Endurance International 10-Q 9 May 16 2016 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2016	Apr. 29, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1
Trading Symbol	EIGI
Entity Registrant Name	Endurance International Group Holdings, Inc.
Entity Central Index Key	1,237,746
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		140,442,439

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 79,277	$ 33,030
Restricted cash	3,481	1,048
Accounts receivable	10,929	12,040
Prepaid domain name registry fees	59,021	55,793
Prepaid expenses and other current assets	40,003	15,675
Total current assets	192,711	117,586
Property and equipment-net	113,707	75,762
Goodwill	1,830,244	1,207,255
Other intangible assets-net	731,941	359,786
Deferred financing costs	6,137
Investments	29,903	27,905
Prepaid domain name registry fees, net of current portion	10,166	9,884
Other assets	5,767	4,322
Total assets	2,920,576	1,802,500
Current liabilities:
Accounts payable	19,989	12,280
Accrued expenses	83,099	50,869
Deferred revenue	349,951	285,945
Current portion of notes payable	35,700	77,500
Current portion of capital lease obligations	6,464	5,866
Deferred consideration-short term	52,436	51,488
Other current liabilities	3,881	3,973
Total current liabilities	551,520	487,921
Long-term deferred revenue	87,464	79,682
Notes payable-long term, net of original issue discounts of $0 and $28,374, and deferred financing costs of $990 and $45,669, respectively	1,992,707	1,014,885
Capital lease obligations-long term	5,191	7,215
Deferred tax liability-long term	47,853	28,786
Deferred consideration-long term		813
Other liabilities	6,105	3,524
Total liabilities	2,690,840	$ 1,622,826
Redeemable non-controlling interest	$ 16,262
Commitments and contingencies
Stockholders' equity:
Preferred Stock-par value $0.0001; 5,000,000 shares authorized; no shares issued or outstanding
Common Stock-par value $0.0001; 500,000,000 shares authorized; 132,024,558 and 132,579,860 shares issued at December 31, 2015 and March 31, 2016, respectively; 131,938,485 and 132,493,787 outstanding at December 31, 2015 and March 31, 2016, respectively	$ 14	$ 14
Additional paid-in capital	861,898	848,740
Accumulated other comprehensive loss	(2,887)	(1,718)
Accumulated deficit	(645,551)	(667,362)
Total stockholders' equity	213,474	179,674
Total liabilities, redeemable non-controlling interest and stockholders' equity	$ 2,920,576	$ 1,802,500

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Notes payable-long term original issue discounts, net	$ 28,374	$ 0
Deferred financing costs	$ 45,669	$ 990
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	132,579,860	132,024,558
Common stock, shares outstanding	132,493,787	131,938,485

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Statement [Abstract]
Revenue	$ 237,113	$ 177,318
Cost of revenue	136,476	100,974
Gross profit	100,637	76,344
Operating expense:
Sales and marketing	79,294	35,044
Engineering and development	16,255	5,371
General and administrative	40,279	17,207
Transaction expenses	31,120	1,523
Total operating expense	166,948	59,145
Income (loss) from operations	(66,311)	17,199
Other income (expense):
Other income	11,410
Interest income	134	92
Interest expense	(30,371)	(14,321)
Total other expense-net	(18,827)	(14,229)
Income (loss) before income taxes and equity earnings of unconsolidated entities	(85,138)	2,970
Income tax expense (benefit)	(99,902)	978
Income before equity earnings of unconsolidated entities	14,764	1,992
Equity loss of unconsolidated entities, net of tax	683	1,108
Net income	14,081	884
Net loss attributable to non-controlling interest	(7,730)
Net income attributable to Endurance International Group Holdings, Inc.	21,811	884
Comprehensive income (loss):
Foreign currency translation adjustments	342	(616)
Unrealized loss on cash flow hedge, net of taxes of $0 and $606 for the three months ended March 31, 2015 and 2016	(1,511)
Total comprehensive income	$ 20,642	$ 268
Basic net income per share	$ 0.17	$ 0.01
Diluted net income per share	$ 0.16	$ 0.01
Weighted-average common shares used in computing net income per share:
Basic	132,178,693	130,996,079
Diluted	133,563,884	132,675,938

Consolidated Statements of Ope5

Consolidated Statements of Operations and Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Statement [Abstract]
Unrealized loss arising during period, tax	$ 606	$ 0

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net income	$ 14,081	$ 884
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of property and equipment	13,172	7,866
Amortization of other intangible assets from acquisitions	29,874	21,298
Impairment of other intangible assets	1,437
Amortization of deferred financing costs	911	20
Amortization of net present value of deferred consideration	783	138
Amortization of original issue discounts	449
Stock-based compensation	18,388	3,971
Deferred tax expense (benefit)	(103,203)	381
(Gain) loss on sale of assets	(1)	40
Gain from unconsolidated entities	(11,410)
Loss of unconsolidated entities	683	1,108
Loss from change in deferred consideration	21	196
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	2,144	1,785
Prepaid expenses and other current assets	(15,673)	(4,741)
Accounts payable and accrued expenses	16,973	2,344
Deferred revenue	43,143	14,933
Net cash provided by operating activities	11,772	50,223
Cash flows from investing activities:
Businesses acquired in purchase transactions, net of cash acquired	(881,709)
Cash paid for minority investment	(600)
Purchases of property and equipment	(10,140)	(7,249)
Proceeds from sale of assets		26
Deposits of principal balances in restricted cash accounts	(737)	(338)
Net cash used in investing activities	(893,186)	(7,561)
Cash flows from financing activities:
Proceeds from issuance of term loan and notes, net of original issue discounts	1,056,178
Repayments of term loans	(8,925)	(2,625)
Proceeds from borrowing of revolver	16,000	7,000
Repayment of revolver	(83,000)	(36,000)
Payment of financing costs	(51,605)
Payment of deferred consideration	(707)	(488)
Payment of redeemable non-controlling interest liability		(10,181)
Principal payments on capital lease obligations	(1,439)	(930)
Proceeds from exercise of stock options	593	353
Net cash provided by (used in) financing activities	927,095	(42,871)
Net effect of exchange rate on cash and cash equivalents	566	(506)
Net (decrease) increase in cash and cash equivalents	46,247	(715)
Cash and cash equivalents:
Beginning of period	33,030	32,379
End of period	79,277	31,664
Supplemental cash flow information:
Interest paid	16,659	14,226
Income taxes paid	$ 968	$ 702

Nature of Business

Nature of Business	3 Months Ended
	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business	1. Nature of Business Formation and Nature of Business Endurance International Group Holdings, Inc., (“Holdings”) is a Delaware corporation which together with its wholly owned subsidiary company, EIG Investors Corp. (“EIG Investors”), its primary operating subsidiary company, The Endurance International Group, Inc. (“EIG”), and other subsidiary companies of EIG, collectively form the “Company.” The Company is a leading provider of cloud-based platform solutions designed to help small- and medium-sized businesses succeed online. EIG and EIG Investors were incorporated in April 1997 and May 2007, respectively, and Holdings was originally formed as a limited liability company in October 2011 in connection with the acquisition by investment funds and entities affiliated with Warburg Pincus and Goldman, Sachs & Co. on December 22, 2011 of a controlling interest in EIG Investors, EIG and EIG’s subsidiary companies. On November 7, 2012, Holdings reorganized as a Delaware limited partnership and on June 25, 2013, Holdings converted into a Delaware C-corporation and changed its name to Endurance International Group Holdings, Inc.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Preparation The accompanying consolidated financial statements, which include the accounts of the Company and its subsidiaries, have been prepared using accounting principles generally accepted in the United States of America (“U.S. GAAP”). All intercompany transactions have been eliminated on consolidation. The Company has reviewed the criteria of the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 280-10, Segment Reporting, Use of Estimates U.S. GAAP requires management to make certain estimates, judgments and assumptions that affect the reported amounts of assets, liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. These estimates, judgments and assumptions used in preparing the accompanying consolidated financial statements are based on the relevant facts and circumstances as of the date of the consolidated financial statements. Although the Company regularly assesses these estimates, judgments and assumptions used in preparing the consolidated financial statements, actual results could differ from those estimates. Changes in estimates are recorded in the period in which they become known. The more significant estimates reflected in these consolidated financial statements include estimates of fair value of assets acquired and liabilities assumed under purchase accounting related to the Company’s acquisitions and when evaluating goodwill and long-lived assets for potential impairment, the estimated useful lives of intangible and depreciable assets, revenue recognition for multiple-element arrangements, stock-based compensation, contingent consideration, derivative instruments, certain accruals, reserves and deferred taxes. Unaudited Interim Financial Information The accompanying interim consolidated balance sheet as of March 31, 2016, and the related statements of operations and comprehensive income for the three months ended March 31, 2015 and 2016, cash flows for the three months ended March 31, 2015 and 2016, and the notes to consolidated financial statements are unaudited. These unaudited consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements. The unaudited consolidated financial statements include, in the opinion of management, all adjustments, consisting only of normal recurring adjustments that are necessary for a fair presentation of the Company’s financial position at March 31, 2016, results of operations for the three months ended March 31, 2015 and 2016 and cash flows for the three months ended March 31, 2015 and 2016. The consolidated results in the consolidated statements of operations and comprehensive income are not necessarily indicative of the results of operations to be expected for the full fiscal year ending December 31, 2016. Accounts Receivable Accounts receivable is primarily composed of cash due from credit card companies for unsettled transactions charged to subscribers’ credit cards. As these amounts reflect authenticated transactions that are fully collectible, the Company does not maintain an allowance for doubtful accounts. The Company also accrues for earned referral fees and commissions, which are governed by reseller or affiliate agreements, when the amount is reasonably estimable. Prepaid Domain Name Registry Fees Prepaid domain name registry fees represent amounts that are paid in full at the time a domain is registered by one of the Company’s registrars on behalf of a customer. The registry fees are recognized on a straight-line basis over the term of the domain registration period. Derivative Instruments and Hedging Activities FASB ASC 815, Derivatives and Hedging, As required by ASC 815, the Company records all derivatives on the balance sheet at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether the Company has elected to designate a derivative in a hedging relationship and apply hedge accounting and whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. Derivatives designated and qualifying as a hedge of the exposure to changes in the fair value of an asset, liability, or firm commitment attributable to a particular risk, such as interest rate risk, are considered fair value hedges. Derivatives designated and qualifying as a hedge of the exposure to variability in expected future cash flows, or other types of forecasted transactions, are considered cash flow hedges. Derivatives may also be designated as hedges of the foreign currency exposure of a net investment in a foreign operation. Hedge accounting generally provides for the matching of the timing of gain or loss recognition on the hedging instrument with the recognition of the changes in the fair value of the hedged asset or liability that are attributable to the hedged risk in a fair value hedge or the earnings effect of the hedged forecasted transactions in a cash flow hedge. The Company may enter into derivative contracts that are intended to economically hedge certain of its risk, even though hedge accounting does not apply or the Company elects not to apply hedge accounting. In accordance with the FASB’s fair value measurement guidance in ASU 2011-04, Fair Value Measurement (Topic 820): Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements, Property and Equipment Property and equipment is recorded at cost or fair value if acquired in an acquisition. The Company also capitalizes the direct costs of constructing additional computer equipment for internal use, as well as upgrades to existing computer equipment which extend the useful life, capacity or operating efficiency of the equipment. Capitalized costs include the cost of materials, shipping and taxes. Materials used for repairs and maintenance of computer equipment are expensed and recorded as a cost of revenue. Materials on hand and construction-in-process are recorded as property and equipment. Assets recorded under capital lease are depreciated over the lease term. Depreciation is computed using the straight-line method over the estimated useful lives of the related assets as follows: Building Thirty-five years Software Two to three years Computers and office equipment Three years Furniture and fixtures Five years Leasehold improvements Shorter of useful life or remaining term of the lease Software Development Costs The Company accounts for software development costs for internal use software under the provisions of ASC 350-40, “Internal-Use Software.” Goodwill Goodwill relates to amounts that arose in connection with the Company’s various business combinations and represents the difference between the purchase price and the fair value of the identifiable intangible and tangible net assets when accounted for using the purchase method of accounting. Goodwill is not amortized, but is subject to periodic review for impairment. Events that would indicate impairment and trigger an interim impairment assessment include, but are not limited to, current economic and market conditions, including a decline in the equity value of the business, a significant adverse change in certain agreements that would materially affect reported operating results, business climate or operational performance of the business and an adverse action or assessment by a regulator. Additionally, the reorganization or change in the number of reporting units could result in the reassignment of goodwill between reporting units and may trigger an impairment assessment. In accordance with ASC 350, Intangibles—Goodwill and Other At December 31, 2015, the Company had one reporting unit. The goodwill impairment assessment as of December 31, 2015 was based on then-current market capitalization. As of December 31, 2015, the fair value of the Company’s reporting unit exceeded the carrying value of the reporting unit’s net assets. Therefore, no impairment existed as of that date. For the three months ended March 31, 2016, the Company determined that there were no factors to indicate that the fair value of its reporting units could be impaired, therefore, no impairment testing was performed during this period. Determining the fair value of a reporting unit, if applicable, requires the Company to make judgments and involves the use of significant estimates and assumptions. These estimates and assumptions relate to, among other things, revenue growth rates and operating margins used to calculate projected future cash flows, risk-adjusted discount rates, future economic and market conditions and determination of appropriate market comparables. The Company bases its fair value estimates on assumptions it believes to be reasonable but that are unpredictable and inherently uncertain. Actual future results may differ from those estimates. The Company had goodwill of $1,207.3 million and $1,830.2 million as of December 31, 2015 and March 31, 2016, respectively, and no impairment charges have been recorded. Long-Lived Assets The Company’s long-lived assets consist primarily of intangible assets, including acquired subscriber relationships, trade names, intellectual property, developed technology, domain names available for sale and in-process research and development (“IPR&D”). The Company also has long-lived tangible assets, primarily consisting of property and equipment. The majority of the Company’s intangible assets are recorded in connection with its various acquisitions. The Company’s intangible assets are recorded at fair value at the time of their acquisition. The Company amortizes intangible assets over their estimated useful lives. Determination of the estimated useful lives of the individual categories of intangible assets is based on the nature of the applicable intangible asset and the expected future cash flows to be derived from the intangible asset. Amortization of intangible assets with finite lives is recognized in accordance with their estimated projected cash flows. The Company evaluates long-lived intangible and tangible assets whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If indicators of impairment are present and undiscounted future cash flows are less than the carrying amount, the fair value of the assets is determined and compared to the carrying value. If the fair value is less than the carrying value, then the carrying value of the asset is reduced to the estimated fair value and an impairment loss is charged to expense in the period the impairment is identified. No such impairment losses have been identified in the three months ended March 31, 2015 and 2016. Indefinite life intangible assets include domain names that are available for sale which are recorded at cost to acquire. These assets are not being amortized and are being tested for impairment annually and whenever events or changes in circumstance indicate that their carrying value may not be recoverable. When a domain name is sold, the Company records the cost of the domain in cost of revenue. Acquired In-Process Research and Development (IPR&D) Acquired IPR&D represents the fair value assigned to research and development assets that the Company acquires in connection with business combinations that have not been completed at the date of acquisition. The acquired IPR&D is capitalized as an intangible asset and reviewed on a quarterly basis to determine future use. Any impairment loss of the acquired IPR&D is charged to expense in the period the impairment is identified. No such impairment loss was identified for the three months ended March 31, 2015. During the three months ended March 31, 2016, the Company identified that the acquired fair value of the remaining IPR&D acquired in connection with its acquisition of Webzai Ltd. (“Webzai”), was impaired. The Company recorded a $1.4 million impairment charge during the three months ended March 31, 2016 in engineering and development expense in the Company’s consolidated statements of operations and comprehensive income. Revenue Recognition The Company generates revenue primarily from selling subscriptions for cloud-based products and services. The subscriptions are similar across all of the Company’s brands and are provided under contracts pursuant to which the Company has ongoing obligations to support the subscriber. These contracts are generally for service periods of up to 36 months and typically require payment in advance. The Company recognizes the associated revenue ratably over the service period , The Company sells domain name registrations that provide a subscriber with the exclusive use of a domain name. These domains are primarily obtained by one of the Company’s registrars on the subscriber’s behalf, or to a lesser extent by the Company from third-party registrars on the subscriber’s behalf. Domain registration fees are non-refundable. Revenue from the sale of a domain name registration by a registrar within the Company is recognized ratably over the subscriber’s service period as the Company has the obligation to provide support over the domain term. Revenue from the sale of a domain name registration purchased by the Company from a third-party registrar is recognized when the subscriber is billed on a gross basis as there are no remaining Company obligations once the sale to the subscriber occurs, and the Company has full discretion on the sales price and bears all credit risk. Revenue from the sale of premium domains is recognized when persuasive evidence of an arrangement to sell such domains exists, delivery of an authorization key to access the domain name has occurred, the fee for the sale of the premium domain is fixed or determinable, and collection of the fee for the sale of the premium domain is deemed probable. Revenue from the sale of non-term based applications and services, such as certain online security products and professional technical services, referral fees and commissions, is recognized when the product is purchased, the service is provided or the referral fee or commission is earned, respectively. A substantial amount of the Company’s revenue is generated from transactions that are multiple-element service arrangements that may include hosting plans, domain name registrations, and other cloud-based products and services. The Company follows the provisions of the FASB, Accounting Standards Update (“ASU”) No. 2009-13 (“ASU 2009-13”), Revenue Recognition (Topic 605), Multiple-Deliverable Revenue Arrangements—a consensus of the FASB Emerging Issues Task Force, Under ASU 2009-13, to treat deliverables in a multiple-element service arrangement as separate units of accounting, the deliverables must have standalone value upon delivery. If the deliverables have standalone value upon delivery, the Company accounts for each deliverable separately. Hosting services, domain name registrations, cloud-based products and services have standalone value and are often sold separately. When multiple deliverables included in a multiple-element service arrangement are separated into different units of accounting, the total transaction amount is allocated to the identified separate units based on a relative selling price hierarchy. The Company determines the relative selling price for a deliverable based on vendor specific objective evidence (“VSOE”) of fair value, if available, or best estimate of selling price (“BESP”), if VSOE is not available. The Company has determined that third-party evidence of selling price (“TPE”) is not a practical alternative due to differences in its multi-brand offerings compared to competitors and the lack of availability of relevant third-party pricing information. The Company has not established VSOE for its offerings due to lack of pricing consistency, the introduction of new products, services and other factors. Accordingly, the Company generally allocates revenue to the deliverables in the arrangement based on the BESP. The Company determines BESP by considering its relative selling prices, competitive prices in the marketplace and management judgment; these selling prices, however, may vary depending upon the particular facts and circumstances related to each deliverable. The Company analyzes the selling prices used in its allocation of transaction amount, at a minimum, on a quarterly basis. Selling prices are analyzed on a more frequent basis if a significant change in the business necessitates a more timely analysis. The Company maintains a reserve for refunds and chargebacks related to revenue that has been recognized and is expected to be refunded. The Company had a refund and chargeback reserve of $0.5 million and $0.6 million as of December 31, 2015 and March 31, 2016, respectively. The portion of deferred revenue that is expected to be refunded at December 31, 2015 and March 31, 2016 was $1.8 million and $2.2 million, respectively. Based on refund history, a significant majority of refunds happen in the same fiscal month that the customer contract starts or renews. Approximately 80% of all refunds happen in the same fiscal month that the contract starts or renews, and approximately 92% of all refunds happen within 45 days of the contract start or renewal date. Income Taxes Income taxes are accounted for in accordance with ASC 740, Accounting for Income Taxes ASC 740 clarifies the accounting for income taxes by prescribing a minimum recognition threshold that a tax position is required to meet before being recognized in the financial statements. The Company recognizes the effect of income tax positions only if those positions are more likely than not to be sustained. Recognized income tax positions are measured at the largest amount that is more likely than not to be realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. There were no unrecognized tax benefits in the three months ended March 31, 2015 and 2016. The Company records interest related to unrecognized tax benefits in interest expense and penalties in operating expenses. During the three months ended March 31, 2015 and 2016, the Company did not recognize any interest and penalties related to unrecognized tax benefits. Stock-Based Compensation The Company may issue restricted stock units, restricted stock awards and stock options which vest upon the satisfaction of a performance condition and/ or a service condition. The Company follows the provisions of ASC 718, Compensation—Stock Compensation The Company estimates the fair value of employee stock options on the date of grant using the Black-Scholes option-pricing model, which requires the use of highly subjective estimates and assumptions. For restricted stock awards granted, the Company estimates the fair value of each restricted stock award based on the closing trading price of its common stock on the date of grant. Net Income per Share The Company considered ASC 260-10, Earnings per Share Three Months Ended March 31, 2015 2016 (unaudited) (in thousands, except share amount and per share data) Net income attributable to Endurance International Group Holdings, Inc. $ 884 $ 21,811 Net income per share attributable to Endurance International Group Holdings, Inc.: Basic $ 0.01 $ 0.17 Diluted $ 0.01 $ 0.16 Weighted-average common shares outstanding used in computing basic net income per share attributable to Endurance International Group Holdings, Inc. 130,996,079 132,178,693 Dilutive common stock options and restricted stock awards 1,679,859 1,385,191 Weighted-average common shares outstanding used in computing diluted net income per share attributable to Endurance International Group Holdings, Inc. 132,675,938 133,563,884 The Company excluded common stock equivalents from the computation of diluted net income per share because they had an anti-dilutive impact as the proceeds under the treasury stock method were in excess of the average fair market value. For the three months ended March 31, 2015 and 2016, the Company excluded stock options, restricted stock awards and restricted shares amounting to 212,150 and 12,459,929, respectively, as their inclusion would have been antidilutive as the proceeds under the treasury stock method were in excess of the average fair market value for the respective periods. Recent Accounting Pronouncements The Company adopted ASU 2015-03, “Simplifying the Presentation of Debt Issuance Cost” In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) Revenue from Contracts with Customers (Topic 606), Principals versus Agent Considerations Revenue from Contracts with Customers (Topic 606), Identifying Performance Obligations and Licensing, . In November 2015, the FASB issued ASU No. 2015-17, Income Taxes: Balance Sheet Classification of Deferred Taxes, In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases In March 2016, the FASB issued Accounting Standards Update No. 2016-07, Investments—Equity Method and Joint Ventures: Simplifying the Transition to the Equity Method of Accounting. This new guidance removes the requirement for retroactive adjustment when an increase or decrease in the level of ownership qualifies an investment for the equity method. This amendment is effective for fiscal years beginning after December 15, 2016. The Company is currently evaluating the impact of its pending adoption of the new standard on its consolidated financial statements. In March 2016, the FASB issued Accounting Standards Update No. 2016-09, Compensation-Stock Compensation: Improvements to Employee Share-Based Payment Accounting. This new standard simplifies the accounting tax aspects, eliminates complex accounting for excess tax deductions, permits higher withholdings for cashless exercises, and eliminates the requirement to estimate a forfeiture rate. This amendment is effective for annual periods beginning after December 15, 2016, and early adoption is permitted. The Company is currently evaluating the impact of its pending adoption of the new standard on its consolidated financial statements.

