Endurance International 10-K 24 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Jan. 31, 2017	Jun. 30, 2016
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
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 Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		142,140,080
Entity Public Float			$ 577,725,323

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 53,596	$ 33,030
Restricted cash	3,302	1,048
Accounts receivable	13,088	12,040
Prepaid domain name registry fees	55,444	55,793
Prepaid expenses and other current assets	28,678	15,675
Total current assets	154,108	117,586
Property and equipment—net	95,272	75,762
Goodwill	1,859,909	1,207,255
Other intangible assets—net	612,057	359,786
Deferred financing costs	4,932	0
Investments	15,857	27,905
Prepaid domain name registry fees, net of current portion	10,429	9,884
Other assets	3,710	4,322
Total assets	2,756,274	1,802,500
Current liabilities:
Accounts payable	16,074	12,280
Accrued expenses	67,722	45,779
Accrued interest	27,246	5,090
Deferred revenue	355,190	285,945
Current portion of notes payable	35,700	77,500
Current portion of capital lease obligations	6,690	5,866
Deferred consideration—short term	5,273	51,488
Other current liabilities	2,890	3,973
Total current liabilities	516,785	487,921
Long-term deferred revenue	89,200	79,682
Notes payable—long term, net of original issue discounts of $0 and $25,853, and deferred financing costs of $990 and $43,342, respectively	1,951,280	1,014,885
Capital lease obligations—long term	512	7,215
Deferred tax liability—long term	39,943	28,786
Deferred consideration—long term	7,444	813
Other liabilities	8,974	3,524
Total liabilities	2,614,138	1,622,826
Redeemable non-controlling interest	17,753	0
Commitments and contingencies (Note 16)
Stockholders’ equity:
Preferred Stock—par value $0.0001; 5,000,000 shares authorized; no shares issued or outstanding	0	0
Common Stock—par value $0.0001; 500,000,000 shares authorized; 132,024,558 and 134,793,857 shares issued at December 31, 2015 and December 31, 2016, respectively; 131,938,485 and 134,793,857 outstanding at December 31, 2015 and December 31, 2016, respectively	14	14
Additional paid-in capital	868,228	848,740
Accumulated other comprehensive loss	(3,666)	(1,718)
Accumulated deficit	(740,193)	(667,362)
Total stockholders’ equity	124,383	179,674
Total liabilities, redeemable non-controlling interest and stockholders’ equity	$ 2,756,274	$ 1,802,500

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Unamortized deferred financing costs	$ 25,853	$ 0
Unamortized original issue discounts	$ 43,342	$ 990
Preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	134,793,857	132,024,558
Common stock, shares outstanding (in shares)	134,793,857	131,938,485

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Revenue	$ 1,111,142	$ 741,315	$ 629,845
Cost of revenue	583,991	425,035	381,488
Gross profit	527,151	316,280	248,357
Operating expense:
Sales and marketing	303,511	145,419	146,797
Engineering and development	87,601	26,707	19,549
General and administrative	143,095	81,386	64,746
Transaction costs	32,284	9,582	4,787
Total operating expense	566,491	263,094	235,879
Income (loss) from operations	(39,340)	53,186	12,478
Other income, net
Other income, net	1,862	5,440	0
Interest income	576	414	331
Interest expense	(152,888)	(58,828)	(57,414)
Total other expense—net	(150,450)	(52,974)	(57,083)
Income (loss) before income taxes and equity earnings of unconsolidated entities	(189,790)	212	(44,605)
Income tax expense (benefit)	(109,858)	11,342	6,186
Loss before equity earnings of unconsolidated entities	(79,932)	(11,130)	(50,791)
Equity loss of unconsolidated entities, net of tax	1,297	14,640	61
Net loss	(81,229)	(25,770)	(50,852)
Net loss attributable to non-controlling interest	(15,167)	0	(8,017)
Excess accretion of non-controlling interest	6,769	0	0
Net loss attributable to non-controlling interest	(8,398)	0	(8,017)
Net loss attributable to Endurance International Group Holdings, Inc.	(72,831)	(25,770)	(42,835)
Comprehensive loss:
Foreign currency translation adjustments	(597)	(1,281)	(462)
Unrealized gain (loss) on cash flow hedge, net of taxes of $0, $46, and ($792) for the years ended December 31, 2014, 2015 and 2016	(1,351)	80	0
Total comprehensive loss	$ (74,779)	$ (26,971)	$ (43,297)
Net loss per share attributable to Endurance International Group Holdings, Inc.—basic and diluted (in usd per share)	$ (0.55)	$ (0.20)	$ (0.34)
Weighted-average number of common shares used in computing net loss per share attributable to Endurance International Group Holdings, Inc.—basic and diluted (in shares)	133,415,732	131,340,557	127,512,346

Consolidated Statements of Ope5

Consolidated Statements of Operations and Comprehensive Loss (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Unrealized gain (loss) arising during period, tax	$ 0	$ 46	$ (792)

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
Beginning balance at Dec. 31, 2013	$ 155,262	$ 13	$ 754,061	$ (55)	$ (598,757)
Beginning balance, (in shares) at Dec. 31, 2013		124,766,544
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted shares	0	$ 1	(1)
Vesting of restricted shares (in shares)		866,820
Exercise of stock options	137		137
Exercise of stock options, (in shares)		11,390
Shares issued in connection with acquisitions	27,235		27,235
Shares issued in connection with acquisitions, (in shares)		2,269,579
Shares issued in follow-on offering, net of issuance costs of $2,405,176	41,095	$ 0	41,095
Shares issued in follow-on offering, net of issuance costs (in shares)		3,000,000
Non-controlling interest accretion	(13,962)		(13,962)
Other comprehensive loss	(462)			(462)
Net loss attributable to non-controlling interest	(8,017)		(8,017)
Net income (loss) attributable to Endurance International Group Holdings, Inc.	(42,835)				(42,835)
Stock-based compensation	16,043		16,043
Ending balance at Dec. 31, 2014	174,496	$ 14	816,591	(517)	(641,592)
Ending balance, (in shares) at Dec. 31, 2014		130,914,333
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted shares	0
Vesting of restricted shares (in shares)		838,809
Exercise of stock options	2,224		2,224
Exercise of stock options, (in shares)		185,343
Other comprehensive loss	(1,201)			(1,201)
Net loss attributable to non-controlling interest	0
Net income (loss) attributable to Endurance International Group Holdings, Inc.	(25,770)				(25,770)
Stock-based compensation	29,925		29,925
Ending balance at Dec. 31, 2015	179,674	$ 14	848,740	(1,718)	(667,362)
Ending balance, (in shares) at Dec. 31, 2015		131,938,485
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted shares	0
Vesting of restricted shares (in shares)		2,458,886
Exercise of stock options	2,564		2,564
Exercise of stock options, (in shares)		396,486
Shares issued in connection with acquisitions	5,395		5,395
Non-controlling interest accretion	(30,844)		(30,844)
Other comprehensive loss	(1,948)			(1,948)
Net loss attributable to non-controlling interest	(15,167)		(15,167)
Net income (loss) attributable to Endurance International Group Holdings, Inc.	(72,831)				(72,831)
Stock-based compensation	57,540		57,540
Ending balance at Dec. 31, 2016	$ 124,383	$ 14	$ 868,228	$ (3,666)	$ (740,193)
Ending balance, (in shares) at Dec. 31, 2016		134,793,857

Consolidated Statements of Cha7

Consolidated Statements of Changes in Shareholders' Equity (Parenthetical)	12 Months Ended
	Dec. 31, 2014USD ($)
Issuance costs of common stock in connection with initial public offering	$ 2,405,176
Common Stock
Issuance costs of common stock in connection with initial public offering	2,405,176
Additional Paid-in Capital
Issuance costs of common stock in connection with initial public offering	$ 2,405,176

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net loss	$ (81,229,000)	$ (25,770,000)	$ (50,852,000)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation of property and equipment	60,360,000	34,010,000	30,956,000
Amortization of other intangible assets from acquisitions	143,562,000	91,057,000	102,723,000
Amortization of deferred financing costs	6,073,000	82,000	83,000
Amortization of net present value of deferred consideration	2,617,000	1,264,000	183,000
Amortization of original issuance discount	2,970,000	0	0
Impairment of other long lived assets	9,039,000	0	0
Stock-based compensation	58,267,000	29,925,000	16,043,000
Deferred tax expense (benefit)	(113,242,000)	7,120,000	3,640,000
Gain on sale of assets	(243,000)	(155,000)	(168,000)
Gain from unconsolidated entities	(1,862,000)	(5,440,000)	0
Loss of unconsolidated entities	1,297,000	14,640,000	61,000
Dividend from minority interest	100,000	0	167,000
(Gain) loss from change in deferred consideration	(20,000)	1,174,000	384,000
Changes in operating assets and liabilities:
Accounts receivable	(1,620,000)	(1,659,000)	(691,000)
Prepaid expenses and other current assets	(4,932,000)	(13,187,000)	(25,675,000)
Accounts payable and accrued expenses	19,458,000	9,926,000	(1,615,000)
Deferred revenue	54,366,000	34,241,000	67,654,000
Net cash provided by operating activities	154,961,000	177,228,000	142,893,000
Cash flows from investing activities:
Businesses acquired in purchase transaction, net of cash acquired	(889,634,000)	(97,795,000)	(93,698,000)
Purchases of property and equipment	(37,259,000)	(31,243,000)	(23,904,000)
Cash paid for minority investment	(5,600,000)	(8,475,000)	(34,140,000)
Proceeds from sale of assets	676,000	284,000	194,000
Proceeds from note receivable	0	3,454,000	0
Purchases of intangible assets	(27,000)	(76,000)	(200,000)
Net (deposits) and withdrawals of principal balances in restricted cash accounts	(557,000)	50,000	433,000
Net cash used in investing activities	(932,401,000)	(133,801,000)	(151,315,000)
Cash flows from financing activities:
Proceeds from issuance of term loan	1,056,178,000	0	0
Repayment of term loan	(55,200,000)	(10,500,000)	(10,500,000)
Proceeds from borrowing of revolver	54,500,000	147,000,000	150,000,000
Repayment of revolver	(121,500,000)	(130,000,000)	(100,000,000)
Payment of financing costs	(52,561,000)	0	(53,000)
Payment of deferred consideration	(51,044,000)	(14,991,000)	(98,318,000)
Payment of redeemable non-controlling interest liability	(33,425,000)	(30,543,000)	(4,190,000)
Principal payments on capital lease obligations	(5,892,000)	(4,822,000)	(3,608,000)
Proceeds from exercise of stock options	2,564,000	2,224,000	137,000
Capital investment from minority interest partner	2,776,000	0	0
Proceeds from issuance of common stock	0	0	43,500,000
Issuance costs of common stock	0	0	(2,904,000)
Net cash provided by (used in) financing activities	796,396,000	(41,632,000)	(25,936,000)
Net effect of exchange rate on cash and cash equivalents	1,610,000	(1,144,000)	(78,000)
Net increase (decrease) in cash and cash equivalents	20,566,000	651,000	(34,436,000)
Cash and cash equivalents:
Beginning of period	33,030,000	32,379,000	66,815,000
End of period	53,596,000	33,030,000	32,379,000
Supplemental cash flow information:
Interest paid	119,063,000	57,338,000	57,418,000
Income taxes paid	4,278,000	4,510,000	2,615,000
Supplemental disclosure of non-cash financing activities:
Shares or awards issued in connection with acquisitions	5,395,000	0	27,235,000
Assets acquired under capital lease	$ 0	$ 9,795,000	$ 11,704,000

