New Accounting Pronouncements and Changes in Accounting Principles [Abstract] Earnings Per Share [Abstract] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] 9% Convertible Junior Subordinated Debentures Convertible Subordinated Debt [Member] Unvested RSUs Unvested restricted stock units [Member] Refers to the unvested restricted stock units. Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Stated interest rate Debt Instrument, Interest Rate, Stated Percentage Basic earnings per share: Earnings Per Share, Basic [Abstract] Net income Net Income (Loss) Attributable to Parent Weighted average common shares outstanding - basic (in shares) Weighted Average Number of Shares Outstanding, Basic Basic earnings per share (in dollars per share) Earnings Per Share, Basic Diluted earnings per share: Earnings Per Share, Diluted [Abstract] Dilutive securities Dilutive Securities, Effect on Basic Earnings Per Share Diluted income available to common shareholders Net Income (Loss) Available to Common Stockholders, Diluted Effect of dilutive securities: Dilutive Securities, Effect on Basic Earnings Per Share [Abstract] Unvested RSUs (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Dilutive securities (in shares) Weighted Average Number Diluted Shares Outstanding Adjustment Weighted average common shares outstanding - diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Diluted earnings per share (in dollars per share) Earnings Per Share, Diluted Effective income tax rate Effective Income Tax Rate Reconciliation, Percent Statutory Capital [Abstract] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Mortgage Guaranty Insurance Corporation Mortgage Guaranty Insurance Corporation [Member] Another company which is controlled, directly or indirectly, by its parent. The usual condition for control is ownership of a majority (over 50%) of the outstanding voting stock. The power to control may also exist with a lesser percentage of ownership, for example, by contract, lease, agreement with other stockholders or by court decree. Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] Statutory capital requirements [Abstract] Statutory capital requirements [Abstract] Number of jurisdictions with risk-to-capital requirements (in jurisdictions) Number of jurisdictions with risk to capital requirements The number of jurisdictions that require a mortgage insurer to maintain a minimum amount of statutory capital relative to the risk in force (or a similar measure) in order for the mortgage insurer to continue to write new business. This is generally referred to as a risk-to-capital requirement. Maximum permitted risk-to-capital ratio commonly applied Description of Regulatory Capital Requirements under Insurance Regulations Maximum risk-to-capital ratio Statutory Accounting Practices, Regulatory Capital Requirements, Risk-to-Capital Ratio, Maximum Statutory Accounting Practices, Regulatory Capital Requirements, Risk-to-Capital Ratio, Maximum Risk to capital ratio at end of period Risk to capital ratio at end of period The entity's risk-to-capital ratio as of the end of the reporting period. Risk-to-capital ratio Statutory Capital Requirements, Risk To Capital Ratio Statutory Capital Requirements, Risk To Capital Ratio Amount of policyholders position above or below required MPP Amount of policyholders position above or below required regulatory minimum The amount by which the entity's policyholders position (the insurer's net worth or surplus, contingency reserve and a portion of the reserves for unearned premiums) was above or below the required regulatory minimum of the entity's domiciliary state. Amount of required MPP Amount of required MPP The amount of minimum policyholder position (MPP) required by the entity's domiciliary state. Risk to capital ratio of combined insurance operations, including reinsurance affiliates, at end of period Risk to capital ratio of combined insurance operations, including reinsurance affiliates, at end of period The risk-to-capital ratio of the entity's combined insurance operations, including its reinsurance affiliates, as of the end of the reporting period. Risk-to-capital ratio for combined insurance operations Statutory Capital Requirements, Risk To Capital Ratio For Combined Insurance Operations Statutory Capital Requirements, Risk To Capital Ratio For Combined Insurance Operations Dividends paid to the parent company SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Subsidiaries and Equity Method Investees Percentage of statutory policyholders surplus used to determine maximum allowable dividends (as a percent) Percentage of statutory policyholders surplus used to determine maximum allowable dividends The percentage of statutory policyholders' surplus, as defined, as of the preceding calendar year end which is used in the determination of the maximum allowable dividends that the insurance subsidiaries may pay in any twelve-month period without regulatory approval by the Office of the Commissioner of Insurance of the State of Wisconsin. Adjusted statutory net income measurement period (in years) Statutory Accounting Practices, Statutory Amount Available For Dividend Payments Without Regulatory Approval, Measurement, Measurement Period Statutory Accounting Practices, Statutory Amount Available For Dividend Payments Without Regulatory Approval, Measurement, Measurement Period Adjusted statutory net income dividend