Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Summary of nonvested Common Share and nonvested Common Share unit activity Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block] Schedule of portion of nonvested Common Shares earned based upon achievement of compounded annual book value per share growth Schedule of Shares Earned Unvested Performance Shares [Table Text Block] Tabular disclosure of shares earned for unvested performance shares. Schedule of compensation expense, net of forfeitures, and related tax effects recognized in connection with nonvested shares Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Fair Value Disclosures [Abstract] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Recurring basis Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Quoted Prices in Active Markets for Identical Instruments (Level 1) Fair Value, Inputs, Level 1 [Member] Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Investment Issuer [Axis] Investment Issuer [Axis] Investment Issuer [Domain] Investment Issuer [Domain] U.S. Agency US Government Corporations and Agencies Securities [Member] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] U.S. Treasury securities US Treasury Securities [Member] U.S. agency securities US Government Agencies Debt Securities [Member] Mortgage backed securities Collateralized Mortgage Backed Securities [Member] Municipal debt securities Municipal Bonds [Member] Corporate debt securities Corporate Debt Securities [Member] Mortgage-backed securities Mortgage-backed Securities, Issued by Private Enterprises [Member] Asset-backed securities Asset-backed Securities [Member] Money market funds Money Market Funds [Member] Fair value of financial instruments Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Total investments Available-for-sale Securities Total assets at fair value Assets, Fair Value Disclosure Derivative liabilities Derivative Liability Total liabilities at fair value Financial Liabilities Fair Value Disclosure Investments, Debt and Equity Securities [Abstract] Realized gross gains and losses on the sale of investments available for sale Available-for-sale Securities, Gross Realized Gain (Loss), Disclosures [Abstract] Realized gross gains Available-for-sale Securities, Gross Realized Gains Realized gross losses Available-for-sale Securities, Gross Realized Losses Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Essent Re Essent Reinsurance Ltd [Member] Represents information pertaining to Essent Reinsurance Ltd. (Essent Re), a wholly-owned Bermuda-domiciled Class 3A Insurer licensed pursuant to Section 4 of the Bermuda Insurance Act 1978, which offers mortgage-related insurance and reinsurance. Investments available for sale Schedule of Available-for-sale Securities [Line Items] Fair Value Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] Less than 12 months Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value 12 months or more Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value Total Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value Gross Unrealized Losses Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss [Abstract] Less than 12 months Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 12 months or more Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Total Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss Other information Available-for-sale Securities, Other Disclosure Items [Abstract] Other-than-temporary impairments Other than Temporary Impairment Losses, Investments, Available-for-sale Securities Fair value of investments deposited with insurance regulatory authorities Available-for-sale Securities, Restricted Fair value of the required investments on deposit in trusts Assets Held-in-trust Insurance [Abstract] Statutory Accounting Statutory Accounting Disclosure [Text Block] Represents the entire disclosure pertaining to the statutory accounting. Statement of Comprehensive Income [Abstract] Revenues: Revenues [Abstract] Net premiums written Premiums Written, Net Increase in unearned premiums (Increase) Decrease in Unearned Premiums, Net Net premiums earned Premiums Earned, Net Net investment income Net Investment Income Realized investment gains, net Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments Other income Other Income Total revenues Revenues Losses and expenses: Benefits, Losses and Expenses [Abstract] Provision for losses and LAE Policyholder Benefits and Claims Incurred, Net Other underwriting and operating expenses Other Underwriting and Operating Expenses Represents the aggregate amount of costs incurred during the period, such as those relating to general administration and policy maintenance that do not vary with, and are not primarily related to the acquisition or renewal of insurance contracts and other operating costs, that are associated with the entity's normal revenue producing operation. Total losses and expenses Benefits, Losses and Expenses Income before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest Income tax expense Income Tax Expense (Benefit) Net income Net Income (Loss) Attributable to Parent Earnings per share: Earnings Per Share, Basic