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Ceded Credit Risk, Commission Earned, Percentage Purchase of fixed-maturity investments, available-for-sale Payments to Acquire Debt Securities, Available-for-Sale Net premiums earned Net premiums earned Premiums Earned, Net Asset-backed securities Debt Securities, Available-for-Sale, Maturity, without Single Maturity Date, Amortized Cost Title of 12(b) Security Title of 12(b) Security Statutory Accounting Practices [Table] Statutory Accounting Practices [Table] Ceded Credit Risk, Reinsurer [Axis] Reinsurer, Name [Axis] Total bonds Bonds [Member] Total expenses Costs and Expenses Threshold for loss ratio on loans to qualify for profit commission Ceded Credit Risk, Profit Commission, Loss Ratio On Loans Threshold Ceded Credit Risk, Profit Commission, Loss Ratio On Loans Threshold Previously ceded primary RIF recaptured Previously Ceded Primary Risk-In-Force Recaptured Previously Ceded Primary Risk-In-Force Recaptured Subsequent Event [Line Items] Subsequent Event [Line Items] Ceded Credit Risk [Table] Ceded Credit Risk [Table] Debt Instrument [Line Items] Debt Instrument [Line Items] Interest payable Interest Payable Unrealized losses, less than 12 months Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Key Inputs and Assumptions, Valuation Techniques Fair Value Measurement Inputs and Valuation Techniques [Line Items] Lease liabilities Present value of lease payments Operating Lease, Liability Reinsurance recoverable on unpaid claims Less reinsurance recoverables Add reinsurance recoverables Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments Net amortization of premium on investment securities Accretion (Amortization) of Discounts and Premiums, Investments Investments, Debt and Equity Securities [Abstract] Investments, Debt and Equity Securities [Abstract] Unrealized loss position, 12 months or greater Unrealized losses, 12 months or greater Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Debt securities, amortized cost Amortized Cost Debt Securities, Available-for-Sale, Amortized Cost Earnings per Share, Basic [Abstract] Net Income (Loss) Available to Common Stockholders, Basic, Operations [Abstract] Aggregate dividend capacity Statutory Accounting Practices, Statutory Amount Available for Dividend Payments Current year Current Year Claims and Claims Adjustment Expense Re One Re One [Member] Re One Ceded risk-in-force Risk In Force, Ceded Risk In Force, Ceded Comprehensive income: Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Schedule of investments by maturity Investments Classified by Contractual Maturity Date [Table Text Block] Warrant liability Warrant [Member] Entity Filer Category Entity Filer Category Basic (in shares) Basic weighted average shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Percentage of population with production prior to period start date Reinsurance Coverage, Percentage Of Population With Production Prior to Period Start Date Reinsurance Coverage, Percentage Of Population With Production Prior to Period Start Date Prior years Prior Year Claims and Claims Adjustment Expense Corporate Headquarters Corporate Headquarters [Member] Corporate Headquarters [Member] Common stock: class A shares issued under stock plans, net of shares withheld for employee taxes (in shares) Stock Issued During Period, Shares, Employee Stock Purchase Plans, Net of Shares For Tax Withholdings Stock Issued During Period, Shares, Employee Stock Purchase Plans, Net of Shares For Tax Withholdings Commitments and contingencies Commitments and Contingencies Security Exchange Name Security Exchange Name Number of operating leases related to corporate headquarters and data center facility Number Of Operating Leases, Corporate Office And Data Center Facility Number Of Operating Leases, Corporate Office And Data Center Facility Schedule of investments by industry group Investments Classified By Issuer Industry Group [Table Text Block] Investments Classified By Issuer Industry Group [Table Text Block] Common stock: class A shares issued related to warrant exercises (in shares) Stock issued upon exercise of warrants (in shares) Stock Issued During Period, Shares, Conversion of Convertible Securities Accrued investment income Increase (Decrease) in Accrued Investment Income Receivable Roll-forward of level 3 liabilities measured at fair value Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Cover page. Cover [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Default percent (in percent) Liability For Unpaid Claims And Claims Adjustment Expense, Incurred But Not Reported (IBNR) Claims, Number Of Primary Loans In Default, Percent Of Total Policies In-Force Liability For Unpaid Claims And Claims Adjustment Expense, Incurred But Not Reported (IBNR) Claims, Number Of Primary Loans In Default, Percent Of Total Policies In-Force Other assets Other Assets Profit Commission Reinsurance Retention Policy, Profit Commission Reinsurance Retention Policy, Profit Commission Number of claims paid Liability for Paid Claims and Claims Adjustment Expense, Number of Paid Claims Liability for Paid Claims and Claims Adjustment Expense, Number of Paid Claims Claims and claim (benefits) expenses incurred: Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract] Net premiums written Premiums Written, Net Forecast Forecast [Member] Due after five through ten years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Amortized Cost Taxes paid related to net share settlement of equity awards Payment, Tax Withholding, Share-Based Payment Arrangement Total liabilities and shareholders' equity Liabilities and Equity Current year Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Remaining authorized repurchase amount Stock Repurchase Program, Remaining Authorized Repurchase Amount Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Current Fiscal Year End Date Current Fiscal Year End Date Gross realized