payment measurement period (in years) Statutory Accounting Practices, Statutory Amount Available for Dividend Payments without Regulatory Approval, Measurement, Dividend Payment Period Statutory Accounting Practices, Statutory Amount Available for Dividend Payments without Regulatory Approval, Measurement, Dividend Payment Period Fair Value Disclosures [Abstract] Fair value measurements for items measured at fair value Fair Value, Assets Measured on Recurring Basis [Table Text Block] Reconciliation of beginning and ending balance for assets and liabilities measured at fair value with significant unobservable inputs (level 3) Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Carrying value and fair value of financial assets and liabilities Fair Value, by Balance Sheet Grouping [Table Text Block] Reinsurance Disclosures [Abstract] Effect of reinsurance agreement Effects of Reinsurance [Table Text Block] Effect of quota share reinsurance agreements on premiums earned and losses incurred Effect Of Quota Share Reinsurance Agreements On Premiums Earned And Losses Incurred [Table Text Block] Tabular disclosure of the effect of quota share reinsurance agreements on premiums earned and losses incurred. Schedule of coverages and retention Reinsurance Retention Policy [Table Text Block] Schedule of total assets of Home Re Schedule of Variable Interest Entities [Table Text Block] Retirement Benefits [Abstract] Components of net periodic benefit cost Schedule of Net Benefit Costs [Table Text Block] Effects of Reinsurance [Table] Effects of Reinsurance [Table] Home Re special purpose insurers Home Re special purpose insurers [Member] Home Re special purpose insurers [Member] Home Re 2018-1 Home Re 2018-1 [Member] Home Re 2018-1 Ltd [Member] Home Re 2019-1 Home Re 2019-1 [Member] Home Re 2019-1 [Member] Effects of Reinsurance [Line Items] Effects of Reinsurance [Line Items] Amortization period excess of loss reinsurance coverage Amortization Period Excess of Loss Reinsurance Coverage Amortization Period Excess of Loss Reinsurance Coverage Term of mortgage insurance-linked notes Reinsurance Retention Policy, Debt Issued To Cover Insurance, Term Reinsurance Retention Policy, Debt Issued To Cover Insurance, Term Remaining First Layer Retention Reinsurance Retention Policy, Amount Retained Remaining Excess of Loss Reinsurance Coverages Reinsurance Retention Policy, Remaining Excess Of Loss Reinsurance Coverages Reinsurance Retention Policy, Remaining Excess of Loss Reinsurance Coverages Total VIE Assets Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets Percent of total trust assets invested in cash or direct U.S. federal government obligations Reinsurance Retention Policy, Percent Of Total Trust Assets Invested In Cash Or Direct U.S. Federal Government Obligations Reinsurance Retention Policy, Percent Of Total Trust Assets Invested In Cash Or Direct U.S. Federal Government Obligations Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Investment portfolio: Debt Securities, Available-for-sale [Abstract] Fixed income, available-for-sale, at fair value (amortized cost 2020 - $5,375,382; 2019 - $5,562,550) Debt Securities, Available-for-sale Equity securities, at fair value (cost 2020 - $29,559; 2019 - $17,188) Equity Securities, FV-NI Other invested assets, at cost Other Investments Total investment portfolio Investments Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Restricted cash and cash equivalents Restricted Cash and Cash Equivalents Accrued investment income Accrued Investment Income Receivable Reinsurance recoverable on loss reserves Reinsurance Recoverable for Unpaid Claims and Claims Adjustments Reinsurance recoverable on paid losses Reinsurance Recoverable for Paid Claims and Claims Adjustments Premiums receivable Premiums Receivable, Net Home office and equipment, net Property, Plant and Equipment, Net Deferred insurance policy acquisition costs Deferred Policy Acquisition Cost Deferred income taxes, net Deferred Income Tax Assets, Net Other assets Other Assets Total assets Assets LIABILITIES AND SHAREHOLDERS’ EQUITY Liabilities and Equity [Abstract] Liabilities: Liabilities [Abstract] Loss reserves Liability for Claims and Claims Adjustment Expense, Property Casualty Liability Unearned premiums Unearned Premiums Federal Home Loan Bank advance Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances Senior notes Senior Notes Convertible junior subordinated debentures Convertible Subordinated Debt Other liabilities Other Liabilities Total liabilities Liabilities Contingencies Commitments and Contingencies Shareholders’ equity: Stockholders' Equity Attributable to Parent [Abstract] Common stock (one dollar par value, shares authorized 1,000,000; shares issued 2020 - 371,353; 2019 - 371,353; shares outstanding 2020 - 338,567; 2019 - 347,308) Common Stock, Value, Issued Paid-in capital Additional Paid in Capital, Common Stock Treasury stock at cost (shares 2020 - 32,786; 2019 - 24,045) Treasury Stock, Value Accumulated other comprehensive income, net of tax Accumulated Other Comprehensive Income (Loss), Net of Tax Retained earnings Retained Earnings (Accumulated Deficit) Total shareholders’ equity Stockholders' Equity Attributable to Parent Total liabilities and shareholders’ equity Liabilities and Equity Insurance Loss Reserves [Abstract] Reconciliation of beginning and ending loss reserves Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block] Prior