Nature of Business

Nature of Business	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Business	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. Common Stock Offerings On November 26, 2014, the Company closed a follow-on offering of its common stock, in which the Company sold 3,000,000 shares of its common stock at a public offering price of $14.50 per share and selling stockholders sold 10,000,000 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 did not receive any proceeds from the sale of shares by the selling stockholders. The follow-on offering resulted in gross proceeds to the Company of $43.5 million and net proceeds to the Company of $41.1 million after deducting underwriting discounts and commissions of $1.7 million and other estimated offering expenses of approximately $0.7 million payable by the Company. The Company incurred an additional $0.3 million of offering expenses on behalf of the selling stockholders, which was included in general and administrative expense in the consolidated statement of operations and comprehensive loss for the year ended December 31, 2014. On March 11, 2015, the Company closed 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 did not receive any proceeds from the sale of shares by the selling stockholders. The Company incurred $0.7 million of offering expenses on behalf of the selling stockholders, which was included in general and administrative expense in the consolidated statement of operations and comprehensive loss for the year ended December 31, 2015.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	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. Segment Information The Company has reviewed the criteria of the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 280-10, Segment Reporting, and determined that the Company is comprised of two segments for reporting purposes: web presence and email marketing. In February 2016, the Company acquired Constant Contact. At the time of the acquisition, the Company anticipated that the gross margins of Constant Contact would become more aligned with the Company's other brands; however, through review of Constant Contact's performance during 2016, the Company noted that Constant Contact continued to return higher margins than originally anticipated, and therefore determined that Constant Contact should be its own reporting segment. As such, the Company determined that it has two reportable segments. The web presence segment consists predominantly of our web hosting brands and related products such as domain names, website security tools, website design tools and services, ecommerce tools and other services designed to grow the online presence of a small business. The email marketing segment consists of the Constant Contact email marketing tools and the SinglePlatform marketing tool, both of which were acquired in the February 2016 acquisition of Constant Contact. 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. Cash Equivalents Cash and cash equivalents include all highly liquid investments with remaining maturities of three months or less at the date of purchase. Restricted Cash Restricted cash is composed of certificates of deposits and cash held by merchant banks and payment processors, which provide collateral against any charge-backs, fees, or other items that may be charged back to the Company by credit card companies and other merchants and collateral for certain facility leases. 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. Fair Value of Financial Instruments The carrying amounts of the Company’s financial instruments, which include cash equivalents, accounts receivable, accounts payable and certain accrued expenses, approximate their fair values due to their short maturities. The carrying amount of the Company’s contingent consideration is recorded at fair value. The fair value of the Company’s notes payable is based on the borrowing rates currently available to the Company for debt with similar terms and average maturities and approximate their carrying value. Derivative Instruments and Hedging Activities FASB ASC 815, Derivatives and Hedging (“ASC 815”), provides the disclosure requirements for derivatives and hedging activities with the intent to provide users of financial statements with an enhanced understanding of: (a) how and why an entity uses derivative instruments, (b) how the entity accounts for derivative instruments and related hedged items, and (c) how derivative instruments and related hedged items affect an entity’s financial position, financial performance, and cash flows. Further, qualitative disclosures are required that explain the Company’s objectives and strategies for using derivatives, as well as quantitative disclosures about the fair value of and gains and losses on derivative instruments, and disclosures about credit-risk-related contingent features in derivative instruments. 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 2011-4, Fair Value Measurement (Topic 820): Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements, the Company made an accounting policy election to measure the credit risk of its derivative financial instruments that are subject to master netting agreements on a net basis by counterparty portfolio. Concentrations of Credit and Other Risks Financial instruments which potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents and accounts receivable. Cash and cash equivalents are maintained at accredited financial institutions, and PayPal balances are at times without and in excess of federally insured limits. The Company has never experienced any losses related to these balances and does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships. For the years ended, December 31, 2014 , 2015 and 2016 , no subscriber represented 10% or more of the Company’s total revenue. Additionally, as of December 31, 2015 and 2016 , no subscriber represented 10% or more of the Company’s total accounts receivable. 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” . Accordingly, certain costs to develop internal-use computer software are capitalized, provided these costs are expected to be recoverable. During the years ended December 31, 2014 , 2015 and 2016 , the Company capitalized internal-use software development costs of $5.4 million , $5.5 million and $11.8 million , respectively. Investments The Company has minority investments in several privately-held companies. Investments in privately-held companies, in which the Company has a voting interest between 20.0% and 50.0% and exercises significant influence, are accounted for using the equity method of accounting. 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. The Company’s share of net earnings or losses of the investee are reflected in equity losses of unconsolidated entities, net of tax, in the Company’s accompanying consolidated statements of operations. Investments in which the Company has a voting interest of less than 20.0% and over which it does not have significant influence are accounted for under the cost method of accounting. During the year ended December 31, 2016, the Company incurred a charge of $4.7 million to impair the Company's 33.0% equity interest in Fortifico Limited, after determining that there were diminishing projected future cash flows on this investment. This charge was recorded in other income, net in the consolidated statement of operations and comprehensive loss. Refer to Note 8: Investments for further details. This impairment was recorded within the web presence segment. Business Combinations The Company accounts for business acquisitions using the purchase method of accounting, in accordance with which assets acquired and liabilities assumed are recorded at their respective fair values at the acquisition date. The fair value of the consideration paid, including contingent consideration, is assigned to the assets acquired and liabilities assumed based on their respective fair values. Goodwill represents excess of the purchase price over the estimated fair values of the assets acquired and liabilities assumed. Significant judgments are used in determining fair values of assets acquired and liabilities assumed, as well as intangibles and their estimated useful lives. Fair value and useful life determinations are based on, among other factors, estimates of future expected cash flows, royalty cost savings and appropriate discount rates used in computing present values. These judgments may materially impact the estimates used in allocating acquisition date fair values to assets acquired and liabilities assumed, as well as the Company's current and future operating results. Actual results may vary from these estimates which may result in adjustments to goodwill and acquisition date fair values of assets and liabilities during a measurement period or upon a final determination of asset and liability fair values, whichever occurs first. Adjustments to fair values of assets and liabilities made after the end of the measurement period are recorded within the Company's operating results. Changes in the fair value of a contingent consideration resulting from a change in the underlying inputs are recognized in results of operations until the arrangement is settled. 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 , or ASC 350, the Company is required to review goodwill by reporting unit for impairment at least annually or more often if there are indicators of impairment present. Under U.S. GAAP, a reporting unit is either the equivalent of, or one level below, an operating segment. The Company has determined it operates in two segments and that each segment is its own reporting unit, and as such, the Company has two reporting units, email marketing and web presence as of December 31, 2016. The provisions of ASC 350 require that a two-step impairment test be performed for goodwill. In the first step, the Company compares the fair value of its reporting unit to which goodwill has been allocated to its carrying value. If the fair value of the reporting unit exceeds the carrying value of the net assets assigned to that reporting unit, goodwill is considered not impaired and the Company is not required to perform further testing. If the carrying value of the net assets assigned to the reporting unit exceeds the fair value of the reporting unit, then the Company must perform the second step of the impairment test in order to determine the implied fair value of the reporting unit’s goodwill. If the carrying value of a reporting unit’s goodwill exceeds its implied fair value, then the Company would record an impairment loss equal to the difference. The Company's annual assessment date is December 31 of each fiscal year. As of December 31, 2016, the Company determined fair values for each of the reporting units based on consideration of the income approach, the market comparable approach and the market transaction approach. For purposes of the income approach, fair value is determined based on the present value of estimated future after-tax cash flows, discounted at an appropriate risk adjusted rate. The Company uses its internal forecasts to estimate future after-tax cash flows and include an estimate of long-term future growth rates based on its most recent views of the long-term outlook for each reporting unit. Actual results may differ from those assumed in our forecasts. The Company derived its discount rates using the weighted average cost of capital, using betas observed in its industry and published rates for industries relevant to our reporting units. The Company uses discount rates that are commensurate with the risks and uncertainty inherent in the respective business and its internally developed forecasts. Discount rates used in the Company's reporting unit valuations ranged from 11.0% to 12.0% . For purposes of the market approach, the Company uses a valuation technique in which values are derived based on market prices of comparable publicly traded companies. The Company also uses a market based valuation technique in which values are determined based on relevant observable information generated by market transactions involving comparable businesses. The Company assesses each valuation methodology based upon the relevance and availability of the data at the time it performs the valuation and weight the methodologies appropriately. The carrying values of the reporting units were determined through specific allocation of assets and liabilities to the reporting units, and an apportionment method relating to our debt, whereby debt that was incurred in order to finance the acquisition of assets or businesses of a reporting unit was allocated to that reporting unit. In prior years, the Company had only one reporting unit. Subsequent to the acquisition of Constant Contact, and as described in Note 20: Segment Information , the Company determined that there is a second reporting unit relating to email marketing. The Company has allocated the fair value of the goodwill acquired through its acquisitions to the applicable reporting unit, and allocated the fair value of the goodwill acquired through its acquisition of Constant Contact to its email marketing reporting unit. As of the Company's assessment date for 2016, the estimated fair values of its reporting units exceeded their carrying values and the Company concluded, based on the first step of the process, that no impairment existed as of that date in either of its reporting units. As of December 31, 2016, the carrying value of goodwill that was allocated to the email marketing reporting unit and the web presence reporting unit was $604.3 million and $1,255.6 million , respectively. As of December 31, 2016, the fair value of the web presence segment exceeded the carrying value of its net assets by 67% and the fair value of the email marketing segment exceeded the carrying value of its net assets by 35% . Goodwill amounted in aggregate to $1,207.3 million and $1,859.9 million as of December 31, 2015 and 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 impairment losses were identified for the years ended December 31, 2014 and December 31, 2015. During the year ended December 31, 2016, the Company determined that a portion of an internally developed software tool would not meet its needs following the acquisition of Constant Contact, resulting in an impairment charge of $2.0 million which was recorded in engineering and development expense in the consolidated statements of operations and comprehensive loss. Additionally, the Company recognized an impairment charge of $0.5 million relating to internally developed software relating to Webzai Ltd. (“Webzai”), and another impairment charge of $4.4 million relating to developed technology acquired in the Webzai acquisition, for a total impairment charge of $4.9 million , which was recorded in engineering and development expense in the consolidated statements of operations and comprehensive loss. Refer to Note 6: Property and Equipment and Capital Lease Obligations and Note 7: Goodwill and Other Intangible Assets for further details. Also during the year ended December 31, 2016, the Company incurred total impairment charges of IPR&D of $2.2 million , consisting of $1.4 million to impair certain acquired IPR&D projects from the Webzai acquisition that were abandoned during the three months ended March 31, 2016 and a charge of $0.8 million to impair certain acquired IPR&D projects from the AppMachine acquisition. Refer to Note 7: Goodwill and Other Intangible Assets , and Acquired In- Process Research and Development (IPR&D) below for further details. All of the impairments described above were recognized in the web presence segment. 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 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. Upon commercialization, the acquired fair value of the IPR&D will be reclassified to developed technology and amortized over its estimated useful life. No such impairment losses were identified for the years ended December 31, 2014 and 2015 . During the year ended December 31, 2016, the Company identified that the acquired fair value of the remaining IPR&D acquired in connection with its acquisition of Webzai was impaired as these IPR&D projects were abandoned in favor of other projects. At that time, and as mentioned above, the Company recorded a $1.4 million impairment charge, which is reflected in engineering and development expense during the year ended December 31, 2016 in the Company’s consolidated statements of operations and comprehensive loss. Additionally, during the year-ended December 31, 2016, the Company identified that the acquired fair value of the remaining IPR&D acquired in connection with its acquisition of AppMachine B.V. was impaired as these projects were abandoned in favor of other projects, and as such, the Company recorded a $0.8 million impairment charge, which is also reflected in engineering and development expense during the year ended December 31, 2016 in the Company’s consolidated statements of operations and comprehensive loss. During 2014, the Company capitalized $4.6 million of IPR&D in connection with its acquisition of Webzai. During the year ended December 31, 2015, $3.2 million was reclassified to developed technology and is being amortized over the estimated useful life of 4.0 years . During 2015, the Company did not capitalize any IPR&D in connection with its acquisitions of the assets of the U.S. retail portion of the Verio business of NTT America, Inc. (“Verio”), the assets of World Wide Web Hosting, LLC (“WWWH”), the assets of Ace Data Centers, Inc. (“Ace DC”) and the ownership interests in Ace Holdings, LLC (“Ace Holdings”) (these acquired assets and ownership interests, collectively, “Ace”) and the assets of Ecommerce, LLC, (“Ecommerce”). During 2016, in addition to the impairment of the Webzai IPR&D mentioned above, the Company also capitalized $1.7 million of IPR&D in connection with its acquisition of AppMachine B.V. ("AppMachine"), of which approximately $0.9 million was reclassified to developed technology and is being amortized over the estimated useful life of 4.0 years, and the remaining $0.8 million was impaired, as previously mentioned. The Company did not capitalize any other IPR&D in connection with its other 2016 acquisitions of WZ (UK) Ltd and Constant Contact. 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 , whether the associated revenue is derived from a direct subscriber or through a reseller. Deferred revenue represents the liability to subscribers for advance billings for services not yet provided and the fair value of the assumed liability outstanding for subscriber relationships purchased in an acquisition. 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 and allocates revenue to each deliverable in a multiple-element service arrangement based on its respective relative selling price. 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 our 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 2016 , respectively. The portion of deferred revenue that is expected to be refunded at December 31, 2015 and 2016 was $1.8 million and $2.1 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 81% of all refunds happen in the same fiscal month that the contract starts or renews, and approximately 94% of all refunds happen within 45 days of the contract start or renewal date. Direct Costs of Revenue The Company’s direct costs of revenue include only those costs directly incurred in connection with the provision of its cloud-based products and services. The direct costs of registering domain names with registries are spread over the terms of the arrangement and the cost of reselling domains of other third-party registrars are expensed as incurred. Cost of revenue includes depreciation on data center equipment and support infrastructure and amortization expense related to the amortization of long-lived intangible assets. Engineering and Development Costs Engineering and development costs incurred in the development and maintenance of the Company’s technology infrastructure are expensed as incurred. Sales and Marketing Costs The Company engages in sales and marketing through various online marketing channels, which include affiliate and search marketing as well as online partnerships. The Company expenses sales and marketing costs as incurred. For the years ended December 31, 2014 , 2015 and 2016 , the Company’s sales and marketing costs were $146.8 million , $145.4 million and $303.5 million , respectively. Foreign Currency The Company has sales in a number of foreign currencies. In 2013, the Company commenced operations in foreign locations which report in the local currency. The assets and liabilities of the Company’s foreign locations are translated into U.S. dollars at current exchange rates as of the balance sheet date, and revenues and

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Acquisitions	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 relief from royalty method. The fair value assigned to IPR&D is based on the relief from royalty method. 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 and comprehensive loss. Acquisitions—2015 Verio On May 26, 2015, the Company acquired the assets of the U.S. retail portion of the Verio business of NTT America, Inc., which is a provider of shared, virtual private server (“VPS”) and dedicated hosting services. The aggregate purchase price was $13.0 million , of which $10.5 million was paid in cash at the closing. The Company was obligated to pay the remaining cash consideration of $2.5 million on the first anniversary of the acquisition, less amounts used to satisfy any obligation determined to be owed to the Company for any indemnity pursuant to the asset purchase agreement. As of December 31, 2016, the Company has paid approximately $2.4 million of the remaining cash consideration, while $50,000 has been retained as a hold-back until certain conditions are satisfied. The purchase price of $13.0 million has been allocated to intangible assets consisting of subscriber relationships and trade names of $13.1 million and $0.1 million , respectively, and goodwill of $1.2 million , offset by deferred revenue of $1.4 million . Goodwill related to the acquisition is deductible for tax purposes and related primarily to expected synergies. World Wide Web Hosting On June 25, 2015, the Company acquired substantially all of the assets of World Wide Web Hosting ("WWWH"), which is a provider of web presence solutions doing business under the brand name Site5. The Company previously had an equity interest in WWWH, which was originally acquired when the Company acquired Hostgator.com LLC on July 13, 2012. The aggregate purchase price was $34.9 million , $23.0 million of which was payable in cash and $11.9 million of which was the implied value of the pro rata interest in the acquired assets that the Company obtained upon the seller’s redemption of its 40% equity interest in WWWH. The Company recognized a $5.4 million gain as a result of this redemption, which was recorded as other income in the Company’s consolidated statement of operations and comprehensive loss. Of the $23.0 million payable in cash, $18.4 million was paid at the closing and the Company was obligated to pay the remaining cash consideration of $4.6 million on the first anniversary of the acquisition, less amounts used to satisfy any obligation determined to be owed to the Company for any indemnity pursuant to the asset purchase agreement. The Company paid the remaining cash consideration of $4.6 million during the year ended December 31, 2016. The purchase price of $34.9 million has been allocated to intangible assets consisting of subscriber relationships and trade names of $11.0 million and $1.9 million , respectively, goodwill of $23.3 million , and prepaid expenses and other current assets of $1.2 million , offset by deferred revenue of $2.5 million . Goodwill related to the acquisition is deductible for tax purposes and related primarily to expected synergies. Ace Data Center and Ace Holdings On September 21, 2015, the Company entered into a purchase agreement with Ace Data Center ("Ace DC") to acquire substantially all of the assets of Ace DC and with Ace Holdings and its owners to acquire all of the ownership interests in Ace Holdings. Ace DC is the manager of a data center that provides colocation, infrastructure and carrier-neutral connectivity services. This data center is the Company’s largest data center. Ace Holdings owns the real property, improvements and building at and on which the data center is located, including certain non-systems equipment and personal property. The aggregate purchase price was $74.0 million , of which $44.4 million was paid in cash at the closing. Under the terms of the purchase agreement, within approximately 75 days of the closing date of the acquisition, the purchase consideration was subject to a working capital adjustment and a tax gross up adjustment, which resulted in an additional $0.7 million payment from the Company on December 2, 2015. The Company was obligated to pay the remaining cash consideration of $31.5 million on the first anniversary of the acquisition, less amounts used to satisfy any obligation determined to be owed to the Company for any indemnity pursuant to the asset purchase agreement. The net present value of the remaining cash consideration was $28.9 million , which was the amount used to calculate the $74.0 million aggregate purchase price above. An aggregate amount of $0.7 million for the accretion of the present value of the remaining cash consideration was included in interest expense for the year ended December 31, 2015, resulting in the net present value of the remaining cash consideration at December 31, 2015 of $29.6 million . The Company paid the remaining cash consideration during the year ended December 31, 2016 of $31.4 million . The purchase price of $74.0 million has been allocated to property and equipment, including real property, of $12.1 million , goodwill of $62.2 million , prepaid expenses and other current assets of $0.2 million and developed technology of $0.1 million , offset by other liabilities of $0.6 million . The goodwill reflects the value of estimated cost efficiencies gained for the Company by owning its own data center. Goodwill related to the acquisition is deductible for tax purposes. Ecommerce On November 2, 2015, the Company acquired the assets of Ecommerce, which is a provider of shared, VPS and cloud hosting services, domain registration services and add-on products. The aggregate purchase price was $28.0 million , of which $23.8 million was paid in cash at the closing. The Company was obligated to pay the remaining cash consideration of $4.2 million on the first anniversary of the acquisition, less amounts used to satisfy any obligation determined to be owed to the Company for any indemnity pursuant to the asset purchase agreement. The Company paid the remaining cash consideration during the year ended December 31, 2016. The purchase price of $28.0 million has been allocated to intangible assets consisting of subscriber relationships, intellectual property and trade names of $9.4 million , $4.4 million and $0.1 million , respectively, and goodwill of $16.7 million , offset by deferred revenue of $2.6 million . Goodwill reflects the value of estimated synergies and is deductible for tax purposes. Acquisitions—2016 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, which is a provider of technology and sales and marketing services associated with web builder solutions. The Company and the other shareholders of WZ UK entered into a put and call option for the Company to acquire additional equity interests WZ UK under certain circumstances. On January 6, 2016, the Company partially exercised this option, which increased its stake in WZ UK 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 noncontrolling interest (“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 49.0% equity investment and the NCI of $10.8 million , which were allocated 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, which is part of the Company’s web presence reporting segment, is not deductible for tax purposes. Goodwill reflected primarily marketing know-how of the acquired company. The Company recognized the $11.4 million gain in other income in the Company’s consolidated statements of operations and comprehensive loss. 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 , was being accreted over the period commencing January 6, 2016, and up to the end of the second call option period which was August 14, 2016. Adjustments to the carrying amount of the redeemable non-controlling interest were charged to additional paid-in capital. On May 16, 2016, the Company amended the put and call option described above to allow it to acquire an additional equity interest in WZ UK earlier than August 2016. Pursuant to this amended option, on the same date the Company acquired an additional 20% stake in WZ UK for $15.4 million , thus increasing its ownership interest from 57.5% to 77.5% . On July 13, 2016, WZ UK completed a restructuring pursuant to which the Company and the minority shareholders of Pseudio Limited and Resume Labs Limited sold their shares in these entities to WZ UK, in exchange for shares in WZ UK. As a result of the restructuring, Pseudio Limited and Resume Labs Limited became wholly-owned subsidiaries of WZ UK, and the Company’s ownership of WZ UK was diluted from 77.5% to 76.4% . Immediately subsequent to the restructuring, the Company acquired an additional 10% equity interest in WZ UK for $18.0 million , thereby increasing the Company’s ownership interest to 86.4% . Concurrent with the restructuring, the Company amended the put and call option described above to provide for Company to acquire the remaining 13.6% equity interest in WZ UK for $25.0 million under certain circumstances, either through a put option that is exercisable by the minority shareholders of WZ UK beginning on July 1, 2017, or by a call option that is exercisable by the Company beginning on January 1, 2018. The Company started accreting the $25.0 million starting in July 2016. Refer to Note 13: Redeemable Non-controlling Interest, for further details. 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 to intangible assets consisting of subscriber relationships, developed technology and trade names of $263.0 million , $83.0 million and $52.0 million , respectively, goodwill of $604.3 million , property and equipment of $39.6 million , and working capital of $184.2 million , offset by a net deferred tax liability of $125.1 million and deferred revenue of $25.2 million . The goodwill reflects the value of expected synergies. Goodwill related to the acquisition, which is included in the Company’s email marketing reporting unit, is not deductible for tax purposes. Pro Forma Disclosure The Company acquired Constant Contact on February 9, 2016, and the results of Constant Contact have been included in the results of the Company since February 10, 2016. The following unaudited information is presented as if the Constant Contact acquisition was completed as of January 1, 2015. The Company has not presented unaudited pro forma results for the quarterly and annual periods following March 31, 2016, as Constant Contact is included for the entire fiscal periods after that date. 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 fiscal years ended December 31, 2015 and 2016 was $1.1 billion and $1.2 billion , respectively. Unaudited pro forma net loss attributable to Endurance International Group Holdings, Inc. for the fiscal years ended December 31, 2015 and 2016 was $107.8 million , and $59.1 million , respectively. Unaudited pro forma net 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 fiscal year ended December 31, 2016 has been reduced by $15.2 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 loss for the year ended December 31, 2016 includes restructuring charges of approximately $22.2 million as the Company implemented plans to reduce the cost structure of the combined businesses. AppMachine B.V. In December 2014, the Company made an aggregate investment of $15.2 million to acquire a 40.0% 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 was obligated to purchase the remaining 60.0% of AppMachine in three tranches of 20.0% within specified periods if AppMachine achieved a specified minimum revenue threshold within a designated timeframe. The consideration for each of those three tranches was to be calculated as the product of AppMachine’s revenue, as defined in that 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 20.0% . On July 27, 2016, the Company acquired the remaining 60% equity interest in AppMachine, increasing the Company’s stake to 100% . In connection with the acquisition, the parties terminated the prior investment agreement pursuant to which the Company was obligated to purchase the remaining shares in AppMachine in three tranches. The total consideration based on the new agreement was $22.5 million , of which $5.5 million was paid upon closing, and the remaining $17.0 million (which includes $4.0 million of post-acquisition compensation expense) will be paid in annual installments over a period of four years , commencing with June 21, 2017. The net present value of the additional consideration is $11.5 million , which is included in the aggregate purchase price and recorded as deferred consideration in the Company’s consolidated balance sheets as of December 31, 2016. The remaining $1.5 million is being accreted as interest expense. The $4.0 million relating to retention bonuses is being accrued over the employment term associated with these employees. On the date of acquisition, the Company recognized a loss of $4.9 million that was calculated based on the implied fair value of the investment, which was recorded in other income (expense) in the Company’s consolidated statements of operations and comprehensive loss. The purchase price of $25.7 million , which consists of the purchase consideration of $13.0 million , at a present value of $11.5 million , and the carrying value of the existing investment of $13.6 million , partially offset by the loss of $4.9 million , is being allocated on a preliminary basis to intangible assets consisting of subscriber relationships of $0.1 million , developed technology of $1.7 million , and technology in the process of development of $1.7 million , goodwill of $21.5 million , property and equipment of $0.6 million , and working capital of approximately $0.4 million , offset by deferred revenue of $0.2 million , and other long term liabilities of $0.1 million . Goodwill related to the acquisition, which is included in the Company’s web presence reporting unit, is not deductible for tax purposes. The goodwill reflects the value of expected synergies and technology know-how. Financial Performance The Company recorded revenue attributable to its 2016 acquisitions in its consolidated statements of operations and comprehensive loss for the year-ended December 31, 2016 of $340.9 million . The 2016 acquisitions generated a net loss for the year ended December 31, 2016 of $46.0 million which is recorded in the Company’s consolidated statements of operations and comprehensive loss. The $32.3 million of transaction expenses in the Company’s consolidated statements of operations and comprehensive loss included a $16.8 million charge related to the accelerated vesting of certain Constant Contact equity awards, and approximately $15.5 million in advisor, legal, and other acquisition-related fees. For the intangible assets acquired in connection with all acquisitions completed during the twelve months ended December 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 . Summary of Deferred Consideration Related to Acquisitions Components of deferred consideration short-term and long-term as of December 31, 2015, consisted of the following: Short- term Long- term (in thousands) Mojoness, Inc. (Acquired in 2012) $ 657 $ 813 Typepad (Acquired in 2013) 2,800 — Webzai (Acquired in 2014) 2,848 — BuyDomains (Acquired in 2014) 4,283 — Verio (Acquired in 2015) 2,474 — WWWH (Acquired in 2015) 4,600 — Ace (Acquired in 2015) 29,626 — Ecommerce (Acquired in 2015) 4,200 — Total $ 51,488 $ 813 Components of deferred consideration short-term and long-term as of December 31, 2016, consisted of the following: Short- term Long- term (in thousands) Mojoness, Inc. (Acquired in 2012) $ 818 $ — Verio (Acquired in 2015) 50 — Social Booster (Acquired in 2016) 40 25 AppMachine (Acquired in 2016) 4,365 7,419 Total $ 5,273 $ 7,444

