000	USD
CY2020Q1	us-gaap	Gain Loss On Investments GainLossOnInvestments	-156700000	USD
CY2021Q1	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	200000	USD
CY2020Q1	us-gaap	Gain Loss On Sale Of Investments GainLossOnSaleOfInvestments	8700000	USD
CY2021Q1	wtm	Debt Securities Held To Maturity Net Foreign Currency Gains DebtSecuritiesHeldToMaturityNetForeignCurrencyGains	100000	USD
CY2021Q1	wtm	Percentage Of Investments Recorded At Fair Value PercentageOfInvestmentsRecordedAtFairValue	0.73
CY2021Q1	us-gaap	Other Long Term Investments OtherLongTermInvestments	1032200000	USD
CY2020Q4	us-gaap	Other Long Term Investments OtherLongTermInvestments	786800000	USD
CY2020Q4	us-gaap	Investments Fair Value Disclosure InvestmentsFairValueDisclosure	2796200000	USD
CY2021Q1	wtm	Fair Value Assets Measured On Recurring Basis Gain Loss Included In Earnings FairValueAssetsMeasuredOnRecurringBasisGainLossIncludedInEarnings	38000000.0	USD
CY2021Q1	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	1400000	USD
CY2021Q1	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchases FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases	591800000	USD
CY2021Q1	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Sales FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales	329600000	USD
CY2021Q1	wtm	Fair Value Assets Measured On Recurring Basis Transfers In FairValueAssetsMeasuredOnRecurringBasisTransfersIn	0	USD
CY2021Q1	wtm	Fair Value Assets Measured On Recurring Basis Transfers Out FairValueAssetsMeasuredOnRecurringBasisTransfersOut	0	USD
CY2021Q1	us-gaap	Investments Fair Value Disclosure InvestmentsFairValueDisclosure	3232600000	USD
CY2019Q4	us-gaap	Investments Fair Value Disclosure InvestmentsFairValueDisclosure	2746000000.0	USD
CY2020Q1	wtm	Fair Value Assets Measured On Recurring Basis Gain Loss Included In Earnings FairValueAssetsMeasuredOnRecurringBasisGainLossIncludedInEarnings	157100000	USD
CY2020Q1	us-gaap	Accretion Amortization Of Discounts And Premiums Investments AccretionAmortizationOfDiscountsAndPremiumsInvestments	800000	USD
CY2020Q1	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Purchases FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases	232900000	USD
CY2020Q1	us-gaap	Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Sales FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSales	279400000	USD
CY2020Q1	wtm	Fair Value Assets Measured On Recurring Basis Transfers In FairValueAssetsMeasuredOnRecurringBasisTransfersIn	0	USD
CY2020Q1	wtm	Fair Value Assets Measured On Recurring Basis Transfers Out FairValueAssetsMeasuredOnRecurringBasisTransfersOut	0	USD
CY2020Q1	us-gaap	Investments Fair Value Disclosure InvestmentsFairValueDisclosure	2541600000	USD
CY2021Q1	us-gaap	Goodwill Fair Value Disclosure GoodwillFairValueDisclosure	643600000	USD
CY2021Q1	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	30200000	USD
CY2021Q1	us-gaap	Goodwill Goodwill	613400000	USD
CY2020Q4	us-gaap	Goodwill Fair Value Disclosure GoodwillFairValueDisclosure	525500000	USD
CY2020	us-gaap	Goodwill Impairment Loss GoodwillImpairmentLoss	0	USD
CY2020Q4	us-gaap	Goodwill Goodwill	525500000	USD
CY2021Q1	us-gaap	Finite Lived Intangible Assets Fair Value Disclosure FiniteLivedIntangibleAssetsFairValueDisclosure	493700000	USD
CY2021Q1	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	63900000	USD
CY2021Q1	us-gaap	Impairment Of Intangible Assets Finitelived ImpairmentOfIntangibleAssetsFinitelived	6200000	USD
CY2021Q1	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	423600000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Fair Value Disclosure FiniteLivedIntangibleAssetsFairValueDisclosure	317800000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	54700000	USD
CY2020	us-gaap	Impairment Of Intangible Assets Finitelived ImpairmentOfIntangibleAssetsFinitelived	6200000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	256900000	USD
CY2021Q1	wtm	Intangible Assets Including Goodwill Fair Value Disclosure IntangibleAssetsIncludingGoodwillFairValueDisclosure	1137300000	USD