year development of the reserves Schedule of Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block] Rollforward of primary delinquent inventory Rollforward of Primary Default Inventory [Table Text Block] Tabular disclosure of the activity related to loans in the primary default inventory. Aging of the primary delinquent inventory Aging of Primary Default Inventory [Table Text Block] Tabular disclosure of the aging of the loan primary default inventory. Statutory Information Statutory Accounting Practices [Text Block] The entire disclosure of how the entity's reporting under GAAP as of the balance sheet date differs from the results based on prescribed and permitted accounting practices of the state or country of domicile in which a relevant statutory filing is made. Investments [Abstract] Schedule of Investments [Table] Schedule of Investments [Table] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] U.S. Treasury securities and obligations of U.S. government corporations and agencies US Treasury and Government [Member] Obligations of U.S. states and political subdivisions US States and Political Subdivisions Debt Securities [Member] Corporate debt securities Corporate Debt Securities [Member] Asset backed securities (“ABS”) Asset-backed Securities [Member] Residential mortgage backed securities (“RMBS”) Residential Mortgage Backed Securities [Member] Commercial mortgage backed securities (“CMBS”) Commercial Mortgage Backed Securities [Member] Collateralized loan obligations (“CLOs”) Collateralized Loan Obligations [Member] Schedule of Investments [Line Items] Schedule of Investments [Line Items] Less Than 12 Months - Fair Value Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months 12 Months or Greater - Fair Value Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer Total - Fair Value Debt Securities, Available-for-sale, Unrealized Loss Position Less Than 12 Months - Unrealized Losses Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 12 Months or Greater - Unrealized Losses Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Total - Unrealized Losses Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss Premiums earned: Premiums Earned, Net [Abstract] Direct Direct Premiums Earned Assumed Assumed Premiums Earned Ceded Ceded Premiums Earned Net premiums earned Premiums Earned, Net, Property and Casualty Losses incurred: Policyholder Benefits and Claims Incurred, Net [Abstract] Direct Policyholder Benefits and Claims Incurred, Direct Assumed Policyholder Benefits and Claims Incurred, Assumed Ceded Policyholder Benefits and Claims Incurred, Ceded Losses incurred, net Policyholder Benefits and Claims Incurred, Net, Property, Casualty and Liability Scenario [Axis] Scenario [Axis] Scenario [Domain] Scenario [Domain] Forecast Forecast [Member] Reinsurance Policy, Type [Axis] Reinsurance Policy, Type [Axis] Reinsurance Policy [Domain] Reinsurance Policy [Domain] Quota Share Reinsurance Agreement, 2020 Quota Share Reinsurance Agreement, 2020 [Member] Quota Share Reinsurance Agreement, 2020 [Member] Quota Share Reinsurance Agreement, 2021 Quota Share Reinsurance Agreement, 2021 [Member] Quota Share Reinsurance Agreement, 2021 [Member] Quota Share Reinsurance Agreements, Excluding Captive Agreements Quota Share Reinsurance Agreements, Excluding Captives [Member] Quota Share Reinsurance Agreements, Excluding Captives [Member] Excess of Loss Reinsurance Agreement, Home Re Excess of Loss Reinsurance Agreements, Home Re Entities [Member] Excess of Loss Reinsurance Agreements, Home Re Entities [Member] Contingent termination fee Reinsurance, Quota Share Reinsurance Agreement, Terms, Contingent Termination Fee Reinsurance, Quota Share Reinsurance Agreement, Terms, Contingent Termination Fee Threshold for private mortgage insurer eligibility requirements for termination election (less than) (as a percent) Reinsurance, Quota Share Reinsurance Agreement, Terms, Threshold For Private Mortgage Insurer Eligibility Requirements For Termination Election Reinsurance, Quota Share Reinsurance Agreement, Terms, Threshold For Private Mortgage Insurer Eligibility Requirements For Termination Election Quota share for all policies covered (as a percent) Reinsurance, Quota Share Reinsurance Agreement, Terms, Quota Share, Percent Reinsurance, Quota Share Reinsurance Agreement, Terms, Quota Share, Percent Cede rate, option 1 (as a percent) Reinsurance, Quota Share Reinsurance Agreement, Terms, Ceding Rate, Percent, Option One Reinsurance, Quota Share Reinsurance Agreement, Terms, Ceding Rate, Percent, Option One Cede rate, option 2 (as a percent) Reinsurance, Quota Share Reinsurance Agreement, Terms, Ceding Rate, Percent, Option Two Reinsurance, Quota Share Reinsurance Agreement, Terms, Ceding Rate, Percent, Option Two Ceding commission, percentage (as a percent) Reinsurance, Quota Share Reinsurance Agreement, Terms, Ceding Commission, Percent Reinsurance, Quota Share Reinsurance Agreement, Terms, Ceding Commission, Percent Loss ratio threshold for profit commissions (as a percent) Loss Ratio Annual loss ratio cap under quota share reinsurance transactions (as a percent) Annual Loss Ratio Cap Under Quota Share Reinsurance Transactions The annual maximum ratio of non-life losses and loss expenses to non-life net premiums earned under our quota share reinsurance transactions. Lifetime loss ratio cap under quota share reinsurance