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The following valuation hierarchy is used for disclosure of the inputs to valuation 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 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 the Mojo acquisition within Level 3 of the fair value hierarchy because the fair value is determined using significant unobservable inputs, which included probability weighted cash flows. During the year ended December 31, 2014, the Company paid $0.2 million related to the earn-out provisions for the Mojo acquisition and recorded $23.0 million related to the 2014 domain name business acquisition of which $14.0 million was paid during the year ended December 31, 2014. The Company recorded a $0.4 million change in fair value of the earn-out consideration related to Mojo and the 2014 domain name business during the year ended December 31, 2014. During the year ended December 31, 2015, the Company paid $0.5 million related to the earn-out provisions for the Mojo acquisition and paid $10.1 million related to the earn-out provisions of the 2014 domain name business acquisition. The Company recorded a $1.2 million change in fair value of the earn-out consideration related to the earn-out provisions of the Mojo and 2014 domain name business acquisitions during the year ended December 31, 2015. During the year ended December 31, 2016, the Company paid $0.7 million related to the earn-out provisions for the Mojo acquisition. The Company recorded an immaterial change in fair value of the earn-out consideration related to the earn-out provisions for the Mojo acquisition. The earn-out consideration in the table below is included in total deferred consideration in the Company’s consolidated balance sheets. 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 December 31, 2016 Financial assets: Interest rate cap (included in other assets) $ 979 — $ 979 $ — Total financial assets $ 979 $ — $ 979 $ — Financial liabilities: Contingent earn-out consideration $ 818 — — $ 818 Total financial liabilities $ 818 $ — $ — $ 818 The following table summarizes the changes in the financial liabilities measured on a recurring basis using Level 3 inputs as of December 31, 2015 and 2016 : Amount (in thousands) Financial liabilities measured using Level 3 inputs at January 1, 2015 $ 10,887 Payment of contingent earn-out related to 2012 and 2014 acquisitions (10,592 ) Change in fair value of contingent earn-outs 1,174 Financial liabilities measured using Level 3 inputs at December 31, 2015 1,469 Payment of contingent earn-outs related to 2012 acquisitions (668 ) Change in fair value of contingent earn-outs 17 Financial liabilities measured using Level 3 inputs at December 31, 2016 $ 818

Derivatives and Hedging Activit

Derivatives and Hedging Activities	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives and Hedging Activities	Derivatives and Hedging Activities Risk Management Objective of Using Derivatives The Company is exposed to certain risks 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 may enter 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 this interest rate cap, designated as cash flow hedges, 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 Accumulated Other Comprehensive Income (“AOCI”), and is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. Amounts reported in accumulated other comprehensive income 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 year ended December 31, 2016 . As of December 31, 2016 , the Company had one interest rate cap with $500.0 million notional outstanding that was designated as a cash flow hedge of interest rate risk. The fair value of the interest rate contracts on the consolidated balance sheet as of December 31, 2015 and 2016 was $3.1 million and $1.0 million , respectively, and the Company recognized an immaterial amount of interest expense in the Company's consolidated statement of operations for both periods. The Company recognized a $ 1.4 million gain, net of tax benefit of $0.8 million in AOCI for the year ended December 31, 2016, of which the Company estimates that $0.6 million will be reclassified as an increase to interest expense in the next twelve months. For the year ended December 31, 2015, the Company recognized a $0.1 million gain in AOCI.

Property and Equipment and Capi

Property and Equipment and Capital Lease Obligations	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Property and Equipment and Capital Lease Obligations	Property and Equipment and Capital Lease Obligations Components of property and equipment consisted of the following: As of December 31, 2015 2016 (in thousands) Land $ 713 $ 790 Building 5,091 5,517 Software 40,336 52,130 Computers and office equipment 97,332 143,091 Furniture and fixtures 5,914 10,892 Leasehold improvements 7,126 21,244 Construction in process 6,137 6,691 Property and equipment—at cost 162,649 240,355 Less accumulated depreciation (86,887 ) (145,083 ) Property and equipment—net $ 75,762 $ 95,272 Depreciation expense related to property and equipment for the years ended December 31, 2014 , 2015 and 2016 , was $31.0 million , $34.0 million , and $60.4 million , respectively. The Company evaluates long-lived assets such as property plant and equipment 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. During the year ended December 31, 2016, the Company determined that a portion of an internally developed software tool would not meet its needs following the acquisition of Constant Contact. As a result, the Company recorded a $2.0 million impairment charge in engineering and development expense in the Company’s consolidated statements of operations and comprehensive loss. Additionally, during the year ended December 31, 2016, the Company recorded an impairment charge of $0.5 million in engineering and development expense relating to internally developed software, developed after the Webzai acquisition, which closed in August 2014, after evaluating it for impairment in accordance with ASC 360, Property, Plant and Equipment. This software is also linked to certain developed technology that was acquired as part of the Webzai acquisition and was also determined to be impaired. Refer to Note 7: Goodwill and Other Intangible Assets for further details. Both of these impairment charges discussed above were recognized in the Company's web presence segment. During the years ended December 31, 2015 and 2016 , the Company entered into agreements to lease software licenses for use on certain data center server equipment for terms ranging from thirty-six months to thirty-nine months . As of December 31, 2015 and 2016 , the Company’s software shown in the above table included the software assets under a capital lease as follows: As of December 31, 2015 2016 (in thousands) Software $ 21,499 $ 21,499 Less accumulated depreciation (8,412 ) (14,750 ) Assets under capital lease—net $ 13,087 $ 6,749 At December 31, 2016 , the expected future minimum lease payments under the capital lease discussed above were approximately as follows: Amount (in thousands) 2017 6,895 2018 575 Total minimum lease payments $ 7,470 Less amount representing interest (268 ) Present value of minimum lease payments (capital lease obligation) $ 7,202 Current portion $ 6,690 Long-term portion $ 512

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets The following table summarizes the changes in the Company’s goodwill balances as of December 31, 2015 and 2016 : Web Presence Unit Email Marketing Unit Total Amount Amount Amount (in thousands) (in thousands) (in thousands) Goodwill balance at January 1, 2015 $ 1,105,023 $ — $ 1,105,023 Goodwill related to 2015 acquisitions 103,444 — 103,444 Foreign translation impact (1,212 ) — (1,212 ) Goodwill balance at December 31, 2015 1,207,255 — 1,207,255 Goodwill related to 2015 acquisitions 5,978 — 5,978 Goodwill related to 2016 acquisitions 43,019 604,305 647,324 Foreign translation impact (648 ) — (648 ) Goodwill balance at December 31, 2016 $ 1,255,604 $ 604,305 $ 1,859,909 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. As of December 31, 2015 and, 2016 , the fair value of each of the Company’s reporting units exceeded the carrying value of the reporting unit’s net assets. Therefore, no impairment existed as of those dates. 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 year In-process research and development 1,438 — 1,438 — Total December 31, 2015 $ 749,139 $ 389,353 $ 359,786 At December 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 $ 284,005 $ 111,348 $ 172,657 7 years Subscriber relationships 659,662 345,070 314,592 7 years Trade-names 133,805 57,789 76,016 8 years Intellectual property 34,084 10,270 23,814 13 years Domain names available for sale 29,954 4,976 24,978 Indefinite Leasehold interests 314 314 — 1 year Total December 31, 2016 $ 1,141,824 $ 529,767 $ 612,057 During the year ended December 31, 2016, the Company wrote-off acquired in-process research and development of $1.4 million related to its acquisition of Webzai and $0.8 million related to its acquisition of AppMachine, as the Company had abandoned certain research and development projects in favor of other projects. Additionally, during the year ended December 31, 2016, the Company recorded an impairment charge of $4.4 million relating to developed technology from the Webzai acquisition, after evaluating it for impairment in accordance with ASC 350. This developed technology is also linked to certain internally developed software that was developed at Webzai after its acquisition by the Company which was also determined to be impaired. Refer to Note 6: Property and Equipment and Capital Lease Obligations , for further details. Both of the impairments described above were recognized in the web presence segment. 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 $102.7 million , $91.1 million , and $143.6 million for the years ended December 31, 2014 , 2015 and 2016 , respectively. At December 31, 2016 , the expected future amortization of the other intangible assets, excluding indefinite life and in-process research and development intangibles, was approximately as follows: Year Ending December 31, Amount (in thousands) 2017 $ 137,000 2018 103,000 2019 86,000 2020 72,000 2021 62,000 Thereafter 127,000 Total $ 587,000

Investments

Investments	12 Months Ended
	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Investments	Investments As of December 31, 2015 and 2016 , the Company’s carrying value of investments in privately-held companies was $27.9 million and $15.9 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 years ended December 31, 2015 and 2016 , the Company purchased $1.1 million and $1.6 million , respectively, of products and services from BlueZone, which is included in the Company’s consolidated statements of operations and comprehensive loss. As of December 31, 2015 and 2016 , $0.1 million and $0.1 million , respectively, relating to our investment in BlueZone was included in accounts payable and accrued expense in the Company’s consolidated balance sheet. In July 2012, the Company assumed a 50% interest in WWWH, a provider of web presence solutions, with a fair value of $10.0 million . On October 31, 2013, the Company sold 20% of its ownership interest, or 10% of the capital stock of WWWH, reducing its equity interest to 40% . On June 25, 2015, the Company acquired substantially all of the assets of WWWH. In connection with the asset purchase agreement dated June 25, 2015, the seller redeemed from the Company its 40% equity interest in exchange for a pro rata interest in the acquired assets, which had an estimated implied value of $11.9 million . The Company recognized a $5.4 million gain as a result of the redemption of its equity interest, which was recorded as other income for the year ended December 31, 2015 in the Company’s consolidated statements of operations and comprehensive loss. In addition, the Company received a $3.5 million repayment of total notes receivable that were due to the Company from the seller of WWWH prior to the acquisition. For more detail, see Note 3: Acquisitions to the consolidated financial statements. 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 5.0% 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 49.0% ownership interest in WZ UK Ltd., which is a provider of technology and sales marketing services associated with web builder solutions. On January 6, 2016, the Company exercised an option to increase its stake in WZ UK Ltd from 49.0% to 57.5% . Refer to Note 3: Acquisitions for further details. During 2014 and 2015, the Company had a license agreement with WZ UK Ltd. to license certain technology to WZ UK Ltd. to enable it to use, develop, market, distribute, host and support website builder applications. Under the terms of the license agreement, the Company received a royalty payment in the amount of 4.5% of all billings in the previous month, net of any refunds, chargebacks and any other credits applied. During the years ended December 31, 2014 and 2015, the Company recognized $0.0 million and $0.4 million , respectively, of royalty revenue under the terms of the license agreement. During the years ended December 31, 2014 and 2015, the Company’s proportionate share of net loss from its investment in WZ UK Ltd. was $0.2 million and $13.9 million , respectively. On July 2, 2015, the Company and the majority investor made additional equity contributions to WZ UK Ltd. The Company’s share of the incremental investments was approximately $7.4 million . On December 21, 2015, the Company and the majority investor made additional equity contributions to WZ UK Ltd. The Company’s share of the incremental investment was $1.1 million . The significance of the net loss of WZ UK Ltd., in comparison to the Company’s net loss requires the disclosure of summarized financial information from the statement of operations and comprehensive loss for WZ UK Ltd. The following table presents a summary of the statement of operations and comprehensive loss for WZ UK Ltd. for the years ended December 31, 2014 and 2015: For the years ended December 31, 2014 2015 (in thousands) Revenue $ 1 $ 4,053 Gross profit (loss) $ (96 ) $ 1,095 Operating loss $ (694 ) $ (28,439 ) Net loss $ (694 ) $ (28,439 ) As of December 31, 2015, WZ UK Ltd. had total assets of $2.1 million , and total liabilities of $6.7 million . On January 6, 2016, the Company exercised its option to increase its stake on WZ UK Ltd. from 49.0% to 57.5% , thereby acquiring a controlling interest. As of December 31, 2016, WZ UK Ltd. is consolidated in the Company's financial statements. Refer to Note 3: Acquisitions and Note 13: Redeemable Non-controlling Interest, for further details. In December 2014, the Company also made an aggregate investment of $15.2 million to acquire a 40.0% ownership interest in 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 was obligated to purchase the remaining 60.0% of AppMachine in three tranches of 20.0% within specified periods if AppMachine achieved a specified minimum revenue threshold within a designated timeframe. The agreement was terminated in July 2016, when the Company acquired the remaining 60.0% of the equity interest in AppMachine. Refer to Note 3: Acquisitions for further details. 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. On April 8, 2016, the Company made an investment of $5.0 million for a 33.0% equity interest in Fortifico Limited, a company providing a billing, CRM, and affiliate management solution to small and mid-sized businesses. During the year ended December 31, 2016, the Company incurred a charge of $4.7 million to impair the Company's 33% equity interest in Fortifico Limited, after determining that there were diminishing projected future cash flows on this investment. Investments in which the Company’s interest is less than 20.0% 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 20.0% and 50.0% , 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 loss. The Company recognized net losses of $0.1 million , $14.6 million , and $1.3 million for the years ended December 31, 2014 , 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 December 31, 2016 , the Company was not obligated to fund any follow-on investments in these investee companies. As of December 31, 2016 , the Company did not have an equity method investment in which the Company’s proportionate share exceeded 10% of the Company’s consolidated assets or income from continuing operations. As of December 31, 2016 , the Company did not have an equity method investment in which the Company’s proportionate share of net losses exceeded 20% of net loss of the Company’s consolidated statement of operations and comprehensive loss.