and Diluted [Abstract] Basic (in dollars per share) Earnings Per Share, Basic Diluted (in dollars per share) Earnings Per Share, Diluted Weighted average shares outstanding: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Basic (in shares) Weighted Average Number of Shares Outstanding, Basic Diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Other comprehensive income (loss): Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Net income Net Income (Loss) Available to Common Stockholders, Basic Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Change in unrealized appreciation (depreciation) of investments, net of tax expense (benefit) of $2,013 and ($494) in the three months ended September 30, 2015 and 2014 and $121 and $1,971 in the nine months ended September 30, 2015 and 2014 Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Total other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Earnings Per Share [Abstract] Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Table] Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Performance-based share awards Performance Shares [Member] EPS calculation Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items] Contingently issuable awards Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Antidilutive nonvested shares Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Percentage of award issuable if current period end were end of contingency period Share-based Compensation Arrangement by Share-based Payment Award, Award Period to Date Vesting Rights, Percentage Percentage of vesting of share-based compensation awards if the end of the current reporting period were the end of the vesting period. Schedule of investments available for sale Schedule of Available-for-sale Securities Reconciliation [Table Text Block] Schedule of available-for-sale securities reconciliation percentages Schedule of Available-for-sale Securities Reconciliation Percentages [Table Text Block] Schedule of Available-for-sale Securities Reconciliation Percentages [Table Text Block] Schedule of amortized cost and fair value of investments available for sale by contractual maturity Investments Classified by Contractual Maturity Date [Table Text Block] Schedule of realized gross gains and losses on sale of investments available for sale Schedule of Realized Gain (Loss) [Table Text Block] Schedule of fair value of investments in an unrealized loss position and related unrealized losses Schedule of Unrealized Loss on Investments [Table Text Block] Schedule of net investment income Investment Income [Table Text Block] Receivables [Abstract] Accounts Receivable Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Schedule of statutory net income, statutory surplus and contingency reserve liability Statutory Accounting Practices Disclosure [Table Text Block] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Receivable Type [Axis] Receivable Type [Axis] Receivable [Domain] Receivable [Domain] Premiums receivable Premiums Receivable [Member] Accounts receivable Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts Receivable Accounts Receivable, Net [Abstract] Premiums receivable Premiums Receivable, Gross Other receivables Other Receivables Total accounts receivable Accounts Receivable, Gross Accounts receivable, net Accounts Receivable, Net Threshold period unpaid for write-off of mortgage insurance premiums Threshold Period Past Due for Write-off of Trade Accounts Receivable Provision for doubtful accounts Provision for Doubtful Accounts Schedule of accounts receivable Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Fair Value of Financial Instruments Fair Value Disclosures [Text Block] Change in unrealized appreciation (depreciation) of investments, tax expense (benefit) Other Comprehensive Income (Loss), Available-for-sale Securities, Tax, Portion Attributable to Parent Fair Value Inputs, Liabilities, Quantitative Information [Table] Fair Value Inputs, Liabilities, Quantitative Information [Table] Liability Class [Axis] Liability Class [Axis] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Derivative Liabilities Derivative Financial Instruments, Liabilities [Member] Valuation Technique [Axis] Valuation Technique [Axis] Valuation Technique [Domain] Valuation Technique [Domain] Discounted cash flows Discounted Cash Flows Approach Valuation Technique [Member] Discounted cash flows approach valuation technique used to measure fair value. Range [Axis] Range [Axis] Range [Domain] Range [Domain] Weighted average Weighted Average [Member] Significant unobservable inputs used in our recurring Level 3 fair value measurements Fair Value Inputs, Liabilities, Quantitative Information [Line Items] Constant prepayment rate Fair Value Inputs, Prepayment Rate Default rate Fair Value Inputs, Probability of Default Reference STACR credit spread Fair Value Inputs, Structured Agency Credit Risk Debt Notes, Credit Spread Credit spread on related Federal Home Loan Mortgage Corporation (Freddie Mac) Structured Agency Credit Risk (STACR) debt notes, used as an input to measure fair value. Schedule of reconciliation of net income and weighted average common shares outstanding