2.2.0.25falsefalse003000 - Statement - Consolidated Statements of Income and Comprehensive Income (Unaudited)truefalseIn Thousands, except Per Share datafalse1falsefalseUSDfalsefalse1/1/2011 - 3/31/2011 USD ($) $FROM_Jan01_2011_TO_Mar31_2011http://www.sec.gov/CIK0001289592duration2011-01-01T00:00:002011-03-31T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDUSD$2falsefalseUSDfalsefalse1/1/2010 - 3/31/2010 USD ($) $FROM_Jan01_2010_TO_Mar31_2010http://www.sec.gov/CIK0001289592duration2010-01-01T00:00:002010-03-31T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDUSD$3true0us-gaap_RevenuesAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseRevenues4false0us-gaap_PremiumsEarnedNetus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse379795000379795falsetruefalsefalsefalse2truefalsefalse268046000268046falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryPremiums earned on the income statement for all insurance and reinsurance contracts after subtracting any amounts ceded to another insurer and adding premiums assumed from other insurers.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 1 -Article 7 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 113 -Paragraph 27 -Subparagraph a, b falsefalseNet premiums earned5false0us-gaap_FeesAndCommissionsOtherus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse81810008181falsefalsefalsefalsefalse2truefalsefalse1018800010188falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryFee and commission revenue earned from sources not otherwise specified in the existing taxonomy.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 13 -Article 9 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number EITF85-24-1 falsefalseCeding commission revenue6false0us-gaap_InsuranceCommissionsAndFeesus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse602000602falsefalsefalsefalsefalse2truefalsefalse556000556falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryIncome from agency and brokerage operations (includes sales of annuities and supplemental contracts); service charges, commissions, and fees from the sale of insurance and related services; and management fees from separate accounts, deferred annuities, and universal life products. May also include an entity's proportionate share of the income or loss before extraordinary items and other adjustments from its investments in: unconsolidated subsidiaries, associated companies, and corporate joint ventures, unincorporated joint ventures, general partnerships, and limited partnerships over which the entity exercises significant influence that are principally engaged in insurance underwriting, reinsurance, or insurance sales activities.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 13 -Subparagraph c, d -Article 9 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 4 -Article 7 falsefalseInsurance services revenue7false0twgp_PolicyBillingFeestwgpfalsecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse21780002178falsefalsefalsefalsefalse2truefalsefalse771000771falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryNo definition available.No authoritative reference available.falsefalsePolicy billing fees8false0us-gaap_NetInvestmentIncomeus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse3237800032378falsefalsefalsefalsefalse2truefalsefalse2317500023175falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe income earned from investments in securities and property, equipment and other capital assets. It includes rent from property and equipment, dividends from shares in corporations, and interest from bonds, loans, mortgages, derivatives, commercial paper, bank accounts, certificates of deposits, treasuries, and other financial securities. It does not include realized gains and losses on investments.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 16 -Article 12 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 2 -Article 7 falsefalseNet investment income9true0us-gaap_RealizedInvestmentGainsLossesAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseNet realized investment gains (losses)10false0us-gaap_MarketableSecuritiesRealizedGainLossOtherThanTemporaryImpairmentsAmountus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-168000-168falsefalsefalsefalsefalse2truefalsefalse-6146000-6146falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis element represents the amount of loss recognized for other than temporary impairments of investments in debt and equity securities.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 16 falsefalseOther-than-temporary impairments11false0twgp_PortionOfLossRecognizedInAccumulatedOtherComprehensiveIncomeLosstwgpfalsecreditdurationPortion of loss recognized in accumulated other comprehensive income (loss).falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse2400024falsefalsefalsefalsefalse2truefalsefalse32150003215falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryPortion of loss recognized in accumulated other comprehensive income (loss).No authoritative reference available.falsefalsePortion of loss recognized in other comprehensive income12false0us-gaap_GainLossOnSaleOfOtherInvestmentsus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse75040007504falsefalsefalsefalsefalse2truefalsefalse36710003671falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe difference between the book value and the sale price of other nonspecific investments. This element is used when other, more specific, elements are not appropriate. This element refers to the gain (loss) included in earnings.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 truefalseOther net realized investment gains13false0us-gaap_RealizedInvestmentGainsLossesus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse73600007360falsefalsefalsefalsefalse2truefalsefalse740000740falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net realized gains or losses on investments during the period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 3 -Subparagraph a -Article 7 truefalseTotal net realized investment gains14false0us-gaap_Revenuesus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse430494000430494falsefalsefalsefalsefalse2truefalsefalse303476000303476falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAggregate revenue recognized during the period (derived from goods sold, services rendered, insurance premiums, or other activities that constitute an entity's earning process). For financial services companies, also includes investment and interest income, and sales and trading gains.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5 falsefalseTotal revenues15true0us-gaap_BenefitsLossesAndExpensesAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseExpenses16false0us-gaap_PolicyholderBenefitsAndClaimsIncurredNetus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse240176000240176falsefalsefalsefalsefalse2truefalsefalse169337000169337falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryProvision for benefits, claims and claims settlement expenses incurred during the period net of the effects of contracts assumed and ceded.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 5 -Article 7 falsefalseLoss and loss adjustment expenses17false0us-gaap_InsuranceCommissionsus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse7660300076603falsefalsefalsefalsefalse2truefalsefalse5804500058045falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe expense incurred by an insurance company to persons or entities for generating or placing insurance or investment contracts with the company, usually determined as a percentage of policy or contract premiums. Excludes advances or draws to be applied against commissions earned.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-LHI -Chapter 3 -Paragraph 3, 22 -IssueDate 2006-05-01 falsefalseDirect and ceding commission expense18false0us-gaap_OtherCostAndExpenseOperatingus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse6633900066339falsefalsefalsefalsefalse2truefalsefalse5100800051008falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe total amount of other operating cost and expense items that are associated with the entity's normal revenue producing operation.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 3 -Article 5 falsefalseOther operating expenses19false0us-gaap_BusinessCombinationAcquisitionRelatedCostsus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse1200012falsefalsefalsefalsefalse2truefalsefalse857000857falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141R -Paragraph 59 falsefalseAcquisition-related transaction costs20false0us-gaap_InterestExpenseDebtus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse81000008100falsefalsefalsefalsefalse2truefalsefalse48810004881falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryRepresents the portion of interest incurred in the period on debt arrangements that was charged against earnings.