Acquisitions

Acquisitions	3 Months Ended
	Mar. 31, 2016
Business Combinations [Abstract]
Acquisitions	3. Acquisitions The Company accounts for the acquisitions of businesses using the purchase method of accounting. The Company allocates the purchase price to the tangible and identifiable intangible assets and liabilities assumed based on their estimated fair values. Purchased identifiable intangible assets typically include subscriber relationships, trade names, domain names held for sale, developed technology and IPR&D. The methodologies used to determine the fair value assigned to subscriber relationships and domain names held for sale are typically based on the excess earnings method that considers the return received from the intangible asset and includes certain expenses and also considers an attrition rate based on the Company’s internal subscriber analysis and an estimate of the average life of the subscribers. The fair value assigned to trade names is typically based on the income approach using a relief from royalty methodology that assumes that the fair value of a trade name can be measured by estimating the cost of licensing and paying a royalty fee for the trade name that the owner of the trade name avoids. The fair value assigned to developed technology typically uses the cost approach. The fair value assigned to IPR&D is based on the cost approach. If applicable, the Company estimates the fair value of contingent consideration payments in determining the purchase price. The contingent consideration is then adjusted to fair value in subsequent periods as an increase or decrease in current earnings in general and administrative expense in the consolidated statements of operations. WZ UK Ltd. In August 2014, the Company made an aggregate investment of $3.9 million for a joint venture with a 49% ownership interest in WZ UK Ltd., which is a provider of technology and sales and marketing services associated with web builder solutions. The Company has an option to acquire additional equity interests from the shareholders of the non-controlling interest (“NCI”) in WZ UK Ltd. On January 6, 2016, the Company partially exercised this option, which increased its stake in WZ UK Ltd. from 49% to 57.5%. Upon the exercise of the option, the Company estimated the fair value of the assets and liabilities in accordance with the guidance for business combinations and estimated that the value of the NCI on January 6, 2016 was $10.8 million. The estimated aggregate purchase price of $22.2 million included a gain of $11.4 million that was calculated based on the implied fair value of the Company’s 49% equity investment and the NCI of $10.8 million, which were allocated on a preliminary basis to goodwill of $21.6 million, intangible assets consisting of subscriber relationships of $4.9 million, and property, plant and equipment of $0.3 million, offset by deferred revenue of $3.3 million and negative working capital of $1.3 million. Goodwill related to the acquisition is not deductible for tax purposes. The $11.4 million gain was recognized in other income in the Company’s consolidated statement of operations and comprehensive income during the three months ended March 31, 2016. As the NCI is subject to a put option that is outside the control of the Company, it is deemed a redeemable non-controlling interest and not recorded in permanent equity, and is being presented as mezzanine redeemable non-controlling interest on the consolidated balance sheet. The difference between the initial fair value of the redeemable non-controlling interest and the value expected to be paid on exercise, which is estimated to be $30.0 million, is being accreted over the period commencing January 6, 2016, and up to the end of the second call option period which is August 14, 2016. Adjustments to the carrying amount of the redeemable non-controlling interest are charged to additional paid-in capital. Constant Contact, Inc. On October 30, 2015, the Company entered into a definitive agreement pursuant to which it agreed to acquire all of the outstanding shares of common stock of Constant Contact for $32.00 per share in cash, for a total purchase price of approximately $1.1 billion. Constant Contact is a leading provider of online marketing tools that are designed for small organizations, including small businesses, associations and non-profits. The acquisition closed on February 9, 2016. The aggregate purchase price of $1.1 billion, which was paid in cash at the closing, is being allocated on a preliminary basis to intangible assets consisting of subscriber relationships, developed technology and trade names of $263.0 million, $52.0 million and $83.0 million, respectively, goodwill of $601.1 million, property and equipment of $40.7 million, working capital of $182.0 million and long-term deposits of $2.0 million, offset by net a net deferred tax liability of $122.9 million, deferred revenue of $25.2 million and long-term obligations of $0.1 million. The goodwill reflects the value of expected synergies. Goodwill related to the acquisition is not deductible for tax purposes. For the three months ended March 31, 2016, $41.7 million of revenue attributable to 2016 acquisitions was included in the Company’s consolidated statement of operations and comprehensive income. The $31.1 million of transaction expenses in the Company’s consolidated statement of operations and comprehensive income included a $16.8 million charge related to the acceleration of the vesting of certain Constant Contact equity awards, $10.8 million of advisor fees and $3.5 million of legal fees. For the intangible assets acquired in connection with all acquisitions completed during the three months ended March 31, 2016, developed technology has a weighted-useful life of 4.1 years, subscriber relationships have a weighted-useful life of 4.4 years and trade names have a weighted-useful life of 4.7 years. Pro Forma Disclosure The following unaudited information is presented as if the Constant Contact acquisition was completed as of January 1, 2015. The unaudited pro forma results are not necessarily indicative of the actual results that would have occurred had the transaction actually taken place at the beginning of the period indicated. Unaudited pro forma revenue for the three months ended March 31, 2015 and 2016 is $267.0 million and $277.8 million, respectively. Unaudited pro forma net loss attributable to Endurance International Group Holdings, Inc. for the three months ended March 31, 2015 is $25.3 million and unaudited pro forma net income attributable to Endurance International Group Holdings, Inc. for the three months ended March 31, 2016 is $35.6 million. The unaudited pro forma net income (loss) includes adjustments for additional interest expense related to the debt incurred in connection with the acquisition of Constant Contact. Pro forma revenue for the three months ended March 31, 2016 has been reduced by $13.7 million due to the application of purchase accounting for Constant Contact, which reduced the fair value of deferred revenue as of the closing date. Additionally, pro forma net income for the three months ended March 31, 2016 includes restructuring charges of approximately $11.4 million as the Company implemented plans to reduce the cost structure of the combined businesses. Summary of Deferred Consideration Related to Acquisitions Components of deferred consideration short-term and long-term as of December 31, 2015 and March 31, 2016, consisted of the following: December 31, 2015 March 31, 2016 Short- term Long- term Short- term Long- term (in thousands) Mojoness, Inc. (Acquired in 2012) $ 657 $ 813 $ 822 $ — Typepad Holdings LLC (Acquired in 2013) 2,800 — 2,800 — Webzai Ltd. (Acquired 2014) 2,848 — 2,909 — BuyDomains (Acquired in 2014) 4,283 — 4,374 — Verio (Acquired in 2015) 2,474 — 2,474 — World Wide Web Hosting (Acquired in 2015) 4,600 — 4,600 — Ace Data Center (Acquired in 2015) 29,626 — 30,257 — Ecommerce LLC (Acquired in 2015) 4,200 — 4,200 — Total $ 51,488 $ 813 $ 52,436 $ —

Property and Equipment and Capi

Property and Equipment and Capital Lease Obligations	3 Months Ended
	Mar. 31, 2016
Property, Plant and Equipment [Abstract]
Property and Equipment and Capital Lease Obligations	4. Property and Equipment and Capital Lease Obligations Components of property and equipment consisted of the following: December 31, 2015 March 31, 2016 (in thousands) Land $ 713 $ 713 Building 5,091 5,092 Software 40,336 45,605 Computers and office equipment 97,332 128,184 Furniture and fixtures 5,914 10,567 Leasehold improvements 7,126 20,634 Construction in process 6,137 4,718 Property and equipment—at cost 162,649 215,513 Less accumulated depreciation (86,887 ) (101,806 ) Property and equipment—net $ 75,762 $ 113,707 Depreciation expense related to property and equipment for the three months ended March 31, 2015 and 2016 was $7.9 million and $13.2 million, respectively. Property under capital lease with a cost basis of $21.5 million was included in software as of March 31, 2016. The net carrying value of property under capital lease as of March 31, 2016 was $11.5 million.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	5. Fair Value Measurements The following valuation hierarchy is used for disclosure of the valuation inputs used to measure fair value. This hierarchy prioritizes the inputs into three broad levels as follows: • Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities. • Level 2 inputs are quoted prices for similar assets or liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument. • Level 3 inputs are unobservable inputs based on the Company’s own assumptions used to measure assets and liabilities at fair value. A financial asset or liability’s classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. As of December 31, 2015 and March 31, 2016, the Company’s financial assets or liabilities required to be measured on a recurring basis are accrued earn-out consideration payable in connection with the 2012 acquisition of certain assets of Mojoness, Inc., or Mojo, and the 2015 interest rate cap. The Company has classified its interest rate cap discussed in Note 5 below within Level 2 of the fair value hierarchy. The Company has classified its liabilities for contingent earn-out consideration related to Mojo within Level 3 of the fair value hierarchy because the fair value is determined using significant unobservable inputs, which include probability weighted cash flows. During the three months ended March 31, 2016, the Company paid $0.7 million related to the earn-out provisions for the Mojo acquisition. Basis of Fair Value Measurements Balance Quoted Prices in Active Markets for Identical Items (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (in thousands) Balance at December 31, 2015: Financial assets: Interest rate cap (included in other assets) $ 3,130 — $ 3,130 $ — Total financial assets $ 3,130 — $ 3,130 $ — Financial liabilities: Contingent earn-out consideration $ 1,469 — — $ 1,469 Total financial liabilities $ 1,469 — — $ 1,469 Balance at March 31, 2016: Financial assets: Interest rate cap (included in other assets) $ 1,013 — $ 1,013 $ — Total financial assets $ 1,013 — $ 1,013 $ — Financial liabilities: Contingent earn-out consideration $ 822 — — $ 822 Total financial liabilities $ 822 — — $ 822 The following table summarizes the changes in the financial liabilities measured on a recurring basis using Level 3 inputs as of March 31, 2016: Amount (in thousands) Financial liabilities measured using Level 3 inputs at December 31, 2015 $ 1,469 Payment of contingent earn-outs related to 2012 acquisition (668 ) Change in fair value of contingent earn-outs 21 Financial liabilities measured using Level 3 inputs at March 31, 2016 $ 822

Derivatives and Hedging Activit

Derivatives and Hedging Activities	3 Months Ended
	Mar. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Activities	6. Derivatives and Hedging Activities Risk Management Objective of Using Derivatives The Company is exposed to certain risk arising from both its business operations and economic conditions. The Company principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The Company manages economic risks, including interest rate, liquidity, and credit risk primarily by managing the amount, sources, and duration of its debt funding and the use of derivative financial instruments. Specifically, the Company enters into derivative financial instruments to manage exposures that arise from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates. The Company’s derivative financial instruments are used to manage differences in the amount, timing, and duration of the Company’s known or expected cash receipts and its known or expected cash payments principally related to the Company’s investments and borrowings. Cash Flow Hedges of Interest Rate Risk The Company entered into a three-year interest rate cap on December 9, 2015 as part of its risk management strategy. The objective of the interest rate cap, designated as a cash flow hedge, involves the receipt of variable amounts from a counterparty if interest rates rise above the strike rate on the contract in exchange for an upfront premium. Therefore, this derivative limits the Company’s exposure if the rate rises, but also allows the Company to benefit when the rate falls. The effective portion of changes in the fair value of derivatives that qualify as cash flow hedges is recorded in AOCI, and is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. Amounts reported in AOCI related to derivatives will be reclassified to interest expense as interest payments are made on the Company’s variable-rate debt. Any ineffective portion of the change in fair value of the derivatives is recognized directly in earnings. There was no ineffectiveness recorded in earnings for the three months ended March 31, 2016. As of March 31, 2016, the Company had one interest rate cap with $500.0 million notional value outstanding that was designated as a cash flow hedge of interest rate risk. The fair value of the interest rate contracts included in other assets on the consolidated balance sheet as of March 31, 2016 was $1.0 million, and there has been no effect on the Company’s consolidated statement of operations. The Company recognized $1.5 million loss, net of a tax benefit of $0.6 million in AOCI, of which the Company estimates that $40,651 will be reclassified as an increase to interest expense in the next twelve months.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	3 Months Ended
	Mar. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	7. Goodwill and Other Intangible Assets The following table summarizes the changes in the Company’s goodwill balances from December 31, 2015 to March 31, 2016: Amount (in thousands) Goodwill balance at December 31, 2015 $ 1,207,255 Goodwill related to 2015 acquisitions 38 Goodwill related to 2016 acquisitions 622,691 Foreign translation impact 260 Goodwill balance at March 31, 2016 $ 1,830,244 In accordance with ASC 350, the Company reviews goodwill and other indefinite-lived intangible assets for indicators of impairment on an annual basis and between tests if an event occurs or circumstances change that would more likely than not reduce the fair value of goodwill below its carrying amount. The Company concluded there were no events during the three months ended March 31, 2016 that would have required the Company to review goodwill and other indefinite-lived intangible assets for indicators of impairment. At December 31, 2015, other intangible assets consisted of the following: Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Useful Life (dollars in thousands) Developed technology $ 205,925 $ 80,795 $ 125,130 7 years Subscriber relationships 397,791 256,461 141,330 5 years Trade-names 81,792 42,080 39,712 6 years Intellectual property 34,020 6,596 27,424 13 years Domain names available for sale 27,859 3,107 24,752 Indefinite Leasehold interests 314 314 — 1 years In-process research and development 1,438 — 1,438 — Total December 31, 2015 $ 749,139 $ 389,353 $ 359,786 During the three months ended March 31, 2016, the Company wrote-off acquired in-process research and development of $1.4 million, related to its acquisition of Webzai in 2014, as the Company had abandoned certain research and development projects in favor of other projects. At March 31, 2016, other intangible assets consisted of the following: Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Useful Life (dollars in thousands) Developed technology $ 288,925 $ 88,275 $ 200,650 7 years Subscriber relationships 665,791 274,296 391,495 7 years Trade-names 133,796 45,330 88,466 8 years Intellectual property 34,030 7,556 26,474 13 years Domain names available for sale 28,513 3,657 24,856 Indefinite Leasehold interests 314 314 — 1 years In-process research and development — — — — Total March 31, 2016 $ 1,151,369 $ 419,428 $ 731,941 The estimated useful lives of the individual categories of other intangible assets are based on the nature of the applicable intangible asset and the expected future cash flows to be derived from the intangible asset. Amortization of intangible assets with finite lives is recognized over the period of time the assets are expected to contribute to future cash flows. The Company amortizes finite-lived intangible assets over the period in which the economic benefits are expected to be realized based upon their estimated projected cash flows. The Company’s amortization expense is included in cost of revenue in the aggregate amounts of $21.3 million and $29.9 million for the three months ended March 31, 2015 and 2016, respectively.

Investments

Investments	3 Months Ended
	Mar. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Investments	8. Investments As of December 31, 2015 and March 31, 2016, the Company’s carrying value of investments in privately-held companies was $27.9 million and $29.9 million, respectively. In January 2012, the Company made an initial investment of $0.3 million to acquire a 25% interest in BlueZone Labs, LLC (“BlueZone”), a provider of “do-it-yourself” tools and managed search engine optimization services. The Company also has an agreement with BlueZone to purchase products and services. During the three months ended March 31, 2015 and 2016, the Company purchased $0.3 million and $0.3 million, respectively, of products and services from BlueZone, which is included in cost of revenue in the Company’s consolidated statements of operations and comprehensive income. As of March 31, 2015 and 2016, $0.1 million and $0.3 million, respectively, relating to the Company’s investment in BlueZone was included in accounts payable and accrued expense in the Company’s consolidated balance sheet. In May 2014, the Company made a strategic investment of $15.0 million in Automattic, Inc. (“Automattic”), which provides content management systems associated with WordPress. The investment represents less than 5% of the outstanding shares of Automattic and better aligns the Company with an important partner. In August, 2014, the Company made an aggregate investment of $3.9 million for a joint venture with a 49% ownership interest in WZ UK Ltd., which is a provider of technology and sales marketing services associated with web builder solutions. The agreement provides for the acquisition of additional equity interests in WZ UK Ltd. at the option of the Company. On January 6, 2016, the Company exercised an option to increase its stake in WZ UK Ltd. from 49% to 57.5%. For more detail see Note 3 to the consolidated financial statements. In December 2014, the Company made an aggregate investment of $15.2 million to acquire a 40% ownership interest in AppMachine B.V. (“AppMachine”), which is a developer of software that allows users to build mobile applications for smart devices such as phones and tablets. Under the terms of the investment agreement for AppMachine, the Company is obligated to purchase the remaining 60% of AppMachine in three tranches of 20% within specified periods if AppMachine achieves a specified minimum revenue threshold within a designated timeframe. The consideration for each of the three tranches is calculated as the product of AppMachine’s revenue, as defined in the investment agreement, for the trailing twelve-month period prior to the applicable determination date times a specified multiple based upon year over year revenue growth multiplied by 20%. As of March 31, 2016, is the Company has not recorded a liability related to the purchase obligation. On March 3, 2016, the Company purchased a $0.6 million convertible promissory note from a business that provides web and mobile money management solutions, with the potential for subsequent purchases of additional convertible notes. Investments in which the Company’s interest is less than 20% and which are not classified as available-for-sale securities are carried at the lower of cost or net realizable value unless it is determined that the Company exercises significant influence over the investee company, in which case the equity method of accounting is used. For those investments in which the Company’s voting interest is between 20% and 50%, the equity method of accounting is used. Under this method, the investment balance, originally recorded at cost, is adjusted to recognize the Company’s share of net earnings or losses of the investee company, as they occur, limited to the extent of the Company’s investment in, advances to and commitments for the investee. These adjustments are reflected in equity (income) loss of unconsolidated entities, net of tax in the Company’s consolidated statements of operations and comprehensive income. The Company recognized net losses of $1.1 million and $0.7 million for the three month periods ended March 31, 2015 and 2016, respectively, related to its investments. From time to time, the Company may make new and follow-on investments and may receive distributions from investee companies. As of March 31, 2016, the Company was not obligated to fund any follow-on investments in these investee companies, other than AppMachine as described above. As of March 31, 2016, the Company did not have an equity method investment in which the Company’s proportionate share of the investees’ net income or loss exceeded 10% of the Company’s consolidated assets or income from continuing operations.