used in computations of basic and diluted earnings per common share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Net income Net income available to common shareholders Basic earnings per share (in dollars per share) Diluted earnings per share (in dollars per share) Basic weighted average shares outstanding (in shares) Dilutive effect of nonvested shares (in shares) Incremental Common Shares Attributable to Dilutive Effect of Nonvested Shares with Forfeitable Dividends Diluted weighted average shares outstanding (in shares) Investment Secondary Categorization [Axis] Investment Secondary Categorization [Axis] Investments by Secondary Categorization [Domain] Investments by Secondary Categorization [Domain] Special revenue bonds Special Revenue Municipal Bonds [Member] A municipal bond whose debt service is payable solely from the revenues derived from operating the facilities acquired or constructed with the proceeds of the bonds. General obligation bonds General Obligation Municipal Bonds [Member] A bond secured by a pledge of the issuer's taxing powers (limited or unlimited). More commonly the general obligation bonds of local governments are paid from ad valorem property taxes and other general revenues. Considered the most secure of all municipal debt. Certificate of participation bonds Certification Of Participation Bonds [Member] Represents a type of financing where an investor purchases a share of the lease revenues of a program rather than the bond being secured by those revenues. Tax allocation bonds Tax Allocation Municipal Bonds [Member] Bonds issued in conjunction with a redevelopment project. The taxes pledged to their repayment come from the increase of assessed value over and above a pre-established base. The redevelopment creates this added value, known as the tax increment. Special assessment bonds Special Assessment Bond [Member] A special type of municipal bond used to fund a development project. Interest owed to lenders is paid by taxes levied on the community benefiting from the particular bond-funded project. Percentage of debt securities Investment Owned, Percent of Net Assets Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Changes in Level 3 Recurring Fair Value Measurements Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value Beginning of Period Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value Net Realized and Unrealized Gains (Losses) Included in Income Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Purchases, Sales, Issues and Settlements, Net Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases, (Sales), Issuances, (Settlements) Fair Value End of Period Changes in Unrealized Gains (Losses) Included in Income on Instruments Held at End of Period Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss) Liability for Future Policy Benefits and Unpaid Claims and Claims Adjustment Expense [Abstract] Reserve for Losses and Loss Adjustment Expenses Liability for Future Policy Benefits and Unpaid Claims Disclosure [Text Block] Schedule of estimated fair values and related carrying amounts of financial instruments Fair Value, by Balance Sheet Grouping [Table Text Block] Schedule of assets and liabilities measured at fair vale on a recurring basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Schedule of changes during period in Level 3 liabilities measured at fair value on a recurring basis, and realized and unrealized gains (losses) related to Level 3 liabilities Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Summary of significant unobservable inputs used in recurring Level 3 fair value measurements Fair Value Inputs, Assets, Quantitative Information [Table 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] Nonvested shares Restricted Stock [Member] Stock-based compensation Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Total fair value of shares vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Total unrecognized compensation expense Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options Expected weighted average period for recognition of expense Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Shares tendered by employees to pay employee withholding taxes Shares Paid for Tax Withholding for Share Based Compensation Compensation expense, net of forfeitures, and related tax effects recognized in connection with nonvested shares Share-based Compensation, Allocation and Classification in Financial Statements [Abstract] Compensation expense Allocated Share-based Compensation Expense Income tax benefit Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Document and Entity Information Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Document Type Document Type Document Period End Date Document Period End Date Amendment Flag Amendment Flag Current Fiscal Year End Date Current Fiscal Year End Date Entity Current Reporting Status Entity Current Reporting Status Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Schedule of reconciliation of beginning and ending reserve balances for losses and loss adjustment expenses (LAE) Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Nature of Operations and Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Rollforward of accumulated other comprehensive income (loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Schedule of Nature of Operations and Basis of Presentation [Table] Schedule of Nature of Operations and Basis of Presentation [Table] Schedule of nature of operations and basis of presentation. Maximum Maximum [Member] Nature of operations and basis of presentation Schedule of Nature of Operations and Basis of Presentation [Line Items] Residential mortgage down payment percentage for which mortgage insurance is generally required Loans and Leases Receivable Consumer Mortgage Insured Down Payment Percentage Represents the percentage of the total sale price that a home buyer contributes in cash towards the purchase of a home for which mortgage insurance is generally required. Vesting Criteria [Axis] Vesting Criteria [Axis] Information about the type of vesting for share-based compensation awards. Vesting Criteria [Domain] Vesting Criteria [Domain] The types of vesting specified for share-based compensation awards. Compounded Annual Book Value Per Share Growth 11% Compounded Annual Book Value Per Share Growth Achieved11 Percent [Member] Represents information pertaining to 11% compounded annual book value per share growth achieved. Compounded Annual Book Value Per Share Growth 12% Compounded Annual Book Value Per Share Growth Achieved12 Percent [Member] Represents information pertaining to 12% compounded annual book value per share growth achieved. Compounded Annual Book Value Per Share Growth 13% Compounded Annual Book Value Per Share Growth Achieved13 Percent [Member] Represents information pertaining to 13% compounded annual book value per share growth achieved. Compounded Annual Book Value Per Share Growth 14% Compounded Annual Book Value Per Share Growth Achieved14 Percent [Member] Represents information pertaining to 14% compounded annual book value per share growth achieved. Compounded Annual Book Value Per Share Growth 15% Compounded Annual Book Value Per Share Growth Achieved15 Percent [Member] Represents information pertaining to 15% compounded annual book value per share growth achieved. Minimum Minimum [Member] Compounded Annual Book Value Per Share Growth (as a percent) Compounded Annual Book Value Per Share Growth Rate Represents the compounded annual book value per share growth rate, expressed as a percentage. Nonvested Common Shares Earned (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage Statement of Financial Position [Abstract] Statement [Table] Statement [Table] Investment Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] Fixed maturities Fixed Maturities [Member] Short-term investments Short-term Investments [Member] Statement Statement [Line Items] Investments available for sale Available-for-sale Securities, Amortized Cost Basis [Abstract] Amortized cost (in dollars) Available-for-sale Securities, Amortized Cost Basis Property and equipment Property, Plant and Equipment, Net [Abstract] Accumulated depreciation (in dollars) Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Stockholders’ Equity Stockholders' Equity Attributable to Parent [Abstract] Common Shares, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common Shares, authorized Common Stock, Shares Authorized Common Shares, issued Common Stock, Shares, Issued Statutory Accounting Practices [Table] Statutory Accounting Practices [Table] Essent Guaranty Essent Guaranty Inc [Member] Represents information pertaining to Essent Guaranty, Inc. (Essent Guaranty), a regulated and licensed indirect wholly-owned subsidiary of the reporting entity. Essent PA Essent Guaranty Of P A Inc [Member] Represents information pertaining to Essent Guaranty of PA, Inc. (Essent PA), a regulated and licensed indirect wholly-owned subsidiary of the reporting entity. Dividends Restrictions Statutory Accounting Practices [Line Items] Statutory net income Statutory Accounting Practices, Statutory Net Income Amount Statutory surplus Statutory Accounting Practices, Statutory Surplus Balance Represents the amount of statutory surplus (stockholders' equity), as of the balance sheet date, using prescribed or permitted statutory accounting practices (rather than GAAP, if different) of the state or country. Contingency reserve liability Statutory Accounting Practices, Statutory Contingency Reserve Liability Represents the amount of contingency reserve liability, as of the balance sheet date, using prescribed or permitted statutory accounting practices (rather than GAAP, if different) of the state or country. Increase in contingency reserve Statutory Accounting Practices, Increase (Decrease) in Contingency Reserve Represents the amount of increase (decrease) in contingency reserve. Stock-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Statement of Cash Flows [Abstract] 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] Gain on the sale of investments, net Depreciation and amortization Depreciation, Depletion and Amortization Amortization of discount on payments due under Asset Purchase Agreement Accretion Expense Stock-based compensation expense Share-based Compensation