Notes Payable

Notes Payable	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Notes Payable	Notes Payable At December 31, 2015 and 2016, notes payable, net of original issuance discount and deferred financing costs, consisted of the following: For the Year Ended December 31, 2015 2016 (in thousands) First Lien Term Loan $ 1,025,385 $ 985,640 Incremental First Lien Term Loan — 674,860 Senior Notes — 326,480 Revolving Credit Facilities 67,000 — Total Notes Payable 1,092,385 1,986,980 Current portion of Notes Payable 77,500 35,700 Notes Payable - long-term $ 1,014,885 $ 1,951,280 First Lien Term Loan The Company has a first lien term loan (“First Lien”), which originated in November 2013, had an original balance of $1,050.0 million and a maturity date of November 9, 2019. As of December 31, 2015 and 2016, the First Lien had an outstanding balance of: For the Year Ended December 31, 2015 2016 First Lien Term Loan $ 1,026,375 $ 985,875 Unamortized deferred financing costs (990 ) (235 ) Net First Lien Term Loan 1,025,385 985,640 Current portion of First Lien Term Loan 10,500 21,000 First Lien Term Loan - long term $ 1,014,885 $ 964,640 The First Lien automatically bears interest at the bank’s reference rate unless the Company gives notice to opt for LIBOR-based interest rate term loans. During the year ended December 31, 2015 and during the period January 1, 2016 through February 8, 2016, the interest rate for a LIBOR based interest term loan was 4.00% plus the greater of the LIBOR rate or 1.00% , and the interest rate for a reference rate term loan was 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% . The First Lien bore interest at a LIBOR-based rate of 5.00% during this period. As a result of the refinancing on February 9, 2016 (the “Refinancing”) in connection with the acquisition of Constant Contact and the triggering of the “most-favored nation” pricing provision in the First Lien, the interest rate on the First Lien increased to LIBOR (subject to a LIBOR floor of 1.0% ) plus 5.23% per annum starting February 9, 2016 and to LIBOR (subject to a LIBOR floor of 1.0% ) plus 5.48% per annum on February 28, 2016. The interest rate on a reference First Lien loan increased to reference rate (subject to a floor of 2.0% ) plus 4.23% per annum starting February 9, 2016 and to reference rate (subject to a floor of 2.0% ) plus 4.48% per annum starting February 28, 2016. The First Lien requires quarterly mandatory repayments of principal. During the year ended December 31, 2015, these mandatory repayments were set at $2.6 million at the end of each quarter. As a result of the Refinancing, the Company is obligated to use commercially reasonable efforts to make voluntary repayments on the First Lien to effectively double the amount of each scheduled amortization payment under this facility. During the year ended December 31, 2015, the Company repaid $10.5 million against the First Lien. During the year ended December 31, 2016, the Company made mandatory repayments of $10.5 million and voluntary prepayments of $30.0 million against the First Lien. Interest is payable on maturity of the elected interest period for a LIBOR-based interest loan, which can be one , two , three or 6 months . Interest is payable at the end of each fiscal quarter for a reference rate interest First Lien loan. Incremental First Lien Term Loan In connection with the acquisition of Constant Contact on February 9, 2016, the Company entered into the Incremental First Lien Term Loan (the “Incremental First Lien”) in the principal amount of $735.0 million . As of December 31, 2016, the First Lien had an outstanding balance of: For the Year Ended December 31, 2016 Incremental First Lien Term Loan $ 720,300 Unamortized deferred financing costs (25,869 ) Unamortized original issue discounts (19,571 ) Net Incremental First Lien Term Loan 674,860 Current portion of Incremental First Lien Term Loan 14,700 Incremental First Lien Term Loan - long term $ 660,160 The Incremental First Lien matures seven years from issuance, was issued at a price of 97.0% 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, or at an alternate rate with a spread of 4.0% , subject to a floor of 2.0% per annum, and has scheduled principal payments equal to 0.50% of the original principal per quarter, or $3.7 million , starting September 30, 2016. The Incremental First Lien automatically bears interest at the bank’s reference rate unless the Company gives notice to opt for LIBOR-based interest rate term loans. Interest is payable on maturity of the elected interest period for a LIBOR-based interest loan, which can be one , two , three or 6 months . Interest is payable at the end of each fiscal quarter for a reference rate loan term loan. During the year ended December 31, 2016, the Company made $14.7 million in mandatory and voluntary prepayments against the Incremental First Lien. Revolving Credit Facilities The Company had an existing credit facility of $125.0 million (the “Prior Revolver”) which originated in November 2013 and had a maturity date of December 22, 2016. The Company could elect to draw down against the Prior Revolver using a LIBOR-rate interest loan or an alternate base interest loan. The interest rate for an alternate rate base revolver loan was 5.25% per annum plus the greater of the prime rate, the federal funds effective rate plus 0.50% , an adjusted LIBOR rate or 2.25% . The interest rate for a LIBOR based revolver loan was 6.25% per annum plus the greater of the LIBOR rate or 1.50% . There was also a non-refundable fee (the "commitment fee"), equal to 0.50% of the daily unused principal amount of the revolver payable in arrears on the last day of each fiscal quarter. As of December 31, 2015, the balance outstanding under the Prior Revolver was $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 rate of 8.50% . As a result of the Refinancing, the Company entered into a new revolving facility (the “Current Revolver”), which increased the Company’s available revolving credit to $165.0 million . The Current Revolver has a “springing” maturity date of August 10, 2019 unless the First Lien has been repaid in full or otherwise extended to at least 91 days after the maturity of the Current Revolver. As of December 31, 2016, the Company did not have any balances outstanding under the Current Revolver, and the full amount of the facility, or $165.0 million , was unused and available. The Company has the ability to draw down against the Current Revolver using a LIBOR-based interest loan or an alternate based interest loan. LIBOR-based interest revolver loans bear interest at a rate of LIBOR plus 4.0% per annum (subject to a leverage-based step-down), without a LIBOR floor. Alternate base interest revolver loans bear interest at the alternate rate plus 3.0% (subject to a leverage-based step down), without an alternate rate floor. There is also a non-refundable commitment fee, equal to 0.50% of the daily unused principal amount (subject to a leverage-based step down), which is payable in arrears on the last day of each fiscal quarter. Interest is payable on maturity of the elected interest period for a LIBOR-based interest loan, which can be one , two , three or 6 months . Interest is payable at the end of each fiscal quarter for a reference rate revolver loan. Senior Notes On February 9, 2016, EIG Investors issued $350.0 million aggregate principal amount of Senior Notes (the “Notes”). The Notes will mature on February 1, 2024, were issued at a price of 98.065% of par and 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). As of December 31, 2016, the Senior Notes had an outstanding balance of: For the Year Ended December 31, 2016 Senior Notes $ 350,000 Unamortized deferred financing costs (17,238 ) Unamortized original issue discounts (6,282 ) Net Senior Notes 326,480 Current portion of Senior Notes — Senior Notes - long term $ 326,480 Interest on the notes is payable twice a year, on August 1 and February 1. On January 30, 2017, the Company completed a registered exchange offer for the Notes, as required under the registration rights agreement we entered into with the initial purchasers of the Notes. All of the $350.0 million aggregate principal amount of the original notes was validly tendered for exchange as part of this exchange offer. Presentation of Debt Issuance Costs The Company adopted ASU 2015-03, “Simplifying the Presentation of Debt Issuance Costs” beginning on January 1, 2016, and retrospectively for all periods presented. ASU 2015-03 requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. Unamortized balances of deferred financing costs relating to the First Lien, and unamortized balances of deferred financing costs and of original issue discounts relating to the Incremental Term Lien and the Notes are presented as a reduction of the notes payable in our consolidated balance sheets. The unamortized value of deferred financing costs associated with our revolving credit facility were not affected by the ASU and continue to be presented as an asset on the Company’s consolidated balance sheets. Maturity of Notes Payable The maturity of the notes payable at December 31, 2016 is as follows: First Lien, Incremental First Lien, and Notes (in thousands) 2017 $ 35,700 2018 35,700 2019 958,575 2020 14,700 2021 14,700 Thereafter 996,800 Total $ 2,056,175 Interest The Company recorded $57.4 million , $58.8 million , and $152.9 million in interest expense for the years ended December 31, 2014 , 2015 and 2016 , respectively. The following table provides a summary of loan interest rates incurred and interest expense for the years ended December 31, 2014 , 2015 and 2016 : For the Year Ended December 31, 2014 2015 2016 (dollars in thousands) Interest rate—LIBOR 5.00%-7.75% 5.00%-7.75% 4.49%-7.75% Interest rate—reference 8.50 % 8.50 % 6.75%-8.75% Interest rate—Notes — % — % 10.875 % Non-refundable fee—unused facility 0.50 % 0.50 % 0.50 % Interest expense and service fees $ 56,247 $ 56,760 $ 140,470 Amortization of deferred financing fees $ 83 $ 82 $ 6,073 Amortization of original issue discounts $ — $ — $ 2,970 Amortization of net present value of deferred consideration $ 183 $ 1,264 $ 2,617 Other interest expense $ 901 $ 722 $ 758 Total interest expense $ 57,414 $ 58,828 $ 152,888 Debt Covenants The First Lien and Incremental First Lien (collectively, the "Senior Credit Facilities") require that the Company complies with a financial covenant to maintain a maximum ratio of consolidated senior secured indebtedness to Bank Adjusted EBITDA (as defined in the credit agreement). Please see " Management's Discussion and Analysis " for further discussion of Bank Adjusted EBITDA and this covenant. The Senior Credit Facilities also 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 December 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. 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 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	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Preferred Stock The Company has 5,000,000 shares of authorized preferred stock, par value $0.0001 . There were no preferred shares issued or outstanding as of December 31, 2015 and 2016 . Common Stock The Company has 500,000,000 shares of authorized common stock, par value $0.0001 . Voting Rights All holders of common stock are entitled to one vote per share.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation The Company follows the provisions of ASC 718, Compensation—Stock Compensation (“ASC 718”), which requires employee stock-based payments to be accounted for under the fair value method. Under this method, the Company is required to record compensation cost based on the estimated fair value for stock-based awards granted over the requisite service periods for the individual awards, which generally equals the vesting periods. The Company uses the straight-line amortization method for recognizing stock-based compensation expense. 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. The Company elected to early adopt Accounting Standards Update No. 2016-09, Compensation-Stock Compensation: Improvements to Employee Share-Based Payment Accounting, in the fourth quarter of fiscal year 2016 which requires it to reflect any adjustments as of January 1, 2016, the beginning of the annual period that includes the interim period of adoption. The guidance simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification of excess tax benefits in the consolidated statements of cash flows. The impact of the early adoption resulted in the following: • Due to the Company's net shortfall position upon the time of adoption, the new standard resulted in additional tax expense in our provision for income taxes rather than paid-in capital of $0.9 million for the year ended December 31, 2016. The Company's beginning retained earnings was not impacted by the early adoption as the Company had a full valuation allowance against the U.S. deferred tax assets as of December 31, 2015. • As a result of prior guidance that required excess tax benefits reduce taxes payable prior to recognition as an increase in paid in capital, the Company had not recognized certain deferred tax assets (loss carryforwards) that could be attributed to tax deductions related to equity compensation in excess of compensation recognized for financial reporting. As of January 1, 2016, the Company had generated federal and state net operating loss carryforwards due to excess tax benefits of $1.5 million and $0.7 million , respectively. • The Company elected to eliminate the forfeiture rate and adopted the new policy to account for forfeitures in the period that they are incurred, and applied this policy on a modified retrospective basis. The impact of eliminating the forfeiture rate increased the stock compensation recorded in 2016 by $0.9 million , which included an immaterial prior period adjustment that the Company recorded through the consolidated statement of operations and comprehensive loss for the year ended December 31, 2016. 2012 Restricted Stock Awards Unless otherwise determined by the Company’s board of directors, stock-based awards granted prior to the IPO generally vested over a four -year period or had vesting that was dependent on the achievement of specified performance targets. The fair value of these stock-based awards was determined as of the grant date of each award using an option-pricing model and assuming no pre-vesting forfeiture of the awards. Given the absence of an active trading market for the Company’s common stock prior to the completion of its IPO, the fair value of the equity interests underlying stock-based awards was determined by the Company’s management. In doing so, valuation analyses were prepared in accordance with the guidelines outlined in the American Institute of Certified Public Accountants Practice Aid, Valuation of Privately-Held-Company Equity Securities Issued as Compensation, and were used by the Company’s management to assist in determining the fair value of the equity interests underlying its stock-based awards. Each equity interest was granted with a “threshold amount” meaning that the recipient of an equity security only participated to the extent that the Company appreciated in value from and after the date of grant of the equity interest (with the value of the entity as of the grant date being the “threshold amount”). The assumptions used in the valuation models were based on future expectations combined with management’s judgment. In the absence of a public trading market, the Company’s management exercised significant judgment and considered numerous objective and subjective factors to determine the fair value of the stock-based awards as of the date of each award. These factors included: • contemporaneous or retrospective valuations for the Company and its securities; • the rights, preferences, and privileges of the stock-based awards relative to each other as well as to the existing shareholders; • lack of marketability of the Company’s equity securities; • historical operating and financial performance; • the Company’s stage of development; • current business conditions and projections; • hiring of key personnel and the experience of the Company’s management team; • risks inherent to the development of the Company’s products and services and delivery of its solutions; • trends and developments in the Company’s industry; • the threshold amount for the stock-based awards and the values at which the stock-based awards would vest; • the market performance of comparable publicly traded companies; • likelihood of achieving a liquidity event, such as an IPO or a merger or acquisition of the Company given prevailing market conditions; and • U.S. and global economic and capital market conditions. The Company completed its IPO in October 2013, and determined that the performance targets associated with the performance-based stock awards were met in full and consequently the performance-based stock awards would be fully vested. However, effective prior to the first day of public trading of the Company’s common stock, the Company accelerated the vesting of 2,167,870 shares of common stock issued in respect of the time-based stock awards and modified the vesting of 3,574,637 shares issued in respect of the performance-based stock awards so that 2,580,271 shares of common stock were fully vested and 994,366 shares of common stock will follow the same vesting schedule as the time-based stock awards that were granted on the same date as such performance-based stock awards. The following tables present a summary of the 2012 restricted stock awards activity for the year ended December 31, 2016 for restricted stock awards that were granted prior to the Company’s IPO: 2012 Restricted Stock Awards Non-Vested at December 31, 2015 46,645 Forfeitures — Vested (46,645 ) Non-Vested at December 31, 2016 — In connection with the IPO the Company granted restricted stock units under the prior equity plan. The following table provides a summary of the restricted stock units that were granted in connection with the IPO under this plan and the non-vested balance as of December 31, 2016 : Restricted Stock Units Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 22,158 $ 12.00 Vested (22,158 ) $ 12.00 Non-vested at December 31, 2016 — $ — 2013 Stock Incentive Plan The Amended and Restated 2013 Stock Incentive Plan (the “2013 Plan”) of the Company became effective upon the closing of our IPO. The 2013 Plan of the Company 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 38,000,000 shares of the Company’s common stock. At December 31, 2016, 16,964,969 shares were available for grant under the 2013 Plan. For stock options issued under the 2013 Plan, the fair value of each option is estimated on the date of grant, and upon the adoption of ASU 2016-09, the Company accounts for forfeitures as they are incurred. Unless otherwise approved by the Company’s board of directors, stock options typically vest over four years and the Company recognizes compensation expense on a straight-line basis over the requisite service period of the award. The Company uses the Black-Scholes option pricing model to estimate the fair value of stock option awards and determine the related compensation expense. The weighted-average assumptions used to compute stock-based compensation expense for awards granted under the 2013 Stock Incentive Plan during the years ended December 31, 2014, 2015 and 2016 are as follows: 2014 2015 2016 Risk-free interest rate 2.1 % 1.8 % 1.6 % Expected volatility 58.3 % 56.1 % 53.1 % Expected life (in years) 6.25 6.25 6.25 Expected dividend yield — — — The risk-free interest rate assumption was based on the U.S. Treasury zero-coupon bonds with maturities similar to those of the expected term of the award being valued. The Company bases its estimate of expected volatility using volatility data from comparable public companies in similar industries and markets because there is currently limited public history for the Company’s common stock, and therefore, a lack of market-based company-specific historical and implied volatility information. The weighted-average expected life for employee options reflects the application of the simplified method, which represents the average of the contractual term of the options and the weighted-average vesting period for all option tranches. The simplified method has been used since the Company does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate expected term due to a limited history of stock option grants. The assumed dividend yield was based on the Company’s expectation of not paying dividends in the foreseeable future. The following table provides a summary of the Company’s stock options as of December 31, 2016 and the stock option activity for all stock options granted under the 2013 Plan during the year ended December 31, 2016 (dollars in thousands except exercise price): 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 3,575,851 $ 10.96 Exercised — $ — Forfeited (595,364 ) $ 13.56 Canceled (323,914 ) $ 13.41 Outstanding at December 31, 2016 9,607,431 $ 12.79 8.0 $ 205 Exercisable as of December 31, 2016 4,435,261 $ 13.15 7.1 $ — Expected to vest after December 31, 2016(1) 5,172,170 $ 12.49 8.7 $ 205 Exercisable as of December 31, 2016 and expected to vest thereafter(2) 9,607,431 $ 12.79 8.0 $ 205 (1) This represents the number of unvested options outstanding as of December 31, 2016 that are expected to vest in the future. (2) This represents the number of vested options as of December 31, 2016 plus the number of unvested options outstanding as of December 31, 2016 that are expected to vest in the future. (3) The aggregate intrinsic value was calculated based on the positive difference between the estimated fair value of the Company’s common stock on December 31, 2016 of $9.30 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 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 performance criteria are weighted and have threshold, target and maximum performance goals. The following table provides a summary of the Company’s restricted stock award activity for the 2013 Plan during the year ended December 31, 2016 : Restricted Stock Awards Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 4,849,290 $ 15.24 Granted 3,355,341 $ 10.36 Vested (613,751 ) $ 13.84 Canceled (258,343 ) $ 12.75 Non-vested at December 31, 2016 7,332,537 $ 13.21 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 year ended December 31, 2016 : Restricted Stock Units Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 220,765 $ 12.00 Vested and unissued (120,396 ) $ 12.00 Non-vested at December 31, 2016 100,369 $ 12.00 2015 Performance Based Award The performance-based award granted to the Company’s chief executive officer during the year ended December 31, 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 (collectively, 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 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. For the fourth quarter of 2016, 184,115 Award Shares were earned for the Performance Quarter ending December 31, 2016 because a performance level between the threshold and target for the performance metric was met. An aggregate total of 1,003,600 Award Shares were earned during the year ended December 31, 2016. Any Award Shares that are earned during the Performance Period will vest on June 30, 2018, provided the chief executive officer is employed by the Company on such date. The requirement that the chief executive officer be employed by the Company on June 30, 2018 is waived in the event the executive’s employment is terminated due to death, disability or by the Company without cause, if the executive terminates employment with the Company for good reason, or if the executive is employed by the Company on the date of a change in control (as such terms are defined in the executive’s employment agreement). Upon the occurrence of any of the foregoing events, additional Award Shares may be earned, as provided for in the performance-based restricted stock agreement. 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 year ended December 31, 2016 , the Company recognized $6.8 million of stock-based compensation expense related to the performance-based 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 provided an opportunity to earn a fully vested right to up to 223,214 shares of the Company’s common stock, with a target of 178,571 shares. The COO performance-based restricted stock award provided an opportunity to earn a fully vested right to up to 260,416 shares of the Company’s common stock, with a target of 208,333 shares. The CAO performance based restricted stock award provided an opportunity to earn a fully vested right to up to 148,810 shares of the Company’s common 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 email marketing segment achieving a pre-established level of adjusted revenue (weighted 50% ), adjusted EBITDA (weighted 25% ) and adjusted free cash flow (weighted 25% ), each as defined in the award agreement and 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”). As of December 31, 2016, the maximum level of the Performance Metric was met and upon Board approval, each executive will earn the maximum number of shares subject to their award. These earned shares will vest on March 31, 2017. During the fiscal year ended December 31, 2016, the Company recognized $4.1 million of stock-based compensation expense related to these performance-based awards. 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 (“the Available Shares”), 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 Assumed Awards were converted into 2,143,987 stock options and 2,202,846 restricted stock units with respect to the Company’s common stock and the Available Shares were converted into 10,000,000 shares of the Company’s common stock reserved for future awards under the 2011 Plan. At December 31, 2016, there were 9,278,088 shares 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, and will be recognized in the Company’s consolidated statements of operations and comprehensive loss over the vesting period of the awards. For stock options issued under the 2011 Plan, the fair value of each option is estimated on the date of grant, and an estimated forfeiture rate is used when calculating stock-based compensation expense for the period. Unless otherwise approved by the Company’s board of directors, stock options typically vest over four years and the Company recognizes compensation expense on a straight-line basis over the requisite service period of the award. The Company uses the Black-Scholes option simplified pricing model to estimate the fair value of stock option awards and determine the related compensation expense. The weighted-average assumptions used to compute stock-based compensation expense for awards granted under the 2011 Stock Incentive Plan during the year ended December 31, 2016 are as follows: 2016 Risk-free interest rate 1.27 % Expected volatility 53.1 % Expected life (in years) 4.75 Expected dividend yield — The following table provides a summary of the Company’s stock options as of December 31, 2016 and the stock option activity for all stock options granted under the 2011 Plan during the year ended December 31, 2016 : Stock Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (In years) Aggregate Intrinsic Value(3) (In thousands) Outstanding at December 31, 2015 — $ — Granted/Exchanged 3,002,887 $ 8.28 Exercised (396,486 ) $ 6.47 Canceled (674,571 ) $ 8.07 Outstanding at December 31, 2016 1,931,830 $ 8.73 5.1 2,606 Exercisable as of December 31, 2016 529,472 $ 7.12 3.7 1,316 Expected to vest after December 31, 2016(1) 1,123,921 $ 9.28 5.6 1,099 Exercisable as of December 31, 2016 and expected to vest thereafter(2) 1,653,393 $ 8.59 5.0 2,415 (1) This represents the number of unvested options outstanding as of December 31, 2016 that are expected to vest in the future. (2) This represents the number of vested options as of December 31, 2016 plus the number of unvested options outstanding as of December 31, 2016 that are expected to vest in the future. (3) The aggregate intrinsic value was calculated based on the positive difference between the estimated fair value of the Company’s common stock on December 31, 2016 of $9.30 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 year ended December 31, 2016: Restricted Stock Units Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 — — Granted 3,154,897 $ 8.49 Vested (1,266,771 ) $ 7.69 Canceled (414,471 ) $ 8.26 Non-vested at December 31, 2016 1,473,655 $ 9.25 2016 Award Obligations At December 31, 2016, stock based compensation expense included $0.7 million of equity award obligations that the Company has agreed to issue in shares of common stock upon the achievement of certain conditions, of which $0.3 million was recorded in sales and marketing expense, $0.1 million was recorded in engineering and development expense, and $0.3 million was recorded in general and administrative expense within the consolidated statement of operations and comprehensive loss for the year ended December 31, 2016. This amount was included in accrued expenses at year end, and will be reclassified against additional paid in capital upon issuance of the shares. All Plans The following table presents total stock-based compensation expense recorded in the consolidated statement of operations and comprehensive loss for all 2012 restricted stock awards and units issued prior to the Company’s IPO in October 2013 and all awards granted under the 2013 Plan in connection with or subsequent to the IPO: For the Year Ended December 31, 2014 2015 2016 (in thousands) Cost of revenue $ 547 $ 1,975 $ 5,855 Sales and marketing 1,585 3,285 8,702 Engineering and development 883 1,988 5,989 General and administrative 13,028 22,677 37,721 Total operating expense $ 16,043 $ 29,925 $ 58,267 The Company recognized tax benefit related to stock compensation expense of $4.6 million , $9.3 million , and $19.2 million , for the years ended December 31, 2014, 2015, and 2016. As of December 31, 2016 the Company has approximately $29.5 million of unrecognized stock-based compensation expense related to option awards that will be recognized over 2.4 years and approximately $40.6 million of unrecognized stock-based compensation expense related to restricted stock awards to be recognized that will be recognized over 2.0 years for the 2013 Stock Incentive Plan. As of December 31, 2016 the Company has approximately $5.0 million of unrecognized stock-based compensation expense related to option awards that will be recognized over 2.7 years and approximately $10.3 million of unrecognized stock-based compensation expense related to restricted stock awards to be recognized that will be recognized over 2.6 years for the 2011 Stock Incentive Plan.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) The components of accumulated other comprehensive loss, net of tax were as follows: Foreign Currency Translation Adjustments Unrealized Gains (Losses) on Cash Flow Hedges Total (in thousands) Balance at December 31, 2014 (517 ) — (517 ) Other comprehensive income (loss) (1,281 ) 80 (1,201 ) Balance at December 31, 2015 $ (1,798 ) $ 80 $ (1,718 ) Other comprehensive income (loss) (597 ) (1,351 ) (1,948 ) Balance at December 31, 2016 $ (2,395 ) $ (1,271 ) $ (3,666 )