Notes Payable

Notes Payable	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Notes Payable	9. Notes Payable In November 2013, following its initial public offering (“IPO”), the Company repaid in full its November 2012 second lien term loan facility of $315.0 million and increased the first lien term loan facility (“November 2013 First Lien”) by $166.2 million to $1,050.0 million. The Company also increased its revolver loan capacity by $40.0 million to $125.0 million, none of which was drawn down at the time of the increase. The mandatory repayment of principal on the November 2013 First Lien was increased to approximately $2.6 million at the end of each quarter. In connection with the acquisition of Constant Contact on February 9, 2016, the Company entered into a $735.0 million incremental first lien term loan facility and a new $165.0 million revolving credit facility (which replaced its existing $125.0 million revolving credit facility), and EIG Investors issued $350.0 million aggregate principal amount of 10.875% senior notes due 2024. The Company refers to the incremental first lien term loan facility and new revolving credit facility, together with its previously existing first lien term loan facility, as the “Senior Credit Facilities,” and to the 10.875% senior notes due 2024 as the “Notes.” Incremental First Lien Term Loan Facility On February 9, 2016, the Company entered into an incremental first lien term loan amendment to its existing credit agreement. Pursuant to this amendment, the Company obtained a seven-year $735.0 million incremental first lien term loan facility, which is in addition to its existing first lien term loan facility. The full amount of this incremental first lien term loan facility was drawn immediately following the effectiveness of the amendment. This incremental first lien term loan facility will mature in seven years, was issued at a price of 97% of par (subject to the payment of an additional upfront fee of 1.0% on February 28, 2016 under certain circumstances), bears interest at a rate of LIBOR plus 5.0% per annum, subject to a LIBOR floor of 1.0% per annum, and has scheduled amortization of 0.50% per quarter. As a result of the “most-favored nation” pricing provision in the Company’s existing credit agreement, the interest rate on its existing first lien term loan facility has increased to LIBOR plus 5.23% per annum (and was further stepped up to LIBOR plus 5.48% per annum on February 28, 2016 since certain circumstances materialized), subject to a LIBOR floor of 1.0% per annum. In addition, the Company is obligated to use commercially reasonable efforts to make voluntary prepayments on its existing first lien term loan facility to effectively double the amount of each scheduled amortization payment under that facility (which is 0.25% per quarter of the principal outstanding as of November 25, 2013). Revolving Credit Facility Also on February 9, 2016, the Company entered into a revolving facility amendment to its existing credit agreement. Pursuant to this amendment, the Company obtained a five-year $165.0 million revolving credit facility, which replaced its existing $125.0 million revolving credit facility. Loans under the facility will bear interest at a rate of LIBOR plus 4.0% per annum (subject to a leverage-based step-down), without a LIBOR floor. This revolving credit facility has a “springing” maturity date of August 10, 2019 unless the existing first lien term loan facility has been repaid in full or otherwise extended to at least 91 days after the maturity of the revolving credit facility. Loans under the Senior Credit Facilities are also subject to a base rate option, with interest rate spreads of 1.0% per annum less than those applicable to LIBOR-based loans. The Senior Credit Facilities have been fully and unconditionally guaranteed, on a senior unsecured basis, by the Company and certain of its subsidiaries (including Constant Contact and certain of its subsidiaries). 10.875% Senior Notes due 2024 On February 9, 2016, EIG Investors issued $350.0 million aggregate principal amount of Notes. The Notes will mature in February 2024, were issued at a price of 98.065% of par and will bear interest at the rate of 10.875% per annum. The Notes have been fully and unconditionally guaranteed, on a senior unsecured basis, by the Company and its subsidiaries that guarantee the Senior Credit Facilities (including Constant Contact and certain of its subsidiaries). In connection with the issuance of the Notes, the Company agreed to assist the initial purchasers of the Notes in marketing the Notes. In addition, the Company entered into a registration rights agreement with the initial purchasers of the Notes, which provides the holders of the Notes certain rights relating to registration of the Notes under the Securities Act. Pursuant to the registration rights agreement, the Company will, among other obligations, use commercially reasonable efforts to file an exchange offer registration statement with respect to a registered offer, or the Exchange Offer, to exchange the Notes for substantially identical notes and consummate the Exchange Offer within 365 days after the issuance of the Notes. The Company will also use commercially reasonable efforts to cause to become effective a shelf registration statement to cover resales of the Notes by the beneficial owners thereof who satisfy certain conditions relating to the provision of information in connection with the shelf registration statement. A registration default will occur if, among other things, (1) the Company fails to consummate the Exchange Offer or have the shelf registration statement become effective on or before the date that is 365 days after the issue date or (2) the shelf registration statement becomes effective but thereafter ceases to be effective or usable in connection with the resale of Notes (subject to certain exceptions) during the periods specified in the registration rights agreement. If a registration default occurs with respect to the Notes, the annual interest rate of the Notes will be increased by 0.25% per annum and will increase again by 0.25% per annum 90 days thereafter until all registration defaults have been cured, up to a maximum amount of additional interest of 0.50% per annum. The Company will also use commercially reasonable efforts to cause to become effective a registration statement providing for the registration of certain secondary transactions in the Notes by Goldman, Sachs & Co. and its affiliates. At December 31, 2015 and March 31, 2016, notes payable consisted of a first lien term loan facility with a principal amount outstanding of $1,026.4 million and $1,021.1 million, respectively, which bore interest at a LIBOR-based rate of 5.00% and 6.48%, respectively. The current portion of the first lien term loan as of December 31, 2015 and March 31, 2016 was $10.5 million and $21.0 million, respectively. As of December 31, 2015, notes payable included a bank revolver loan (“2015 Revolver loan”) of $67.0 million, consisting of a loan of $59.0 million which bore interest at a LIBOR-based rate of 7.75% and a loan of $8.0 million which bore interest at an alternate base rate of 8.50%. The amount outstanding under the 2015 Revolver loan as of December 31, 2015 was classified as current notes payable on the consolidated balance sheet. In addition, as of March 31, 2016, the notes payable included $731.3 million, net of original issue discounts related to the incremental first lien term loan facility, which bore interest at a LIBOR-based rate of 6.0%. The current portion of the incremental first lien term loan as of March 31, 2016 was $14.7 million. As of March 31, 2016, notes payable also included the $350.0 million of 10.875% senior notes due 2024, net of original issue discounts. There were no amounts outstanding under the revolving credit facility. During the three months ended March 31, 2015 and 2016, the Company made aggregate mandatory repayments on the November 2013 First Lien of $2.6 million and $5.3 million, respectively. Also, during the three months ended March 31, 2016, the Company made a voluntary repayment on the incremental first lien term loan facility of $3.7 million. During the three months ended March 31, 2015 and 2016, the Company had drawn down an aggregate amount of $7.0 million and $16.0 million, respectively, on its Revolver loan, and repaid an aggregate amount of $36.0 million and $83.0 million, respectively, of the amounts drawn down, resulting in $21.0 million and $0.0 million, outstanding under the Revolver loan at March 31, 2015 and 2016, respectively. The maturity dates of the November 2013 First Lien, the incremental first lien term loan facility and the $350.0 million of 10.875% senior notes are November 9, 2019, February 9, 2023, and February 9, 2024, respectively. There is a springing maturity related to the revolving credit facility. If the Company’s November 2013 First Lien has not been paid in full prior to August 10, 2019 and the final maturity has not been extended to May 11, 2021 or later, then the maturity date of the revolving credit facility is February 9, 2019. Effective November 25, 2013, the interest rate for a LIBOR based interest loan was reduced to 4.00% plus the greater of the LIBOR rate or 1.00%. The interest rate for a reference rate loan was reduced to 3.00% per annum plus the greater of the prime rate, the federal funds effective rate plus 0.50%, an Adjusted LIBOR rate or 2.00%. Effective February 9, 2016, the interest rates for a revolver loan are subject to variability based on certain covenants. Interest is payable on maturity of the elected interest period for a LIBOR-based interest loan, which can be one, two, three or six months. Interest is payable at the end of each fiscal quarter for a reference rate loan, term loan or an ABR revolver loan. The Company adopted ASU 2015-03, “Simplifying the Presentation of Debt Issuance Cost” Interest The Company recorded $14.3 million and $30.4 million in interest expense for the three months ended March 31, 2015 and 2016, respectively. The following table provides a summary of interest rates and interest expense for the three months ended March 31, 2015 and 2016: Three Months Ended March 31, 2015 2016 (dollars in thousands) Interest rate—LIBOR 5.00%-7.75 % 6.00%-7.75 % Interest rate—reference 8.50 % 7.50%-8.50 % Interest rate—Senior notes — 10.875 % Non-refundable fee—unused facility 0.50 % 0.50 % Interest expense and service fees $ 13,976 $ 27,996 Amortization of deferred financing fees $ 20 $ 911 Amortization of original issue discounts $ — $ 449 Amortization of net present value of deferred consideration $ 138 $ 783 Interest expense for capital lease obligations $ 98 $ 157 Interest expense for deferred consideration promissory note $ 70 $ 70 Other interest expense $ 19 $ 5 Total interest expense $ 14,321 $ 30,371 Debt Covenants Senior Credit Facilities The Senior Credit Facilities require that the Company complies with a financial covenant to maintain a maximum ratio of net first lien debt to EBITDA (as defined in the Company’s existing credit agreement). The Senior Credit Facilities contain covenants that limit the Company’s ability to, among other things, incur additional debt or issue certain preferred shares; pay dividends on or make other distributions in respect of capital stock; make other restricted payments; make certain investments; sell or transfer certain assets; create liens on certain assets to secure debt; consolidate, merge, sell or otherwise dispose of all or substantially all of its assets; and enter into certain transactions with affiliates. Additionally, the Senior Credit Facilities require the Company to comply with certain negative covenants and specify certain events of default that could result in amounts becoming payable, in whole or in part, prior to their maturity dates. The Company was in compliance with all covenants at March 31, 2016. With the exception of certain equity interests and other excluded assets under the terms of the Senior Credit Facilities, substantially all of the Company’s assets are pledged as collateral for the obligations under the Senior Credit Facilities. Notes The indenture with respect to the Notes contains covenants that limit the Company’s ability to, among other things, incur additional debt or issue certain preferred shares; pay dividends on or make other distributions in respect of capital stock; make other restricted payments; make certain investments; sell or transfer certain assets; create liens on certain assets to secure debt; consolidate, merge, sell or otherwise dispose of all or substantially all of its assets; and enter into certain transactions with affiliates. Upon a change of control as defined in the Indenture, the Company or EIG Investors must offer to repurchase the Notes at 101% of the aggregate principal amount thereof, plus accrued and unpaid interest, if any, up to, but not including, the repurchase date. These covenants are subject to a number of important limitations and exceptions. The indenture also provides for events of default, which, if any of them occurs, may permit or, in certain circumstances, require the principal, premium, if any, interest and any other monetary obligations on all the then outstanding Notes to be due and payable immediately.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2016
Equity [Abstract]
Stockholders' Equity	10. Stockholders’ Equity Voting Rights All holders of common stock are entitled to one vote per share. The following table presents the changes in total stockholders’ equity: Total Stockholders’ Equity (in thousands) Balance, December 31, 2015 $ 179,674 Stock-based compensation 18,388 Stock option exercises 593 Foreign currency translation adjustment 342 Unrealized loss on derivative (1,511 ) Minority interest accretion (3,472 ) Investment in Constant Contact 5,395 Income tax from the exercise of stock options (16 ) Net income 14,081 Balance, March 31, 2016 $ 213,474

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	11. Stock-Based Compensation 2013 Stock Incentive Plan The 2013 Stock Incentive Plan (the “2013 Plan”) of the Company became effective upon the closing of its IPO. The 2013 Plan provides for the grant of options, stock appreciation rights, restricted stock, restricted stock units and other stock-based awards to employees, officers, directors, consultants and advisors of the Company. Under the 2013 Plan, the Company may issue up to 18,000,000 shares of the Company’s common stock. At March 31, 2016, 4,618,955 shares were available for grant under the 2013 Plan. 2011 Stock Incentive Plan As of February 9, 2016, the effective date of the acquisition of Constant Contact, the Company assumed and converted certain outstanding equity awards granted by Constant Contact under the Constant Contact 2011 Stock Incentive Plan (“2011 Plan”) prior to the effective date of the acquisition (the “Assumed Awards”) into corresponding equity awards with respect to shares of the Company’s common stock. In addition, the Company assumed certain shares of Constant Contact common stock, par value $0.01 per share, available for issuance under the 2011 Plan, which will be available for future issuance under the 2011 Plan in satisfaction of the vesting, exercise or other settlement of options and other equity awards that may be granted by the Company following the effective date of the acquisition of Constant Contact in reliance on the prior approval of the 2011 Plan by the stockholders of Constant Contact. The Company assumed 2,143,987 stock options and 2,202,846 restricted stock units with respect to the Assumed Awards. There are 14,346,830 shares of Endurance International Group Holdings, Inc. common stock reserved for issuance under the 2011 Plan. At March 31, 2016, 10,320,757 shares were available for grant under the 2011 Plan. The Company calculated the fair value of the exchanged awards in accordance with the provisions of ASC 718 as of the acquisition date. The Company allocated the fair value of these awards between the pre-acquisition and post-acquisition stock-based compensation expense. The Company determined that the value of the awards under this plan was $22.3 million, of which $5.4 million was attributed to the pre-acquisition period and recognized as part of the purchase consideration for Constant Contact. The balance of $16.9 million has been attributed to the post-acquisition period. Of the $16.9 million, the Company recognized approximately $3.7 million during the three months ended March 31, 2016. The following table presents total stock-based compensation expense recorded in the consolidated statement of operations and comprehensive income for all 2012 restricted stock awards and units issued prior to the IPO, all awards granted under the Company’s 2013 Plan and the 2011 Plan: Three Months Ended March 31, 2015 2016 (in thousands) Cost of revenue $ 113 $ 770 Sales and marketing 390 1,722 Engineering and development 217 764 General and administrative 3,251 15,132 Total stock-based compensation expense $ 3,971 $ 18,388 2012 Restricted Stock Awards The following table provides a summary of the 2012 restricted stock awards activity for the three months ended March 31, 2016 for restricted stock awards that were granted prior to the IPO, including the non-vested balance as of March 31, 2016: 2012 Restricted Stock Awards Non-vested at December 31, 2015 46,645 Vested (27,818 ) Canceled — Non-vested at March 31, 2016 18,827 The following table provides a summary of the activity for the three months ended March 31, 2016 for the restricted stock units that were granted in connection with the IPO, including the non-vested balance as of March 31, 2016: Restricted Stock Units Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 22,158 $ 12.00 Vested and unissued (22,158 ) $ 12.00 Non-vested at March 31, 2016 — — 2013 Stock Incentive Plan The following table provides a summary of the Company’s stock options as of March 31, 2016 and the stock option activity for all stock options granted under the 2013 Plan during the three months ended March 31, 2016: Stock Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (In Years) Aggregate Intrinsic Value(3) Outstanding at December 31, 2015 6,950,858 $ 13.83 Granted — $ — Exercised — $ — Forfeited (57,440 ) $ 17.41 Expired (231,799 ) $ 12.68 Outstanding at March 31, 2016 6,661,619 $ 13.84 8.1 $ — Exercisable at March 31, 2016 2,832,742 $ 12.07 7.6 $ — Expected to vest after March 31, 2016 (1) 3,776,172 $ 15.12 8.4 $ — Exercisable as of March 31, 2016 and expected to vest thereafter (2) 6,608,914 $ 13.81 8.1 $ — (1) This represents the number of unvested options outstanding as of March 31, 2016 that are expected to vest in the future, which have been reduced using an estimated forfeiture rate. (2) This represents the number of vested options as of March 31, 2016 plus the number of unvested options outstanding as of March 31, 2016 that are expected to vest in the future, which have been reduced using an estimated forfeiture rate. (3) The aggregate intrinsic value was calculated based on the positive difference, if any, between the estimated fair value of the Company’s common stock on March 31, 2016 of $10.53 per share, or the date of exercise, as appropriate, and the exercise price of the underlying options. Unless otherwise determined by the Company’s board of directors, restricted stock units granted under the 2013 Plan generally vest monthly over a four-year period. The following table provides a summary of the Company’s restricted stock unit activity for the 2013 Plan during the three months ended March 31, 2016: Restricted Stock Units Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 220,765 $ 12.00 Vested and unissued (30,099 ) $ 12.00 Non-vested at March 31, 2016 190,666 $ 12.00 Unless otherwise determined by the Company’s board of directors, restricted stock awards granted under the 2013 Plan generally vest annually over a four-year period. Performance-based restricted stock awards are earned based on the achievement of performance criteria established by the Company’s Compensation Committee and Board of Directors. The following table provides a summary of the Company’s restricted stock award activity for the 2013 Plan during the three months ended March 31, 2016: Restricted Stock Awards Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 4,849,290 $ 15.24 Granted 743,514 $ 8.74 Vested (92,368 ) $ 12.03 Canceled (24,522 ) $ 17.00 Non-vested at March 31, 2016 5,475,914 $ 14.40 2015 Performance Based Award The performance-based award granted to the Company’s chief executive officer during 2015 provides an opportunity for the participant to earn a fully vested right to up to 3,693,754 shares of the Company’s common stock (the “Award Shares”) over a three-year period beginning July 1, 2015 and ending on June 30, 2018 (the “Performance Period”). Award Shares may be earned based on the Company achieving pre-established, threshold, target and maximum performance metrics. Award Shares may be earned during each calendar quarter during the Performance Period (each, a “Performance Quarter”) if the Company achieves a threshold, target or maximum level of the performance metric for the Performance Quarter. If the performance metric is less than the threshold level for a Performance Quarter, no Award Shares will be earned during the Performance Quarter. Award Shares that were not earned during a Performance Quarter may be earned later during the then current twelve-month period from July 1 st th This performance-based award is evaluated quarterly to determine the probability of its vesting and determine the amount of stock-based compensation to be recognized. During the three months ended March 31, 2016, the Company recognized $7.9 million of stock-based compensation expense related to this performance-based award. Of the $7.9 million, $3.3 million was additional stock-based compensation expense recognized during the three months ended March 31, 2016, due to changes in assumptions regarding the vesting of the award. 2016 Performance Based Awards On February 16, 2016, the Compensation Committee of the Board of Directors of the Company approved the grant of performance-based restricted stock awards to the Company’s Chief Financial Officer (“CFO”), Chief Operating Officer (“COO”) and Chief Administrative Officer (“CAO”). The CFO performance-based restricted stock award provides an opportunity to earn a fully vested right to up to 223,214 shares of the Company’s stock, with a target of 178,571 shares. The COO performance-based restricted stock award provides an opportunity to earn a fully vested right to up to 260,416 shares of the Company’s stock, with a target of 208,333 shares. The CAO performance-based restricted stock award provides an opportunity to earn a fully vested right to up to 148,810 shares of the Company’s stock, with a target of 119,048 shares. The shares subject to the performance-based restricted stock awards will be earned based on the Company’s Constant Contact brand achieving a pre-established level of adjusted revenue (weighted 50%), adjusted EBITDA (weighted 25%) and adjusted free cash flow (weighted 25%), in each case for the twelve months ending December 31, 2016, assuming for this purpose that the Company’s acquisition of Constant Contact had taken place on January 1, 2016 (the “Performance Metric”). Adjusted free cash flow is defined for this purpose as adjusted EBITDA, less (i) cash paid for restructuring charges and capital expenditures, plus or minus (ii) the change in working capital. Each executive will earn from 0% to 125% of the target number of shares subject to their performance-based restricted stock award based on the level of achievement of the Performance Metric. Shares that are earned based on the achievement of the Performance Metric will vest on March 31, 2017 and any unearned shares as of that date will be forfeited. These performance-based awards are evaluated quarterly to determine the probability of vesting and determine the amount of stock-based compensation to be recognized. During the three months ended March 31, 2016, the Company recognized $0.6 million of stock-based compensation expense related to these performance-based awards. 2011 Stock Incentive Plan The following table provides a summary of the Company’s stock options as of March 31, 2016 and the stock option activity for all stock options granted under the 2011 Plan during the three months ended March 31, 2016: Stock Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (In Years) Aggregate Intrinsic Value(3) Outstanding at December 31, 2015 — $ — Granted/ Exchanged 2,143,987 $ 7.28 Exercised (89,572 ) $ 6.60 Forfeited (240,559 ) $ 7.18 Outstanding at March 31, 2016 1,813,856 $ 7.33 5.2 $ 5,809 Exercisable at March 31, 2016 351,727 $ 8.90 5.3 $ 572 Expected to vest after March 31, 2016 (1) 1,462,129 $ 6.95 5.1 $ 5,237 Exercisable as of March 31, 2016 and expected to vest thereafter (2) 1,813,856 $ 7.33 5.2 $ 5,809 (1) This represents the number of unvested options outstanding as of March 31, 2016 that are expected to vest in the future, which have been reduced using an estimated forfeiture rate. (2) This represents the number of vested options as of March 31, 2016 plus the number of unvested options outstanding as of March 31, 2016 that are expected to vest in the future, which have been reduced using an estimated forfeiture rate. (3) The aggregate intrinsic value was calculated based on the positive difference, if any, between the estimated fair value of the Company’s common stock on March 31, 2016 of $10.53 per share, or the date of exercise, as appropriate, and the exercise price of the underlying options. Unless otherwise determined by the Company’s board of directors, restricted stock units granted under the 2011 Plan generally vest annually over a four-year period. The following table provides a summary of the Company’s restricted stock unit activity for the 2011 Plan during the three months ended March 31, 2016: Restricted Stock Units Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 — $ — Granted/ Exchanged 2,202,846 $ 7.69 Vested (345,544 ) $ 7.69 Canceled (80,201 ) $ 7.69 Non-vested at March 31, 2016 1,777,101 $ 7.69