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 8 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 34 -Paragraph 21 truefalseInterest expense21false0us-gaap_BenefitsLossesAndExpensesus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse391230000391230falsefalsefalsefalsefalse2truefalsefalse284128000284128falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe total amount of expense recognized during the period for future policy benefits, claims and claims adjustment costs, and for selling, general and administrative costs.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 5, 6, 7 -Article 7 falsefalseTotal expenses22true0twgp_OtherIncomeExpenseAbstracttwgpfalsenadurationOther Income 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available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse3926400039264falsefalsefalsefalsefalse2truefalsefalse1888200018882falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe portion of earnings (loss) from continuing operations before income taxes that is attributable to domestic operations.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Subparagraph 1(i) -Article 4 falsefalseIncome before income taxes25false0us-gaap_IncomeTaxExpenseBenefitus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse1275800012758falsefalsefalsefalsefalse2truefalsefalse58300005830falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe sum of the current income tax expense (benefit) and the deferred income tax expense (benefit) pertaining to continuing operations.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Article 4 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 45 -Subparagraph a, b truefalseIncome tax expense26false0us-gaap_ProfitLossus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse2650600026506falsefalsefalsefalsefalse2truefalsefalse1305200013052falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A1, A4, A5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting 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parent.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(1) Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A1, A4, A5 falsefalseLess: Net income attributable to Reciprocal Exchanges28false0us-gaap_NetIncomeLossus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse2568500025685falsefalsefalsefalsefalse2truefalsefalse1305200013052falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe portion of consolidated profit or loss for the period, net of income taxes, which is attributable to the parent. If the entity does not present consolidated financial statements, the amount of profit or loss for the period, net of income taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 19 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph d Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A7 -Appendix A Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 20 -Article 9 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 10, 15 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 87-21 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28, 29, 30 falsefalseNet income attributable to Tower Group, Inc.29false0us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTaxus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse-1325000-1325falsefalsefalsefalsefalse2truefalsefalse2381100023811falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryGross appreciation or the gross loss in value of the total of unsold available-for-sale securities during the period being reported (except when designated as a fair value hedge).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 24 -Subparagraph b Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 13 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 17 falsefalseGross unrealized investment holding gains (losses) arising during periods30false0twgp_GrossUnrealizedGainsLossOnInterestRateSwapstwgpfalsecreditdurationAmount of unrealized gain (loss) related to the increase (decrease) in fair value of interest rate derivatives designated as...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1truefalsefalse938000938falsefalsefalsefalsefalse2truefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAmount of unrealized gain (loss) related to the increase (decrease) in fair value of interest rate derivatives designated as cash flow hedging instruments, which was recorded in accumulated other comprehensive income to the extent that the cash flow hedge was determined to be effective.No authoritative reference available.falsefalseGross unrealized gains on interest rate swaps31false0twgp_LessReclassificationAdjustmentForGainsLossesIncludedInNetIncometwgpfalsedebitdurationLess: reclassification adjustment for (gains) losses included in net income.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-7360000-7360falsefalsefalsefalsefalse2truefalsefalse-740000-740falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryLess: reclassification adjustment for (gains) losses included in net income.No authoritative reference available.falsefalseLess: reclassification adjustment for gains included in net income32false0us-gaap_OtherComprehensiveIncomeLossTaxus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegatedtotal1truefalsefalse27590002759falsefalsefalsefalsefalse2truefalsefalse-7594000-7594falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryTax effect of the change in accumulated other comprehensive income, that is, the tax effect on items included in other comprehensive income during the period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 36 -Subparagraph b Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 10 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 24 -Subparagraph b Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 31 -Article 5 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 truefalseIncome tax (expense) related to items of other comprehensive income33false0us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterestus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse2151800021518falsefalsefalsefalsefalse2truefalsefalse2852900028529falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the economic entity, including both controlling (parent) and noncontrolling interests. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, including any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A5 -Appendix A Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 29 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a truefalseComprehensive income34false0us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterestus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truefalsefalse815000815falsefalsefalsefalsefalse2truefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to noncontrolling interests, if any. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 30 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A5 -Appendix A falsefalseLess: Comprehensive income attributable to Reciprocal Exchanges35false0us-gaap_ComprehensiveIncomeNetOfTaxus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse2070300020703falsetruefalsefalsefalse2truefalsefalse2852900028529falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the reporting entity. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, but excludes any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A5 -Appendix A Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 30 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(3) Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 8, 9, 10, 11, 12, 13, 14 truefalseComprehensive income attributable to Tower Group, Inc.37true0us-gaap_EarningsPerShareBasicAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseEarnings per share attributable to Tower stockholders:38false0us-gaap_EarningsPerShareBasicus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse0.610.61falsetruefalsefalsefalse2truefalsefalse0.290.29falsetruefalsefalsefalseEPSus-types:perShareItemTypedecimalThe amount of net income or loss for the period per each share of common stock outstanding during the reporting period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 21 -Article 9 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial 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