Amendment Flag Current Fiscal Year End Date Document Period End Date Entities [Table] Entity Information [Line Items] Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Filer Category Entity Public Float Entity Registrant Name Entity Central Index Key Entity Common Stock, Shares Outstanding Document Fiscal Year Focus Document Fiscal Period Focus Document Type Entity Shell Company Entity Emerging Growth Company Entity Ex Transition Period Entity Small Business AOCI Attributable to Parent, Net of Tax [Roll Forward] Award Date [Domain] Award Type [Axis] Award Date [Axis] Number of securities, total Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions Number of securities, Greater than 12 months Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year ASU 2016-18 [Member] Summary of Significant Accounting Policies [Abstract] ASU 2016-01 [Member] Accounts receivable Accounts payable and other liabilities Unrealized Holding Gains on Available-for-sale Securities [Member] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Line Items] Foreign Currency [Member] Foreign exchange adjustment Other Comprehensive Income (Loss) [Member] Additional paid-in capital Additional Paid-in Capital [Member] Adjustments to reconcile net income to net cash provided by operating activities Adjustments for New Accounting Pronouncements [Axis] Asset-backed Securities [Member] Assets Assets [Abstract] Total fair value Assets, Fair Value Disclosure Total Assets Assets Available-for-sale Securities Continuous Unrealized Loss Position [Abstract] Gross unrealized gains Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax Gross unrealized loss, 12 months or less Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Gross unrealized losses Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Net unrealized gains (losses) Available-for-sale Securities, Accumulated Gross Unrealized Gain (Loss), before Tax Fair value Available-for-sale Securities Number of securities, 12 months or less Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year Available-for-sale Securities Continuous Unrealized Loss Position, Aggregate Losses [Abstract] Cost or amortized cost Available-for-sale Equity Securities, Amortized Cost Basis Gross unrealized losses Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax Cost or amortized cost Available-for-sale Securities, Amortized Cost Basis Gross unrealized gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Gross unrealized loss, total Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss Gross unrealized loss, Greater than 12 months Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Available-for-sale Securities, Fair Value to Amortized Cost Basis [Abstract] Gross unrealized losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Total contractual maturities, Cost or Amortized Cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Amortized Cost Available-for-sale Debt Securities [Abstract] Debt Securities, Available-for-sale [Abstract] Gross unrealized gains Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Total contractual maturities, Fair Value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Fair Value Available-for-Sale Securities Available-for-sale Securities [Table Text Block] Cost or amortized cost Debt Securities, Available-for-sale, Amortized Cost Available-for-sale Securities Continuous Unrealized Loss Position, Fair Value [Abstract] Excess of five years to ten years, Cost or Amortized Cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Amortized Cost Fair value, 12 months or less Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value One year or less, Cost or Amortized Cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, within One Year, Amortized Cost Available-for-sale Securities Debt Maturities Amortized Cost Basis [Abstract] Available-for-sale Securities Debt Maturities Fair Value [Abstract] Fair value, Greater than 12 months Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Fair value, total Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Excess of ten years, Cost or Amortized Cost Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost Excess of ten years, Fair Value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value Excess of five years to ten years, Fair Value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after Five Through Ten Years, Fair Value Asset-backed securities, Fair Value Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value Excess of one year to five years, Fair Value Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Fair Value Fair value Total, Fair Value Excess of one year to five years, Cost or Amortized Cost Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after One Through Five Years, Amortized Cost Asset-backed securities, Cost or Amortized Cost Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Amortized Cost Fair value Available-for-sale Securities, Equity Securities One year or less, Fair Value Total losses Available-for-sale Securities, Gross Realized Losses Total gains Available-for-sale Securities, Gross Realized Gains Expenses Total expenses Benefits, Losses and Expenses Description of Business Net realized gains on investments, excluding impairment losses Cost-method Investments, Realized Gain (Loss), Excluding Other than Temporary Impairments Carrying Value [Member] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Cash, cash equivalents and restricted cash at