Redeemable Non-controlling Inte

Redeemable Non-controlling Interest	3 Months Ended
	Mar. 31, 2016
Noncontrolling Interest [Abstract]
Redeemable Non-controlling Interest	12. Redeemable Non-controlling Interest In connection with a 2014 equity investment in WZ UK Ltd., on January 6, 2016, the Company exercised its option to increase its stake in WZ UK Ltd from 49% to 57.5%, where the Company acquired a controlling interest, in exchange for a payment of approximately $2.1 million to the other shareholders of WZ UK Ltd. The agreement related to the transaction provides for a put option for the then NCI shareholders to put the remaining equity interest to the Company within pre-specified put periods. As the NCI is subject to a put option that is outside the control of the Company, it is deemed a redeemable non-controlling interest and is not recorded in permanent equity, and is presented as mezzanine redeemable non-controlling interest on the consolidated balance sheet, and is subject to the guidance of the Securities and Exchange Commission (“SEC”) under ASC 480-10-S99, Accounting for Redeemable Equity Securities. During the three months ended March 31, 2016, the Company obtained a controlling interest in Resume Labs Ltd. for $1.5 million and Pseudio Limited for $1.5 million. The agreements related to these transactions provide for put options for the NCI shareholders of each company to put the remaining equity interest to the Company within pre-specified put periods. As the NCI for these entities are subject to put options that are outside the control of the Company, they are deemed redeemable non-controlling interests and are also not recorded in permanent equity, and are presented as part of the mezzanine redeemable non-controlling interest on the consolidated balance sheet. As of March 31, 2016, the Company has not determined that it is probable that the minority interest put option for each company will be triggered. Therefore, the Company is not accreting to a minimum fair value as of March 31, 2016. Non-controlling interest arising from the application of the consolidation rules is classified within total stockholders’ equity with any adjustments charged to net loss attributable to non-controlling interest in a consolidated subsidiary in the consolidated statement of operations and comprehensive income.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	13. Income Taxes The Company files income tax returns in the United States for federal income taxes and in various state jurisdictions. The Company also files in several foreign jurisdictions. In the normal course of business, the Company is subject to examination by tax authorities throughout the world. Since the Company is in a loss carry-forward position, the Company is generally subject to U.S. federal and state income tax examinations by tax authorities for all years for which a loss carry-forward is utilized. The Company is currently under audit in India for fiscal year ended March 31, 2015 and Israel for the fiscal years ended December 31, 2012, 2013 and 2014. The statutes of limitations in the Company’s other tax jurisdictions remains open for various periods between 2011 and the present. However, carryforward attributes from prior years may still be adjusted upon examination by tax authorities if they are used in an open period. The Company does not expect material changes as a result of the audits. The Company recognizes, in its consolidated financial statements, the effect of a tax position when it is more likely than not, based on the technical merits, that the position will be sustained upon examination. The Company has no unrecognized tax positions at December 31, 2015 and March 31, 2016 that would affect its effective tax rate. The Company does not expect a significant change in the liability for unrecognized tax benefits in the next 12 months. The Company regularly assesses its ability to realize its deferred tax assets. Assessing the realization of deferred tax assets requires significant management judgment. In determining whether its deferred tax assets are more likely than not realizable, the Company evaluated all available positive and negative evidence, and weighted the evidence based on its objectivity. Evidence the Company considered included: • Net Operating Losses (“NOL”) incurred from the Company’s inception to March 31, 2016; • Expiration of various federal and state tax attributes; • Reversals of existing temporary differences; • Composition and cumulative amounts of existing temporary differences; and • Forecasted profit before tax. Prior to the acquisition of Constant Contact, the Company maintained a valuation allowance against certain deferred tax assets. The acquisition of Constant Contacted resulted in a significant increase in deferred tax liabilities, which far exceeded pre-acquisition deferred tax assets. The Company scheduled out the reversal of deferred tax assets and liabilities as of March 31, 2016, and determined that these reversals would be sufficient to realize most domestic deferred tax assets. The deferred tax liabilities supporting the realizability of these deferred tax assets in the acquisition will reverse in the same period, are in the same jurisdiction and are of the same character as the temporary differences that gave rise to these deferred tax assets. As a result, the Company recorded a tax benefit of $73.6 million to reverse valuation allowances during the three months ended March 31, 2016. For the three months ended March 31, 2015 and 2016, the Company recognized tax expense of $1.0 million and a tax benefit of $99.9 million, respectively, in the consolidated statements of operations and comprehensive income. The income tax benefit for the three months ended March 31, 2016 was primarily attributable to a $73.6 million reversal of the valuation allowance, a federal and state deferred tax benefit of $29.0 million, which includes the identification and recognition of $7.3 million of U.S. federal research and development tax credits, and a foreign deferred tax benefit of $0.7 million, partially offset by a provision for federal and state current income taxes of $2.2 million and foreign current tax expense of $1.1 million. The income tax expense for the three months ended March 31, 2015 is primarily attributable to a provision for foreign taxes of $0.4 million, federal and state current income taxes of $0.2 million, U.S. deferred income tax of $0.5 million related to the differences in the accounting treatment of goodwill under U.S. GAAP and the tax accounting for goodwill and foreign deferred tax expense of $0.2 million related to the increases of deferred liabilities, partially offset by a $0.3 million reduction of the valuation allowance. The provision for income taxes shown on the consolidated statements of operations and comprehensive income differs from amounts that would result from applying the statutory tax rates to income before taxes primarily because of state income taxes and certain expenses that were non-deductible, as well as the application of valuation allowances against U.S. and foreign assets. As of December 31, 2015, the Company had NOL carry-forwards available to offset future U.S. federal taxable income of approximately $97.8 million and future state taxable income of approximately $111.2 million. These NOL carry-forwards expire on various dates through 2034. Approximately $1.6 million of the U.S. federal NOL carry-forwards and $0.7 million of the state NOL carry-forwards are from excess stock-based compensation, for which the benefit will be recorded to additional paid-in capital when recognized. As of December 31, 2015, the Company had NOL carry-forwards in foreign jurisdictions available to offset future foreign taxable income by approximately $27.4 million. The Company has loss carry-forwards in India totaling $2.9 million that expire in 2021. The Company also has loss carry-forwards in the United Kingdom, Israel and Singapore of $23.4 million, $0.9 million, and $0.2 million, respectively, which have an indefinite carry-forward period. Utilization of the NOL carry-forwards may be subject to an annual limitation due to the ownership percentage change limitations under Section 382 of the Internal Revenue Code (“Section 382 limitation”). Ownership changes can limit the amount of net operating loss and other tax attributes that a company can use each year to offset future taxable income and taxes payable. In connection with a change in control in 2011 the Company was subject to Section 382 limitations of $77.1 million against the balance of NOL carry-forwards generated prior to the change in control in 2011. Through December 31, 2013, the Company accumulated the unused amount of Section 382 limitations in excess of the amount of NOL carry-forwards that were originally subject to limitation. Therefore, these unused NOL carry-forwards are available for future use to offset taxable income. The Company has completed an analysis of changes in its ownership from 2011, through its IPO, to December 31, 2013. The Company concluded that there was not a Section 382 ownership change during this period and therefore any NOLs generated through December 31, 2013, are not subject to any new Section 382 limitations on NOL carry-forwards. On November 20, 2014, the Company completed a follow-on offering of 13,000,000 shares of common stock. The underwriters also exercised their overallotment option to purchase an additional 1,950,000 shares of common stock from the selling stockholders. The Company performed an analysis of the impact of this offering and determined that no Section 382 change in ownership had occurred. On March 11, 2015, the Company completed a follow-on offering of its common stock, in which selling stockholders sold 12,000,000 shares of common stock at a public offering price of $19.00 per share. The underwriter also exercised its overallotment option to purchase an additional 1,800,000 shares of common stock from the selling stockholders. The Company is currently completing an analysis of its ownership changes from March 11, 2015 through December 31, 2015, but does not believe the outcome of this analysis will result in an additional ownership change based on the information available at this time. As of the Company’s acquisition of Constant Contact, Constant Contact had approximately $57.7 million and $31.9 million of federal and state NOLs, respectively, and approximately $10.6 million of U.S. federal research and development credits and $9.6 million of state credits. All of the acquired tax attributes (NOLs and tax credits) from the transaction are subject to a Section 382 ownership change as a result of the transaction. Although an ownership change was triggered, the Company does not expect that the limitations placed on its NOLs and research and development tax credits will result in a restriction on their use or the expiration of its NOLs and research and development tax credit carryforwards. However, future equity transactions could further limit the utilization of these tax attributes. As a result, all unused NOL carry-forwards at December 31, 2015 are available for future use to offset taxable income.

Severance and Other Exit Costs

Severance and Other Exit Costs	3 Months Ended
	Mar. 31, 2016
Restructuring and Related Activities [Abstract]
Severance and Other Exit Costs	14. Severance and Other Exit Costs In connection with acquisitions, the Company may evaluate its data center, sales and marketing, support and engineering operations and the general and administrative function in an effort to eliminate redundant costs. As a result, the Company may incur charges for employee severance, exiting facilities and restructuring data center commitments and other related costs. 2014 Restructuring Plan During the year ended December 31, 2014, the Company implemented plans to further integrate and consolidate its data center, support and engineering operations, resulting in severance and facility exit costs. The severance charges were associated with eliminating approximately 90 positions across primarily support, engineering operations and sales and marketing. The Company incurred severance costs of $2.3 million in the year ended December 31, 2014 related to these restructuring activities. The employee-related charges associated with these restructurings were completed during the year ended December 31, 2014. As of March 31, 2016, the Company did not have any remaining accrued employee-severance related to these severance costs. The Company had incurred facility costs associated with closing offices in Redwood City, California and Englewood, Colorado. At the time of closing these offices, the Company had remaining lease obligations of approximately $3.0 million for these vacated facilities through March 31, 2018. The Company recorded a facilities charge for these future lease payments, less expected sublease income, of $2.1 million during the year ended December 31, 2014. During the three months ended March 31, 2016, the Company recorded an adjustment of $0.2 million relating to the lease agreement for the Englewood, Colorado facility. The following table provides a summary of the activity for the three months ended March 31, 2016 related to the Company’s facilities exit costs accrual: Facilities (in thousands) Balance at December 31, 2015 $ 479 Cash paid (236 ) Sublease income 41 Adjustments 186 Balance at March 31, 2016 $ 470 2015 Restructuring Plan During the year ended December 31, 2015, the Company implemented plans to enhance operational efficiencies across the business, resulting in severance costs (the “2015 Restructuring Plan”). The severance charges were associated with eliminating approximately 67 positions across the business. The Company incurred severance costs of $2.1 million during the year ended December 31, 2015 related to the 2015 Restructuring Plan. The Company completed employee-related charges associated with the 2015 Restructuring Plans during the year ended December 31, 2015. The Company paid $0.6 million of severance costs during the three months ended March 31, 2016 and had a remaining accrued severance liability of $0.6 million as of March 31, 2016. The Company expects payments to related to the 2015 Restructuring Plan be completed during the year ended December 31, 2016. The following table provides a summary of the activity for the three months ended March 31, 2016 related to the Company’s 2015 Restructuring Plan severance accrual: 2015 Plan Employee Severance (in thousands) Balance at December 31, 2015 $ 1,201 Severance adjustments (15 ) Cash paid (623 ) Balance at March 31, 2016 $ 563 2016 Restructuring Plan In connection with the Company’s acquisition of Constant Contact on February 9, 2016, during the three months ended March 31, 2016, the Company implemented plans to create operational efficiencies and synergies resulting in severance costs and facility exit costs (the “2016 Constant Contact Restructuring Plan”). The severance charges were associated with eliminating approximately 180 positions across the business. The Company incurred severance costs of $8.0 million during the three months ended March 31, 2016 related to the 2016 Constant Contact Restructuring Plan. The Company expects to complete employee-related charges associated with the 2016 Constant Contact Restructuring Plan during the year ended December 31, 2016. The Company paid $1.5 million of severance costs during the three months ended March 31, 2016 and had a remaining accrued severance liability of $6.5 million as of March 31, 2016. The Company expects payments related to the 2016 Constant Contact Restructuring Plan to be completed during the year ended December 31, 2016. The following table provides a summary of the activity for the three months ended March 31, 2016 related to the Company’s 2016 Constant Contact Restructuring Plan severance accrual: 2016 Constant Contact Plan Employee Severance (in thousands) Balance at December 31, 2015 $ — Severance charges 8,015 Cash paid (1,470 ) Balance at March 31, 2016 $ 6,545 The Company’s 2016 Constant Contact Restructuring Plan includes a plan to close offices in San Francisco, California, Delray Beach, Florida, New York, New York and the United Kingdom. The Company is also closing a portion of the Constant Contact offices in Waltham, Massachusetts. During the three months ended March 31, 2016, the Company recorded a facilities charge for future lease payments of $7.6 million, less expected sublease income of $4.2 million. The following table provides a summary of the activity for the three months ended March 31, 2016 related to the Company’s 2016 Constant Contact Restructuring Plan facilities exit costs accrual: Facilities (in thousands) Balance at December 31, 2015 $ — Facilities exit charges, net of estimated sublease income 3,416 Cash paid (147 ) Balance at March 31, 2016 $ 3,269 The following table presents restructuring charges recorded in the consolidated statement of operations and comprehensive income for the periods presented: For the Three Months Ended March 31, 2015 2016 (in thousands) Cost of revenue $ (49 ) $ 3,279 Sales and marketing (14 ) 3,901 Engineering and development (67 ) 2,018 General and administrative 40 2,218 Total restructuring charges $ (90 ) $ 11,416