Amortization of premium on investment securities Investment Income, Amortization of Premium Deferred income tax provision Deferred Income Tax Expense (Benefit) Excess tax benefits from stock-based compensation Excess Tax Benefit from Share-based Compensation, Operating Activities Change in: Increase (Decrease) in Operating Capital [Abstract] Accrued investment income Increase (Decrease) in Accrued Investment Income Receivable Accounts receivable Increase (Decrease) in Accounts Receivable Deferred policy acquisition costs Increase (Decrease) in Deferred Policy Acquisition Costs Prepaid federal income tax Increase (Decrease) in Mortgage Guaranty Insurer United States Mortgage Guaranty Tax and Loss Bonds Represents, for a mortgage guaranty insurer, the increase (decrease) during the reporting period in the amount of investment in United States Mortgage Guaranty Tax and Loss Bonds issued by the Treasury Department for eligibility for certain tax deductions under enacted tax laws. Other assets Increase (Decrease) in Other Operating Assets Reserve for losses and LAE Increase (Decrease) in Loss and Loss Adjustment Expense Reserve Unearned premium reserve Increase (Decrease) in Unearned Premiums Accrued liabilities Increase (Decrease) in Accrued Liabilities Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Investing Activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Net change in short-term investments Payments for (Proceeds from) Short-term Investments Purchase of investments available for sale Payments to Acquire Available-for-sale Securities Proceeds from maturity of investments available for sale Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities Proceeds from sales of investments available for sale Proceeds from Sale of Available-for-sale Securities Purchase of property and equipment, net Payments to Acquire Property, Plant, and Equipment Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Financing Activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Treasury stock acquired Payments for Repurchase of Common Stock Payment of offering costs Payments of Stock Issuance Costs Excess tax benefits from stock-based compensation Excess Tax Benefit from Share-based Compensation, Financing Activities Payments under Asset Purchase Agreement Repayments Of Contractual Obligations To Seller Represents the cash outflow from the repayments of contractual obligations to seller arising from a purchase transactions. Other financing activities Proceeds from (Payments for) Other Financing Activities Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Net decrease in cash Cash and Cash Equivalents, Period Increase (Decrease) Cash at beginning of year Cash and Cash Equivalents, at Carrying Value Cash at end of period Supplemental Disclosure of Cash Flow Information Supplemental Cash Flow Information [Abstract] Income tax (payments) refunds Income Taxes Paid, Net Noncash Transactions Noncash Investing and Financing Items [Abstract] Issuance of management incentive shares Stock Issued Before Tax Accumulated Other Comprehensive Income (Loss), before Tax [Roll Forward] Balance at beginning of period Accumulated Other Comprehensive Income (Loss), before Tax Other comprehensive income (loss): Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent [Abstract] Unrealized holding gains arising during the period Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax Less: Reclassification adjustment for gains included in net income Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax Net unrealized gains on investments Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent Other comprehensive income (loss) Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent Balance at end of period Tax Effect Accumulated Other Comprehensive Income (Loss) Tax Effect [Roll Forward] Balance at beginning of period Accumulated Other Comprehensive Income (Loss) Tax Represents the tax expense (benefit) on the amount of increase (decrease) in accumulated in equity from transactions and other events and circumstances from non-owner sources attributable to the parent entity. Other comprehensive income (loss): Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent, Parenthetical Disclosures [Abstract] Unrealized holding gains arising during the period Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax Less: Reclassification adjustment for gains included in net income Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax Net unrealized gains on investments Other comprehensive income (loss) Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Balance at end of period Net of Tax Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward] Balance at beginning of period Accumulated Other Comprehensive Income (Loss), Net of Tax Other comprehensive income (loss): Unrealized holding gains arising during the period Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Less: Reclassification adjustment for gains included in net income Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax Net unrealized gains on investments Balance at end of period Investment Income [Table] Investment Income [Table] Components of net investment