beginning of period Cash, cash equivalents and restricted cash at end of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Increase in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash equivalents Cash Equivalents, at Carrying Value Premiums ceded to reinsurers Certificates of Deposit [Member] Class of Stock [Domain] Collateralized Mortgage Obligations [Member] Litigation, Commitments and Contingencies Litigation, Commitments and Contingencies [Abstract] Class A Voting [Member] Class A (voting) [Member] Class A [Member] Common Stock [Member] Common stock, shares authorized (in shares) Class B [Member] Class B Non-voting [Member] Class B (nonvoting) [Member] Common stock, par value (in dollars per share) Dividends paid to shareholders (in dollars per share) Common Stock, Dividends, Per Share, Cash Paid Balance, Beginning period Balance, Period end Common Stock, Value, Outstanding Common stock, shares outstanding (in shares) Balance, Beginning period (in shares) Balance, Period end (in shares) Common stock Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Basis of Presentation Consolidation, Policy [Policy Text Block] Corporate Securities [Member] Corporate Debt Securities [Member] Credit Facility [Axis] Credit Facility [Domain] Cumulative-effect adjustment to reclassify unrealized gains on equity securities after tax Cumulative effect of adoption Net unrealized gains (losses) Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax Debt [Abstract] Debt Debt Disclosure [Text Block] Fixed Maturities [Member] Debt Securities [Member] Deferred federal income taxes Director [Member] Stock Based Compensation [Abstract] Stock Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Dividend payable, date to be paid Dividend payable (in dollars per share) Dividend payable, date declared Dividend payable, date of record Subsequent Event [Abstract] Dividends, Common Stock [Abstract] Cash dividends paid to shareholders Dividends, Common Stock, Cash Basic and diluted earnings (loss) (in dollars per share) Per share data: Earnings Per Share [Abstract] Reconciliation of shares outstanding: Effect of foreign exchange rates on cash and cash equivalents Corporate income tax rate Effective federal tax rate on consolidated loss Effective Income Tax Rate Reconciliation, Percent Realized gains on equity securities Equity Securities, FV-NI, Realized Gain Realized gains on equity securities sold during the period Equity Securities, FV-NI, Realized Gain (Loss) Gains (losses) on equity securities [Abstract] Equity Securities, FV-NI, Gain (Loss), Alternative [Abstract] Unrealized gains (losses) on equity securities held at the end of the period Equity Securities, FV-NI, Unrealized Gain (Loss) Realized and unrealized losses on equity securities held at the end of the period Equity Securities, FV-NI, Gain (Loss) Equity Component [Domain] Equity securities Total equity securities Limited partnerships Limited partnerships Equity Securities [Member] Fair Value [Member] Estimate of Fair Value Measurement [Member] Total gains or losses (realized) included in income Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value [Abstract] Measurement Basis [Axis] Measurement Frequency [Axis] Fair Value Hierarchy and NAV [Axis] Recurring [Member] Fair Value, Measurements, Recurring [Member] Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Transfers into Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 Transfers out of Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 Fair Value, Measurement Frequency [Domain] Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Fair Value Hierarchy and NAV [Domain] Fair Value Fair Value Disclosures [Text Block] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Carrying Value and Fair Value by Level of Financial Instruments Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward] Fair Value, by Balance Sheet Grouping [Table] Fair Value Measurement [Domain] Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Beginning of period balance End of period balance Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Reconciliation of Beginning and Ending Balances of Assets Measured at Fair Value on Recurring Basis Using Level 3 Inputs Federal income taxes Financial Instrument [Axis] Liabilities [Abstract] Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Assets [Abstract] Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Total Fixed Maturities [Member] Fixed Maturities [Member] Non-U.S. Government Obligations [Member] Debt Security, Government, Non-US [Member] Net Realized and Unrealized Gains (Losses) on Investments Net realized and unrealized gains (losses) on investments Net realized and unrealized gains (losses) on investments Gain (Loss) on Investments Other-than-temporary impairment losses on investments Other than Temporary Impairment Losses, Investments Taxes [Abstract] Income (loss) before federal income tax expense (benefit) Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Unaudited Condensed Consolidated Statements of Operations [Abstract] Federal income tax expense (benefit) Income Tax Expense (Benefit) Taxes Income Tax Disclosure [Text Block] Current federal income taxes recoverable Income Taxes Receivable Taxes paid Increase (Decrease) in Stockholders' Equity [Roll Forward] Industrial [Member] Industrial, Miscellaneous, and All Others [Member] Loss and Loss Expense Reserves Insurance Disclosure [Text Block] Commissions from