Redeemable Non-Controlling Inte

Redeemable Non-Controlling Interest	12 Months Ended
	Dec. 31, 2016
Noncontrolling Interest [Abstract]
Redeemable Non-Controlling Interest	Redeemable Non-Controlling Interest 2014 Non-controlling interest In connection with a 2013 equity investment in JDI Backup Ltd., where the Company acquired a controlling interest, the agreement provided for a put option for the then non-controlling interest (“NCI”) shareholders to put the remaining equity interest to the Company within pre-specified put periods. As the NCI was subject to a put option that was outside the control of the Company, it was deemed a redeemable non-controlling interest and not recorded in permanent equity, and was presented as mezzanine redeemable non-controlling interest on the consolidated balance sheet, and was subject to the guidance of the Securities and Exchange Commission (“SEC”) under ASC 480-10-S99, Accounting for Redeemable Equity Securities. The difference between the $20.8 million initial fair value of the redeemable non-controlling interest and the value that was expected to be paid upon exercise of the put option was being accreted over the period commencing December 11, 2013 and up to the end of the first put option period, which commenced on the 18-month anniversary of the acquisition date. Adjustments to the carrying amount of the redeemable non-controlling interest were charged to additional paid-in capital. Non-controlling interest arising from the application of the consolidation rules was 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 loss. During the year ended December 31, 2014, the Company paid $4.2 million to increase its investment in JDI Backup Ltd. and entered into an amendment to the put option with the NCI shareholders. During the year ended December 31, 2014, due to the Company’s assessment of the financial performance and forecasted profitability of JDI Backup Ltd., the Company changed its estimate of the expected exercise amount of the put option. The change in estimate resulted in the fair value of the put option increasing to $30.5 million as of December 31, 2014. On January 13, 2015, the Company entered into an agreement to acquire the remaining interests owned by the NCI shareholders for $30.5 million , which was originally payable in three equal installments on January 13, 2015, June 15, 2015 and September 15, 2015. During the year ended December 31, 2015, the Company entered into amendments to change the dates of the second installment from June 15, 2015 to April 10, 2015 and the date of the third installment from September 15, 2015 to July 2, 2015. The Company will continue to consolidate JDI Backup Ltd. for financial reporting purposes, however, because the Company now owns 100.0% of JDI Backup Ltd., commencing on January 13, 2015, the Company no longer records a non-controlling interest in the consolidated statement of operations and comprehensive loss. 2016 Non-controlling interest In connection with a 2014 equity investment in WZ UK, on January 6, 2016, the Company exercised its option to increase its stake in WZ UK from 49.0% to 57.5% , thereby acquiring a controlling interest, in exchange for a payment of approximately $2.1 million to the other shareholders of WZ UK. 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. The difference between the $10.8 million fair value of the redeemable NCI and the $30.0 million value that is expected to be paid upon exercise of the put option was being accreted over the period commencing January 6, 2016 and up to the first put option period, which commenced on the 24 months anniversary of the acquisition date, August 14, 2016. Adjustments to the carrying amount of the redeemable non-controlling interest were charged to additional paid-in capital. In January 2016, the Company obtained a controlling interest in Resume Labs Limited 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 were subject to put options that are outside the control of the Company, they were deemed redeemable non-controlling interests and were also not recorded in permanent equity, and were presented as part of the mezzanine redeemable non-controlling interest on the consolidated balance sheet. On May 16, 2016, the Company amended the put option with respect to WZ UK to allow it to acquire an additional equity interest in WZ UK earlier than August 2016. Pursuant to this amended option, on the same date the Company acquired an additional 20.0% stake in WZ UK for $15.4 million , thus increasing its ownership interest from 57.5% to 77.5% . On July 13, 2016, WZ UK completed a restructuring pursuant to which Pseudio Limited and Resume Labs became wholly owned subsidiaries of WZ UK. As a result of the restructuring, WZ UK became the 100.0% owner of Pseudio Limited and Resume Labs Limited and the Company’s ownership of WZ UK was diluted from 77.5% to 76.4% . Immediately subsequent to the restructuring, the Company acquired an additional 10.0% stake in WZ UK on July 13, 2016 for $18.0 million , bringing the Company’s aggregate stake in WZ UK to 86.4% . The restructuring significantly reduced the amount of the potential redemption amount payable to the minority shareholders of WZ UK, and gave the Company the flexibility to reduce investments in this business. Based on these reduced investments, and based on the Company's fair value measurement of the NCI using market multiples and discounted cash flows, the Company determined that the estimated fair value of the non-controlling interest is below the expected redemption amount of $25.0 million , which resulted in $14.2 million of excess accretion that reduces income available to common shareholders for the period starting on the date of the restructuring through the redemption date of July 1, 2017. The Company recognized excess accretion of $6.8 million during the year ended December 31, 2016, which is reflected in net loss attributable to accretion of non-controlling interest in the Company’s consolidated statements of operations and comprehensive loss. Prior to the third quarter of 2016, the Company did not have any accretion amounts in excess of fair value. The following table presents changes in this redeemable non-controlling interest: Redeemable noncontrolling Interest (in thousands) Balance as of December 31, 2015 $ — Additions to non-controlling interest upon acquisition 12,790 Capital contribution from non-controlling interest 1,775 Accretion to redemption value 30,844 Accretion in excess of fair value 6,769 Adjustment to non-controlling interest (1,000 ) Redemption of non-controlling interest (33,425 ) Balance as of December 31, 2016 $ 17,753 The Company starts accreting non-controlling interest to its redeemable value from the date the redemption of the noncontrolling interest becomes probable through the earliest redemption date. If the non-controlling interest is redeemable at an amount higher than its fair value, the excess accretion is taken into consideration in the calculation of loss per share.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company accounts for income taxes in accordance with authoritative guidance, which requires the use of the asset and liability method. Under this method, deferred income tax assets and liabilities are determined based upon the difference between the consolidated financial statement carrying amounts and the tax basis of assets and liabilities and are measured using the enacted tax rate expected to apply in the years in which the differences are expected to be reversed. The domestic and foreign components of income (loss) before income taxes for the periods presented: Year Ended December 31, 2014 2015 2016 (in thousands) United States $ (17,002 ) $ 1,258 $ (137,197 ) Foreign (27,603 ) (1,046 ) (52,593 ) Total income (loss) before income taxes $ (44,605 ) $ 212 $ (189,790 ) The components of the provision (benefit) for income taxes consisted of the following: Year Ended December 31, 2014 2015 2016 (in thousands) Current: U.S. federal $ 781 $ 1,827 $ 328 State 183 696 744 Foreign 1,582 1,699 2,312 Total current provision 2,546 4,222 3,384 Deferred: U.S. federal (581 ) (1,103 ) (44,447 ) State (3,983 ) 1,952 (6,225 ) Foreign (5,310 ) (818 ) (10,037 ) Change in valuation allowance 13,514 7,089 (52,533 ) Total deferred provision 3,640 7,120 (113,242 ) Total expense (benefit) $ 6,186 $ 11,342 $ (109,858 ) The Company established a valuation allowance on substantially all of its deferred tax assets during the year ended December 31, 2013. The benefit had been reduced after the establishment of the valuation allowance by the deferred tax expense associated with the tax amortization of assets that have an indefinite life for U.S. GAAP purposes. The Company maintained a valuation allowance against certain U.S. deferred tax assets until the acquisition of Constant Contact. The acquisition of Constant Contact resulted in a significant increase in deferred tax liabilities, which far exceeded deferred tax assets. The Company scheduled out the reversal of the consolidated U.S. 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 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 deferred tax benefit to reverse the valuation allowances during the year ended December 31, 2016. The Company recorded a valuation allowance against the majority of the state research and development tax credits and state investment tax credits, a portion of state operating loss credit carryforwards, federal and state capital loss carryforwards, and federal research credits which the Company projected to expire prior to utilization. The following table presents a reconciliation of the statutory federal rate, and the Company’s effective tax rate, for the periods presented: Year Ended December 31, 2014 2015 2016 U.S. federal taxes at statutory rate 34.0 % 34.0 % 35.0 % State income taxes, net of federal benefit 5.9 685.0 0.9 Nondeductible stock-based compensation (2.5 ) 827.3 (1.5 ) Nondeductible transaction costs (1.0 ) 856.5 (2.9 ) Nontaxable gain on redemption of equity interest — (674.9 ) — Other foreign permanent differences (2.5 ) 187.8 (0.4 ) Credits 0.6 — 3.7 Foreign rate differential (11.7 ) 299.7 (4.6 ) Change in valuation allowance—U.S. (23.2 ) 3,398.6 31.2 Change in valuation allowance—foreign (7.0 ) (130.8 ) (4.1 ) Rate change (1.1 ) 216.5 0.4 Prior year true-up stock-based compensation—U.S. (2.0 ) (132.8 ) — Other (3.4 ) (217.5 ) (0.5 ) Total (13.9 )% 5,349.4 % 57.2 % The provision (benefit) for income taxes shown on the consolidated statements of operations differs from amounts that would result from applying the statutory tax rates to income before taxes primarily because of the release of the valuation allowance on U.S. deferred tax assets, state income taxes, the impact of changes in state apportionment, jurisdiction mix of earnings, nondeductible expenses, as well as the application of valuation allowances against foreign deferred tax assets. The significant components of the Company’s deferred income tax assets and liabilities are as follows: As of December 31, 2015 2016 Deferred income tax assets: Net operating loss carry forward $ 43,698 $ 76,060 Credit carryforward 2,190 28,271 Other 6,612 5,414 Deferred compensation 497 364 Deferred revenue 21,327 26,291 Other reserves 4,895 3,545 Stock-based compensation 13,221 25,424 Total deferred income tax assets 92,440 165,369 Deferred income tax liabilities: Purchased intangible assets (11,098 ) (119,719 ) Goodwill (26,062 ) (37,099 ) Property and equipment (8,361 ) (12,403 ) Total deferred income tax liabilities (45,521 ) (169,221 ) Valuation allowance (75,705 ) (36,091 ) Net deferred income tax liabilities $ (28,786 ) $ (39,943 ) The Company conducts business globally and, as a result, its subsidiaries file income tax returns in U.S. federal and state jurisdictions and various foreign jurisdictions. In the normal course of business, the Company may be subject to examination by taxing authorities throughout the world, including such major jurisdictions as Brazil, India, the United Kingdom, the Netherlands and the United States. 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 years ended March 31, 2014 and 2015 and Israel for the fiscal years ended December 31, 2012, 2013 and 2014. The Company does not expect material changes as a result of the audits. The statute of limitations in the Company’s other tax jurisdictions, the United Kingdom and Brazil, 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 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 December 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 December 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 Contact resulted in a significant increase in deferred tax liabilities, which far exceeded pre-acquisition deferred tax assets. The Company, with the significant deferred tax liabilities resulting from the acquisition, scheduled out the reversal of the consolidated U.S. 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. The Company maintained a valuation allowance on the acquired Massachusetts research and development tax credits and limited life investment tax credit carryforwards and a portion of the acquired Colorado and Utah operating loss carryforwards. The Company maintained its valuation allowance on the several of the legacy state net operating loss carryforwards expected to expire unused as a result of the scheduling analysis. As a result, the Company recorded a tax benefit of $70.6 million to reverse valuation allowances during the year ended December 31, 2016. The Company performed a deferred scheduling analysis as of December 31, 2016, and as a result recorded a valuation allowance against $7.8 million of federal research credits, $1.2 million of federal and state capital loss carryforwards, and $1.0 million of additional state net operating losses, which resulted in Company recording an increase in tax expense of $10.0 million related to the increase in the U.S. valuation allowance. The Company assessed its ability to realize its foreign deferred tax assets as of December 31, 2016 and determined that, it was more likely than not that the Company would not realize $13.1 million of net deferred tax assets in the United Kingdom, $2.5 million of net deferred tax assets in the Netherlands, $0.8 million of net deferred tax assets in India, $0.5 million of net deferred tax assets in Israel, $0.1 million of net deferred tax assets in China. For the years ended December 31, 2014 , 2015 and 2016 , the Company has recognized a tax expense (benefit) of $6.2 million , $11.3 million and $(109.9) million , respectively, in the consolidated statements of operations and comprehensive loss. The income tax expense for the year ended December 31, 2016 is primarily attributable to a provision for federal and state current income taxes of $1.1 million , foreign current tax expense of $2.3 million , federal and state deferred tax benefit of $111.2 million and attributable to the $70.6 million release of valuation allowance and $40.6 million of deferred tax benefit related to an increase in deferred tax assets, and foreign deferred benefit of $2.0 million related to the reductions of deferred liabilities created in purchase accounting. The income tax expense for the year ended December 31, 2015 is primarily attributable to a provision for federal and state current income taxes of $2.5 million , foreign current tax expense of $1.7 million , federal and state deferred tax expense of $0.8 million and attributable to a $7.1 million increase in the valuation allowance, partially offset by a foreign deferred benefit of $0.8 million related to the reductions of deferred liabilities created in purchase accounting. The income tax expense for the year ended December 31, 2014 was primarily attributable to a provision for foreign taxes of $1.8 million , including $0.2 million of withholding taxes, and U.S. alternative minimum taxes of $0.5 million and $0.2 million of state taxes. The remaining balance of $3.6 million for the year ended December 31, 2014 was primarily attributable to an increase in U.S. deferred tax liabilities due to the differences in the accounting treatment of goodwill under U.S. GAAP and the tax accounting treatment for goodwill of $5.8 million of U.S. federal and state deferred taxes, partially offset by a foreign deferred benefit of $2.2 million related to the reductions of deferred liabilities created in purchase accounting. As of December 31, 2016 , the Company had NOL carry-forwards available to offset future U.S. federal taxable income of approximately $142.7 million and future state taxable income of approximately $125.6 million . These NOL carry-forwards expire on various dates through 2036. As of December 31, 2016, the Company had NOL carry-forwards in foreign jurisdictions available to offset future foreign taxable income by approximately $96.8 million . The Company has loss carry-forwards that begin to expire in 2021 in India totaling $2.5 million and in China totaling $0.3 million . The Company has loss carry-forwards that begin to expire in 2020 in the Netherlands totaling $10.7 million . The Company also has loss carry-forwards in the United Kingdom, Israel and Singapore of $81.1 million , $1.9 million , and $0.3 million , respectively, which have an indefinite carry-forward period. In addition, the Company has $3.4 million of U.S. federal capital loss carry-forwards and $1.4 million in state capital loss-forwards, generally expiring through 2021. As of December 31, 2016, the Company had U.S. tax credit carryforwards available to offset future U.S. federal and state taxes of approximately $20.3 million and $12.2 million , respectively. These credit carryforwards expire on various dates through 2036. 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 annual 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 annual 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 closed 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 completed an analysis of its ownership changes in the first half of 2016, which resulted in no ownership-change for tax purposes within the meaning of the Internal Revenue Code Section 382(g). As of the date of the Company’s acquisition of Constant Contact, Constant Contact had approximately $60.2 million and $32.4 million of federal and state NOLs, respectively, and approximately $10.9 million of U.S. federal research and development credits and $9.2 million of state credits. These losses and credits are not subject to limitation under Internal Revenue Code Sections 382 and 383. As a result, all unused NOL carry-forwards at December 31, 2016 are available for future use to offset taxable income. Permanent Reinvestment of Foreign Earnings As of December 31, 2016, the cumulative amount of undistributed earnings of our foreign subsidiaries amounted to $7.9 million . We have not provided U.S. taxes on these undistributed earnings of our foreign subsidiaries that we consider indefinitely reinvested. Our indefinite reinvestment determination is based on the future operational and capital requirements of our domestic and foreign operations. We expect the cash held by our foreign subsidiaries of $14.1 million will continue to be used for our foreign operations and therefore do not anticipate repatriating these funds. Except for Subpart F income, the Company has not provided taxes for the remaining $7.9 million of undistributed earnings of its foreign subsidiaries because we plan to keep these amounts permanently reinvested overseas except for instances where we can remit such earnings to the U.S. without an associated net tax cost. If the Company decides to repatriate the foreign earnings, it would need to adjust its income tax provision in the period it determines that the earnings will no longer be indefinitely invested outside the United States. Due to the timing and circumstances of repatriation of such earnings, if any, it is not practicable to determine the unrecognized deferred tax liability relating to such amounts. Adoption of ASU 2016-09 In March 2016, the FASB issued ASU 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”). ASU 2016-09 intends to simplify various aspects of how share-based payments are accounted for and presented in the financial statements. The main provisions include: all tax effects related to stock awards will now be recorded through the income statement instead of through equity, all tax-related cash flows resulting from stock awards will be reported as operating activities on the cash flow statement, and entities can make an accounting policy election to either estimate forfeitures or account for forfeitures as they occur. The amendments in ASU 2016-09, required to be updated for all annual periods and interim reporting periods beginning after December 15, 2016, were adopted early by the Company in the fourth quarter of 2016 and were applied to its related consolidated financial statements on a prospective basis. The adoption of these amendments had an impact of $0.9 million on the consolidated statement of operations and comprehensive loss through December 31, 2016 due to the reclassification of shortfalls from additional paid in capital. The Company also elected to account for forfeitures as they occur with no adjustment for estimated forfeitures, which had an impact of $0.9 million to the Company’s consolidated statement of operations and comprehensive loss. As previously mentioned, as a result of prior guidance that required excess tax benefits reduce taxes payable prior to recognition as an increase in paid in capital, the Company had not recognized certain deferred tax assets (loss carryforwards) that could be attributed to tax deductions related to equity compensation in excess of compensation recognized for financial reporting. As of January 1, 2016, the Company had generated U.S. federal and state net operating loss carryforwards due to excess tax benefits of $1.5 million and $0.7 million , respectively.