CY2021Q1	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	63900000	USD
CY2021Q1	wtm	Impairmentof Intangible Assets Including Goodwill ImpairmentofIntangibleAssetsIncludingGoodwill	36400000	USD
CY2021Q1	us-gaap	Intangible Assets Net Including Goodwill IntangibleAssetsNetIncludingGoodwill	1037000000.0	USD
CY2020Q4	wtm	Intangible Assets Including Goodwill Fair Value Disclosure IntangibleAssetsIncludingGoodwillFairValueDisclosure	843300000	USD
CY2020Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	54700000	USD
CY2020	wtm	Impairmentof Intangible Assets Including Goodwill ImpairmentofIntangibleAssetsIncludingGoodwill	6200000	USD
CY2021Q1	us-gaap	Long Term Debt LongTermDebt	429700000	USD
CY2020Q4	us-gaap	Long Term Debt LongTermDebt	376400000	USD
CY2020Q2	us-gaap	Line Of Credit Facility Maximum Borrowing Capacity LineOfCreditFacilityMaximumBorrowingCapacity	291400000	USD
CY2020Q4	us-gaap	Intangible Assets Net Including Goodwill IntangibleAssetsNetIncludingGoodwill	782400000	USD
CY2021Q1	wtm	Disposal Group Held For Sale Remeasurement Loss DisposalGroupHeldForSaleRemeasurementLoss	28700000	USD
CY2021Q1	wtm	Debt Weighted Average Interest Rate Excluding Amortization Of Debt Issuance Costs DebtWeightedAverageInterestRateExcludingAmortizationOfDebtIssuanceCosts	0.071
CY2020	wtm	Debt Weighted Average Interest Rate Excluding Amortization Of Debt Issuance Costs DebtWeightedAverageInterestRateExcludingAmortizationOfDebtIssuanceCosts	0.070
CY2020Q1	us-gaap	Line Of Credit Facility Maximum Borrowing Capacity LineOfCreditFacilityMaximumBorrowingCapacity	234000000.0	USD
CY2021Q1	wtm	Debt Covenant Loan To Value Maximum Percent Period One DebtCovenantLoanToValueMaximumPercentPeriodOne	0.50
CY2021Q1	wtm	Debt Covenant Loan To Value Maximum Percent Period Two DebtCovenantLoanToValueMaximumPercentPeriodTwo	0.40
CY2021Q1	wtm	Debt Covenant Loan To Value Maximum Percent Period Three DebtCovenantLoanToValueMaximumPercentPeriodThree	0.25
CY2020Q1	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2021Q1	us-gaap	Effective Income Tax Rate Reconciliation At Federal Statutory Income Tax Rate EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate	0.210
CY2020Q1	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.154
CY2021Q1	wtm	Percentageof Risk Premium Ceded PercentageofRiskPremiumCeded	0.60
CY2021Q1	wtm	Debt Covenant Loan To Value Maximum Percent Period Four DebtCovenantLoanToValueMaximumPercentPeriodFour	0.15
CY2021Q1	wtm	Debt Covenant Loan To Value Maximum Percent Period Five DebtCovenantLoanToValueMaximumPercentPeriodFive	0
CY2021Q1	wtm	Debt Covenant Loan To Value Maximum Percent DebtCovenantLoanToValueMaximumPercent	0.295
CY2021Q1	us-gaap	Effective Income Tax Rate Continuing Operations EffectiveIncomeTaxRateContinuingOperations	0.069
CY2018Q2	wtm	Insurance Linked Securities Term InsuranceLinkedSecuritiesTerm	P12Y
CY2018Q2	wtm	Insurance Linked Securities Callable Term InsuranceLinkedSecuritiesCallableTerm	P5Y
CY2018Q2	wtm	Insurance Linked Securities Term InsuranceLinkedSecuritiesTerm	P12Y
CY2018Q2	wtm	Insurance Linked Securities Callable Term InsuranceLinkedSecuritiesCallableTerm	P5Y
CY2021Q1	wtm	Percentchangeindiscountedfuturecashflows Percentchangeindiscountedfuturecashflows	0.10
CY2021Q1	wtm	Percentchangeindiscountedfuturecashflows Percentchangeindiscountedfuturecashflows	0.10
CY2021Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-75300000	USD
CY2020Q1	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	-128800000	USD
CY2021Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-18700000	USD
CY2020Q1	us-gaap	Income Loss From Discontinued Operations Net Of Tax Attributable To Reporting Entity IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity	-900000	USD
CY2021Q1	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-94000000.0	USD
CY2020Q1	us-gaap	Income Loss From Continuing Operations IncomeLossFromContinuingOperations	-129700000	USD