reinsurers Insurance Commissions and Fees Loss and Loss Expense Reserves [Abstract] Investments Investment, Policy [Policy Text Block] Fair Value and Cost or Amortized Cost of Fixed Maturity Investments by Contractual Maturity Investments [Abstract] Investments: Total Investments Investments Investments Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Liabilities and shareholders' equity Total Liabilities Liabilities Total liabilities and shareholders' equity Liabilities and Equity Total incurred Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims Reserves for losses and loss expenses Liability for Claims and Claims Adjustment Expense Claims occurring during prior periods Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years Claims occurring during the current period Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year Activity in the reserve for losses and loss expenses [Roll Forward] Provision for losses and loss expenses [Abstract] Reinsurance recoverable on unpaid losses at the end of the period Reinsurance recoverable on unpaid losses at the beginning of the year Liability for Unpaid Claims and Claims Adjustment Expense, Reported Claims, Amount Reserves at the beginning of the year Reserves at the end of the period Liability for Unpaid Claims and Claims Adjustment Expense, Net Loss and loss expense payments [Abstract] Line of Credit Facility [Table] Line of Credit Facility [Line Items] Outstanding drawings Long-term Line of Credit Expiration date Line of Credit Facility, Expiration Date Maximum credit limit Line of Credit Facility, Maximum Borrowing Capacity Amount remaining on credit facility Line of Credit Facility, Remaining Borrowing Capacity Effective interest rate Line of Credit Facility, Interest Rate at Period End Bank loans Loans Receivable, Fair Value Disclosure Agency Mortgage-backed Securities [Member] Mortgage-backed Securities [Member] Collateralized Mortgage Backed Securities [Member] Bank Loans [Member] Mortgage-backed Securities, Issued by Private Enterprises [Member] Mortgage-backed securities Mortgage-backed Securities Available-for-sale, Fair Value Disclosure Financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Net investment income Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities Investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Operating activities Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Net income (loss) Net income (loss) Recently Issued Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Adjustments for New Accounting Pronouncement [Member] New Accounting Pronouncements or Change in Accounting Principle [Table] Number of reportable segments Other comprehensive income (loss) before reclassifications OCI, before Reclassifications, Net of Tax, Attributable to Parent Summary of Significant Accounting Policies Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Less: reclassification adjustment for net gains included in net income (loss) Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax Other-than-temporary impairments Other than Temporary Impairment Losses, Investments, Available-for-sale Securities Other assets Unrealized net gains (losses) on fixed income securities: Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax [Abstract] Other comprehensive income (loss), net of tax: Other operating expenses Unrealized net gains (losses) arising during the period Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax Short-term and other Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax, Portion Attributable to Parent Change in unrealized gains (losses) on investments Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Other comprehensive income (loss) Other comprehensive income (loss) Repurchase of common shares Payments for Repurchase of Common Stock Net sales of short-term investments Payments for (Proceeds from) Short-term Investments Total paid Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid Purchase of insurance company-owned life insurance Payment to Acquire Life Insurance Policy, Investing Activities Dividends paid to shareholders Payments of Ordinary Dividends, Common Stock Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Purchases of fixed maturities and equity securities Payments to Acquire Marketable Securities Purchases of limited partnership interests Payments to Acquire Limited Partnership Interests Performance Based Equity Award [Member] Performance Shares [Member] Plan Name [Axis] Plan Name [Domain] Losses and loss expenses incurred Portion at Fair Value Measurement [Member] Net premiums earned Proceeds from maturities Proceeds from sales of equity securities Proceeds from Sale of Available-for-sale Securities, Equity Proceeds from disposals of property and equipment Proceeds from sales of fixed maturities Proceeds from Sale of Debt Securities, Available-for-sale Distributions from limited partnerships Property and Casualty Insurance [Member] Property, Liability and Casualty Insurance Product Line [Member] Net worth and maximum consolidated leverage ratio Ratio of Indebtedness to Net Capital Amounts reclassified from accumulated other comprehensive income (loss) Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent Segment Revenues Summary of Segment Revenue [Abstract] Segment Reconciliation [Abstract] Reconciliation of Revenue from Segments to Consolidated [Table] Reinsurance [Abstract] Reinsurance recoverable Reinsurance Reinsurance [Text Block] Related Parties [Abstract] Related Party Transaction [Line Items] Related Party Transaction [Domain] Estimated aggregate value of investment in limited partnerships Related Party Transaction, Amounts of Transaction Related Party [Domain] Related Party [Axis] Management fees and commissions Related Parties Related Party Transaction [Axis] Restricted [Member] Restricted Stock Units (RSUs) [Member] Restricted cash and cash equivalents Restricted cash Retained earnings Retained Earnings (Accumulated Deficit) Retained Earnings [Member] Revenue Recognition Revenues Revenues [Abstract] Total revenues Revenues Revolving Credit Facility [Member] Short-term borrowings Short-term Debt, Fair Value Changes in Common Stock Outstanding and Additional Paid-in-Capital Fixed Maturity and Equity Security Investments in Unrealized Loss Position Fair Value Measurements by Level for Assets Measured at Fair Value on Recurring Basis Debt Securities, Available-for-sale [Line Items] Changes in Accumulated Other Comprehensive Income (Loss) by Component Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Reinsurance Ceded Credit Risk [Table Text Block] Schedule of Available-for-Sale Securities [Table] Activity in Reserves for Losses and Loss Expenses Schedule of Related Party Transactions, by Related Party [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Segment Information Segment Reporting Disclosure [Text Block] Segment Information [Abstract] Segment [Domain] Segment Reporting, Revenue Reconciling Item [Line Items] Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Stock Based Compensation [Abstract] Share-based Arrangements with Employees and Nonemployees [Abstract] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Stock based compensation expense Number of shares issued (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Grant date fair value per share (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 Equity Award [Domain] Short-term borrowings Short-term Short-term Investments Unaudited Condensed Consolidated Balance Sheets [Abstract] Unaudited Condensed Consolidated Statements of Comprehensive Income (Loss) [Abstract] Class of Stock [Axis] Segments [Axis] Segments [Axis] Statement [Line Items] Statement [Table] Unaudited Condensed Consolidated Statements of Cash Flows [Abstract] Equity Components [Axis] Restricted stock grants (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Gross Repurchase of common shares Stock Repurchased During Period, Value Repurchase of common shares (in shares) Stock Repurchased During Period, Shares Restricted stock grants Restricted stock grants Shareholders' Equity Shareholders' equity Beginning balance Ending balance Stockholders' Equity Attributable to Parent Adjusted beginning balance Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest, Adjusted Balance Shareholders' equity: Shareholders' Equity [Abstract] Subsequent Event [Table] Subsequent Event Type [Domain] Subsequent Event [Line Items] Subsequent Events [Abstract] Subsequent Event Type [Axis] Subsequent Events Subsequent Events [Text Block] Subsequent Event [Member] Claims occurring during the current period Claims occurring during prior periods Market value of equity and fixed maturity securities portfolio Debt Securities, Trading, and Equity Securities, FV-NI Fixed maturities Total fixed maturities Financial Instruments [Domain] Type of Adoption [Domain] Reserves for unearned premiums Net unrealized gains (losses) on equity securities and limited partnership investments Agency Collateralized Mortgage Obligations [Member] US Government Agencies Debt Securities [Member] Municipal Obligations [Member] U.S. Government Obligations [Member] US Treasury and Government [Member] Average shares outstanding - basic (in shares) Dilutive effect of share equivalents (in shares) Average shares outstanding - diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Ownership [Domain] Ownership [Axis] Summary of stock Issuances [Abstract] Period which an executive's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition. Share Based Compensation Arrangement by Share Based Payment, Share vesting period Service period Period for distributing shares following the grant date of the shares. Shares distribution period from grant date Shares distribution period from grant date Date the equity-based award vests, in CCYY-MM-DD format. Share Based Compensation Arrangement By Share Based Payment Award Vesting Date Vesting date Date or year of grant of shares. Award Date 2018-02-09 [Member] 2/9/2018 [Member] Date or year of grant of shares. Award Date 2017-08-31 [Member] 8/31/2017 [Member] Date or year of grant of shares. Award Date 2017-05-09 [Member] 5/9/2017 [Member] Information about 2017 Long-Term Incentive Plan pertaining to equity-based compensation arrangements. Long-Term Incentive Plan 2017 [Member] 2017 LTIP Awards [Member] Information about 2017 Value Creation Incentive Plan pertaining to equity-based compensation arrangements. Value Creation Incentive Plan 2017 [Member] 2017 VCIP Awards [Member] Information about 2018 Long-Term Incentive Plan pertaining to equity-based compensation arrangements. Long-Term Incentive Plan 2018 [Member] 2018 LTIP Awards [Member] Information about 2018 Value Creation Incentive Plan pertaining to equity-based compensation arrangements. Value Creation Incentive Plan 2018 [Member] 2018 VCIP Awards [Member] Period over which certain