Severance and Other Exit Costs

Severance and Other Exit Costs	12 Months Ended
	Dec. 31, 2016
Restructuring and Related Activities [Abstract]
Severance and Other Exit Costs	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 December 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 year ended December 31, 2015 the Company recorded an adjustment of $0.6 million as a result of entering an agreement for an early buyout of the lease agreement for the Englewood, Colorado facility. During the year ended December 31, 2016, the Company recorded a true-up adjustment of $0.2 million . The Company paid $1.0 million of facility costs and received sublease income of $0.6 million related to the 2014 Restructuring Plan during the year ended December 31, 2016, and had a remaining accrued facility liability of $0.3 million as of December 31, 2016. The Company expects payments related to the 2014 Restructuring Plan to be completed during the year ended December 31, 2018. 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 $1.2 million of severance costs during the year ended December 31, 2016 and did not have any remaining severance liability accrued as of December 31, 2016. Payments related to the 2015 Restructuring Plan have been completed during the year ended December 31, 2016. 2016 Restructuring Plan In connection with the Company’s acquisition of Constant Contact on February 9, 2016, the Company implemented a plan to create operational efficiencies and synergies resulting in severance costs and facility exit costs (the “2016 Restructuring Plan”). The severance charges were associated with eliminating approximately 265 positions across the business. The Company incurred severance costs of $11.7 million during the year ended December 31, 2016. The Company paid $10.2 million of severance costs during the year ended December 31, 2016 and had a remaining accrued severance liability of $1.6 million as of December 31, 2016. The Company’s 2016 Restructuring Plan included a plan to close offices in San Francisco, California, Delray Beach, Florida, New York, New York, United Kingdom, Porto Alegre, Brazil and Miami, Florida, and a plan to relocate certain employees to its Austin Office. The Company also closed a portion of the Constant Contact offices in Waltham, Massachusetts. During the year ended December 31, 2016, the Company recorded a facilities charge for future lease payments of $23.6 million , less expected sublease income of $12.0 million . The Company also recorded $0.7 million in relocation charges during the year ended December 31, 2016 after closing these facilities. The Company paid $3.6 million of facility costs related to the 2016 Restructuring Plan during the year ended December 31, 2016 and had a remaining accrued facility liability of $8.7 million as of December 31, 2016. The Company does not expect any additional employee-related charges associated with the 2016 Restructuring Plan after December 31, 2016, and expects severance payments related to the 2016 Restructuring Plan to be completed during the year ended December 31, 2017. The Company expects to complete facility-related charges associated with the 2016 Restructuring Plan during the year ended December 31, 2016, and expects to complete facility exit cost payments related to the plan during the year ended December 31, 2022. The following table provides a summary of the aggregate activity for the year ended December 31, 2016 related to the Company’s combined Restructuring Plans severance accrual for each reporting segment: (in thousands) Web presence segment Email marketing segment Total Balance at December 31, 2015 $ 1,201 $ — $ 1,201 Severance Charges 1,596 10,113 $ 11,709 Cash Paid (2,164 ) (9,187 ) $ (11,351 ) Balance at December 31, 2016 $ 633 $ 926 $ 1,559 The following table provides a summary of the aggregate activity for the year ended December 31, 2016 related to the Company’s combined Restructuring Plans facilities exit accrual for each reporting segment: Facility (in thousands) Web presence segment Email marketing segment Total Balance at December 31, 2015 $ 479 $ — $ 479 Facility charges, net of estimated sublease income 445 12,070 12,515 Sublease income received 596 — 596 Cash paid (1,247 ) (3,323 ) (4,570 ) Balance at December 31, 2016 $ 273 $ 8,747 $ 9,020 The following table presents restructuring charges recorded in the consolidated statement of operations and comprehensive loss for the periods presented: For the Year Ended December 31, 2014 2015 2016 (in thousands) Cost of revenue $ 2,349 $ (45 ) $ 8,986 Sales and marketing 301 555 6,550 Engineering and development 960 636 4,288 General and administrative 850 343 4,400 Total severance charges $ 4,460 $ 1,489 $ 24,224

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Operating Leases The Company has operating lease commitments for certain facilities and equipment that expire on various dates through 2026 . The following table outlines future minimum annual rental payments under these leases at December 31, 2016 : Year Ending December 31, Amount (in thousands) 2017 20,058 2018 18,367 2019 17,457 2020 17,120 2021 14,074 Thereafter 27,779 Total minimum lease payments $ 114,855 Total net rent expense incurred under non-cancellable operating leases for the years ended December 31, 2014 , 2015 and 2016 , were $9.8 million , $8.2 million and $20.0 million , respectively. Total sublease income for the years ended 2015 and 2016 was $0.2 million , and $0.4 million , respectively. 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., et al, Civil Action No. 1:15-cv-11775-GAO. In a second amended complaint, filed on March 18, 2016, the plaintiff alleged claims for violations of Section 10(b) and 20(a) of the Exchange Act, on behalf of a purported class of purchasers of the Company’s securities between February 25, 2014 and February 29, 2016. Those claims challenged as false or misleading certain of the Company’s disclosures about its total number of subscribers, average revenue per subscriber, the number of customers paying over $500 per year for the Company’s products and services, the average number of products sold per subscriber, and customer churn. The plaintiff seeks, on behalf of himself and the purported class, compensatory damages and his costs and expenses of litigation. The Company filed a motion to dismiss on May 16, 2016, which remains pending. In August 2016, the parties in the Machado action and another potential claimant, who asserts that he purchased common stock in the Company’s initial public offering, agreed to toll, as of July 1, 2016, the statutes of limitation and repose for all claims under the Securities Act of 1933 that the plaintiff and claimant might bring, individually or in a representative capacity, arising from alleged actions or omissions between September 9, 2013 and February 29, 2016. The Company and the individual defendants intend to deny any liability or wrongdoing and to vigorously defend all claims asserted. The Company cannot, however, make any assurances as to the outcome of the current proceeding or any additional claims if they are brought. 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. 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. 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, as well as 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. An amended complaint, which named an additional former officer as a defendant, was filed December 19, 2016. 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 nondisclosure 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 remains in its 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 August 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 case continues to be stayed pending the state court and bankruptcy actions. Meanwhile, RPost asserted the same patents asserted against Constant Contact in litigation against Go Daddy. In June 2016, Go Daddy succeeded in invalidating all of those RPost patents. RPost has appealed, and the appellate court is expected to hear oral argument on the appeal in the Spring of 2017. The litigation against Constant Contact remains stayed, and is in its 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, 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 (together , the "Complaints") were 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 alleged, 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 sought, among other things, to rescind the acquisition, as well as award of plaintiffs’ attorneys’ fees and costs in the action. The Complaints were consolidated on January 12, 2016. On December 5, 2016, plaintiff Myers filed a consolidated amended complaint (the "Amended Complaint") naming as defendants the former Constant Contact directors and Morgan Stanley & Co. LLC ("Morgan Stanley"), Constant Contact’s financial adviser for the acquisition, alleging breach of fiduciary duty by the former directors, and aiding and abetting the alleged breach by Morgan Stanley. On December 15, 2016, the Constant Contact defendants filed a motion to dismiss. On February 14, 2017, the court approved a briefing schedule for the motion, with defendants' opening brief due March 17, 2017. The defendants believe the claims asserted in the Amended Complaint are without merit and intend to defend against them vigorously.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	Employee Benefit Plans The Company has a defined contribution plan established under Section 401(k) of the Internal Revenue Code (the “401(k) Plan”), which covers substantially all employees. Employees are eligible to participate in the 401(k) Plan beginning on the first day of the month following commencement of their employment. The 401(k) Plan includes a salary deferral arrangement pursuant to which participants may elect to reduce their current compensation by up to the statutorily prescribed limit, equal to $18,000 in 2016 , and have the amount of the reduction contributed to the 401(k) Plan. Beginning January 1, 2013, the Company matched 100% of each participant’s annual contribution to the 401(k) plan up to 3% of the participant’s salary and then 50% of each participant’s contribution up to 2% of each participant’s salary. The match immediately vests 100% . Matching contributions by the Company to the 401(k) Plan related to the 2014 , 2015 and 2016 plan years were approximately $2.2 million , $2.5 million , $5.7 million respectively. In connection with an acquisition in 2011, the Company assumed a defined contribution plan established under Section 401(k) of the Internal Revenue Code (the “Dotster 401(k) Plan”), in which employees were eligible to participate upon the date of hire. Under the Dotster 401(k) Plan, the Company matched 100% of each participant’s annual contribution to the Dotster 401(k) Plan up to 3% of each participant’s salary and then 50% of each participant’s annual contribution to the Dotster 401(k) Plan up to 2% of each participant’s salary. The match immediately vested 100% . A matching contribution by the Company related to the 2013 plan year in the amount of $0.4 million was made to the Dotster 401(k) Plan. The Dotster 401(k) plan merged with the Company’s 401(k) plan during the year ended December 31, 2014. In connection with the HostGator acquisition in 2012, the Company assumed a defined contribution plan established under Section 401(k) of the Internal Revenue Code (the “HostGator 401(k) Plan”), in which employees were eligible to participate on the date of hire. Under the HostGator 401(k) Plan, the Company matched 25% of each participant’s annual contribution up to 4% of each participant’s salary, vesting 100% after three years of service. A matching contribution by the Company related to the 2013 plan year in the amount of $0.1 million was made to the HostGator 401(k) Plan. The HostGator 401(k) plan merged with the Company’s 401(k) plan during the year ended December 31, 2014.

Variable Interest Entity

Variable Interest Entity	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entity	Variable Interest Entity The Company, through a subsidiary formed in China, has entered into various agreements with Shanghai Xiao Lan Network Technology Co., Ltd (“Shanghai Xiao”) and its shareholders that allow the Company to effectively control Shanghai Xiao, making it a variable interest entity (“VIE”). Shanghai Xiao has a technology license that allows it to provide local hosting services to customers located in China. The shareholders of Shanghai Xiao cannot transfer their equity interests without the approval of the Company, and as a result, are considered de facto agents of the Company in accordance with ASC 810-10-25-43. The Company and its de facto agents acting together have the power to direct the activities that most significantly impact the entity’s economic performance and they have the obligation to absorb losses and the right to receive benefits from the entity. In situations where a de facto agency relationship is present, one party is required to be identified as the primary beneficiary. The factors considered include the presence of a principal/agent relationship, the relationship and significance of activities to the reporting entity, the variability associated with the VIE’s anticipated economics and the design of the VIE. The analysis is qualitative in nature and is based on weighting the relative importance on each of the factors in relation to the specifics of the VIE arrangement. Upon the execution of the agreements with Shanghai Xiao and its shareholders, the Company performed an analysis and concluded that the Company is the party that is most closely associated with Shanghai Xiao, as it is the most exposed to the variability of the VIE’s economics and therefore is the primary beneficiary of the VIE. As of December 31, 2016, the financial position and results of operations of Shanghai Xiao are consolidated within, but are not material to, the Company’s consolidated financial position or results of operations.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions The Company has various agreements in place with related parties. Below are details of related party transactions that occurred during the years ended December 31, 2014 , 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, web design and web building services, and an office space lease. 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. The following table includes the amounts of related party transactions recorded in the consolidated statements of operations and comprehensive loss for the years ended December 31, 2014 , 2015 and 2016 relating to services provided by Tregaron and its affiliates under these agreements: For the Year Ended December 31, 2014 2015 2016 (in thousands) Cost of revenue $ 7,300 $ 10,200 $ 12,200 Sales and marketing 500 700 500 Engineering and development 1,700 1,100 1,300 General and administrative 900 300 300 Total related party transaction expense $ 10,400 $ 12,300 $ 14,300 As of December 31, 2015 , and 2016 approximately $1.9 million and $1.3 million , respectively, 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 following table includes the revised amounts of related party transactions recorded in the consolidated statements of operations and comprehensive loss for the years ended December 31, 2014 , 2015 and 2016 relating to services provided by IBS under these agreements: For the Year Ended December 31, 2014 2015 2016 (in thousands) Revenue $ (400 ) $ (1,300 ) $ (3,100 ) Revenue (contra) 600 7,000 7,500 Total related party transaction impact to revenue $ 200 $ 5,700 $ 4,400 Cost of revenue 4,600 600 700 Total related party transaction expense, net $ 4,800 $ 6,300 $ 5,100 As of December 31, 2015 and 2016 , approximately $0.2 million and $0.2 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 2016 , approximately $1.1 million and $1.1 million , respectively was included in accounts payable and accrued expense relating to the Company’s agreements with IBS. As of December 31, 2015 and 2016 , approximately $0.3 million and $0.6 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"). Goldman Sachs is a significant shareholder of the Company. Refer to Note 4: Fair Value Measurements, for further details 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 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 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 and certain other investment banks in November 2015. Refer to Note 9: Notes Payable , for further details. Goldman Sachs also served as a financial advisor in connection with the acquisition of Constant Contact and during the year ended December 31, 2016, the Company paid approximately $8.6 million to Goldman Sachs in connection with these services. In connection with the issuance of the Notes, the Company agreed to assist the initial purchasers, including Goldman Sachs, in marketing the Notes. Through December 31, 2016, the Company incurred expenses on behalf of the initial purchasers of approximately $0.8 million . A subsidiary of Goldman Sachs is also the counterparty to our interest rate cap, for which the Company paid $3.0 million to the counterparty as a premium during the year ended December 31, 2016. No further premiums are payable under this interest rate cap.