income Net Investment Income [Line Items] Gross investment income Gross Investment Income, Operating Investment expenses Investment Income, Investment Expense Net investment income Investments Available for Sale Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Amortized Cost Due in 1 year Available-for-sale Securities, Debt Maturities, Next Rolling Twelve Months, Amortized Cost Basis Due after 1 but within 5 years Available-for-sale Securities, Debt Maturities, Rolling Year Two Through Five, Amortized Cost Basis Due after 5 but within 10 years Available-for-sale Securities, Debt Maturities, Rolling Year Six Through Ten, Amortized Cost Basis Due after 10 years Available-for-sale Securities, Debt Maturities, Rolling after Year Ten, Amortized Cost Basis Subtotal Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis Total amortized investment Fair Value Available-for-sale Securities [Abstract] Due in 1 year Available-for-sale Securities, Debt Maturities, Next Rolling Twelve Months, Fair Value Due after 1 but within 5 years Available-for-sale Securities, Debt Maturities, Rolling Year Two Through Five, Fair Value Due after 5 but within 10 years Available-for-sale Securities, Debt Maturities, Rolling Year Six Through Ten, Fair Value Due after 10 years Available-for-sale Securities, Debt Maturities, Rolling after Year Ten, Fair Value Subtotal Available-for-sale Securities, Debt Maturities, Single Maturity Date Total investments Statement of Stockholders' Equity [Abstract] Sale of Stock [Axis] Sale of Stock [Axis] Sale of Stock [Domain] Sale of Stock [Domain] Public offering Secondary Offering [Member] The issuance of new stock for public sale from a company that has already made its initial public offering (IPO). Common Shares, issuance cost Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs Amortized Cost Unrealized Gains Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Unrealized Losses Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Fair Value Loss Contingencies [Table] Loss Contingencies [Table] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Indemnifications related to contract underwriting services Indemnification Agreement [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Amount paid for remedies Loss Contingency Accrual, Payments Time and Performance-Based Vesting Based On Service And Performance [Member] Represents a share based compensation award with vesting based on a combination of length of service and achievement of performance conditions. Time-Based Vesting Based On Service [Member] Represents a share based compensation award with vesting based on length of service. Nonvested share units Restricted Stock Units (RSUs) [Member] Number of Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Outstanding at beginning of year (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Outstanding at end of period (in shares) Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Outstanding at beginning of year (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted (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 Vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Outstanding at end of period (in dollars per share) Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Carrying Amount Reported Value Measurement [Member] Estimated fair values and carrying amounts of financial instruments Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Financial Assets: Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Financial Liabilities: Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Reconciliation of the beginning and ending reserve balances for losses and loss adjustment expenses (LAE) Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward] Reserve for losses and LAE at beginning of period Liability for Claims and Claims Adjustment Expense Net reserve for losses and LAE at beginning of period Liability for Unpaid Claims and Claims Adjustment Expense, Net Add provision for losses and LAE, net of reinsurance, occurring in: Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract] Current period Current Year Claims and Claims Adjustment Expense Prior years Prior Year Claims and Claims Adjustment Expense Net incurred losses during the current period Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims Deduct payments for losses and LAE, net of reinsurance, occurring in: Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract] Current period 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 Net loss and LAE payments during the current period Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid Net reserve for losses and LAE at end of period Reserve for losses and LAE at end of period Loans in default at end of period Number of Loans in Default Represents the number of loans in default. Reserve for losses and LAE, for prior years Liability for Unpaid Claims and Claims Adjustment Expense Prior Years Liability, as of the balance sheet date, for amounts representing estimated cost of settling unpaid claims for prior years 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. Title of Individual [Axis] Title of Individual [Axis] Relationship to Entity [Domain] Relationship to Entity [Domain] Director Director [Member] Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] First Vesting Period Share-based Compensation Award, Tranche One [Member] Second Vesting Period Share-based Compensation Award, Tranche Two [Member] Third Vesting Period Share-based Compensation Award, Tranche Three [Member] Equity-Based Arrangements, Individual Contracts, Type of Deferred Compensation [Axis] Equity-Based Arrangements, Individual Contracts, Type of Deferred Compensation [Axis] Equity-Based Arrangements, Individual Contracts, Type of Deferred Compensation [Domain] Equity-Based Arrangements, Individual Contracts, Type of Deferred Compensation [Domain] Incentive Program Bonus Award Fiscal Year Performance Incentive Program Bonus Award Fiscal Year Performance [Member] Represents an incentive program covering bonus awards based on performance for previous fiscal year. Vesting (as a percent) Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Earnings per Share (EPS) Earnings Per Share [Text Block] Accumulated Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Shares Common Stock [Member] Additional Paid-In Capital Additional Paid-in Capital [Member] Accumulated Other Comprehensive Income (Loss) Accumulated Other Comprehensive Income (Loss) [Member] Retained Earnings (Accumulated Deficit) Retained Earnings [Member] Treasury Stock Treasury Stock [Member] Changes in Stockholders' Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Balance Stockholders' Equity Attributable to Parent Net income Other comprehensive income (loss) Issuance of common shares net of issuance cost of $6,761 Stock Issued During Period, Value, New Issues Issuance of management incentive shares Stock Issued During Period, Value, Share-based Compensation, Gross Forfeiture of management incentive shares Stock Issued During Period, Value, Share-based Compensation, Forfeited Stock-based compensation expense Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Excess tax benefits from stock-based compensation expense Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation Treasury stock acquired Treasury Stock, Value, Acquired, Cost Method Cancellation of treasury stock Treasury Stock, Retired, Cost Method, Amount Other equity transactions Adjustments to Additional Paid in Capital, Other Balance Assets Assets [Abstract] Investments available for sale, at fair value Fixed maturities (amortized cost: 2015 — $1,111,701; 2014 — $840,213) Marketable Securities, Fixed Maturities Short-term investments (amortized cost: 2015 — $121,599; 2014 — $210,688) Short-term Investments Total investments Investments Cash Cash Accrued investment income Accrued Investment Income Receivable Accounts receivable Deferred policy acquisition costs Deferred Policy Acquisition Costs Property and equipment (at cost, less accumulated depreciation of $41,646 in 2015 and $39,260 in 2014) Property, Plant and Equipment, Net Prepaid federal income tax Mortgage Guaranty Insurer United States Mortgage Guaranty Tax and Loss Bonds Represents, for a mortgage guaranty insurer, the amount of investment in United States Mortgage Guaranty Tax and Loss Bonds issued by the Treasury Department for eligibility for certain tax deductions under enacted tax laws. Other assets Other Assets Total assets Assets Liabilities and Stockholders’ Equity Liabilities and Equity [Abstract] Liabilities Liabilities [Abstract] Reserve for losses and LAE Unearned premium reserve Unearned Premiums Accrued payroll and bonuses Employee-related Liabilities Net deferred tax liability Deferred Tax Liabilities, Net Securities purchases payable Investment-related Liabilities Other accrued liabilities Other Accrued Liabilities Total liabilities Liabilities Commitments and contingencies Commitments and Contingencies Common Shares, $0.015 par value: Authorized - 233,333; issued - 92,659 shares in 2015 and 92,546 shares in 2014 Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Accumulated other comprehensive income Retained earnings Retained Earnings (Accumulated Deficit) Total stockholders’ equity Total liabilities and stockholders’ equity Liabilities and Equity Fourth Vesting Period Share-based Compensation Award, Tranche Four [Member] Share-based Compensation Award, Tranche Four [Member] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] 2013 Plan Essent Group Limited2013 Long Term Incentive Plan [Member] Represents the Essent Group Limited 2013 Long-term Incentive Plan (2013 Plan). Performance-Based Vesting Based On Performance [Member] Represents a share based compensation award with vesting based on achievement of performance conditions. Certain members of senior management Certain Senior Management [Member] Represents some, but not all, of a team of individuals at the highest level of organizational management who have the day-to-day responsibilities of managing the entity. Employee [Member] Employee [Member] Employee [Member] Performance period Share Based Compensation Arrangement by Share Based Payment Award Performance Period Represents the period over which a performance condition to the award is measured, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.