transactions (as a percent) Lifetime Loss Ratio Cap Under Quota Share Reinsurance Transactions The lifetime maximum ratio of non-life losses and loss expenses to non-life net premiums earned under our quota share reinsurance transactions. Ceded premiums Fixed maturities, amortized cost Debt Securities, Available-for-sale, Amortized Cost Cost Equity Securities, FV-NI, Cost Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (in shares) Common Stock, Shares Authorized Common stock, shares issued (in shares) Common Stock, Shares, Issued Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Treasury stock, shares at cost (in shares) Treasury Stock, Shares Fair Value Measurements Fair Value Disclosures [Text Block] Statement of Comprehensive Income [Abstract] Other comprehensive (loss) income, net of tax: Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Change in unrealized investment gains and losses Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Benefit plan adjustments Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent Other comprehensive (loss) income, net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Ceded premiums written and earned, net of profit commission Ceded Premiums Written and Earned, Net of Profit Commission Ceded Premiums Written and Earned, Net of Profit Commission Ceded losses incurred Ceding commissions Reinsurance Ceding Commission Earned Reinsurance Ceding Commission Earned Profit commission Reinsurance, Profit Commission Reinsurance, Profit Commission Reinsurance recoverable on loss reserves Amortized cost, gross unrealized gains and losses and fair value of fixed income securities Schedule of Available-for-sale Securities Reconciliation [Table Text Block] Amortized cost and fair values of fixed income securities by contractual maturity Investments Classified by Contractual Maturity Date [Table Text Block] Cost and fair value of investments in equity securities Equity Securities [Table Text Block] Tabular disclosure of investments in equity securities. Aging of the fair values of securities in an unrealized loss position Schedule of Unrealized Loss on Investments [Table Text Block] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Total fixed income securities Debt Securities [Member] Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-sale [Line Items] Amortized Cost Gross Unrealized Gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Gross Unrealized Losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Fair Value Credit allowance on available for sale fixed income securities Debt Securities, Available-for-sale, Allowance for Credit Loss Other-than-temporary impairment losses recorded in other comprehensive income Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Loss, before Tax, Portion Attributable to Parent Assets held by insurance regulators Assets Held by Insurance Regulators Proceeds from sales of fixed income securities Proceeds from Sale of Debt Securities, Available-for-sale Gross realized gains, fixed income securities Available-for-sale Securities, Gross Realized Gains Gross realized losses, fixed income securities Available-for-sale Securities, Realized Losses, Excluding Other than Temporary Impairments Impairment charges recognized in net realized gains (losses) on securities with the intent to sell Debt Securities, Available for Sale, Impairment Charges Intent To Sell No Allowance Previously Recorded Recognized in Net Realized Investment Gains Losses Amount of impairment charges recognized in net realized investment gains (losses) on debt securities where no previous allowance for credit losses has been recorded, but for which the Company intends to sell the securities. Net impairment losses recognized in earnings Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net Collateral, market value to principal balance of FHLB (as a percent) Federal Home Loan Bank Advances, Collateral, Market Value Of Principal, Percent Federal Home Loan Bank Advances, Collateral, Market Value Of Principal, Percent FHLB advance, collateral pledged Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged Number of securities in unrealized loss position (in securities) Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions Cover [Abstract] Document Type Document Type Document Quarterly Report Document Quarterly Report Document Period End Date Document Period End Date Document Transition Report Document Transition Report Entity File Number Entity File Number Entity Registrant Name Entity Registrant Name Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line One Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Entity Address, Postal Zip Code Entity Address, Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Title of each class Title of 12(b) Security Trading Symbol Trading Symbol Security Exchange Name Security Exchange Name Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Shell Company Entity Shell Company Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Summary of amounts disclosed under statutory accounting practices Statutory Accounting Practices Disclosure [Table Text Block] Benefit Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Aging of the Primary Delinquent Inventory [Abstract] Aging of the Primary Default Inventory [Abstract] 3 months or less (in loans) Primary Default Inventory, Three months or less The number of loans that have been in the primary default inventory for three