Segment Information (Notes)

Segment Information (Notes)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Segment Information	Segment Information Operating segments are defined as components of an enterprise that engage in business activities for which discrete financial information is available and regularly reviewed by the chief operating decision maker. The Company's Chief Executive Officer is the Company's chief operating decision maker. On February 9, 2016, the Company acquired Constant Contact. The Company evaluated the criteria in ASC 280-10-50-11 contemporaneously with its acquisition of Constant Contact, which closed on February 9, 2016. Based on the Company's original evaluation, the Company believed that it met the qualitative aggregation criteria in ASC 280-10-50-11, and that the economic characteristics of the Constant Contact and legacy businesses were similar. In particular, at the time of this evaluation, the Company expected that the gross margin of Constant Contact and its legacy business would be similar. However, beginning with the second quarter of 2016, the Company recognized that the legacy business did not meet expectations and as such resulted in lower legacy gross margin than originally anticipated, which continued into the third and fourth quarter. As such, during the Company's annual assessment of segments, and due to the resulting 2016 legacy performance, the Company determined it had two reportable segments: • Email marketing , which includes the products and services acquired as part of the Constant Contact acquisition in February 2016. The services included in this segment are primarily email marketing, and to a lesser extent, event marketing, survey tools and the Single Platform digital storefront product. • Web presence , which consists of all of the Company's web hosting and related services such as domain names, website security, website design tools and services, ecommerce services and other services and tools to expand the online presence of a small business. The Company measures profitably of these segments based on revenue, gross profit, and adjusted EBITDA. The accounting policies of each segment are the same as those described in the summary of significant accounting policies, refer to Note 2: Summary of Significant Accounting Policies , for further details. The following tables contain financial information for each reportable segment for the year ended December 31, 2016: Web presence Email marketing Total (in thousands) Revenue $ 784,334 $ 326,808 $ 1,111,142 Gross profit $ 353,988 $ 173,163 $ 527,151 Adjusted EBITDA $ 172,135 $ 116,261 $ 288,396 Less: Interest expense, net (including impact of amortization of deferred financing costs and original issuance discount) 152,312 Income tax expense (benefit) (109,858 ) Depreciation 60,360 Amortization of other intangible assets 143,562 Stock-based compensation 58,267 Restructuring expenses 24,224 Transaction expenses and charges 32,284 Gain of unconsolidated entities (565 ) Impairment of other long lived assets 9,039 Net loss $ (81,229 ) Total assets $ 1,507,977 $ 1,248,297 $ 2,756,274 Depreciation expense $ 36,613 $ 23,747 $ 60,360 Amortization expense $ 78,883 $ 64,679 $ 143,562 Prior to 2016 and prior to the acquisition of Constant Contact, the Company reported as one single reporting segment. Geographic and Other Information Revenue, classified by the major geographic areas in which our customers are located, was as follows: Year Ended December 31, 2014 2015 2016 (in thousands) United States $ 409,765 $ 465,446 $ 787,915 International 220,080 275,869 323,227 Total $ 629,845 $ 741,315 $ 1,111,142 The following table presents the amount of tangible long-lived assets by geographic area: 2015 2016 (in thousands) United States $ 72,025 $ 89,147 International 3,737 6,125 Total $ 75,762 $ 95,272 The Company’s revenues are generated primarily from products and services delivered on a subscription basis, which include web hosting, domains, website builders, search engine marketing, email marketing and other similar services. The Company also generates non-subscription revenues through domain monetization and marketing development funds. Non-subscription revenues increased from $28.3 million , or 4% of total revenue for the year ended December 31, 2014 to $52.5 million , or 7% of revenue for the year ended December 31, 2015, and decreased to $39.4 million , or 4% of total revenue for the year ended December 31, 2016. Substantially all of the Company's non-subscription revenues are included in its web presence segment. No individual international country represented more than 10% of total revenue in any period presented. Furthermore, substantially all of the Company's tangible long-lived assets are located in the U.S.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events In January 2017, the Company announced its plans to close certain facilities as part of a plan to consolidate certain web presence customer support operations. As a result of this plan, the Company expects to incur approximately $8.0 million in charges during fiscal year 2017, mostly related to severance. On January 30, 2017, the Company completed a registered exchange offer for the Notes, as required under the registration rights agreement we entered into with the initial purchasers of the Notes. All of the $350.0 million aggregate principal amount of the original notes was validly tendered for exchange as part of this exchange offer.

Geographic and Other Informatio

Geographic and Other Information	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Segment Information	Segment Information Operating segments are defined as components of an enterprise that engage in business activities for which discrete financial information is available and regularly reviewed by the chief operating decision maker. The Company's Chief Executive Officer is the Company's chief operating decision maker. On February 9, 2016, the Company acquired Constant Contact. The Company evaluated the criteria in ASC 280-10-50-11 contemporaneously with its acquisition of Constant Contact, which closed on February 9, 2016. Based on the Company's original evaluation, the Company believed that it met the qualitative aggregation criteria in ASC 280-10-50-11, and that the economic characteristics of the Constant Contact and legacy businesses were similar. In particular, at the time of this evaluation, the Company expected that the gross margin of Constant Contact and its legacy business would be similar. However, beginning with the second quarter of 2016, the Company recognized that the legacy business did not meet expectations and as such resulted in lower legacy gross margin than originally anticipated, which continued into the third and fourth quarter. As such, during the Company's annual assessment of segments, and due to the resulting 2016 legacy performance, the Company determined it had two reportable segments: • Email marketing , which includes the products and services acquired as part of the Constant Contact acquisition in February 2016. The services included in this segment are primarily email marketing, and to a lesser extent, event marketing, survey tools and the Single Platform digital storefront product. • Web presence , which consists of all of the Company's web hosting and related services such as domain names, website security, website design tools and services, ecommerce services and other services and tools to expand the online presence of a small business. The Company measures profitably of these segments based on revenue, gross profit, and adjusted EBITDA. The accounting policies of each segment are the same as those described in the summary of significant accounting policies, refer to Note 2: Summary of Significant Accounting Policies , for further details. The following tables contain financial information for each reportable segment for the year ended December 31, 2016: Web presence Email marketing Total (in thousands) Revenue $ 784,334 $ 326,808 $ 1,111,142 Gross profit $ 353,988 $ 173,163 $ 527,151 Adjusted EBITDA $ 172,135 $ 116,261 $ 288,396 Less: Interest expense, net (including impact of amortization of deferred financing costs and original issuance discount) 152,312 Income tax expense (benefit) (109,858 ) Depreciation 60,360 Amortization of other intangible assets 143,562 Stock-based compensation 58,267 Restructuring expenses 24,224 Transaction expenses and charges 32,284 Gain of unconsolidated entities (565 ) Impairment of other long lived assets 9,039 Net loss $ (81,229 ) Total assets $ 1,507,977 $ 1,248,297 $ 2,756,274 Depreciation expense $ 36,613 $ 23,747 $ 60,360 Amortization expense $ 78,883 $ 64,679 $ 143,562 Prior to 2016 and prior to the acquisition of Constant Contact, the Company reported as one single reporting segment. Geographic and Other Information Revenue, classified by the major geographic areas in which our customers are located, was as follows: Year Ended December 31, 2014 2015 2016 (in thousands) United States $ 409,765 $ 465,446 $ 787,915 International 220,080 275,869 323,227 Total $ 629,845 $ 741,315 $ 1,111,142 The following table presents the amount of tangible long-lived assets by geographic area: 2015 2016 (in thousands) United States $ 72,025 $ 89,147 International 3,737 6,125 Total $ 75,762 $ 95,272 The Company’s revenues are generated primarily from products and services delivered on a subscription basis, which include web hosting, domains, website builders, search engine marketing, email marketing and other similar services. The Company also generates non-subscription revenues through domain monetization and marketing development funds. Non-subscription revenues increased from $28.3 million , or 4% of total revenue for the year ended December 31, 2014 to $52.5 million , or 7% of revenue for the year ended December 31, 2015, and decreased to $39.4 million , or 4% of total revenue for the year ended December 31, 2016. Substantially all of the Company's non-subscription revenues are included in its web presence segment. No individual international country represented more than 10% of total revenue in any period presented. Furthermore, substantially all of the Company's tangible long-lived assets are located in the U.S.

Quarterly Financial Data (unaud

Quarterly Financial Data (unaudited)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (unaudited)	Quarterly Financial Data (unaudited) The following table presents the Company’s unaudited quarterly financial data: For the three months ended March 31, June 30, Sept. 30, Dec. 31, March 31, June 30, Sept. 30, Dec. 31, (in thousands, except per share data) Revenue $ 177,318 $ 182,431 $ 188,523 $ 193,043 $ 237,113 $ 290,713 $ 291,193 $ 292,123 Gross profit $ 76,344 $ 77,494 $ 77,750 $ 84,692 $ 100,637 $ 137,636 $ 141,766 $ 147,112 Income (loss) from operations $ 17,199 $ 12,548 $ 9,113 $ 14,326 $ (66,311 ) $ (6,168 ) $ 8,879 $ 24,260 Net income (loss) attributable to Endurance International Group Holdings, Inc. $ 884 $ (2,071 ) $ (15,351 ) $ (9,232 ) $ 21,811 $ (28,040 ) $ (31,737 ) $ (34,865 ) Basic net income (loss) per share attributable to Endurance International Group Holdings, Inc. $ 0.01 $ (0.02 ) $ (0.12 ) $ (0.07 ) $ 0.17 $ (0.21 ) $ (0.24 ) $ (0.26 ) Diluted net income (loss) per share attributable to Endurance International Group Holdings, Inc. $ 0.01 $ (0.02 ) $ (0.12 ) $ (0.07 ) $ 0.16 $ (0.21 ) $ (0.24 ) $ (0.26 ) On February 9, 2016, the Company acquired Constant Contact for $1.1 billion . As such, financial results reflected above were materially impacted by this acquisition. Revenue and gross profit increases throughout 2016 are primarily driven by this acquisition. The loss from operations has also been impacted by the Constant Contact acquisition due to the $31.1 million of transaction costs incurred in the first quarter of 2016, and higher operating expenses from Constant Contact, including $22.4 million of restructuring costs incurred throughout 2016, of which, $11.6 million was incurred during the first quarter. Net income (loss) was impacted by all of the factors previously noted, and a $94.1 million increase in interest expense for all of 2016 as well as a $109.9 million tax benefit recorded during 2016. The tax benefit was primarily related to the reduction of valuation allowances on deferred tax assets which occurred during the first quarter of 2016, partially offset by increased valuation allowances of $10.0 million during the fourth quarter of 2016.