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	15. Commitments and Contingencies From time to time, the Company is involved in legal proceedings or subject to claims arising in the ordinary course of its business. The Company is not presently involved in any such legal proceeding or subject to any such claim that, in the opinion of its management would have a material adverse effect on its business, operating results or financial condition. However, the results of such legal proceedings or claims cannot be predicted with certainty, and regardless of the outcome, can have an adverse impact on the Company because of defense and settlement costs, diversion of management resources and other factors. Neither the ultimate outcome of the matters listed below nor an estimate of any probable losses or any reasonably possible losses can be assessed at this time. On May 4, 2015, Christopher Machado, a purported holder of the Company’s common stock, filed a civil action in the United States District Court for the District of Massachusetts against the Company and its chief executive officer and former chief financial officer, Machado v. Endurance International Group Holdings, Inc., The Company received a subpoena dated December 10, 2015 from the Boston Regional Office of the SEC, requiring the production of certain documents, including, among other things, documents related to its financial reporting, including operating and non-GAAP metrics, refund, sales and marketing practices and transactions with related parties. The Company is fully cooperating with the SEC’s investigation, which is still in its preliminary stages. The Company can make no assurances as to the time or resources that will need to be devoted to this investigation or the final outcome, or the impact, if any, of this investigation on its business, financial condition, results of operations and cash flows. Constant Contact On October 30, 2015, the Company entered into a definitive agreement pursuant to which it agreed to acquire all of the outstanding shares of common stock of Constant Contact. The acquisition closed on February 9, 2016. Constant Contact contingencies are noted below. On December 10, 2015, Constant Contact received a subpoena from the Boston Regional Office of the SEC, requiring the production of documents pertaining to Constant Contact’s sales, marketing, and customer retention practices, and periodic public disclosure of financial and operating metrics. The Company is fully cooperating with the SEC’s investigation. The Company can make no assurances as to the time or resources that will need to be devoted to this investigation or its final outcome, or the impact, if any, of this investigation or any related legal or regulatory proceedings on the Company’s business, financial condition, results of operations and cash flows. On August 7, 2015, a purported class action lawsuit, William McGee v. Constant Contact, Inc., et al, was filed in the United States District Court for the District of Massachusetts against Constant Contact and two of its former officers. The lawsuit asserts claims under Sections 10(b) and 20(a) of the Exchange Act, and is premised on allegedly false and/or misleading statements, and non-disclosure of material facts, regarding Constant Contact’s business, operations, prospects and performance during the proposed class period of October 23, 2014 to July 23, 2015. This litigation is in its very early stages. The Company and the individual defendants intend to vigorously defend all claims asserted. The Company cannot, however, make any assurances as to the outcome of this proceeding. In September 2012, RPost Holdings, Inc., RPost Communications Limited and RMail Limited, or collectively, RPost, filed a complaint in the United States District Court for the Eastern District of Texas that named Constant Contact as a defendant in a lawsuit. The complaint alleged that certain elements of Constant Contact’s email marketing technology infringe five patents held by RPost. RPost seeks an award for damages in an unspecified amount and injunctive relief. In February 2013, RPost amended its complaint to name five of Constant Contact’s marketing partners as defendants. Under Constant Contact’s contractual agreements with these marketing partners, it is obligated to indemnify them for claims related to patent infringement. Constant Contact filed a motion to sever and stay the claims against its partners and multiple motions to dismiss the claims against it. In January 2014, the case was stayed pending the resolution of certain state court and bankruptcy actions involving RPost, to which Constant Contact is not a party. The stay was extended by agreement of the parties in December 2014. This litigation is in its very early stages. The Company believes it has meritorious defenses to any claim of infringement and intends to defend against the lawsuit vigorously. On December 11, 2015, a putative class action lawsuit relating to the Constant Contact acquisition, captioned Irfan Chawdry, Individually and On Behalf of All Others Similarly Situated v. Gail Goodman, et al. Case No. 11797, or the Chawdry Complaint, and on December 21, 2015, a putative class action lawsuit relating to the acquisition captioned David V. Myers, Individually and On Behalf of All Others Similarly Situated v. Gail Goodman, et al. Case No. 11828, or the Myers Complaint (together with the Chawdry Complaint, the Complaints) filed in the Court of Chancery of the State of Delaware naming Constant Contact, each of Constant Contact’s directors, Endurance and Paintbrush Acquisition Corporation as defendants. The Complaints generally allege, among other things, that in connection with the acquisition the directors of Constant Contact breached their fiduciary duties owed to the stockholders of Constant Contact by agreeing to sell Constant Contact for purportedly inadequate consideration, engaging in a flawed sales process, omitting material information necessary for stockholders to make an informed vote, and agreeing to a number of purportedly preclusive deal protection devices. The Complaints seek, among other things, to rescind the acquisition, as well as award of plaintiffs’ attorneys’ fees and costs in the action. The defendants have not yet answered or otherwise responded to either of these Complaints. The defendants believe the claims asserted in the Complaints are without merit and intend to defend against these lawsuits vigorously.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2016
Related Party Transactions [Abstract]
Related Party Transactions	16. Related Party Transactions The Company has various agreements in place with related parties. Below are details of related party transactions that occurred during the three months ended March 31, 2015 and 2016. Tregaron : The Company has contracts with Tregaron India Holdings, LLC and its affiliates, including Diya Systems (Mangalore) Private Limited, Glowtouch Technologies Pvt. Ltd. and Touchweb Designs, LLC (collectively, “Tregaron”), for outsourced services, including email- and chat-based customer and technical support, network monitoring, engineering and development support and web design and web building services. These entities are owned directly or indirectly by family members of the Company’s chief executive officer, who is also a director and stockholder of the Company. During 2013 the Company expanded the services provided by Tregaron under the agreements to include support of a newly formed entity in India related to our acquisition of HostGator India. The following table presents the amounts of related party transactions recorded in the consolidated statements of operations and comprehensive income for the periods presented relating to services provided by Tregaron and its affiliates under these agreements: Three Months Ended March 31, 2015 2016 (in thousands) Cost of revenue $ 2,400 $ 3,100 Sales and marketing 100 100 Engineering and development 400 300 General and administrative 100 100 Total related party transaction expense $ 3,000 $ 3,600 As of December 31, 2015, approximately $1.9 million was included in accounts payable and accrued expense relating to services provided by Tregaron. As of March 31, 2016, approximately $1.7 million was included in accounts payable and accrued expense relating to services provided by Tregaron. Innovative Business Services, LLC: The Company also has agreements with Innovative Business Services, LLC (“IBS”), which provides multi-layered third-party security applications that are sold by the Company. IBS is indirectly majority owned by the Company’s chief executive officer and a director of the Company, each of whom are also stockholders of the Company. During the year ended December 31, 2014, the Company’s principal agreement with this entity was amended which resulted in the accounting treatment of expenses being recorded against revenue. The Company inadvertently excluded the revenue related to the expanded relationship with IBS from related party disclosures the three months ended March 31, 2015. The following table includes the revised amount of related party transactions recorded in the consolidated statements of operations and comprehensive income for the three months March 31, 2015 relating to services provided by IBS under these agreements: Three Months Ended March 31, As Reported As Revised 2015 2015 2016 (in thousands) Revenue $ — $ (150 ) $ (600 ) Revenue (contra) 1,800 1,800 2,100 Total related party transaction impact to revenue $ 1,800 $ 1,650 $ 1,500 Cost of revenue 200 200 200 Total related party transaction expense, net $ 2,000 $ 1,850 $ 1,700 As of December 31, 2015 and March 31, 2016, approximately $0.2 million and $0.1 million, respectively, was included in prepaid expenses and other current assets relating to the Company’s agreements with IBS. As of December 31, 2015 and March 31, 2016, approximately $1.1 million and $1.5 million, respectively was included in accounts payable and accrued expense relating to the Company’s agreements with IBS. As of December 31, 2015 and March 31, 2016, approximately $0.3 million and $0.4 million, respectively, was included in accounts receivable relating to the Company’s agreements with IBS. Goldman, Sachs & Co. The Company entered into a three-year interest rate cap on December 9, 2015 with a subsidiary of Goldman, Sachs & Co. Goldman, Sachs & Co. is a significant shareholder of the Company. For more detail refer to Note 5 in the consolidated financial statements. In connection with and concurrently with the acquisition of Constant Contact in February 2016, the Company entered into the $735.0 million incremental first lien term loan facility and the $165.0 million revolving credit facility, and EIG Investors Corp. issued Notes in the aggregate principal amount of $350.0 million. An affiliate of Goldman, Sachs & Co. provided loans in the aggregate principal amount of $312.4 million under the incremental first lien term loan facility and a commitment in the aggregate principal amount of $57.6 million under the revolving credit facility, and Goldman, Sachs & Co. acted as a book-running manager in the Company’s offering of the Notes and purchased approximately $148.8 million worth of the Notes. The foregoing financing arrangements were provided in accordance with a commitment letter the Company entered into with an affiliate of Goldman, Sachs & Co. and certain other investment banks in November 2015. Goldman, Sachs & Co. also served as a financial advisor in connection with the acquisition of Constant Contact and in the three months ended March 31, 2016, the Company paid approximately $8.6 million to Goldman, Sachs & Co. in connection with these services.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	17. Subsequent Events On April 8, 2016, the Company made an investment of $5.0 million in Fortifico Limited for a 33% equity interest in Fortifico Limited.

Summary of Significant Accoun24

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Basis of Preparation	Basis of Preparation The accompanying consolidated financial statements, which include the accounts of the Company and its subsidiaries, have been prepared using accounting principles generally accepted in the United States of America (“U.S. GAAP”). All intercompany transactions have been eliminated on consolidation. The Company has reviewed the criteria of the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 280-10, Segment Reporting,
Use of Estimates	Use of Estimates U.S. GAAP requires management to make certain estimates, judgments and assumptions that affect the reported amounts of assets, liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. These estimates, judgments and assumptions used in preparing the accompanying consolidated financial statements are based on the relevant facts and circumstances as of the date of the consolidated financial statements. Although the Company regularly assesses these estimates, judgments and assumptions used in preparing the consolidated financial statements, actual results could differ from those estimates. Changes in estimates are recorded in the period in which they become known. The more significant estimates reflected in these consolidated financial statements include estimates of fair value of assets acquired and liabilities assumed under purchase accounting related to the Company’s acquisitions and when evaluating goodwill and long-lived assets for potential impairment, the estimated useful lives of intangible and depreciable assets, revenue recognition for multiple-element arrangements, stock-based compensation, contingent consideration, derivative instruments, certain accruals, reserves and deferred taxes.
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying interim consolidated balance sheet as of March 31, 2016, and the related statements of operations and comprehensive income for the three months ended March 31, 2015 and 2016, cash flows for the three months ended March 31, 2015 and 2016, and the notes to consolidated financial statements are unaudited. These unaudited consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements. The unaudited consolidated financial statements include, in the opinion of management, all adjustments, consisting only of normal recurring adjustments that are necessary for a fair presentation of the Company’s financial position at March 31, 2016, results of operations for the three months ended March 31, 2015 and 2016 and cash flows for the three months ended March 31, 2015 and 2016. The consolidated results in the consolidated statements of operations and comprehensive income are not necessarily indicative of the results of operations to be expected for the full fiscal year ending December 31, 2016.
Accounts Receivable	Accounts Receivable Accounts receivable is primarily composed of cash due from credit card companies for unsettled transactions charged to subscribers’ credit cards. As these amounts reflect authenticated transactions that are fully collectible, the Company does not maintain an allowance for doubtful accounts. The Company also accrues for earned referral fees and commissions, which are governed by reseller or affiliate agreements, when the amount is reasonably estimable.
Prepaid Domain Name Registry Fees	Prepaid Domain Name Registry Fees Prepaid domain name registry fees represent amounts that are paid in full at the time a domain is registered by one of the Company’s registrars on behalf of a customer. The registry fees are recognized on a straight-line basis over the term of the domain registration period.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities FASB ASC 815, Derivatives and Hedging, As required by ASC 815, the Company records all derivatives on the balance sheet at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether the Company has elected to designate a derivative in a hedging relationship and apply hedge accounting and whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. Derivatives designated and qualifying as a hedge of the exposure to changes in the fair value of an asset, liability, or firm commitment attributable to a particular risk, such as interest rate risk, are considered fair value hedges. Derivatives designated and qualifying as a hedge of the exposure to variability in expected future cash flows, or other types of forecasted transactions, are considered cash flow hedges. Derivatives may also be designated as hedges of the foreign currency exposure of a net investment in a foreign operation. Hedge accounting generally provides for the matching of the timing of gain or loss recognition on the hedging instrument with the recognition of the changes in the fair value of the hedged asset or liability that are attributable to the hedged risk in a fair value hedge or the earnings effect of the hedged forecasted transactions in a cash flow hedge. The Company may enter into derivative contracts that are intended to economically hedge certain of its risk, even though hedge accounting does not apply or the Company elects not to apply hedge accounting. In accordance with the FASB’s fair value measurement guidance in ASU 2011-04, Fair Value Measurement (Topic 820): Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements,
Property and Equipment	Property and Equipment Property and equipment is recorded at cost or fair value if acquired in an acquisition. The Company also capitalizes the direct costs of constructing additional computer equipment for internal use, as well as upgrades to existing computer equipment which extend the useful life, capacity or operating efficiency of the equipment. Capitalized costs include the cost of materials, shipping and taxes. Materials used for repairs and maintenance of computer equipment are expensed and recorded as a cost of revenue. Materials on hand and construction-in-process are recorded as property and equipment. Assets recorded under capital lease are depreciated over the lease term. Depreciation is computed using the straight-line method over the estimated useful lives of the related assets as follows: Building Thirty-five years Software Two to three years Computers and office equipment Three years Furniture and fixtures Five years Leasehold improvements Shorter of useful life or remaining term of the lease
Software Development Costs	Software Development Costs The Company accounts for software development costs for internal use software under the provisions of ASC 350-40, “Internal-Use Software.”
Goodwill	Goodwill Goodwill relates to amounts that arose in connection with the Company’s various business combinations and represents the difference between the purchase price and the fair value of the identifiable intangible and tangible net assets when accounted for using the purchase method of accounting. Goodwill is not amortized, but is subject to periodic review for impairment. Events that would indicate impairment and trigger an interim impairment assessment include, but are not limited to, current economic and market conditions, including a decline in the equity value of the business, a significant adverse change in certain agreements that would materially affect reported operating results, business climate or operational performance of the business and an adverse action or assessment by a regulator. Additionally, the reorganization or change in the number of reporting units could result in the reassignment of goodwill between reporting units and may trigger an impairment assessment. In accordance with ASC 350, Intangibles—Goodwill and Other At December 31, 2015, the Company had one reporting unit. The goodwill impairment assessment as of December 31, 2015 was based on then-current market capitalization. As of December 31, 2015, the fair value of the Company’s reporting unit exceeded the carrying value of the reporting unit’s net assets. Therefore, no impairment existed as of that date. For the three months ended March 31, 2016, the Company determined that there were no factors to indicate that the fair value of its reporting units could be impaired, therefore, no impairment testing was performed during this period. Determining the fair value of a reporting unit, if applicable, requires the Company to make judgments and involves the use of significant estimates and assumptions. These estimates and assumptions relate to, among other things, revenue growth rates and operating margins used to calculate projected future cash flows, risk-adjusted discount rates, future economic and market conditions and determination of appropriate market comparables. The Company bases its fair value estimates on assumptions it believes to be reasonable but that are unpredictable and inherently uncertain. Actual future results may differ from those estimates. The Company had goodwill of $1,207.3 million and $1,830.2 million as of December 31, 2015 and March 31, 2016, respectively, and no impairment charges have been recorded.
Long-Lived Assets	Long-Lived Assets The Company’s long-lived assets consist primarily of intangible assets, including acquired subscriber relationships, trade names, intellectual property, developed technology, domain names available for sale and in-process research and development (“IPR&D”). The Company also has long-lived tangible assets, primarily consisting of property and equipment. The majority of the Company’s intangible assets are recorded in connection with its various acquisitions. The Company’s intangible assets are recorded at fair value at the time of their acquisition. The Company amortizes intangible assets over their estimated useful lives. Determination of the estimated useful lives of the individual categories of intangible assets is based on the nature of the applicable intangible asset and the expected future cash flows to be derived from the intangible asset. Amortization of intangible assets with finite lives is recognized in accordance with their estimated projected cash flows. The Company evaluates long-lived intangible and tangible assets whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If indicators of impairment are present and undiscounted future cash flows are less than the carrying amount, the fair value of the assets is determined and compared to the carrying value. If the fair value is less than the carrying value, then the carrying value of the asset is reduced to the estimated fair value and an impairment loss is charged to expense in the period the impairment is identified. No such impairment losses have been identified in the three months ended March 31, 2015 and 2016. Indefinite life intangible assets include domain names that are available for sale which are recorded at cost to acquire. These assets are not being amortized and are being tested for impairment annually and whenever events or changes in circumstance indicate that their carrying value may not be recoverable. When a domain name is sold, the Company records the cost of the domain in cost of revenue.
Acquired In-Process Research and Development (IPR&D)	Acquired In-Process Research and Development (IPR&D) Acquired IPR&D represents the fair value assigned to research and development assets that the Company acquires in connection with business combinations that have not been completed at the date of acquisition. The acquired IPR&D is capitalized as an intangible asset and reviewed on a quarterly basis to determine future use. Any impairment loss of the acquired IPR&D is charged to expense in the period the impairment is identified. No such impairment loss was identified for the three months ended March 31, 2015. During the three months ended March 31, 2016, the Company identified that the acquired fair value of the remaining IPR&D acquired in connection with its acquisition of Webzai Ltd. (“Webzai”), was impaired. The Company recorded a $1.4 million impairment charge during the three months ended March 31, 2016 in engineering and development expense in the Company’s consolidated statements of operations and comprehensive income.
Revenue Recognition	Revenue Recognition The Company generates revenue primarily from selling subscriptions for cloud-based products and services. The subscriptions are similar across all of the Company’s brands and are provided under contracts pursuant to which the Company has ongoing obligations to support the subscriber. These contracts are generally for service periods of up to 36 months and typically require payment in advance. The Company recognizes the associated revenue ratably over the service period , The Company sells domain name registrations that provide a subscriber with the exclusive use of a domain name. These domains are primarily obtained by one of the Company’s registrars on the subscriber’s behalf, or to a lesser extent by the Company from third-party registrars on the subscriber’s behalf. Domain registration fees are non-refundable. Revenue from the sale of a domain name registration by a registrar within the Company is recognized ratably over the subscriber’s service period as the Company has the obligation to provide support over the domain term. Revenue from the sale of a domain name registration purchased by the Company from a third-party registrar is recognized when the subscriber is billed on a gross basis as there are no remaining Company obligations once the sale to the subscriber occurs, and the Company has full discretion on the sales price and bears all credit risk. Revenue from the sale of premium domains is recognized when persuasive evidence of an arrangement to sell such domains exists, delivery of an authorization key to access the domain name has occurred, the fee for the sale of the premium domain is fixed or determinable, and collection of the fee for the sale of the premium domain is deemed probable. Revenue from the sale of non-term based applications and services, such as certain online security products and professional technical services, referral fees and commissions, is recognized when the product is purchased, the service is provided or the referral fee or commission is earned, respectively. A substantial amount of the Company’s revenue is generated from transactions that are multiple-element service arrangements that may include hosting plans, domain name registrations, and other cloud-based products and services. The Company follows the provisions of the FASB, Accounting Standards Update (“ASU”) No. 2009-13 (“ASU 2009-13”), Revenue Recognition (Topic 605), Multiple-Deliverable Revenue Arrangements—a consensus of the FASB Emerging Issues Task Force, Under ASU 2009-13, to treat deliverables in a multiple-element service arrangement as separate units of accounting, the deliverables must have standalone value upon delivery. If the deliverables have standalone value upon delivery, the Company accounts for each deliverable separately. Hosting services, domain name registrations, cloud-based products and services have standalone value and are often sold separately. When multiple deliverables included in a multiple-element service arrangement are separated into different units of accounting, the total transaction amount is allocated to the identified separate units based on a relative selling price hierarchy. The Company determines the relative selling price for a deliverable based on vendor specific objective evidence (“VSOE”) of fair value, if available, or best estimate of selling price (“BESP”), if VSOE is not available. The Company has determined that third-party evidence of selling price (“TPE”) is not a practical alternative due to differences in its multi-brand offerings compared to competitors and the lack of availability of relevant third-party pricing information. The Company has not established VSOE for its offerings due to lack of pricing consistency, the introduction of new products, services and other factors. Accordingly, the Company generally allocates revenue to the deliverables in the arrangement based on the BESP. The Company determines BESP by considering its relative selling prices, competitive prices in the marketplace and management judgment; these selling prices, however, may vary depending upon the particular facts and circumstances related to each deliverable. The Company analyzes the selling prices used in its allocation of transaction amount, at a minimum, on a quarterly basis. Selling prices are analyzed on a more frequent basis if a significant change in the business necessitates a more timely analysis. The Company maintains a reserve for refunds and chargebacks related to revenue that has been recognized and is expected to be refunded. The Company had a refund and chargeback reserve of $0.5 million and $0.6 million as of December 31, 2015 and March 31, 2016, respectively. The portion of deferred revenue that is expected to be refunded at December 31, 2015 and March 31, 2016 was $1.8 million and $2.2 million, respectively. Based on refund history, a significant majority of refunds happen in the same fiscal month that the customer contract starts or renews. Approximately 80% of all refunds happen in the same fiscal month that the contract starts or renews, and approximately 92% of all refunds happen within 45 days of the contract start or renewal date.
Income Taxes	Income Taxes Income taxes are accounted for in accordance with ASC 740, Accounting for Income Taxes ASC 740 clarifies the accounting for income taxes by prescribing a minimum recognition threshold that a tax position is required to meet before being recognized in the financial statements. The Company recognizes the effect of income tax positions only if those positions are more likely than not to be sustained. Recognized income tax positions are measured at the largest amount that is more likely than not to be realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. There were no unrecognized tax benefits in the three months ended March 31, 2015 and 2016. The Company records interest related to unrecognized tax benefits in interest expense and penalties in operating expenses. During the three months ended March 31, 2015 and 2016, the Company did not recognize any interest and penalties related to unrecognized tax benefits.
Stock-Based Compensation	Stock-Based Compensation The Company may issue restricted stock units, restricted stock awards and stock options which vest upon the satisfaction of a performance condition and/ or a service condition. The Company follows the provisions of ASC 718, Compensation—Stock Compensation The Company estimates the fair value of employee stock options on the date of grant using the Black-Scholes option-pricing model, which requires the use of highly subjective estimates and assumptions. For restricted stock awards granted, the Company estimates the fair value of each restricted stock award based on the closing trading price of its common stock on the date of grant.
Net Income per Share	Net Income per Share The Company considered ASC 260-10, Earnings per Share Three Months Ended March 31, 2015 2016 (unaudited) (in thousands, except share amount and per share data) Net income attributable to Endurance International Group Holdings, Inc. $ 884 $ 21,811 Net income per share attributable to Endurance International Group Holdings, Inc.: Basic $ 0.01 $ 0.17 Diluted $ 0.01 $ 0.16 Weighted-average common shares outstanding used in computing basic net income per share attributable to Endurance International Group Holdings, Inc. 130,996,079 132,178,693 Dilutive common stock options and restricted stock awards 1,679,859 1,385,191 Weighted-average common shares outstanding used in computing diluted net income per share attributable to Endurance International Group Holdings, Inc. 132,675,938 133,563,884 The Company excluded common stock equivalents from the computation of diluted net income per share because they had an anti-dilutive impact as the proceeds under the treasury stock method were in excess of the average fair market value. For the three months ended March 31, 2015 and 2016, the Company excluded stock options, restricted stock awards and restricted shares amounting to 212,150 and 12,459,929, respectively, as their inclusion would have been antidilutive as the proceeds under the treasury stock method were in excess of the average fair market value for the respective periods.
Recent Accounting Pronouncements	Recent Accounting Pronouncements The Company adopted ASU 2015-03, “Simplifying the Presentation of Debt Issuance Cost” In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) Revenue from Contracts with Customers (Topic 606), Principals versus Agent Considerations Revenue from Contracts with Customers (Topic 606), Identifying Performance Obligations and Licensing, . In November 2015, the FASB issued ASU No. 2015-17, Income Taxes: Balance Sheet Classification of Deferred Taxes, In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases In March 2016, the FASB issued Accounting Standards Update No. 2016-07, Investments—Equity Method and Joint Ventures: Simplifying the Transition to the Equity Method of Accounting. This new guidance removes the requirement for retroactive adjustment when an increase or decrease in the level of ownership qualifies an investment for the equity method. This amendment is effective for fiscal years beginning after December 15, 2016. The Company is currently evaluating the impact of its pending adoption of the new standard on its consolidated financial statements. In March 2016, the FASB issued Accounting Standards Update No. 2016-09, Compensation-Stock Compensation: Improvements to Employee Share-Based Payment Accounting. This new standard simplifies the accounting tax aspects, eliminates complex accounting for excess tax deductions, permits higher withholdings for cashless exercises, and eliminates the requirement to estimate a forfeiture rate. This amendment is effective for annual periods beginning after December 15, 2016, and early adoption is permitted. The Company is currently evaluating the impact of its pending adoption of the new standard on its consolidated financial statements.