CY2021Q1	wtm	Income Loss Allocated To Participating Unvested Restricted Common Shares IncomeLossAllocatedToParticipatingUnvestedRestrictedCommonShares	900000	USD
CY2020Q1	wtm	Income Loss Allocated To Participating Unvested Restricted Common Shares IncomeLossAllocatedToParticipatingUnvestedRestrictedCommonShares	1300000	USD
CY2021Q1	wtm	Net Income Loss Attributableto Parent Basicand Diluted Earnings Per Share Numerators NetIncomeLossAttributabletoParentBasicandDilutedEarningsPerShareNumerators	-93100000	USD
CY2020Q1	wtm	Net Income Loss Attributableto Parent Basicand Diluted Earnings Per Share Numerators NetIncomeLossAttributabletoParentBasicandDilutedEarningsPerShareNumerators	-128400000	USD
CY2021Q1	us-gaap	Weighted Average Number Of Shares Issued Basic WeightedAverageNumberOfSharesIssuedBasic	3100200	shares
CY2020Q1	us-gaap	Weighted Average Number Of Shares Issued Basic WeightedAverageNumberOfSharesIssuedBasic	3178000.0	shares
CY2021Q1	us-gaap	Weighted Average Number Of Shares Restricted Stock WeightedAverageNumberOfSharesRestrictedStock	32400	shares
CY2020Q1	us-gaap	Weighted Average Number Of Shares Restricted Stock WeightedAverageNumberOfSharesRestrictedStock	33800	shares
CY2021Q1	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	3067800	shares
CY2020Q1	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	3144200	shares
CY2021Q1	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	3100200	shares
CY2020Q1	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	3178000.0	shares
CY2021Q1	us-gaap	Weighted Average Number Of Shares Restricted Stock WeightedAverageNumberOfSharesRestrictedStock	32400	shares
CY2020Q1	us-gaap	Weighted Average Number Of Shares Restricted Stock WeightedAverageNumberOfSharesRestrictedStock	33800	shares
CY2021Q1	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	3067800	shares
CY2020Q1	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	3144200	shares
CY2021Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.00
CY2020Q1	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.00
CY2021Q1	us-gaap	Earnings Per Share Diluted Undistributed EarningsPerShareDilutedUndistributed	-31.33
CY2020Q1	us-gaap	Earnings Per Share Diluted Undistributed EarningsPerShareDilutedUndistributed	-41.82
CY2021Q1	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	-30.33
CY2020Q1	us-gaap	Earnings Per Share Basic And Diluted EarningsPerShareBasicAndDiluted	-40.82
CY2021Q1	wtm	Net Income Loss Attributableto Parent Netof Restricted Common Share Amounts NetIncomeLossAttributabletoParentNetofRestrictedCommonShareAmounts	-93100000	USD
CY2020Q1	wtm	Net Income Loss Attributableto Parent Netof Restricted Common Share Amounts NetIncomeLossAttributabletoParentNetofRestrictedCommonShareAmounts	-128400000	USD
CY2021Q1	us-gaap	Dividends Dividends	3100000	USD
CY2020Q1	us-gaap	Dividends Dividends	3100000	USD
CY2021Q1	us-gaap	Undistributed Earnings UndistributedEarnings	-96200000	USD
CY2020Q1	us-gaap	Undistributed Earnings UndistributedEarnings	-131500000	USD
CY2021Q1	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	40300000	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	37600000	USD
CY2021Q1	us-gaap	Operating Lease Liability OperatingLeaseLiability	41000000.0	USD
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	38300000	USD
CY2021Q1	us-gaap	Operating Lease Cost OperatingLeaseCost	1900000	USD
CY2020Q1	us-gaap	Operating Lease Cost OperatingLeaseCost	2000000.0	USD
CY2021Q1	us-gaap	Sublease Income SubleaseIncome	100000	USD
CY2020Q1	us-gaap	Sublease Income SubleaseIncome	100000	USD
CY2021Q1	us-gaap	Lease Cost LeaseCost	1800000	USD
CY2020Q1	us-gaap	Lease Cost LeaseCost	1900000	USD
CY2021Q1	us-gaap	Lessee Operating Lease Liability Payments Remainder Of Fiscal Year LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear	5700000	USD
CY2021Q1	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	9800000	USD
CY2021Q1	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	8500000	USD
CY2021Q1	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	7100000	USD