results must be met in accordance with a established performance matrix for employee to earn the right to receive performance-based equity awards. Share-based Compensation Arrangement by Share-based Payment Award, Performance Period Performance period Date or year of grant of shares. Award Date 2018-05-08 [Member] 5/8/2018 [Member] Tabular disclosure of the summary of stock issuances during the period. Summary of Stock Issuances [Table Text Block] Detail of Restricted Stock Issuances Amount of fees and commissions from financial services and banking activities and correspondent clearing. Includes fees from depositor accounts, credit cards, merchant discounts, and fiduciary and trust activities, guarantee fees, investment advisory, management, and administrative fees, transfer agent fees, insurance commissions, and income classified as other. Commissions and Other Income Commissions and other income Commissions and other income The net change in the difference between the fair value and the carrying value, or in the comparative fair values on investments included in stockholders' equity as of the balance sheet date. Unrealized net gains on investments Unrealized net gains (losses) on investments Components of net realized and unrealized gains (losses) on investments [Abstract] Components of net realized and unrealized gains (losses) on investments [Abstract] Gross gains on available-for-sale investments sold during the period [Abstract] Gross gains on available-for-sale investments sold during the period [Abstract] Gross losses on available-for-sale investments sold during the period [Abstract] Gross losses on available-for-sale investments sold during the period [Abstract] Amount of realized gain (loss) from a change in the value of investments in limited partnerships. Investments in Limited Partnership, Realized Gain Loss Change in value of limited partnership investments Represents investments in equity securities of companies categorized as financial institutions. Financial Institution [Member] Financial [Member] This item represents investments by the reporting entity in equity securities issued by consumer. Consumer [Member] Consumer [Member] Ownership interest or right to acquire or dispose of ownership interest in corporations and other legal entities for which ownership interest is represented by shares of common or preferred stock, convertible securities, stock rights, or stock warrants. Equity Securities, Consumer, Corporate, and Other [Member] Total Equity Securities [Member] This item represents investments by the reporting entity in equity securities issued by energy. Energy [Member] Energy [Member] Fund that invests in mutual funds, closed end funds, ETFs. Funds [Member] Funds (e.g. mutual funds, closed end funds, ETFs) [Member] This item represents investments by the reporting entity in equity securities issued by technology. Technology [Member] Technology [Member] This item represents investments by the reporting entity in equity securities issued by other. Other [Member] Other [Member] Available-for-sale Equity Securities [Abstract] Amount before tax of unrealized gain (loss) in accumulated other comprehensive income (AOCI) on investments in equity securities classified as available-for-sale. Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain (Loss), before Tax Net unrealized gains (losses) Equity Securities [Abstract] Equity securities [Abstract] This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents consumer. Consumer Fair Value Disclosure Consumer This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents technology. Technology Fair Value Disclosure Technology This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents energy. Energy Fair Value Disclosure Energy This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents mutual fund. Mutual fund Fair Value Disclosure Funds (e.g. mutual funds, closed end funds, ETFs) This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents financial. Financial Fair Value Disclosure Financial This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents other. Other Fair Value Disclosure Other Fixed Maturities [Abstract] Fixed maturities [Abstract] This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents asset-backed securities. Asset Backed Securities Fair Value Disclosure Asset-backed securities This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents US government obligations. US Government Obligations Fair Value Disclosure U.S. government obligations This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents certificates of deposit. Certificates of deposit fair value disclosure Certificates of deposit This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents states and political subdivision obligations. States And Municipal Obligations Fair Value Disclosure Municipal obligations This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents agency mortgage-backed securities. Agency mortgage-backed securities fair value disclosure Agency mortgage-backed securities This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents agency collateralized mortgage obligations. Agency collateralized mortgage obligations fair value disclosure Agency collateralized mortgage obligations This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents non-u.s. government obligations. Non-U.S. government obligations fair value disclosure Non-U.S. government obligations