Summary of Significant Accoun25

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Summary of Estimated Useful Lives	Depreciation is computed using the straight-line method over the estimated useful lives of the related assets as follows: Building Thirty-five years Software Two to three years Computers and office equipment Three years Furniture and fixtures Five years Leasehold improvements Shorter of useful life or remaining term of the lease
Summary of Calculation of Basic and Diluted Net Income Per Share	The Company’s basic net income per share is computed by dividing net income by the weighted average number of shares of common stock outstanding for the period, and, if there are dilutive securities, diluted income per share is computed by including common stock equivalents which includes shares issuable upon the exercise of stock options, net of shares assumed to have been purchased with the proceeds, using the treasury stock method. Three Months Ended March 31, 2015 2016 (unaudited) (in thousands, except share amount and per share data) Net income attributable to Endurance International Group Holdings, Inc. $ 884 $ 21,811 Net income per share attributable to Endurance International Group Holdings, Inc.: Basic $ 0.01 $ 0.17 Diluted $ 0.01 $ 0.16 Weighted-average common shares outstanding used in computing basic net income per share attributable to Endurance International Group Holdings, Inc. 130,996,079 132,178,693 Dilutive common stock options and restricted stock awards 1,679,859 1,385,191 Weighted-average common shares outstanding used in computing diluted net income per share attributable to Endurance International Group Holdings, Inc. 132,675,938 133,563,884

Acquisitions (Tables)

Acquisitions (Tables)	3 Months Ended
	Mar. 31, 2016
Business Combinations [Abstract]
Summary of Deferred Consideration Related to Acquisition	Summary of Deferred Consideration Related to Acquisitions Components of deferred consideration short-term and long-term as of December 31, 2015 and March 31, 2016, consisted of the following: December 31, 2015 March 31, 2016 Short- term Long- term Short- term Long- term (in thousands) Mojoness, Inc. (Acquired in 2012) $ 657 $ 813 $ 822 $ — Typepad Holdings LLC (Acquired in 2013) 2,800 — 2,800 — Webzai Ltd. (Acquired 2014) 2,848 — 2,909 — BuyDomains (Acquired in 2014) 4,283 — 4,374 — Verio (Acquired in 2015) 2,474 — 2,474 — World Wide Web Hosting (Acquired in 2015) 4,600 — 4,600 — Ace Data Center (Acquired in 2015) 29,626 — 30,257 — Ecommerce LLC (Acquired in 2015) 4,200 — 4,200 — Total $ 51,488 $ 813 $ 52,436 $ —

Property and Equipment and Ca27

Property and Equipment and Capital Lease Obligations (Tables)	3 Months Ended
	Mar. 31, 2016
Property, Plant and Equipment [Abstract]
Components of Property and Equipment	Components of property and equipment consisted of the following: December 31, 2015 March 31, 2016 (in thousands) Land $ 713 $ 713 Building 5,091 5,092 Software 40,336 45,605 Computers and office equipment 97,332 128,184 Furniture and fixtures 5,914 10,567 Leasehold improvements 7,126 20,634 Construction in process 6,137 4,718 Property and equipment—at cost 162,649 215,513 Less accumulated depreciation (86,887 ) (101,806 ) Property and equipment—net $ 75,762 $ 113,707

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2016
Basis of Fair Value Measurements	Basis of Fair Value Measurements Balance Quoted Prices in Active Markets for Identical Items (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (in thousands) Balance at December 31, 2015: Financial assets: Interest rate cap (included in other assets) $ 3,130 — $ 3,130 $ — Total financial assets $ 3,130 — $ 3,130 $ — Financial liabilities: Contingent earn-out consideration $ 1,469 — — $ 1,469 Total financial liabilities $ 1,469 — — $ 1,469 Balance at March 31, 2016: Financial assets: Interest rate cap (included in other assets) $ 1,013 — $ 1,013 $ — Total financial assets $ 1,013 — $ 1,013 $ — Financial liabilities: Contingent earn-out consideration $ 822 — — $ 822 Total financial liabilities $ 822 — — $ 822
Significant Unobservable Inputs (Level 3) [Member]
Summary of Changes in the Financial Liabilities Measured on a Recurring Basis Using Level 3 Inputs	The following table summarizes the changes in the financial liabilities measured on a recurring basis using Level 3 inputs as of March 31, 2016: Amount (in thousands) Financial liabilities measured using Level 3 inputs at December 31, 2015 $ 1,469 Payment of contingent earn-outs related to 2012 acquisition (668 ) Change in fair value of contingent earn-outs 21 Financial liabilities measured using Level 3 inputs at March 31, 2016 $ 822

Goodwill and Other Intangible29

Goodwill and Other Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in Goodwill Balances	The following table summarizes the changes in the Company’s goodwill balances from December 31, 2015 to March 31, 2016: Amount (in thousands) Goodwill balance at December 31, 2015 $ 1,207,255 Goodwill related to 2015 acquisitions 38 Goodwill related to 2016 acquisitions 622,691 Foreign translation impact 260 Goodwill balance at March 31, 2016 $ 1,830,244
Summary of Other Intangible Assets	At December 31, 2015, other intangible assets consisted of the following: Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Useful Life (dollars in thousands) Developed technology $ 205,925 $ 80,795 $ 125,130 7 years Subscriber relationships 397,791 256,461 141,330 5 years Trade-names 81,792 42,080 39,712 6 years Intellectual property 34,020 6,596 27,424 13 years Domain names available for sale 27,859 3,107 24,752 Indefinite Leasehold interests 314 314 — 1 years In-process research and development 1,438 — 1,438 — Total December 31, 2015 $ 749,139 $ 389,353 $ 359,786 During the three months ended March 31, 2016, the Company wrote-off acquired in-process research and development of $1.4 million, related to its acquisition of Webzai in 2014, as the Company had abandoned certain research and development projects in favor of other projects. At March 31, 2016, other intangible assets consisted of the following: Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Useful Life (dollars in thousands) Developed technology $ 288,925 $ 88,275 $ 200,650 7 years Subscriber relationships 665,791 274,296 391,495 7 years Trade-names 133,796 45,330 88,466 8 years Intellectual property 34,030 7,556 26,474 13 years Domain names available for sale 28,513 3,657 24,856 Indefinite Leasehold interests 314 314 — 1 years In-process research and development — — — — Total March 31, 2016 $ 1,151,369 $ 419,428 $ 731,941

Notes Payable (Tables)

Notes Payable (Tables)	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Summary of Interest Rates and Interest Expense	The following table provides a summary of interest rates and interest expense for the three months ended March 31, 2015 and 2016: Three Months Ended March 31, 2015 2016 (dollars in thousands) Interest rate—LIBOR 5.00%-7.75 % 6.00%-7.75 % Interest rate—reference 8.50 % 7.50%-8.50 % Interest rate—Senior notes — 10.875 % Non-refundable fee—unused facility 0.50 % 0.50 % Interest expense and service fees $ 13,976 $ 27,996 Amortization of deferred financing fees $ 20 $ 911 Amortization of original issue discounts $ — $ 449 Amortization of net present value of deferred consideration $ 138 $ 783 Interest expense for capital lease obligations $ 98 $ 157 Interest expense for deferred consideration promissory note $ 70 $ 70 Other interest expense $ 19 $ 5 Total interest expense $ 14,321 $ 30,371

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2016
Equity [Abstract]
Summary of Changes in Stockholders' Equity	The following table presents the changes in total stockholders’ equity: Total Stockholders’ Equity (in thousands) Balance, December 31, 2015 $ 179,674 Stock-based compensation 18,388 Stock option exercises 593 Foreign currency translation adjustment 342 Unrealized loss on derivative (1,511 ) Minority interest accretion (3,472 ) Investment in Constant Contact 5,395 Income tax from the exercise of stock options (16 ) Net income 14,081 Balance, March 31, 2016 $ 213,474

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2016
Summary of 2012 Restricted Stock Awards Activity for Restricted Stock Awards that were Granted Prior to Company's IPO Including Non-Vested Balance	The following table provides a summary of the 2012 restricted stock awards activity for the three months ended March 31, 2016 for restricted stock awards that were granted prior to the IPO, including the non-vested balance as of March 31, 2016: 2012 Restricted Stock Awards Non-vested at December 31, 2015 46,645 Vested (27,818 ) Canceled — Non-vested at March 31, 2016 18,827
Summary of Restricted Stock Units that were Granted in Connection with IPO Including Non-Vested Balance	The following table provides a summary of the activity for the three months ended March 31, 2016 for the restricted stock units that were granted in connection with the IPO, including the non-vested balance as of March 31, 2016: Restricted Stock Units Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 22,158 $ 12.00 Vested and unissued (22,158 ) $ 12.00 Non-vested at March 31, 2016 — —
Restricted Stock Units [Member]
Summary of Restricted Stock Awards and Restricted Stock Units	The following table provides a summary of the Company’s restricted stock unit activity for the 2013 Plan during the three months ended March 31, 2016: Restricted Stock Units Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 220,765 $ 12.00 Vested and unissued (30,099 ) $ 12.00 Non-vested at March 31, 2016 190,666 $ 12.00
Restricted Stock Awards [Member]
Summary of Restricted Stock Awards and Restricted Stock Units	The following table provides a summary of the Company’s restricted stock award activity for the 2013 Plan during the three months ended March 31, 2016: Restricted Stock Awards Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 4,849,290 $ 15.24 Granted 743,514 $ 8.74 Vested (92,368 ) $ 12.03 Canceled (24,522 ) $ 17.00 Non-vested at March 31, 2016 5,475,914 $ 14.40
2011 Stock Incentive Plan [Member]
Summary of Total Stock-Based Compensation Expense	The following table presents total stock-based compensation expense recorded in the consolidated statement of operations and comprehensive income for all 2012 restricted stock awards and units issued prior to the IPO, all awards granted under the Company’s 2013 Plan and the 2011 Plan: Three Months Ended March 31, 2015 2016 (in thousands) Cost of revenue $ 113 $ 770 Sales and marketing 390 1,722 Engineering and development 217 764 General and administrative 3,251 15,132 Total stock-based compensation expense $ 3,971 $ 18,388
Summary of Stock Options	The following table provides a summary of the Company’s stock options as of March 31, 2016 and the stock option activity for all stock options granted under the 2011 Plan during the three months ended March 31, 2016: Stock Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (In Years) Aggregate Intrinsic Value(3) Outstanding at December 31, 2015 — $ — Granted/ Exchanged 2,143,987 $ 7.28 Exercised (89,572 ) $ 6.60 Forfeited (240,559 ) $ 7.18 Outstanding at March 31, 2016 1,813,856 $ 7.33 5.2 $ 5,809 Exercisable at March 31, 2016 351,727 $ 8.90 5.3 $ 572 Expected to vest after March 31, 2016 (1) 1,462,129 $ 6.95 5.1 $ 5,237 Exercisable as of March 31, 2016 and expected to vest thereafter (2) 1,813,856 $ 7.33 5.2 $ 5,809 (1) This represents the number of unvested options outstanding as of March 31, 2016 that are expected to vest in the future, which have been reduced using an estimated forfeiture rate. (2) This represents the number of vested options as of March 31, 2016 plus the number of unvested options outstanding as of March 31, 2016 that are expected to vest in the future, which have been reduced using an estimated forfeiture rate. (3) The aggregate intrinsic value was calculated based on the positive difference, if any, between the estimated fair value of the Company’s common stock on March 31, 2016 of $10.53 per share, or the date of exercise, as appropriate, and the exercise price of the underlying options.
Summary of Restricted Stock Awards and Restricted Stock Units	The following table provides a summary of the Company’s restricted stock unit activity for the 2011 Plan during the three months ended March 31, 2016: Restricted Stock Units Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 — $ — Granted/ Exchanged 2,202,846 $ 7.69 Vested (345,544 ) $ 7.69 Canceled (80,201 ) $ 7.69 Non-vested at March 31, 2016 1,777,101 $ 7.69
2013 Stock Incentive Plan [Member]
Summary of Stock Options	The following table provides a summary of the Company’s stock options as of March 31, 2016 and the stock option activity for all stock options granted under the 2013 Plan during the three months ended March 31, 2016: Stock Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (In Years) Aggregate Intrinsic Value(3) Outstanding at December 31, 2015 6,950,858 $ 13.83 Granted — $ — Exercised — $ — Forfeited (57,440 ) $ 17.41 Expired (231,799 ) $ 12.68 Outstanding at March 31, 2016 6,661,619 $ 13.84 8.1 $ — Exercisable at March 31, 2016 2,832,742 $ 12.07 7.6 $ — Expected to vest after March 31, 2016 (1) 3,776,172 $ 15.12 8.4 $ — Exercisable as of March 31, 2016 and expected to vest thereafter (2) 6,608,914 $ 13.81 8.1 $ — (1) This represents the number of unvested options outstanding as of March 31, 2016 that are expected to vest in the future, which have been reduced using an estimated forfeiture rate. (2) This represents the number of vested options as of March 31, 2016 plus the number of unvested options outstanding as of March 31, 2016 that are expected to vest in the future, which have been reduced using an estimated forfeiture rate. (3) The aggregate intrinsic value was calculated based on the positive difference, if any, between the estimated fair value of the Company’s common stock on March 31, 2016 of $10.53 per share, or the date of exercise, as appropriate, and the exercise price of the underlying options.

Severance and Other Exit Costs

Severance and Other Exit Costs (Tables)	3 Months Ended
	Mar. 31, 2016
Summary of Total Restructuring Charges Recorded in the Consolidated Statement of Operations and Comprehensive Income	The following table presents restructuring charges recorded in the consolidated statement of operations and comprehensive income for the periods presented: For the Three Months Ended March 31, 2015 2016 (in thousands) Cost of revenue $ (49 ) $ 3,279 Sales and marketing (14 ) 3,901 Engineering and development (67 ) 2,018 General and administrative 40 2,218 Total restructuring charges $ (90 ) $ 11,416
Closing Office Facility in Redwood City [Member]
Summary of Activity Related to Company's Facilities Exit Costs Accrual	The following table provides a summary of the activity for the three months ended March 31, 2016 related to the Company’s facilities exit costs accrual: Facilities (in thousands) Balance at December 31, 2015 $ 479 Cash paid (236 ) Sublease income 41 Adjustments 186 Balance at March 31, 2016 $ 470
Closing Office Facility in Redwood City [Member] | 2016 Constant Contact Restructuring Plan [Member]
Summary of Activity Related to Company's Facilities Exit Costs Accrual	The following table provides a summary of the activity for the three months ended March 31, 2016 related to the Company’s 2016 Constant Contact Restructuring Plan facilities exit costs accrual: Facilities (in thousands) Balance at December 31, 2015 $ — Facilities exit charges, net of estimated sublease income 3,416 Cash paid (147 ) Balance at March 31, 2016 $ 3,269
Employee Severance [Member]
Summary of Activity Related to Company's Facilities Exit Costs Accrual	The following table provides a summary of the activity for the three months ended March 31, 2016 related to the Company’s 2015 Restructuring Plan severance accrual: 2015 Plan Employee Severance (in thousands) Balance at December 31, 2015 $ 1,201 Severance adjustments (15 ) Cash paid (623 ) Balance at March 31, 2016 $ 563
Employee Severance [Member] | 2016 Constant Contact Restructuring Plan [Member]
Summary of Activity Related to Company's Facilities Exit Costs Accrual	The following table provides a summary of the activity for the three months ended March 31, 2016 related to the Company’s 2016 Constant Contact Restructuring Plan severance accrual: 2016 Constant Contact Plan Employee Severance (in thousands) Balance at December 31, 2015 $ — Severance charges 8,015 Cash paid (1,470 ) Balance at March 31, 2016 $ 6,545

Related Party Transactions (Tab

Related Party Transactions (Tables)	3 Months Ended
	Mar. 31, 2016
Immediate Family Member of Management or Principal Owner [Member]
Summary of Related Party Transactions	The following table presents the amounts of related party transactions recorded in the consolidated statements of operations and comprehensive income for the periods presented relating to services provided by Tregaron and its affiliates under these agreements: Three Months Ended March 31, 2015 2016 (in thousands) Cost of revenue $ 2,400 $ 3,100 Sales and marketing 100 100 Engineering and development 400 300 General and administrative 100 100 Total related party transaction expense $ 3,000 $ 3,600
Director [Member]
Summary of Related Party Transactions	The following table includes the revised amount of related party transactions recorded in the consolidated statements of operations and comprehensive income for the three months March 31, 2015 relating to services provided by IBS under these agreements: Three Months Ended March 31, As Reported As Revised 2015 2015 2016 (in thousands) Revenue $ — $ (150 ) $ (600 ) Revenue (contra) 1,800 1,800 2,100 Total related party transaction impact to revenue $ 1,800 $ 1,650 $ 1,500 Cost of revenue 200 200 200 Total related party transaction expense, net $ 2,000 $ 1,850 $ 1,700

Summary of Significant Accoun35

Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended		12 Months Ended
	Mar. 31, 2016USD ($)Segmentshares	Mar. 31, 2015USD ($)shares	Dec. 31, 2015USD ($)Segment
Accounting Policies [Line Items]
Number of reportable segments | Segment	2		1
Number of operating segments | Segment	2
Software development cost capitalized	$ 2,600,000	$ 1,300,000
Impairment	0		$ 0
Goodwill	1,830,244,000		1,207,255,000
Impairment charges	0		0
Impairment loss charged to expense	$ 0	0
Contract service period	36 months
Reserves for refunds and chargebacks	$ 600,000		500,000
Deferred revenue expected to be refunded	$ 2,200,000		$ 1,800,000
Percentage of deferred revenue refunded within same fiscal month	80.00%
Percentage of deferred revenue refunded within 45 days	92.00%
Unrecognized tax benefits	$ 0	0
Interest expense and penalties	$ 0	$ 0
Antidilutive securities excluded from computation of earnings per share, amount | shares	12,459,929	212,150
IPR&D [Member]
Accounting Policies [Line Items]
Impairment loss charged to expense		$ 0
Webzai Ltd [Member] | Engineering and Development [Member]
Accounting Policies [Line Items]
Impairment charges	$ 1,400,000

Summary of Significant Accoun36

Summary of Significant Accounting Policies - Summary of Estimated Useful Lives (Detail)	3 Months Ended
	Mar. 31, 2016
Building [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	35 years
Software [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	2 years
Software [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	3 years
Computers and Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	3 years
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	5 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Leasehold improvements	Shorter of useful life or remaining term of the lease

Summary of Significant Accoun37

Summary of Significant Accounting Policies - Summary of Calculation of Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Accounting Policies [Abstract]
Net income attributable to Endurance International Group Holdings, Inc.	$ 21,811	$ 884
Basic	$ 0.17	$ 0.01
Diluted	$ 0.16	$ 0.01
Weighted-average common shares outstanding used in computing basic net income per share attributable to Endurance International Group Holdings, Inc.	132,178,693	130,996,079
Dilutive common stock options and restricted stock awards	1,385,191	1,679,859
Weighted-average common shares outstanding used in computing diluted net income per share attributable to Endurance International Group Holdings, Inc.	133,563,884	132,675,938