investment gains Debt Securities, Available-for-Sale, Realized Gain Less effects of discounting Lessee, Operating Lease, Liability, Undiscounted Excess Amount Fair value of warrant liability reclassified to additional paid in capital upon exercise Class Of Warrant Or Right, Fair Value Of Warrant Liability Reclassified To Additional Paid In Capital Upon Exercise Class Of Warrant Or Right, Fair Value Of Warrant Liability Reclassified To Additional Paid In Capital Upon Exercise Diluted (in dollars per share) Diluted earnings per share (in dollars per share) Earnings Per Share, Diluted Communications Communications, Industry Group [Member] Communications, Industry Group [Member] Share-based compensation expense APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Gain from change in fair value of warrant liability Fair Value Adjustment of Warrants 2024 Lessee, Operating Lease, Liability, to be Paid, Year Two Applicable premium Debt Instrument, Covenant Terms, Applicable Premium Debt Instrument, Covenant Terms, Applicable Premium Schedule of Available-for-sale Securities [Table] Schedule of Available-for-Sale Securities [Table] Beginning balance, net of reinsurance recoverables Reserve at end of period, net of reinsurance recoverables Liability for Unpaid Claims and Claims Adjustment Expense, Net Corporate debt securities Corporate debt securities Corporate Debt Securities [Member] Investment expenses Investment Income, Investment Expense Schedule of future payments due under operating leases Lessee, Operating Lease, Liability, Maturity [Table Text Block] Entity Address, Address Line One Entity Address, Address Line One Reinsurance Reinsurance [Text Block] Amount retained Reinsurance, Amount Retained, Per Policy Fannie Mae Fannie Mae [Member] Fannie Mae [Member] Ceded Ceded Premiums Written Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Total claims and claim (benefits) expenses incurred Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims Interest expense Interest Expense Credit Facility [Axis] Credit Facility [Axis] Unrealized (losses) gains in accumulated other comprehensive income (loss), net of tax (benefit) expense of $(17,004) and $4,995 for the three months ended June 30, 2022 and 2021, and $(43,180) and $(7,003) for the six month ended June 30, 2022 and 2021, respectively OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, after Tax Proceeds from redemptions, maturities and sale of fixed-maturity investments, available-for-sale Proceeds from Sale and Maturity of Debt Securities, Available-for-Sale Equity [Abstract] Subsequent Event [Table] Subsequent Event [Table] Entity Tax Identification Number Entity Tax Identification Number Reserves for Insurance Claims and Claim Expenses Liability for Future Policy Benefits and Unpaid Claims Disclosure [Text Block] Reserve for prior year insurance claims and claim expenses Liability for Prior Year Claims and Claims Adjustment Expense Liability for Prior Year Claims and Claims Adjustment Expense Debt Securities By Industry [Domain] Debt Securities By Industry [Domain] [Domain] for Debt Securities By Industry [Axis] Premiums receivable Increase (Decrease) in Premiums Receivable Reinsurance Disclosures [Abstract] Reinsurance Disclosures [Abstract] Current Reinsurance Coverage Current Reinsurance Coverage Current Reinsurance Coverage Reinsurance Policy, Type [Axis] Reinsurance Contract [Axis] Roll-forward of Level 3 liabilities: Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Net decrease in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Commitment fees in interest expense Line of Credit Facility, Commitment Fee Amount Accrued investment income Accrued Investment Income Receivable Dilutive effect of issuable shares (in shares) Weighted Average Number of Shares Outstanding, Diluted, Adjustment Entity Central Index Key Entity Central Index Key Measurement Frequency [Axis] Measurement Frequency [Axis] Number of days to be written off Premium Receivable, Number of Days to be Written Off Premium Receivable, Number of Days to be Written Off Name of Property [Axis] Name of Property [Axis] Reinsurance balances, net Increase (Decrease) in Reinsurance Assets and Liabilities Increase (Decrease) in Reinsurance Assets and Liabilities Measurement Input Type [Axis] Measurement Input Type [Axis] Entity [Domain] Entity [Domain] City Area Code City Area Code Assets Assets [Abstract] Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Direct Direct Premiums Written Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Axis] Fair Value Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Fair Value [Abstract] Initial Reinsurance Coverage Initial Reinsurance Coverage Initial Reinsurance Coverage Financial Financial, Industry Group [Member] Financial, Industry Group [Member] Cash flows from financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Earnings Per Share Earnings Per Share, Policy [Policy Text Block] Profit commission Reinsurance Profit Commission Reinsurance Profit Commission Share-based compensation expense Share-Based Payment Arrangement, Noncash Expense Variable Rate [Axis] Variable Rate [Axis] Warrant liability Class of Warrant or Right, Outstanding Schedule of aging unrealized losses Debt Securities, Available-for-sale, In Continuous Unrealized Loss Position [Table Text Block] Debt Securities, Available-for-sale, In Continuous Unrealized Loss Position Software and equipment Payments to Acquire Property, Plant, and Equipment Schedule of earnings per share, basic and diluted Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Right-of-use assets obtained in exchange for new operating lease liabilities Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Gross realized investment losses Debt Securities, Available-for-Sale, Realized Loss Unearned premiums Unearned Premiums Organization, Basis of Presentation and Summary of Accounting Principles Business Description and Basis of Presentation [Text Block]