months or less as of the balance sheet date. 3 months or less (as a percent) Primary Default Inventory, Three months or less, Percentage The percentage of loans that have been in the primary default inventory for three months or less as of the balance sheet date. 4 - 11 months (in loans) Primary Default Inventory, four to eleven months The number of loans that have been in the primary default inventory for at least four months but no greater than eleven months as of the balance sheet date. 4 - 11 months (as a percent) Primary Default Inventory, four to eleven months, Percentage The percentage of loans that have been in the primary default inventory for at least four months but no greater than eleven months as of the balance sheet date. 12 months or more (in loans) Primary Default Inventory, Twelve Months or More The number of loans that have been in the primary default inventory for twelve months or more as of the balance sheet date. 12 months or more (as a percent) Primary Default Inventory, Twelve Months or More, Percentage The percentage of loans that have been in the primary default inventory for twelve months or more as of the balance sheet date. Total primary delinquent inventory (in loans) Primary Default Inventory The number of loans in the primary default inventory. Total primary delinquent inventory (as a percent) Primary default inventory, Percentage The percentage of loans in the primary default inventory. Primary claims received inventory included in ending delinquent inventory (in loans) Primary Default Inventory, Claims Received Inventory The number of loans in the primary default inventory that are in the claims received inventory. Percent of 12 months or more delinquent inventory, delinquent for more than 36 months (as a percent) Primary Default Inventory Twelve Months Or More, Percent Of Primary Default Inventory In Default For Twelve Months Or More In Default For More Than Thirty Six Consecutive Months Primary Default Inventory Twelve Months Or More, Percent Of Primary Default Inventory In Default For Twelve Months Or More In Default For More Than Thirty Six Consecutive Months Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Senior Notes Senior Notes [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] 5.75% Senior Notes Due 2023 Five Point Seven Five Percent Senior Notes [Member] Five Point Seven Five Percent Senior Notes [Member] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Carrying Value Reported Value Measurement [Member] Fair Value Estimate of Fair Value Measurement [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Other invested assets Other Invested Assets, Fair Value Disclosure Fair value portion of other invested assets. FHLB Advance Notes Payable, Fair Value Disclosure 5.75% Senior Notes Senior Notes, Fair Value Disclosure Senior Notes, Fair Value Disclosure 9% Convertible Junior Subordinated Debentures Subordinated Debt Obligations, Fair Value Disclosure Total financial liabilities Debt Instrument, Fair Value Disclosure Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Debt Instrument [Line Items] Debt Instrument [Line Items] Conversion rate (in shares per $1,000 note) Debt Instrument, Convertible, Conversion Ratio Principal amount of notes used in determining conversion rate Principal amount of notes used in determining conversion rate The principal amount of notes used in the determination of the initial conversion rate, which is subject to adjustment. Convertible debt, conversion price (in dollars per share) Debt Instrument, Convertible, Conversion Price Total interest payments Interest Paid, Including Capitalized Interest, Operating and Investing Activities Organization, Consolidation and Presentation of Financial Statements [Abstract] Nature of Business and Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Reinsurance Reinsurance [Text Block] Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Accumulated other comprehensive income (loss) AOCI Attributable to Parent [Member] Net unrealized gains and (losses) on available-for-sale securities AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member] Net benefit plan assets and (obligations) recognized in shareholders' equity Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification from Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Member] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Total other comprehensive (loss) income Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent Income tax (expense) benefit Other Comprehensive Income (Loss), Tax Amounts Reclassified From Accumulated Other Comprehensive Income [Abstract] Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Income before tax Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Income tax (expense) benefit Income Tax Expense (Benefit) Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] AOCI Attributable to Parent, Net of Tax [Roll Forward] AOCI Attributable to Parent, Net of Tax [Roll Forward] Balance, beginning of period Other comprehensive income before reclassifications OCI, before Reclassifications, Net of Tax, Attributable to Parent Less: Amounts reclassified from AOCI Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent Balance, end of period Commitments and Contingencies Disclosure [Abstract] Average paid claim reduction due to curtailments (as a percent) Average paid claims reduction due to curtailments Average paid claim reduction due