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Oct. 30, 2015	Mar. 31, 2016	Mar. 31, 2015	Jan. 06, 2016	Dec. 31, 2015	Aug. 31, 2014
Business Acquisition [Line Items]
Amount of investment for acquisition		$ 29,900			$ 27,900
Gain (loss) of unconsolidated entities		(683)	$ (1,108)
Goodwill		1,830,244			$ 1,207,255
Revenue from acquisitions		41,700
Unaudited pro forma revenue		277,800	267,000
Unaudited pro forma net income (loss)		$ 35,600	$ (25,300)
WZ UK Ltd. [Member]
Business Acquisition [Line Items]
Amount of investment for acquisition						$ 3,900
Ownership interest		49.00%				49.00%
Estimated value of the non-controlling interest		$ 10,800		$ 10,800
Business acquisition, estimated aggregate purchase price		22,200
Deferred revenue		3,300
Negative working capital		1,300
Gain (loss) of unconsolidated entities		11,400
Property and equipment		300
Expected value upon exercise of put option				$ 30,000
WZ UK Ltd. [Member]
Business Acquisition [Line Items]
Ownership interest				57.50%
WZ UK Ltd. [Member] | WZ UK Ltd. [Member]
Business Acquisition [Line Items]
Ownership interest				5750.00%
Constant Contact, Inc. [Member]
Business Acquisition [Line Items]
Deferred revenue	$ 25,200
Property and equipment	$ 40,700
Price per share	$ 32
Enterprise value	$ 1,100,000
Goodwill	601,100
Working capital	182,000
Long-term deposits	2,000
Deferred tax liability, net	122,900
Long-term obligations	100
Business acquisition transaction expenses		31,100
Unaudited pro forma net income (loss)		11,400
Reduction in proforma revenue		13,700
Constant Contact, Inc. [Member] | Accelerated Vesting of Equity Awards Charge [Member]
Business Acquisition [Line Items]
Business acquisition transaction expenses		16,800
Constant Contact, Inc. [Member] | Advisory Fees [Member]
Business Acquisition [Line Items]
Business acquisition transaction expenses		10,800
Constant Contact, Inc. [Member] | Legal Fees [Member]
Business Acquisition [Line Items]
Business acquisition transaction expenses		$ 3,500
Developed Technology [Member]
Business Acquisition [Line Items]
Weighted average useful life		4 years 1 month 6 days
Developed Technology [Member] | Constant Contact, Inc. [Member]
Business Acquisition [Line Items]
Purchase price of intangible assets	52,000
Subscriber Relationships [Member]
Business Acquisition [Line Items]
Weighted average useful life		4 years 4 months 24 days
Subscriber Relationships [Member] | WZ UK Ltd. [Member]
Business Acquisition [Line Items]
Purchase price of intangible assets		$ 4,900
Subscriber Relationships [Member] | Constant Contact, Inc. [Member]
Business Acquisition [Line Items]
Purchase price of intangible assets	263,000
Trademarks [Member]
Business Acquisition [Line Items]
Weighted average useful life		4 years 8 months 12 days
Trade-Names [Member] | Constant Contact, Inc. [Member]
Business Acquisition [Line Items]
Purchase price of intangible assets	$ 83,000

Acquisitions - Summary of Defer

Acquisitions - Summary of Deferred Consideration Related to Acquisition (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Deferred consideration short-term	$ 52,436	$ 51,488
Deferred consideration long-term		813
Mojoness Inc [Member]
Business Acquisition [Line Items]
Deferred consideration short-term	822	657
Deferred consideration long-term		813
Typepad Holdings LLC [Member]
Business Acquisition [Line Items]
Deferred consideration short-term	2,800	2,800
Webzai Ltd [Member]
Business Acquisition [Line Items]
Deferred consideration short-term	2,909	2,848
BuyDomains [Member]
Business Acquisition [Line Items]
Deferred consideration short-term	4,374	4,283
Verio [Member]
Business Acquisition [Line Items]
Deferred consideration short-term	2,474	2,474
Ace Data Centers Inc [Member]
Business Acquisition [Line Items]
Deferred consideration short-term	30,257	29,626
Ecommerce, LLC [Member]
Business Acquisition [Line Items]
Deferred consideration short-term	4,200	4,200
World Wide Web Hosting, LLC [Member]
Business Acquisition [Line Items]
Deferred consideration short-term	$ 4,600	$ 4,600

Property and Equipment and Ca40

Property and Equipment and Capital Lease Obligations - Components of Property and Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property and equipment-at cost	$ 215,513	$ 162,649
Less accumulated depreciation	(101,806)	(86,887)
Property and equipment-net	113,707	75,762
Land [Member]
Property, Plant and Equipment [Line Items]
Property and equipment-at cost	713	713
Building [Member]
Property, Plant and Equipment [Line Items]
Property and equipment-at cost	5,092	5,091
Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment-at cost	45,605	40,336
Computers and Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment-at cost	128,184	97,332
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and equipment-at cost	10,567	5,914
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment-at cost	20,634	7,126
Construction in Process [Member]
Property, Plant and Equipment [Line Items]
Property and equipment-at cost	$ 4,718	$ 6,137

Property and Equipment and Ca41

Property and Equipment and Capital Lease Obligations - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 13,172	$ 7,866
Capital lease included in software	21,500
Property under capital lease, net	11,500
Property and Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 13,200	$ 7,900

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - Fair Value, Measurements, Recurring [Member] - Significant Unobservable Inputs (Level 3) [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payment of contingent earn-out related to acquisition	$ 668
Mojoness Inc [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payment of contingent earn-out related to acquisition	$ 700

Fair Value Measurements - Basis

Fair Value Measurements - Basis of Fair Value Measurements (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Financial assets:
Interest rate cap (included in other assets)	$ 1,013	$ 3,130
Total financial assets	1,013	3,130
Financial liabilities:
Contingent earn-out consideration	822	1,469
Total financial liabilities	822	1,469
Significant Other Observable Inputs (Level 2) [Member]
Financial assets:
Interest rate cap (included in other assets)	1,013	3,130
Total financial assets	1,013	3,130
Significant Unobservable Inputs (Level 3) [Member]
Financial liabilities:
Contingent earn-out consideration	822	1,469
Total financial liabilities	$ 822	$ 1,469

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Changes in the Financial Liabilities Measured on a Recurring Basis Using Level 3 Inputs (Detail) - Significant Unobservable Inputs (Level 3) [Member] - Fair Value, Measurements, Recurring [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial liabilities measured using Level 3 inputs, Opening balance	$ 1,469
Payment of contingent earn-outs related to 2012 acquisition	(668)
Change in fair value of contingent earn-outs	21
Financial liabilities measured using Level 3 inputs, Ending balance	$ 822

Derivatives And Hedging Activ45

Derivatives And Hedging Activities - Additional Information (Detail)	Dec. 09, 2015	Mar. 31, 2016USD ($)Agreement
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate cap agreement period	3 years
Gain on interest rate cash flow hedge ineffectiveness		$ 0
Fair value of the interest rate contracts		1,000,000
Reclassification out of Accumulated Other Comprehensive Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gain to be reclassified as increase to interest expense in the next twelve months		$ 40,651
Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Number of interest rate cap agreements | Agreement		1
Notional amount outstanding		$ 500,000,000
Tax benefit		(600,000)
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Recognized loss		$ (1,500,000)

Goodwill and Other Intangible46

Goodwill and Other Intangible Assets - Changes in Goodwill Balances (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)
Goodwill [Line Items]
Goodwill, beginning balance	$ 1,207,255
Foreign translation impact	260
Goodwill, ending balance	1,830,244
2015 Acquisitions [Member]
Goodwill [Line Items]
Goodwill related to acquisitions	38
2016 Acquisitions [Member]
Goodwill [Line Items]
Goodwill related to acquisitions	$ 622,691

Goodwill and Other Intangible47

Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Amortization expense included in cost of revenue	$ 29,874	$ 21,298
IPR&D [Member] | Webzai UK Ltd [Member]
Finite-Lived Intangible Assets [Line Items]
Wrote-off acquired in-process research and development	$ 1,400

Goodwill and Other Intangible48

Goodwill and Other Intangible Assets - Summary of Other Intangible Assets (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,151,369	$ 749,139
Accumulated Amortization	419,428	389,353
Net Carrying Amount	731,941	359,786
Domains Names Available for Sale [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	28,513	27,859
Accumulated Amortization	3,657	3,107
Net Carrying Amount	$ 24,856	24,752
Weighted Average Useful Life	Indefinite
Developed Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 288,925	205,925
Accumulated Amortization	88,275	80,795
Net Carrying Amount	$ 200,650	$ 125,130
Weighted Average Useful Life	7 years	7 years
Subscriber Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 665,791	$ 397,791
Accumulated Amortization	274,296	256,461
Net Carrying Amount	$ 391,495	$ 141,330
Weighted Average Useful Life	7 years	5 years
Trade-Names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 133,796	$ 81,792
Accumulated Amortization	45,330	42,080
Net Carrying Amount	$ 88,466	$ 39,712
Weighted Average Useful Life	8 years	6 years
Intellectual Property [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 34,030	$ 34,020
Accumulated Amortization	7,556	6,596
Net Carrying Amount	$ 26,474	$ 27,424
Weighted Average Useful Life	13 years	13 years
Leasehold Interests [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 314	$ 314
Accumulated Amortization	$ 314	$ 314
Weighted Average Useful Life	1 year	1 year
IPR&D [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		$ 1,438
Net Carrying Amount		$ 1,438

Investments - Additional Inform

Investments - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended
	Dec. 31, 2014	May. 31, 2014	Mar. 31, 2016	Mar. 31, 2015	Jan. 06, 2016	Dec. 31, 2015	Aug. 31, 2014	Jan. 31, 2012
Schedule of Cost-method Investments [Line Items]
Amount of investment for acquisition			$ 29,900,000			$ 27,900,000
Accounts payable			19,989,000			12,280,000
Accrued expense			83,099,000			$ 50,869,000
Convertible promissory note purchased			600,000
Loss of unconsolidated entities			$ (683,000)	$ (1,108,000)
Proportionate share exceed of the company's consolidated assets or income			10.00%
Equity method investment, description			As of March 31, 2016, the Company did not have an equity method investment in which the Company’s proportionate share of the investees’ net income or loss exceeded 10% of the Company’s consolidated assets or income from continuing operations.
Bluezone Labs, LLC [Member]
Schedule of Cost-method Investments [Line Items]
Amount of investment for acquisition								$ 300,000
Ownership interest								25.00%
Purchase of products and services			$ 300,000	300,000
Accounts payable			300,000	100,000
Accrued expense			$ 300,000	$ 100,000
WZ UK Ltd. [Member]
Schedule of Cost-method Investments [Line Items]
Amount of investment for acquisition							$ 3,900,000
Ownership interest			49.00%				49.00%
Loss of unconsolidated entities			$ 11,400,000
AppMachine [Member]
Schedule of Cost-method Investments [Line Items]
Amount of investment for acquisition	$ 15,200,000
Ownership interest	40.00%
Remaining percentage of acquisition	60.00%
Periodic payment on equity method investment, percentage	20.00%
Periodic payment on equity method investment determination percentage	20.00%
Liabilities reported in equity method investment			$ 0
Minimum [Member]
Schedule of Cost-method Investments [Line Items]
Voting interest			20.00%
Maximum [Member]
Schedule of Cost-method Investments [Line Items]
Voting interest			50.00%
WZ UK Ltd. [Member]
Schedule of Cost-method Investments [Line Items]
Ownership interest					57.50%
WZ UK Ltd. [Member] | WZ UK Ltd. [Member]
Schedule of Cost-method Investments [Line Items]
Ownership interest					5750.00%
Automattic [Member]
Schedule of Cost-method Investments [Line Items]
Investment made on asset		$ 15,000,000
Percentage of outstanding shares invested		5.00%

Notes Payable - Additional Info

Notes Payable - Additional Information (Detail) - USD ($)	Feb. 09, 2016	Nov. 25, 2013	Nov. 30, 2013	Mar. 31, 2016	Mar. 31, 2015	Feb. 29, 2016	Feb. 28, 2016	Feb. 08, 2016	Dec. 31, 2015
Long-Term Debt [Line Items]
Mandatory repayments on term loan				$ 8,925,000	$ 2,625,000
First lien term loan outstanding				600,000
Current portion of notes payable				35,700,000					$ 77,500,000
Interest expense				30,371,000	14,321,000
Shelf Registration Statement [Member]
Long-Term Debt [Line Items]
Effective period to consummate the Exchange Offer or have the shelf registration statement	365 days
Interest rate, percentage of increase per annum	0.25%
Interest rate, additional increase per annum	0.25%
Period of alternate increase in interest rate	90 days
Maximum [Member] | Shelf Registration Statement [Member]
Long-Term Debt [Line Items]
Interest rate, additional increase per annum	0.50%
Bank Revolving Loan [Member]
Long-Term Debt [Line Items]
Revolving credit facility increase in borrowing amount				40,000,000
Aggregate principal amount not to exceed	$ 165,000,000			$ 125,000,000				$ 125,000,000
Maturity term	5 years
Maturity date	Aug. 10, 2019
Maturity term, extension period	91 days
Revolver maturity period				If the Company's November 2013 First Lien has not been paid in full prior to August 10, 2019 and the final maturity has not been extended to May 11, 2021 or later, then the maturity date of the revolving credit facility is February 9, 2019.
Bank Revolving Loan [Member] | Constant Contact, Inc. [Member]
Long-Term Debt [Line Items]
Aggregate principal amount not to exceed	$ 165,000,000					$ 165,000,000		$ 125,000,000
2012 November Second Lien Term Loan Facility [Member]
Long-Term Debt [Line Items]
Mandatory repayments on term loan			$ 315,000,000
November 2013 First Lien [Member]
Long-Term Debt [Line Items]
Mandatory repayments on term loan			2,600,000	$ 5,300,000	2,600,000
Additional repayment of term loan			166,200,000
First lien term loan outstanding			$ 1,050,000,000
Maturity date				Nov. 9, 2019
Current portion of notes payable				$ 21,000,000					10,500,000
November 2013 First Lien [Member] | Voluntary Payment [Member]
Long-Term Debt [Line Items]
Mandatory repayments on term loan				$ 3,700,000
November 2013 First Lien [Member] | Reference Rate Loan [Member]
Long-Term Debt [Line Items]
Debt instrument reference rate		3.00%
Percentage points added to federal funds effective rate		0.50%
Adjusted LIBOR rate		2.00%
First Lien Term Loan Facility [Member]
Long-Term Debt [Line Items]
Scheduled amortization percentage per quarter		0.25%
Interest rate, percentage of increase	5.23%						5.48%
Maturity date				Feb. 9, 2023
Principal amount of term loan outstanding				$ 731,300,000
First Lien Term Loan Facility [Member] | Term Loan Credit Facility [Member] | Constant Contact, Inc. [Member]
Long-Term Debt [Line Items]
Revolving credit facility increase in borrowing amount	$ 735,000,000					735,000,000
Senior Notes Due 2024 [Member]
Long-Term Debt [Line Items]
Senior notes due	$ 350,000,000			$ 350,000,000
Interest rate on senior notes	10.875%			10.875%
Debt instrument, par value percentage	98.065%
Maturity date				Feb. 9, 2024
Repurchase price percentage				101.00%
Senior Notes Due 2024 [Member] | Constant Contact, Inc. [Member]
Long-Term Debt [Line Items]
Senior notes due	$ 350,000,000					$ 350,000,000
Interest rate on senior notes	10.875%
Senior Notes Due 2024 [Member] | Bank Revolving Loan [Member]
Long-Term Debt [Line Items]
Aggregate principal amount not to exceed				$ 14,700,000
Bank Revolver Loans [Member]
Long-Term Debt [Line Items]
First lien term loan outstanding				0	21,000,000				67,000,000
Borrowing from revolving credit facility				16,000,000	7,000,000
Repayment of revolving credit facility				83,000,000	$ 36,000,000
Bank Revolver Loans [Member] | Bank Revolving Loan [Member]
Long-Term Debt [Line Items]
Notes payable amount outstanding				$ 0
Bank Revolver Loans 7.75% [Member]
Long-Term Debt [Line Items]
Principal amount of term loan outstanding									$ 59,000,000
Interest at LIBOR based rates									7.75%
Bank Revolver Loans 8.50% [Member]
Long-Term Debt [Line Items]
Principal amount of term loan outstanding									$ 8,000,000
Interest at LIBOR based rates									8.50%
LIBOR Based Interest Rate Loan [Member]
Long-Term Debt [Line Items]
LIBOR based interest rate reduced		4.00%
Greater of the LIBOR rate		1.00%
Incremental First Lien Term Loan Facility [Member]
Long-Term Debt [Line Items]
Revolving credit facility increase in borrowing amount	$ 735,000,000
Maturity term	7 years
Interest rate description	This incremental first lien term loan facility will mature in seven years, was issued at a price of 97% of par (subject to the payment of an additional upfront fee of 1.0% on February 28, 2016 under certain circumstances), bears interest at a rate of LIBOR plus 5.0% per annum, subject to a LIBOR floor of 1.0% per annum, and has scheduled amortization of 0.50% per quarter.
Debt instrument, par value percentage	97.00%
Additional upfront fee percentage upon payment							1.00%
Scheduled amortization percentage per quarter	0.50%
Senior Credit Facilities [Member]
Long-Term Debt [Line Items]
Interest rate	1.00%
London Interbank Offered Rate (LIBOR) [Member] | First Lien Term Loan Facility [Member]
Long-Term Debt [Line Items]
Interest at LIBOR based rates				6.00%
London Interbank Offered Rate (LIBOR) [Member] | First Lien [Member]
Long-Term Debt [Line Items]
Principal amount of term loan outstanding				$ 1,021,100,000					$ 1,026,400,000
Interest at LIBOR based rates				6.48%					5.00%
London Interbank Offered Rate (LIBOR) [Member] | Incremental First Lien Term Loan Facility [Member]
Long-Term Debt [Line Items]
Interest rate	5.00%
London Interbank Offered Rate Floor [Member] | Bank Revolving Loan [Member]
Long-Term Debt [Line Items]
Interest rate	4.00%
London Interbank Offered Rate Floor [Member] | First Lien Term Loan Facility [Member]
Long-Term Debt [Line Items]
Interest rate	1.00%
London Interbank Offered Rate Floor [Member] | Incremental First Lien Term Loan Facility [Member]
Long-Term Debt [Line Items]
Interest rate	1.00%

Notes Payable - Schedule of Int

Notes Payable - Schedule of Interest Rates and Interest Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Feb. 09, 2016
Long-Term Debt [Line Items]
Interest rate-reference		8.50%
Non-refundable fee-unused facility	0.50%	0.50%
Interest expense and service fees	$ 27,996	$ 13,976
Amortization of deferred financing fees	911	20
Amortization of original issue discounts	449
Amortization of net present value of deferred consideration	783	138
Interest expense for capital lease obligations	157	98
Other interest expense	5	19
Total interest expense	$ 30,371	14,321
Senior Notes Due 2024 [Member]
Long-Term Debt [Line Items]
Interest rate-Senior notes	10.875%		10.875%
Promissory Note [Member]
Long-Term Debt [Line Items]
Interest expense for deferred consideration promissory note	$ 70	$ 70
Minimum [Member]
Long-Term Debt [Line Items]
Interest rate-LIBOR	6.00%	5.00%
Interest rate-reference	7.50%
Maximum [Member]
Long-Term Debt [Line Items]
Interest rate-LIBOR	7.75%	7.75%
Interest rate-reference	8.50%

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2016$ / shares
Equity [Abstract]
Number of vote per share	$ 1

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Changes in Stockholders' Equity (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Equity [Abstract]
Beginning balance	$ 179,674
Stock-based compensation	18,388	$ 3,971
Stock option exercises	593
Foreign currency translation adjustment	342	(616)
Unrealized loss on derivative	(1,511)
Minority interest accretion	(3,472)
Investment in Constant Contact	5,395
Income tax from the exercise of stock options	(16)
Net income	14,081	$ 884
Ending balance	$ 213,474