CY2021Q1	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	5400000	USD
CY2021Q1	wtm	Lessee Operating Lease Liabilitytobe Paid After Year Four LesseeOperatingLeaseLiabilitytobePaidAfterYearFour	12200000	USD
CY2021Q1	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	48700000	USD
CY2021Q1	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	7700000	USD
CY2021Q1	us-gaap	Operating Lease Liability OperatingLeaseLiability	41000000.0	USD
CY2021Q1	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	40300000	USD
CY2021Q1	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.048
CY2021Q1	us-gaap	Operating Lease Liability OperatingLeaseLiability	41000000.0	USD
CY2020Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	37600000	USD
CY2020Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.046
CY2020Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	38300000	USD
CY2021Q1	us-gaap	Minority Interest MinorityInterest	110000000.0	USD
CY2020Q4	us-gaap	Minority Interest MinorityInterest	-88100000	USD
CY2021Q1	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	5	numberOfSegments
CY2021Q1	us-gaap	Premiums Earned Net PremiumsEarnedNet	111000000.0	USD
CY2021Q1	us-gaap	Net Investment Income NetInvestmentIncome	20600000	USD
CY2021Q1	wtm	Insurance Loss And Loss Adjustments Expense InsuranceLossAndLossAdjustmentsExpense	66000000.0	USD
CY2021Q1	wtm	Insurance And Reinsurance Acquisition Expenses InsuranceAndReinsuranceAcquisitionExpenses	38600000	USD
CY2021Q1	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	4000000.0	USD
CY2021Q1	wtm	Gain Loss On Investments Net Of Tax GainLossOnInvestmentsNetOfTax	1100000	USD
CY2021Q1	wtm	Commission Revenue CommissionRevenue	61900000	USD
CY2021Q1	us-gaap	Other Income OtherIncome	25300000	USD
CY2021Q1	us-gaap	Revenues Revenues	178200000	USD
CY2021Q1	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	138400000	USD
CY2021Q1	wtm	Broker Commission Expense BrokerCommissionExpense	18900000	USD
CY2021Q1	us-gaap	Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1	0	USD
CY2021Q1	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	9200000	USD
CY2021Q1	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	-28700000	USD
CY2021Q1	us-gaap	Interest Expense Debt InterestExpenseDebt	13100000	USD
CY2021Q1	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	316900000	USD
CY2021Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-138700000	USD
CY2020Q1	us-gaap	Premiums Earned Net PremiumsEarnedNet	5400000	USD
CY2020Q1	us-gaap	Net Investment Income NetInvestmentIncome	22900000	USD
CY2020Q1	wtm	Gain Loss On Investments Net Of Tax GainLossOnInvestmentsNetOfTax	-186700000	USD
CY2020Q1	wtm	Commission Revenue CommissionRevenue	55100000	USD
CY2020Q1	us-gaap	Other Income OtherIncome	14100000	USD
CY2020Q1	us-gaap	Revenues Revenues	-59200000	USD
CY2020Q1	us-gaap	Deferred Policy Acquisition Cost Amortization Expense DeferredPolicyAcquisitionCostAmortizationExpense	1700000	USD
CY2020Q1	us-gaap	Cost Of Goods And Services Sold CostOfGoodsAndServicesSold	2000000.0	USD
CY2020Q1	us-gaap	General And Administrative Expense GeneralAndAdministrativeExpense	74300000	USD
CY2020Q1	wtm	Broker Commission Expense BrokerCommissionExpense	18300000	USD
CY2020Q1	us-gaap	Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1 BusinessCombinationContingentConsiderationArrangementsChangeInAmountOfContingentConsiderationLiability1	-600000	USD
CY2020Q1	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	5100000	USD
CY2020Q1	us-gaap	Interest Expense Debt InterestExpenseDebt	6000000.0	USD
CY2020Q1	us-gaap	Benefits Losses And Expenses BenefitsLossesAndExpenses	106800000	USD
CY2020Q1	us-gaap	Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments	-166000000.0	USD
CY2021Q1	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	83600000	USD
CY2021Q1	wtm	Other Revenue OtherRevenue	94600000	USD
CY2021Q1	us-gaap	Revenues Revenues	178200000	USD
CY2020Q1	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	68500000	USD