This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents options embedded in convertible securities. Options Embedded In Convertible Securities Fair Value Disclosure Options embedded in convertible securities This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents corporate securities. Corporate Securities Fair Value Disclosure Corporate securities This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents collateralized mortgage obligations. Collateralized mortgage obligations fair value disclosure Collateralized mortgage obligations This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents industrial. Industrial Fair Value Disclosure Industrial Amounts for the processing of insurance claims, such as legal fees and estimator fees that have been assumed by and are receivable from the identified reinsurer with respect to disclosure of a concentration of credit risk. Ceded Credit Risk Claims Loss And Expense Incurred Losses and loss expenses ceded to reinsurers Accounting Standards Update 2018-02 Income Statement - Reporting Comprehensive Income (Topic 220). Accounting Standards Update 2018-02 [Member] ASU 2018-02 [Member] Recently Adopted Accounting Pronouncements [Abstract] Amount before tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption. Cumulative Effect of New Accounting Principle in Period of Adoption Before Tax Cumulative-effect adjustment to reclassify unrealized gains on equity securities before tax Description of Business [Abstract] Description of Business [Abstract] Gross liability as of the balance sheet date for amounts representing estimated cost of settling unpaid claims under the terms of the underlying insurance policies, less estimated reinsurance recoveries on such claims. This includes an estimate for claims which have been incurred but not reported. Claim adjustment expenses represent the costs estimated to be incurred in the settlement of unpaid claims. Liability for Unpaid Claims and Claims Adjustment Expense Reserves, gross of reinsurance recoverable, at the beginning of the year Reserves, gross of reinsurance recoverable, at the end of the period Disclosure of accounting policy pertaining to new accounting pronouncements adopted that impact the entity's financial reporting. New Accounting Pronouncements Adopted [Policy Text Block] Recently Adopted Accounting Pronouncements Credit Agreement [Abstract] Additional maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed at the discretion of the lender. Line of Credit Facility, Additional Maximum Borrowing Capacity Additional incremental loans limit Number of financial debt covenants. Number of Financial Covenants Number of financial covenants This element represents the period of fixed interest on line of credit referenced to LIBOR. Period of fixed interest on line of credit at Entity options Optional period of fixed interest Document and Entity Information [Abstract] Tabular disclosure of changes in the separate accounts comprising stockholders' equity and of the changes in the number of shares of equity securities during at least the most recent annual fiscal period and any subsequent interim period presented is required to make the financial statements sufficiently informative if both financial position and results of operations are presented. Components Of Equity [Table Text Block] Change in Equity Schedule detailing information related to changes in common stock outstanding and additional paid-in capital. Schedule of Changes in Common Stock and Additional Paid In Capital [Table] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Changes in common stock outstanding and additional paid in capital [Line Items] Changes in common stock outstanding and additional paid-in-capital [Line Items] A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. Increase (Decrease) in Common Stock Outstanding and Additional Paid In Capital [Roll Forward] Increase (Decrease) in Common Stock Outstanding and Additional Paid-In Capital [Roll Forward] Common Shares Outstanding [Abstract] Shares [Abstract] Common Stock Outstanding, Amount [Abstract] Amount [Abstract] The services of investment firms of which two directors of the Company are employees or partial owners. Related Party Transactions, Investment Firm Services [Member] Investment Firm Services [Member] This element represent the number of related party investments. Related Party, Number of Investments Number of investments The equity interest of partners or other equity holders in a limited partnership. Ownership Interest in Limited Partnership Ownership interest in limited partnership Refers to a limited partnership business who has limited liability. New Vernon Global Opportunity Fund II [Member] New Vernon Global Opportunity Fund II [Member] Refers to a limited partnership business who has limited liability. New Vernon India Fund [Member] New Vernon India Fund [Member] Refers to a limited partnership business who has limited liability. New Vernon Global Opportunity Fund [Member] New Vernon Global Opportunity Fund [Member] The investment into limited partnerships. Related Party Transactions, Limited Partnerships [Member] Limited Partnerships [Member] Number of the Company's directors that are executive officers, directors, and owners of organizations outside of the Company. Number of Related Parties that are Managers of Outside Entity Number of related parties Related Party [Abstract] Related Party [Abstract]