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Feb. 09, 2016	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, par value		$ 0.0001		$ 0.0001
Stock-based compensation expense		$ 18,388	$ 3,971
2015 Performance Based Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		7,900
Additional stock-based compensation expense due to change in vesting assumptions		3,300
2016 Performance Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 600
Percentage of weighted adjusted revenue required to earn performance-based restricted stock awards		50.00%
Percentage of weighted adjusted EBITDA required to earn performance-based restricted stock awards		25.00%
Percentage of weighted adjusted free cash flow required to earn performance-based restricted stock awards		25.00%
2016 Performance Based Awards [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target number of shares on achievement of performance metric		0.00%
2016 Performance Based Awards [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of target number of shares on achievement of performance metric		125.00%
Chief Executive Officer [Member] | 2015 Performance Based Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award shares granted for vesting			195,881	3,693,754
Vested period of award shares				3 years
Vesting terms of award shares		Award Shares may be earned during each calendar quarter during the Performance Period (each, a “Performance Quarter”) if the Company achieves a threshold, target or maximum level of the performance metric for the Performance Quarter. If the performance metric is less than the threshold level for a Performance Quarter, no Award Shares will be earned during the Performance Quarter. Award Shares that were not earned during a Performance Quarter may be earned later during the then current twelve-month period from July 1st to June 30th during the Performance Period (each, a “Performance Year”) at a threshold, target or maximum level of the performance metric for the Performance Year. No Award Shares were earned for the Performance Quarter ending September 30, 2015 because the threshold level for the performance metric was not met. Approximately 195,881 Award Shares were earned for the Performance Quarter ending December 31, 2015 because the target level for the performance metric was met.
Chief Financial Officer [Member] | 2016 Performance Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award shares granted for vesting		223,214
Target award shares granted for vesting		178,571
Chief Operating Officer [Member] | 2016 Performance Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award shares granted for vesting		260,416
Target award shares granted for vesting		208,333
Chief Administrative Officer [Member] | 2016 Performance Based Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award shares granted for vesting		148,810
Target award shares granted for vesting		119,048
2013 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance		18,000,000
Shares available for grant		4,618,955
2013 Stock Incentive Plan [Member] | Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award shares granted for vesting		743,514
Vesting period		4 years
2013 Stock Incentive Plan [Member] | Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		4 years
2011 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance		14,346,830
Shares available for grant		10,320,757
Common stock, par value	$ 0.01
Stock options, Granted		2,143,987
Stock-based compensation expense		$ 22,300
2011 Stock Incentive Plan [Member] | Pre-Acquisition Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		5,400
2011 Stock Incentive Plan [Member] | Post-Acquisition Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		16,900
Recognized stock-based compensation expense		$ 3,700
2011 Stock Incentive Plan [Member] | Stock Option Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, Granted	2,143,987
2011 Stock Incentive Plan [Member] | Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award shares granted for vesting	2,202,846	2,202,846
Vesting period		4 years

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Total Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]
Stock-based compensation expense	$ 18,388	$ 3,971
Two Thousand Eleven And Two Thousand Thirteen Stock Incentive Plan [Member]
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]
Stock-based compensation expense	18,388	3,971
Cost of Revenue [Member] | Two Thousand Eleven And Two Thousand Thirteen Stock Incentive Plan [Member]
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]
Stock-based compensation expense	770	113
Sales and Marketing [Member] | Two Thousand Eleven And Two Thousand Thirteen Stock Incentive Plan [Member]
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]
Stock-based compensation expense	1,722	390
Engineering and Development [Member] | Two Thousand Eleven And Two Thousand Thirteen Stock Incentive Plan [Member]
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]
Stock-based compensation expense	764	217
General and Administrative [Member] | Two Thousand Eleven And Two Thousand Thirteen Stock Incentive Plan [Member]
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]
Stock-based compensation expense	$ 15,132	$ 3,251

Stock-Based Compensation - Su56

Stock-Based Compensation - Summary of 2012 Restricted Stock Awards Activity for Restricted Stock Awards that were Granted Prior to Company's IPO Including Non-Vested Balance (Detail) - 2012 Restricted Stock Awards [Member] - Restricted Stock Awards [Member]	3 Months Ended
	Mar. 31, 2016shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested, Beginning balance	46,645
Vested	(27,818)
Canceled	0
Non-vested, Ending balance	18,827

Stock-Based Compensation - Su57

Stock-Based Compensation - Summary of Restricted Stock Units that were Granted in Connection with IPO Including Non-Vested Balance (Detail) - Prior Equity Plan [Member] - Restricted Stock Units [Member]	3 Months Ended
	Mar. 31, 2016$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested, Beginning balance | shares	22,158
Vested and unissued | shares	(22,158)
Weighted Average Grant Date Fair Value, Non-vested, Beginning balance | $ / shares	$ 12
Weighted Average Grant Date Fair Value, Vested and unissued | $ / shares	$ 12

Stock-Based Compensation - Su58

Stock-Based Compensation - Summary of Stock Options (Detail) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)$ / sharesshares
2013 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Options, Outstanding | shares	6,950,858
Stock Options, Forfeited | shares	(57,440)
Stock Options, Expired | shares	(231,799)
Stock Options, Outstanding | shares	6,661,619
Stock options, Exercisable at March 31, 2016 | shares	2,832,742
Stock Options, Expected to vest after March 31, 2016 | shares	3,776,172
Stock Options, Exercisable as of March 31, 2016 and expected to vest thereafter | shares	6,608,914
Weighted - Average Exercise Price, Outstanding | $ / shares	$ 13.83
Weighted - Average Exercise Price, Forfeited | $ / shares	17.41
Weighted - Average Exercise Price, Expired | $ / shares	12.68
Weighted - Average Exercise Price, Outstanding | $ / shares	13.84
Weighted - Average Exercise Price Exercisable at March 31, 2016 | $ / shares	12.07
Weighted - Average Exercise Price, Expected to vest after March 31, 2016 | $ / shares	15.12
Weighted - Average Exercise Price, Exercisable as of March 31, 2016 and expected to vest thereafter | $ / shares	$ 13.81
Weighted - Average Remaining Contractual Term, Outstanding	8 years 1 month 6 days
Weighted - Average Remaining Contractual Term, Exercisable at March 31, 2016	7 years 7 months 6 days
Weighted - Average Remaining Contractual Term, Expected to vest after March 31, 2016	8 years 4 months 24 days
Weighted - Average Remaining Contractual Term, Exercisable as of March 31, 2016 and expected to vest thereafter	8 years 1 month 6 days
2011 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, Granted | shares	2,143,987
Stock Options, Exercised | shares	(89,572)
Stock Options, Forfeited | shares	(240,559)
Stock Options, Outstanding | shares	1,813,856
Stock options, Exercisable at March 31, 2016 | shares	351,727
Stock Options, Expected to vest after March 31, 2016 | shares	1,462,129
Stock Options, Exercisable as of March 31, 2016 and expected to vest thereafter | shares	1,813,856
Weighted - Average Exercise Price, Granted | $ / shares	$ 7.28
Weighted - Average Exercise Price, Exercised | $ / shares	6.60
Weighted - Average Exercise Price, Forfeited | $ / shares	7.18
Weighted - Average Exercise Price, Outstanding | $ / shares	7.33
Weighted - Average Exercise Price Exercisable at March 31, 2016 | $ / shares	8.90
Weighted - Average Exercise Price, Expected to vest after March 31, 2016 | $ / shares	6.95
Weighted - Average Exercise Price, Exercisable as of March 31, 2016 and expected to vest thereafter | $ / shares	$ 7.33
Weighted - Average Remaining Contractual Term, Outstanding	5 years 2 months 12 days
Weighted - Average Remaining Contractual Term, Exercisable at March 31, 2016	5 years 3 months 18 days
Weighted - Average Remaining Contractual Term, Expected to vest after March 31, 2016	5 years 1 month 6 days
Weighted - Average Remaining Contractual Term, Exercisable as of March 31, 2016 and expected to vest thereafter	5 years 2 months 12 days
Aggregate Intrinsic Value, Outstanding | $	$ 5,809
Aggregate Intrinsic Value, Exercisable at March 31, 2016 | $	572
Aggregate Intrinsic Value, Expected to vest after March 31, 2016 | $	5,237
Aggregate Intrinsic Value, Exercisable as of March 31, 2016 and expected to vest thereafter | $	$ 5,809

Stock-Based Compensation - Su59

Stock-Based Compensation - Summary of Stock Options (Parenthetical) (Detail)	3 Months Ended
	Mar. 31, 2016$ / shares
2013 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated fair value of the Company's common stock	$ 10.53
2011 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated fair value of the Company's common stock	$ 10.53

Stock-Based Compensation - Su60

Stock-Based Compensation - Summary of Restricted Stock Awards and Restricted Stock Units (Detail) - $ / shares	Feb. 09, 2016	Mar. 31, 2016
Restricted Stock Awards [Member] | 2013 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested, Beginning balance		4,849,290
Granted		743,514
Vested		(92,368)
Canceled		(24,522)
Non-vested, Ending balance		5,475,914
Weighted Average Grant Date Fair Value, Non-vested, Beginning balance		$ 15.24
Weighted Average Grant Date Fair Value, Granted		8.74
Weighted Average Grant Date Fair Value, Vested		12.03
Weighted Average Grant Date Fair Value, Canceled		17
Weighted Average Grant Date Fair Value, Non-vested, Ending balance		$ 14.40
Restricted Stock Units [Member] | 2013 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested, Beginning balance		220,765
Vested		(30,099)
Non-vested, Ending balance		190,666
Weighted Average Grant Date Fair Value, Non-vested, Beginning balance		$ 12
Weighted Average Grant Date Fair Value, Vested		12
Weighted Average Grant Date Fair Value, Non-vested, Ending balance		$ 12
Restricted Stock Units [Member] | 2011 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted	2,202,846	2,202,846
Vested		(345,544)
Canceled		(80,201)
Non-vested, Ending balance		1,777,101
Weighted Average Grant Date Fair Value, Granted		$ 7.69
Weighted Average Grant Date Fair Value, Vested		7.69
Weighted Average Grant Date Fair Value, Canceled		7.69
Weighted Average Grant Date Fair Value, Non-vested, Ending balance		$ 7.69

Redeemable Non-Controlling In61

Redeemable Non-Controlling Interest - Additional Information (Detail) - USD ($) $ in Thousands	Jan. 06, 2016	Mar. 31, 2016	Aug. 31, 2014
Redeemable Noncontrolling Interest [Line Items]
Cash paid for minority investment		$ 600
Redeemable non-controlling interest	$ 10,800	$ 16,262
WZ UK Ltd. [Member]
Redeemable Noncontrolling Interest [Line Items]
Cash paid for minority investment	$ 2,100
Ownership interest	57.50%
WZ UK Ltd. [Member]
Redeemable Noncontrolling Interest [Line Items]
Ownership interest		49.00%	49.00%
Expected value upon exercise of put option	$ 30,000
WZ UK Ltd. [Member] | WZ UK Ltd. [Member]
Redeemable Noncontrolling Interest [Line Items]
Ownership interest	5750.00%
Resume Labs Ltd [Member]
Redeemable Noncontrolling Interest [Line Items]
Payments to acquire controlling interest		$ 1,500
Pseudio Limited [Member]
Redeemable Noncontrolling Interest [Line Items]
Payments to acquire controlling interest		$ 1,500

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	Feb. 09, 2016	Mar. 11, 2015	Nov. 20, 2014	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Unrecognized tax positions				$ 0		$ 0
Deferred tax benefit				73,600,000
Income tax expense (benefit)				(99,902,000)	$ 978,000
Reversal of valuation allowance				(73,600,000)
Deferred federal and state deferred tax expense (benefit)				(29,000,000)
Foreign deferred tax expense (benefit)				(700,000)	200,000
Federal and state current income taxes				2,200,000	200,000
Foreign current tax				$ 1,100,000	400,000
US deferred tax expense					300,000
Reduction of valuation allowance					$ 200,000
Amount of net operating loss carry-forwards available to offset future U.S. federal taxable income						97,800,000
Amount of net operating loss carry-forwards available to offset future state taxable income						111,200,000
Expire date of carry-forwards				Through 2,034
Loss carry-forwards available to future foreign taxable income						$ 27,400,000
Net operating loss carry-forwards annual limitations				$ 77,100,000
Common stock, shares issued				132,579,860		132,024,558
Follow-On Public Offering [Member]
Operating Loss Carryforwards [Line Items]
Common stock, shares issued			13,000,000
Number of shares sold by the selling stockholders		12,000,000
Common stock, per share		$ 19
Over-Allotment Option [Member]
Operating Loss Carryforwards [Line Items]
Number of shares sold by the selling stockholders		1,800,000	1,950,000
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
U.S. federal research and development tax credits				$ 7,300,000
Federal NOL carry-forward						$ 1,600,000
Domestic Tax Authority [Member] | Constant Contact, Inc. [Member]
Operating Loss Carryforwards [Line Items]
U.S. federal research and development tax credits	$ 10,600,000
Federal NOL carry-forward	57,700,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Federal NOL carry-forward						700,000
State and Local Jurisdiction [Member] | Constant Contact, Inc. [Member]
Operating Loss Carryforwards [Line Items]
U.S. federal research and development tax credits	9,600,000
Federal NOL carry-forward	$ 31,900,000
India [Member]
Operating Loss Carryforwards [Line Items]
Loss carry-forwards available to future foreign taxable income						2,900,000
Loss carry-forwards, expiration date				2,021
United Kingdom [Member]
Operating Loss Carryforwards [Line Items]
Loss carry-forwards available to future foreign taxable income						23,400,000
ISRAEL
Operating Loss Carryforwards [Line Items]
Loss carry-forwards available to future foreign taxable income						900,000
SINGAPORE
Operating Loss Carryforwards [Line Items]
Loss carry-forwards available to future foreign taxable income						$ 200,000

Severance and Other Exit Cost63

Severance and Other Exit Costs - Additional Information (Detail) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016USD ($)Positions	Dec. 31, 2015USD ($)Positions	Dec. 31, 2014USD ($)Positions
Closing Office Facility in Redwood City [Member]
Restructuring Cost and Reserve [Line Items]
Severance and other exit costs accrued	$ 470	$ 479
Future lease payments			$ 3,000
Facilities charge			$ 2,100
Adjustments relating to lease agreement	(186)
Severance costs paid	236
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance and other exit costs accrued	563	$ 1,201
Adjustments relating to lease agreement	15
Severance costs paid	623
Integration And Consolidation Plan [Member]
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated | Positions			90
Severance cost incurred to date			$ 2,300
Integration And Consolidation Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance and other exit costs accrued	0
2015 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated | Positions		67
Severance cost incurred to date		$ 2,100
2015 Restructuring Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance and other exit costs accrued	600
Severance costs paid	$ 600
2016 Constant Contact Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated | Positions	180
Severance cost incurred to date	$ 8,000
2016 Constant Contact Restructuring Plan [Member] | Closing Office Facility in Redwood City [Member]
Restructuring Cost and Reserve [Line Items]
Severance and other exit costs accrued	3,269
Future lease payments	7,600
Facilities charge	3,416
Severance costs paid	147
2016 Constant Contact Restructuring Plan [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Severance and other exit costs accrued	6,545
Severance costs paid	$ 1,470

Severance and Other Exit Cost64

Severance and Other Exit Costs - Summary of Activity Related to Company's Facilities Exit Costs Accrual (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2014
Closing Office Facility in Redwood City [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	$ 479
Facilities exit charges, net of estimated sublease income		$ 2,100
Cash paid	(236)
Sublease income	41
Adjustments	186
Ending Balance	470
Closing Office Facility in Redwood City [Member] | 2016 Constant Contact Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Facilities exit charges, net of estimated sublease income	3,416
Cash paid	(147)
Ending Balance	3,269
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Beginning Balance	1,201
Cash paid	(623)
Adjustments	(15)
Ending Balance	563
Employee Severance [Member] | 2016 Constant Contact Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Severance charges	8,015
Cash paid	(1,470)
Ending Balance	$ 6,545

Severance and Other Exit Cost65

Severance and Other Exit Costs - Summary of Total Restructuring Charges Recorded in the Consolidated Statement of Operations and Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	$ 11,416	$ (90)
Cost of Revenue [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	3,279	(49)
Sales and Marketing [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	3,901	(14)
Engineering and Development [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	2,018	(67)
General and Administrative [Member]
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	$ 2,218	$ 40

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	Mar. 18, 2016USD ($)
Commitments and Contingencies Disclosure [Abstract]
Minimum revenue requirement from single customer per year	$ 500

Related Party Transactions - Su

Related Party Transactions - Summary of Related Party Transactions (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Related Party Transaction [Line Items]
Revenue	$ (237,113)	$ (177,318)
Sales and marketing	79,294	35,044
Engineering and development	16,255	5,371
General and administrative	40,279	17,207
Immediate Family Member of Management or Principal Owner [Member]
Related Party Transaction [Line Items]
Cost of revenue	3,100	2,400
Sales and marketing	100	100
Engineering and development	300	400
General and administrative	100	100
Total related party transaction expense, net	3,600	3,000
Chief Executive Officer and a Director [Member]
Related Party Transaction [Line Items]
Revenue	(600)	(150)
Revenue (contra)	2,100	1,800
Total related party transaction impact to revenue	1,500	1,650
Cost of revenue	200	200
Total related party transaction expense, net	$ 1,700	1,850
Chief Executive Officer and a Director [Member] | As Reported [Member]
Related Party Transaction [Line Items]
Revenue (contra)		1,800
Total related party transaction impact to revenue		1,800
Cost of revenue		200
Total related party transaction expense, net		$ 2,000

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Feb. 29, 2016	Feb. 09, 2016	Feb. 08, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Prepaid expenses and other current assets	$ 40,003,000					$ 15,675,000
Amount included in accounts receivable	10,929,000					12,040,000
Notes purchased	1,992,707,000					1,014,885,000
Bank Revolving Loan [Member]
Related Party Transaction [Line Items]
Revolving credit facility increase in borrowing amount	40,000,000
Revolving credit facility maximum borrowing amount	125,000,000			$ 165,000,000	$ 125,000,000
Bank Revolving Loan [Member] | Constant Contact, Inc. [Member]
Related Party Transaction [Line Items]
Revolving credit facility maximum borrowing amount			$ 165,000,000	165,000,000	$ 125,000,000
First Lien Term Loan Facility [Member] | Term Loan Credit Facility [Member] | Constant Contact, Inc. [Member]
Related Party Transaction [Line Items]
Revolving credit facility increase in borrowing amount			735,000,000	735,000,000
Senior Notes Due 2024 [Member]
Related Party Transaction [Line Items]
Senior notes due	350,000,000			350,000,000
Senior Notes Due 2024 [Member] | Constant Contact, Inc. [Member]
Related Party Transaction [Line Items]
Senior notes due			350,000,000	$ 350,000,000
Senior Notes Due 2024 [Member] | Bank Revolving Loan [Member]
Related Party Transaction [Line Items]
Revolving credit facility maximum borrowing amount	14,700,000
Immediate Family Member of Management or Principal Owner [Member]
Related Party Transaction [Line Items]
Amount included in accounts payable and accrued expense	1,700,000					1,900,000
Related party transaction expense	3,600,000	$ 3,000,000
Chief Executive Officer and a Director [Member]
Related Party Transaction [Line Items]
Amount included in accounts payable and accrued expense	1,500,000					1,100,000
Prepaid expenses and other current assets	100,000					200,000
Amount included in accounts receivable	400,000					$ 300,000
Related party transaction expense	1,700,000	$ 1,850,000
Goldman, Sachs & Co. [Member]
Related Party Transaction [Line Items]
Notes purchased			148,800,000
Related party transaction expense	$ 8,600,000
Goldman, Sachs & Co. [Member] | Bank Revolving Loan [Member]
Related Party Transaction [Line Items]
Revolving credit facility maximum borrowing amount			57,600,000
Goldman, Sachs & Co. [Member] | First Lien Term Loan Facility [Member] | Term Loan Credit Facility [Member]
Related Party Transaction [Line Items]
Revolving credit facility increase in borrowing amount			$ 312,400,000

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ in Thousands	Apr. 08, 2016	Mar. 31, 2016
Subsequent Event [Line Items]
Equity method investment		$ 600
Subsequent Event [Member] | Fortifico Limited [Member]
Subsequent Event [Line Items]
Equity method investment ownership percentage	33.00%
Equity method investment	$ 5,000