CY2020Q1	wtm	Other Revenue OtherRevenue	-127700000	USD
CY2020Q1	us-gaap	Revenues Revenues	-59200000	USD
CY2021Q1	us-gaap	Loss Contingency Disclosures LossContingencyDisclosures	Commitments and Contingencies<div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Legal Contingencies</span></div><div><span><br/></span></div><div style="text-indent:18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">White Mountains is subject to litigation and arbitration in the normal course of business. White Mountains considers the requirements of ASC 450 when evaluating its exposure to litigation and arbitration. ASC 450 requires that accruals be established for litigation and arbitration if it is probable that a loss has been incurred and it can be reasonably estimated. ASC 450 also requires that litigation and arbitration be disclosed if it is probable that a loss has been incurred or if there is a reasonable possibility that a loss may have been incurred. White Mountains does not have any current litigation that may have a material adverse effect on White Mountains’s financial condition, results of operations or cash flows. </span></div><div style="text-indent:18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The following description presents significant legal contingencies, ongoing non-claims related litigation or arbitration as of March 31, 2021: </span></div><div><span><br/></span></div><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Esurance</span></div><div style="text-indent:18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">On October 7, 2011, the Company completed the sale of its Esurance Holdings, Inc. and its subsidiaries and Answer Financial Inc. and its subsidiaries (collectively, “Esurance”) to The Allstate Corporation (“Allstate”) pursuant to a Stock Purchase Agreement dated as of May 17, 2011. Subject to specified thresholds and limits, the Company remains contingently liable to Allstate for specified matters related to the pre-closing period, including (a) losses of Esurance arising from extra-contractual claims and claims in excess of policy limits, (b) certain corporate reorganizations effected to remove entities from Esurance that were not being sold in the transaction, and (c) certain tax matters, including certain net operating losses being less than stated levels. </span></div><div><span><br/></span></div><div><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-style:italic;font-weight:700;line-height:120%">Sirius Group Tax Contingency</span></div><div style="text-indent:18pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">In the first quarter of 2021, White Mountains recorded a $17.6 million gain within discontinued operations as a result of reversing a liability arising from the tax indemnification provided in connection with the sale of Sirius International Insurance Group, Ltd. (“Sirius Group”) in 2016. The liability related to certain interest deductions claimed by Sirius Group that had been disputed by the Swedish Tax Agency (STA). In April 2021, the STA informed the Swedish Administrative Court of Appeal that, as a result of the Swedish Supreme Administrative Court having ruled that the Swedish interest disallowance rules violate the European Union’s freedom of establishment principle, Sirius Group should prevail in its appeal (and that the interest deductions should not be disallowed).</span></div>
CY2021Q1	wtm	Disposal Group Held For Sale Remeasurement Loss DisposalGroupHeldForSaleRemeasurementLoss	28700000	USD

Files In Submission

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$WTM
WHITE MOUNTAINS INSURANCE GROUP LTD Stock $wtm

2021 Q1 Form 10-Q Financial Statement

#000077686721000008 Filed on May 10, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WTM WHITE MOUNTAINS INSURANCE GROUP LTD Stock $wtm

2021 Q1 Form 10-Q Financial Statement

#000077686721000008 Filed on May 10, 2021

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$WTM
WHITE MOUNTAINS INSURANCE GROUP LTD Stock $wtm