to curtailments. Maximum exposure associated with other discussions and legal proceedings Maximum Exposure Associated With Other Discussions Legal Proceedings Estimated maximum exposure associated with other discussions and legal proceedings related to claims paying practices. Loss Reserve [Roll Forward] Movement in Liability for Future Policy Benefits [Roll Forward] Reserve at beginning of period Liability for Claims and Claims Adjustment Expense Less reinsurance recoverable Net reserve at beginning of period Liability for Unpaid Claims and Claims Adjustment Expense, Net Losses incurred: Losses incurred: [Abstract] Losses and LAE incurred in respect of delinquency notices received in: Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract] Current year Current Year Claims and Claims Adjustment Expense Prior years Prior Year Claims and Claims Adjustment Expense Total losses incurred Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims Losses paid: Losses paid [Abstract] Losses and LAE paid in respect of delinquency notices received in: Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract] Current year Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year Prior years Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years Reinsurance terminations Reinsurance terminations Decrease in losses paid resulting from cancellations of reinsurance agreements, with no future premium ceded and funds for any incurred but unpaid losses transferred to the entity. Total losses paid Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid Net reserve at end of period Plus reinsurance recoverables Reserve at end of period Other comprehensive income Comprehensive Income (Loss) [Table Text Block] Reclassification out of accumulated other comprehensive income Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Accumulated other comprehensive income (loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Share-based Payment Arrangement [Abstract] Share-Based Compensation Share-based Payment Arrangement [Text Block] Other Comprehensive Income Comprehensive Income (Loss) Note [Text Block] Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Table] Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Table] Non Catastrophic Event [Axis] Noncatastrophic Event [Axis] Non Catastrophic Event [Domain] Noncatastrophic Event [Domain] Decrease in estimated claim rate on primary defaults Increase Decrease in Expected Claim Rate [Member] The increase (decrease) in the expected claim rate on primary and/or pool defaults that occurred in prior periods. Increase in estimated severity on primary defaults Increase Decrease in Estimated Severity Primary Defaults [Member] The increase (decrease) in estimated severity on primary defaults that occurred in prior periods. Change in estimates related to pool reserves, LAE reserves, reinsurance, and other Increase Decrease Related To IBNR, Pool Reserves, LAE Reserves and Reinsurance [Member] The decrease in losses incurred related to prior years related to IBNR, pool reserves, LAE reserves, reinsurance and other. Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] Decrease in delinquency notices, percent Increase (Decrease) In Delinquency Notices, Percent Increase (Decrease) In Delinquency Notices, Percent Increase in IBNR reserves Increase (Decrease) In IBNR Reserves Increase (Decrease) In IBNR Reserves Premium refund liability, expected claim payments Premium refund liability, expected claim payments The carrying amount for the estimate of premiums to be refunded on expected claim payments. Primary Delinquent Inventory [Roll Forward] Primary Default Inventory [Roll Forward] A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. Delinquent inventory at the beginning of period (in loans) New notices (in loans) Primary Default Inventory, New Notices Additions to the primary default inventory resulting from new notices of defaulted loans. Cures (in loans) Primary Default Inventory, Cures Deductions from the primary default inventory resulting from loans in default being brought current. Paids (including those charged to a deductible or captive) (in loans) Primary Default Inventory, Paids Deductions from the primary default inventory resulting from claims being paid, including those charged to a deductible or captive. Rescissions and denials (in loans) Primary Default Inventory, Rescissions and Denials Deductions from the primary default inventory resulting from rescissions and denials. Delinquent inventory at end of period (in loans) Equity securities Equity Securities [Member] Quoted Prices in Active Markets for Identical Assets (Level 1) Fair Value, Inputs, Level 1 [Member] Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Other Other Assets, Fair Value Disclosure Real estate acquired Real Estate Assets Acquired, Fair Value Disclosure Real Estate Assets Acquired, Fair Value Disclosure Total assets Assets, Fair Value Disclosure Investments Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Pension and Supplemental Executive Retirement Plans Pension And Supplemental Plans [Member] Pension And Supplemental Plans [Member] Other Postretirement Benefit Plans Other Postretirement Benefits Plan [Member] Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items] Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] Components of Net Periodic Benefit Cost [Abstract] Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Amortization of net actuarial losses/(gains) Defined Benefit Plan, Amortization of Gain (Loss) Amortization of prior service cost/(credit) Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Net periodic benefit cost (benefit) Defined Benefit Plan, Net Periodic Benefit Cost Before Cost of Settlements and Curtailments The total amount of net periodic benefit cost for defined benefit plans for the period, before the effect of the cost of settlements and curtailments. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, and transition asset or obligation. Estimated employer contributions in current fiscal year Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year Statement of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Amortization and Accretion, Net Deferred tax expense Deferred Income Tax Expense (Benefit) Net realized investment (gains) losses Gain (Loss) on Investments Change in certain assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accrued investment income Increase (Decrease) in Accrued Investment Income Receivable Reinsurance recoverable on loss reserves Increase (Decrease) in Reinsurance Recoverable Reinsurance recoverable on paid losses Increase Decrease In Reinsurance Recoverable On Paid Losses The net change during the reporting period in the amount of receivables currently due from reinsurers for ceded claims paid. Premium receivable Increase (Decrease) in Premiums Receivable Deferred insurance policy acquisition costs Increase (Decrease) in Deferred Policy Acquisition Costs Profit commission receivable Increase Decrease in Profit Commission Receivable The net change during the reporting period in the amount of profit commission receivable. Loss reserves Increase (Decrease) in Liability for Claims and Claims Adjustment Expense Reserve Unearned premiums Increase (Decrease) in Unearned Premiums Return premium accrual Increase (Decrease) in Other Insurance Liabilities Current income taxes Increase (Decrease) in Income Taxes Payable, Net of Income Taxes Receivable Other, net Increase (Decrease) in Other Operating Assets and Liabilities, Net Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Purchases of investments Payments to Acquire Investments Proceeds from sales of investments Proceeds from Sale, Maturity and Collection of Investments Proceeds from maturity of fixed income securities Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-sale Additions to property and equipment Payments to Acquire Property, Plant, and Equipment Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Repurchase of common stock Payments for Repurchase of Common Stock Dividends paid Payments of Ordinary Dividends, Common Stock Payment of withholding taxes related to share-based compensation net share settlement Payment, Tax Withholding, Share-based Payment Arrangement Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Net increase in cash and cash equivalents and restricted cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Cash and cash equivalents and restricted cash and cash equivalents at beginning of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash and cash equivalents and restricted cash and cash equivalents at end of period Stockholders' Equity Note [Abstract] Shareholders' Equity Stockholders' Equity Note Disclosure [Text Block] Calculation of earnings (loss) per share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Amortized cost Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract] Due in one year or less Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost Due after one year through five years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost Due after five years through ten years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost Due after ten years Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost Total debt securities with single maturity date, amortized cost Available For Sale Securities, Debt Maturities, With Single Maturity Date, Amortized Cost This item represents the total debt securities, categorized neither as held-to-maturity nor trading securities, which have a single maturity date, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments, as defined), and fair value hedge accounting adjustments, if any. Total debt securities without single maturity date, amortized cost Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Amortized Cost Fair Value Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract] Due in one year or less Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Fair Value Due after one year through five years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value Due after five years through ten years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value Due after ten years Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value Total debt securities with single maturity date, fair value Available For Sale Securities, Debt Maturities, With Single Maturity Date, Fair Value This item represents the total fair value of debt securities, categorized neither as held-to-maturity nor trading securities, which have a single maturity date. Total debt securities without single maturity date, fair value Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value Total at end of period Reclassifications Reclassification, Policy [Policy Text Block] Investments Investment, Policy [Policy Text Block] Reinsurance Recoverables Reinsurance Accounting Policy [Policy Text Block] Premiums Receivable Premiums Receivable, Basis of Accounting, Policy [Policy Text Block] Prospective Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Fixed income Real Estate Acquired Real Estate Acquired [Member] This category includes information about real estate acquired by the entity through claim settlement. Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Balance at beginning of period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales Included in earnings and reported as losses incurred, net Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included In Earnings, Reported As Loss Incurred, Net Fair Value, Measurement With Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included In Earnings, Reported As Loss Incurred, Net Balance at end of period Significant Accounting Policies New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Long-term debt Schedule of Debt [Table Text Block] Litigation and Contingencies Legal Matters and Contingencies [Text Block] Statutory net income Statutory Accounting Practices, Statutory Net Income Amount Statutory policyholders' surplus Statutory Accounting Practices, Statutory Capital and Surplus, Balance Contingency reserve Contingency Reserve An amount of money established from retained earnings to allow for unforeseen losses in business. Amount of reserves for future policy claims payable and loss expenses to be incurred. Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Common stock Common Stock [Member] Paid-in capital Additional Paid-in Capital [Member] Treasury stock Treasury Stock [Member] Retained earnings Retained Earnings [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Reissuance of treasury stock, net under share-based compensation plans Stock Issued During Period, Value, Treasury Stock Reissued For Share Based Compensation Stock Issued During Period, Value, Treasury Stock Reissued For Share Based Compensation Equity compensation APIC, Share-based Payment Arrangement, Increase for Cost Recognition Repurchase of common stock Treasury Stock, Value, Acquired, Cost Method Other comprehensive (loss) income, net of tax Cash dividends Dividends, Cash Loss Reserves Liability for Future Policy Benefits and Unpaid Claims Disclosure [Text Block] Schedule of stock-based compensation, activity Share-based Payment Arrangement, Activity [Table Text Block] Schedule of Prospective Accounting Standards, Not Yet Effective Or Adopted Schedule of Prospective Accounting Standards, Not Yet Effective Or Adopted [Table Text Block] Schedule of Prospective Accounting Standards, Not Yet Effective Or Adopted [Table Text Block] Earnings per Share Earnings Per Share [Text Block] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Award Type [Axis] Award Type [Axis] Award Type [Domain] Award Type [Domain] RSUs subject to performance conditions Performance Shares [Member] RSUs subject only to service conditions Restricted Stock Units (RSUs) [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Award vesting period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Weighted Average Share Fair Value (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Class of Stock [Line Items] Class of Stock [Line Items] Shares repurchased in period (in shares) Treasury Stock, Shares, Acquired Shares repurchased, weighted average price per share Treasury Stock Acquired, Average Cost Per Share Remaining authorized repurchase amount Stock Repurchase Program, Remaining Authorized Repurchase Amount Quarterly cash dividend paid (per share) Common Stock, Dividends, Per Share, Cash Paid Total dividends paid Quarterly cash dividend declared (per share) Common Stock, Dividends, Per Share, Declared Debt Debt Disclosure [Text Block] Equity Securities, FV-NI, Gain (Loss) [Abstract] Equity Securities, FV-NI, Gain (Loss) [Abstract] Gross Gains Equity Securities, FV-NI, Unrealized Gain Gross Losses Equity Securities, FV-NI, Unrealized Loss Fair Value Unrealized Gain (Loss) on Equity Securities [Abstract] Debt Securities, Trading, Gain (Loss) [Abstract] Recognized net gains (losses) on equity securities still held Equity Securities, FV-NI, Unrealized Gain (Loss) Federal Home Loan Bank Advances (FHLB) Federal Home Loan Bank Advances [Member] Long-term debt, carrying value Long-term Debt Debt instrument, face amount Debt Instrument, Face Amount Income Statement [Abstract] Revenues: Revenues [Abstract] Premiums written: Premiums Written, Gross [Abstract] Direct Direct Premiums Written Assumed Assumed Premiums Written Ceded Ceded Premiums Written Net premiums written Premiums Written, Net Decrease in unearned premiums, net (Increase) Decrease in Unearned Premiums, Net Investment income, net of expenses Net Investment Income Net realized investment gains (losses) Other revenue Other Income Total revenues Revenues Losses and expenses: Benefits, Losses and Expenses [Abstract] Losses incurred, net Amortization of deferred policy acquisition costs Deferred Policy Acquisition Costs, Amortization Expense Other underwriting and operating expenses, net Other Underwriting Expense Interest expense Interest Expense, Debt Total losses and expenses Benefits, Losses and Expenses Income before tax Provision for income taxes Net income Earnings per share: Basic (in dollars per share) Diluted (in dollars per share) Weighted average common shares outstanding - basic (in shares) Weighted average common shares outstanding - diluted (in shares)