Supplemental Guarantor Financia

Supplemental Guarantor Financial Information (Notes)	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Supplemental Guarantor Financial Information	Supplemental Guarantor Financial Information In February 2016, EIG Investors Corp., a wholly-owned subsidiary of the Company (the “Issuer”), issued $350.0 million aggregate principal amount of its 10.875% Senior Notes due 2024 (the “Original Notes”) (refer to Note 9: Notes Payables, in the consolidated financial statements), which it expects to exchange for new 10.875% Senior Notes due 2024 (the “Exchange Notes” and together with the Original Notes, collectively, the “Notes”) pursuant to a registration statement on Form S-4. The Notes are fully and unconditionally guaranteed, jointly and severally, on a senior unsecured basis by the Company, and the following wholly-owned subsidiaries: The Endurance International Group, Inc., Bluehost Inc., FastDomain Inc., Domain Name Holding Company, Inc., Endurance International Group – West, Inc., HostGator.com LLC, A Small Orange, LLC, Constant Contact, Inc., and SinglePlatform, LLC, (collectively, the “Subsidiary Guarantors”), subject to certain customary guarantor release conditions. The Company’s other domestic subsidiaries and its foreign subsidiaries (collectively, the “Non-Guarantor Subsidiaries”) have not guaranteed the Notes. The Company sold two immaterial guarantors, CardStar, Inc. and CardStar Publishing, LLC (collectively, "CardStar"), during the quarter ended December 31, 2016. CardStar was released and discharged from the guarantee as a result of the sale and no longer guarantees the debt of the Company as of December 1, 2016. Proceeds from the sale of CardStar were approximately $0.1 million . The following tables present supplemental condensed consolidating balance sheet information of the Company (“Parent”), the Issuer, the Subsidiary Guarantors and the Non-Guarantor Subsidiaries as of December 31, 2015 and December 31, 2016, and supplemental condensed consolidating results of operations and cash flow information for the years ended December 31, 2014, 2015 and 2016: Condensed Consolidating Balance Sheets December 31, 2015 (in thousands) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Assets: Current assets: Cash and cash equivalents $ 12 $ 67 $ 21,286 $ 11,665 — $ 33,030 Restricted cash — — 973 75 — 1,048 Accounts receivable — — 7,120 4,920 — 12,040 Prepaid domain name registry fees — — 29,250 26,878 (335 ) 55,793 Prepaid expenses & other current assets — 62 9,722 8,263 (2,372 ) 15,675 Total current assets 12 129 68,351 51,801 (2,707 ) 117,586 Intercompany receivables, net 29,092 (10,324 ) 91,938 (110,706 ) — — Property and equipment, net — — 66,011 9,751 — 75,762 Goodwill — — 1,072,838 134,417 — 1,207,255 Other intangible assets, net — — 328,922 30,864 — 359,786 Investment in subsidiaries 150,164 1,260,399 38,819 — (1,449,382 ) — Other assets — 3,130 34,151 4,830 — 42,111 Total assets $ 179,268 $ 1,253,334 $ 1,701,030 $ 120,957 $ (1,452,089 ) $ 1,802,500 Liabilities, redeemable non-controlling interest and stockholders' equity Current liabilities: Accounts payable $ — $ 3,769 $ 7,269 $ 1,242 — $ 12,280 Accrued expenses and other current liabilities — 7,016 38,092 12,106 (2,372 ) 54,842 Deferred revenue — — 230,396 56,290 (741 ) 285,945 Current portion of notes payable — 77,500 — — — 77,500 Current portion of capital lease obligations — — 5,866 — — 5,866 Deferred consideration, short-term — — 50,840 648 — 51,488 Total current liabilities — 88,285 332,463 70,286 (3,113 ) 487,921 Deferred revenue, long-term — — 71,982 7,700 — 79,682 Notes payable — 1,014,885 — — — 1,014,885 Capital lease obligations — — 7,215 — — 7,215 Deferred consideration — — — 813 — 813 Other long-term liabilities — — 28,970 3,340 — 32,310 Total liabilities — 1,103,170 440,630 82,139 (3,113 ) 1,622,826 Redeemable non-controlling interest — — — — — — Equity 179,268 150,164 1,260,400 38,818 (1,448,976 ) 179,674 Total liabilities and equity $ 179,268 $ 1,253,334 $ 1,701,030 $ 120,957 $ (1,452,089 ) $ 1,802,500 Condensed Consolidating Balance Sheets December 31, 2016 (in thousands) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Assets: Current assets: Cash and cash equivalents $ 3 $ 4 $ 39,034 $ 14,555 $ — $ 53,596 Restricted cash — — 2,620 682 — 3,302 Accounts receivable — — 10,148 2,940 — 13,088 Prepaid domain name registry fees — — 31,044 24,697 (297 ) 55,444 Prepaid expenses & other current assets — 81 17,996 10,601 — 28,678 Total current assets 3 85 100,842 53,475 (297 ) 154,108 Intercompany receivables, net 31,665 799,953 (690,761 ) (140,857 ) — — Property and equipment, net — — 82,901 12,371 — 95,272 Goodwill — — 1,683,121 176,788 — 1,859,909 Other intangible assets, net — — 592,095 19,962 — 612,057 Investment in subsidiaries 92,068 1,299,562 40,651 — (1,432,281 ) — Other assets — 5,911 23,153 5,864 — 34,928 Total assets $ 123,736 $ 2,105,511 $ 1,832,002 $ 127,603 $ (1,432,578 ) $ 2,756,274 Liabilities, redeemable non-controlling interest and stockholders' equity: Current liabilities: Accounts payable $ — $ — $ 13,801 $ 2,273 $ — $ 16,074 Accrued expenses and other current liabilities — 27,208 60,760 9,890 — 97,858 Deferred revenue — — 295,208 60,925 (943 ) 355,190 Current portion of notes payable — 35,700 — — — 35,700 Current portion of capital lease obligations — — 6,690 — — 6,690 Deferred consideration, short-term — — 4,415 858 — 5,273 Total current liabilities — 62,908 380,874 73,946 (943 ) 516,785 Deferred revenue, long-term — — 77,649 11,551 — 89,200 Notes payable — 1,951,280 — — — 1,951,280 Capital lease obligations — — 512 — — 512 Deferred consideration — — 7,419 25 — 7,444 Other long-term liabilities — (745 ) 48,233 1,429 — 48,917 Total liabilities — 2,013,443 514,687 86,951 (943 ) 2,614,138 Redeemable non-controlling interest — — 17,753 — — 17,753 Equity 123,736 92,068 1,299,562 40,652 (1,431,635 ) 124,383 Total liabilities and equity $ 123,736 $ 2,105,511 $ 1,832,002 $ 127,603 $ (1,432,578 ) $ 2,756,274 Condensed Consolidating Statements of Operations and Comprehensive Loss Year Ended December 31, 2014 (in thousands) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Revenue $ — $ — $ 559,434 $ 70,990 $ (579 ) $ 629,845 Cost of revenue — — 327,225 54,500 (237 ) 381,488 Gross profit — — 232,209 16,490 (342 ) 248,357 Operating expense: Sales & marketing — — 114,367 32,607 (177 ) 146,797 Engineering and development — — 16,805 2,744 — 19,549 General and administrative — 232 61,291 8,010 — 69,533 Total operating expense — 232 192,463 43,361 (177 ) 235,879 Income (loss) from operations — (232 ) 39,746 (26,871 ) (165 ) 12,478 Interest expense, net — 56,330 829 (76 ) — 57,083 Income (loss) before income taxes and equity earnings of unconsolidated entities — (56,562 ) 38,917 (26,795 ) (165 ) (44,605 ) Income tax expense (benefit) — 6,163 613 (590 ) — 6,186 Loss before equity earnings of unconsolidated entities — (62,725 ) 38,304 (26,205 ) (165 ) (50,791 ) Equity loss of unconsolidated entities, net of tax 42,835 (19,890 ) 26,500 — (49,384 ) 61 Net loss (42,835 ) (42,835 ) 11,804 (26,205 ) 49,219 (50,852 ) Net loss attributable to non-controlling interest — — (8,017 ) — — (8,017 ) Net loss attributable to Endurance $ (42,835 ) $ (42,835 ) $ 19,821 $ (26,205 ) $ 49,219 $ (42,835 ) Comprehensive loss Foreign currency translation adjustments — — — (462 ) — (462 ) Total comprehensive loss $ (42,835 ) $ (42,835 ) $ 19,821 $ (26,667 ) $ 49,219 $ (43,297 ) Condensed Consolidating Statements of Operations and Comprehensive Loss Year Ended December 31, 2015 (in thousands) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Revenue $ — $ — $ 628,266 $ 113,766 $ (717 ) $ 741,315 Cost of revenue — — 349,059 77,177 (1,201 ) 425,035 Gross profit — — 279,207 36,589 484 316,280 Operating expense: Sales & marketing — — 120,637 24,815 (33 ) 145,419 Engineering and development — — 23,019 3,688 — 26,707 General and administrative — 177 80,548 10,132 111 90,968 Total operating expense — 177 224,204 38,635 78 263,094 Income (loss) from operations — (177 ) 55,003 (2,046 ) 406 53,186 Interest expense and other income, net — 56,843 (3,554 ) (315 ) — 52,974 Income (loss) before income taxes and equity earnings of unconsolidated entities — (57,020 ) 58,557 (1,731 ) 406 212 Income tax expense (benefit) — 10,320 331 691 — 11,342 Loss before equity earnings of unconsolidated entities — (67,340 ) 58,226 (2,422 ) 406 (11,130 ) Equity loss of unconsolidated entities, net of tax 26,176 (41,164 ) 17,063 — 12,565 14,640 Net loss (26,176 ) (26,176 ) 41,163 (2,422 ) (12,159 ) (25,770 ) Net loss attributable to non-controlling interest — — — — — — Net loss attributable to Endurance $ (26,176 ) $ (26,176 ) $ 41,163 $ (2,422 ) $ (12,159 ) $ (25,770 ) Comprehensive loss — Foreign currency translation adjustments — — — (1,281 ) — (1,281 ) Unrealized gain on cash flow hedge — 80 — — — 80 Total comprehensive loss $ (26,176 ) $ (26,096 ) $ 41,163 $ (3,703 ) $ (12,159 ) $ (26,971 ) Condensed Consolidating Statements of Operations and Comprehensive Loss Year Ended December 31, 2016 (in thousands) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Revenue $ — $ — $ 978,690 $ 133,274 $ (822 ) $ 1,111,142 Cost of revenue — — 496,267 88,753 (1,029 ) 583,991 Gross profit — — 482,423 44,521 207 527,151 Operating expense: Sales and marketing — — 235,988 67,556 (33 ) 303,511 Engineering and development — — 72,922 14,679 — 87,601 General and administrative — 242 128,337 14,516 — 143,095 Transaction expenses — — 32,284 — — 32,284 Total operating expense — 242 469,531 96,751 (33 ) 566,491 Income (loss) from operations — (242 ) 12,892 (52,230 ) 240 (39,340 ) Interest expense and other income —net — 149,512 (3,606 ) 4,544 — 150,450 Income (loss) before income taxes and equity earnings of unconsolidated entities — (149,754 ) 16,498 (56,774 ) 240 (189,790 ) Income tax expense (benefit) — (53,847 ) (55,953 ) (58 ) — (109,858 ) Loss before equity earnings of unconsolidated entities — (95,907 ) 72,451 (56,716 ) 240 (79,932 ) Equity loss of unconsolidated entities, net of tax 73,071 (22,837 ) 58,014 297 (107,248 ) 1,297 Net loss $ (73,071 ) $ (73,070 ) $ 14,437 $ (57,013 ) $ 107,488 $ (81,229 ) Net loss attributable to non-controlling interest — — (8,398 ) — — (8,398 ) Net loss attributable to Endurance International Group Holdings, Inc. (73,071 ) (73,070 ) 22,835 (57,013 ) 107,488 (72,831 ) Comprehensive loss: — Foreign currency translation adjustments — — — (597 ) — (597 ) Unrealized gain (loss) on cash flow hedge (1,351 ) — — — (1,351 ) Total comprehensive loss $ (73,071 ) $ (74,421 ) $ 22,835 $ (57,610 ) $ 107,488 $ (74,779 ) Condensed Consolidating Statements of Cash Flows Year Ended December 31, 2014 (in thousands) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided by (used in) operating activities $ (1 ) $ (63,853 ) $ 215,212 $ (8,465 ) — $ 142,893 Cash flows from investing activities: Businesses acquired in purchase transaction, net of cash acquired — — (69,578 ) (24,120 ) — (93,698 ) Purchases of property and equipment — — (22,850 ) (1,054 ) — (23,904 ) Cash paid for minority investments — — (34,140 ) — — (34,140 ) Proceeds from sale of property and equipment — — 39 55 — 94 Proceeds from sale of assets — — 100 — — 100 Purchases of intangible assets — — (200 ) — — (200 ) Net (deposits) and withdrawals of principal balances in restricted cash accounts — — 191 242 — 433 Net cash used in investing activities — — (126,438 ) (24,877 ) — (151,315 ) Cash flows from financing activities: Proceeds from issuance of notes payable and draws on revolver — 150,000 — — — 150,000 Repayment of notes payable and revolver — (110,500 ) — — — (110,500 ) Payment of financing costs — (53 ) — — — (53 ) Payment of deferred consideration — — (41,244 ) (57,074 ) — (98,318 ) Payment of redeemable non-controlling interest liability — — (4,190 ) — — (4,190 ) Principal payments on capital lease obligations — — (3,608 ) — — (3,608 ) Proceeds from exercise of stock options 137 — — — — 137 Proceeds from issuance of common stock 43,500 — — — — 43,500 Issuance costs of common stock (2,904 ) — — — — (2,904 ) Intercompany loans and investments (40,731 ) (7,126 ) (46,073 ) 93,930 — — Net cash provided by (used in) financing activities 2 32,321 (95,115 ) 36,856 — (25,936 ) Net effect of exchange rate on cash and cash equivalents — — — (78 ) — (78 ) Net increase (decrease) in cash and cash equivalents 1 (31,532 ) (6,341 ) 3,436 — (34,436 ) Cash and cash equivalents: Beginning of period — 35,879 25,043 5,893 — $ 66,815 End of period $ 1 $ 4,347 $ 18,702 $ 9,329 $ — $ 32,379 Condensed Consolidating Statements of Cash Flows Year Ended December 31, 2015 (in thousands) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided by (used in) operating activities $ 2 $ (50,147 ) $ 220,468 6,905 — $ 177,228 Cash flows from investing activities: Businesses acquired in purchase transaction, net of cash acquired — — (92,376 ) (5,419 ) — (97,795 ) Purchases of property and equipment — — (28,058 ) (3,185 ) — (31,243 ) Cash paid for minority investments — — (8,475 ) — — (8,475 ) Proceeds from sale of property and equipment — — 51 42 — 93 Proceeds from note receivable — — 3,454 — — 3,454 Proceeds from sale of assets — — 191 — — 191 Purchases of intangible assets — — (76 ) — — (76 ) Net (deposits) and withdrawals of principal balances in restricted cash accounts — — (296 ) 346 — 50 Net cash used in investing activities — — (125,585 ) (8,216 ) — (133,801 ) Cash flows from financing activities: Proceeds from issuance of notes payable and draws on revolver — 147,000 — — — 147,000 Repayment of notes payable and revolver — (140,500 ) — — — (140,500 ) Payment of financing costs — — — — — — Payment of deferred consideration — — (14,503 ) (488 ) — (14,991 ) Payment of redeemable non-controlling interest liability — — (30,543 ) — — (30,543 ) Principal payments on capital lease obligations — — (4,822 ) — — (4,822 ) Proceeds from exercise of stock options 2,224 — — — — 2,224 Intercompany loans and investments (2,215 ) 39,367 (42,431 ) 5,279 — — Net cash provided by (used in) financing activities 9 45,867 (92,299 ) 4,791 — (41,632 ) Net effect of exchange rate on cash and cash equivalents — — — (1,144 ) — (1,144 ) Net increase (decrease) in cash and cash equivalents 11 (4,280 ) 2,584 2,336 — 651 Cash and cash equivalents: Beginning of period 1 4,347 18,702 9,329 — 32,379 End of period $ 12 $ 67 $ 21,286 $ 11,665 $ — $ 33,030 Condensed Consolidating Statements of Cash Flows Year Ended December 31, 2016 (in thousands) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided by (used in) operating activities $ (71,204 ) $ 256,461 (30,296 ) $ 154,961 Cash flows from investing activities: — — — — — Businesses acquired in purchase transaction, net of cash acquired — — (889,634 ) — — (889,634 ) Purchases of property and equipment — — (32,528 ) (4,731 ) — (37,259 ) Cash paid for minority investments — — (5,600 ) — — (5,600 ) Proceeds from sale of property and equipment — — 674 2 — 676 Proceeds from note receivable — — — — — — Proceeds from sale of assets — — — — — — Purchases of intangible assets — — (7 ) (20 ) — (27 ) Net (deposits) and withdrawals of principal balances in restricted cash accounts — — (347 ) (210 ) — (557 ) Net cash used in investing activities — — (927,442 ) (4,959 ) — (932,401 ) Cash flows from financing activities: Proceeds from issuance of notes payable and draws on revolver — 1,110,678 — — — 1,110,678 Repayment of notes payable and revolver — (176,700 ) — — — (176,700 ) Payment of financing costs — (52,561 ) — — — (52,561 ) Payment of deferred consideration — — (50,375 ) (669 ) — (51,044 ) Payment of redeemable non-controlling interest liability — — (33,425 ) — — (33,425 ) Principal payments on capital lease obligations — — (5,892 ) — — (5,892 ) Proceeds from exercise of stock options 2,564 — — — — 2,564 Capital investments from minority partner — — — 2,776 — 2,776 Intercompany loans and investments (2,573 ) (810,276 ) 778,421 34,428 — — Net cash provided by (used in) financing activities (9 ) 71,141 688,729 36,535 — 796,396 Net effect of exchange rate on cash and cash equivalents — — — 1,610 — 1,610 Net increase (decrease) in cash and cash equivalents (9 ) (63 ) 17,748 2,890 — 20,566 Cash and cash equivalents: Beginning of period 12 67 21,286 11,665 33,030 End of period $ 3 $ 4 $ 39,034 $ 14,555 $ — $ 53,596

Summary of Significant Accoun33

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 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.
Segment Information	Segment Information The Company has reviewed the criteria of the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 280-10, Segment Reporting, and determined that the Company is comprised of two segments for reporting purposes: web presence and email marketing. In February 2016, the Company acquired Constant Contact. At the time of the acquisition, the Company anticipated that the gross margins of Constant Contact would become more aligned with the Company's other brands; however, through review of Constant Contact's performance during 2016, the Company noted that Constant Contact continued to return higher margins than originally anticipated, and therefore determined that Constant Contact should be its own reporting segment.
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.
Cash Equivalents	Cash Equivalents Cash and cash equivalents include all highly liquid investments with remaining maturities of three months or less at the date of purchase.
Restricted Cash	Restricted Cash Restricted cash is composed of certificates of deposits and cash held by merchant banks and payment processors, which provide collateral against any charge-backs, fees, or other items that may be charged back to the Company by credit card companies and other merchants and collateral for certain facility leases.
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.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying amounts of the Company’s financial instruments, which include cash equivalents, accounts receivable, accounts payable and certain accrued expenses, approximate their fair values due to their short maturities. The carrying amount of the Company’s contingent consideration is recorded at fair value. The fair value of the Company’s notes payable is based on the borrowing rates currently available to the Company for debt with similar terms and average maturities and approximate their carrying value.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities FASB ASC 815, Derivatives and Hedging (“ASC 815”), provides the disclosure requirements for derivatives and hedging activities with the intent to provide users of financial statements with an enhanced understanding of: (a) how and why an entity uses derivative instruments, (b) how the entity accounts for derivative instruments and related hedged items, and (c) how derivative instruments and related hedged items affect an entity’s financial position, financial performance, and cash flows. Further, qualitative disclosures are required that explain the Company’s objectives and strategies for using derivatives, as well as quantitative disclosures about the fair value of and gains and losses on derivative instruments, and disclosures about credit-risk-related contingent features in derivative instruments. 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 2011-4, Fair Value Measurement (Topic 820): Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements, the Company made an accounting policy election to measure the credit risk of its derivative financial instruments that are subject to master netting agreements on a net basis by counterparty portfolio.
Concentrations of Credit and Other Risks	Concentrations of Credit and Other Risks Financial instruments which potentially subject the Company to concentrations of credit risk consist principally of cash and cash equivalents and accounts receivable. Cash and cash equivalents are maintained at accredited financial institutions, and PayPal balances are at times without and in excess of federally insured limits. The Company has never experienced any losses related to these balances and does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships.
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” . Accordingly, certain costs to develop internal-use computer software are capitalized, provided these costs are expected to be recoverable.
Investments	Investments The Company has minority investments in several privately-held companies. Investments in privately-held companies, in which the Company has a voting interest between 20.0% and 50.0% and exercises significant influence, are accounted for using the equity method of accounting. 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. The Company’s share of net earnings or losses of the investee are reflected in equity losses of unconsolidated entities, net of tax, in the Company’s accompanying consolidated statements of operations. Investments in which the Company has a voting interest of less than 20.0% and over which it does not have significant influence are accounted for under the cost method of accounting.
Business Combinations	Business Combinations The Company accounts for business acquisitions using the purchase method of accounting, in accordance with which assets acquired and liabilities assumed are recorded at their respective fair values at the acquisition date. The fair value of the consideration paid, including contingent consideration, is assigned to the assets acquired and liabilities assumed based on their respective fair values. Goodwill represents excess of the purchase price over the estimated fair values of the assets acquired and liabilities assumed. Significant judgments are used in determining fair values of assets acquired and liabilities assumed, as well as intangibles and their estimated useful lives. Fair value and useful life determinations are based on, among other factors, estimates of future expected cash flows, royalty cost savings and appropriate discount rates used in computing present values. These judgments may materially impact the estimates used in allocating acquisition date fair values to assets acquired and liabilities assumed, as well as the Company's current and future operating results. Actual results may vary from these estimates which may result in adjustments to goodwill and acquisition date fair values of assets and liabilities during a measurement period or upon a final determination of asset and liability fair values, whichever occurs first. Adjustments to fair values of assets and liabilities made after the end of the measurement period are recorded within the Company's operating results. Changes in the fair value of a contingent consideration resulting from a change in the underlying inputs are recognized in results of operations until the arrangement is settled.
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 , or ASC 350, the Company is required to review goodwill by reporting unit for impairment at least annually or more often if there are indicators of impairment present. Under U.S. GAAP, a reporting unit is either the equivalent of, or one level below, an operating segment. The Company has determined it operates in two segments and that each segment is its own reporting unit, and as such, the Company has two reporting units, email marketing and web presence as of December 31, 2016. The provisions of ASC 350 require that a two-step impairment test be performed for goodwill. In the first step, the Company compares the fair value of its reporting unit to which goodwill has been allocated to its carrying value. If the fair value of the reporting unit exceeds the carrying value of the net assets assigned to that reporting unit, goodwill is considered not impaired and the Company is not required to perform further testing. If the carrying value of the net assets assigned to the reporting unit exceeds the fair value of the reporting unit, then the Company must perform the second step of the impairment test in order to determine the implied fair value of the reporting unit’s goodwill. If the carrying value of a reporting unit’s goodwill exceeds its implied fair value, then the Company would record an impairment loss equal to the difference. The Company's annual assessment date is December 31 of each fiscal year. As of December 31, 2016, the Company determined fair values for each of the reporting units based on consideration of the income approach, the market comparable approach and the market transaction approach. For purposes of the income approach, fair value is determined based on the present value of estimated future after-tax cash flows, discounted at an appropriate risk adjusted rate. The Company uses its internal forecasts to estimate future after-tax cash flows and include an estimate of long-term future growth rates based on its most recent views of the long-term outlook for each reporting unit. Actual results may differ from those assumed in our forecasts. The Company derived its discount rates using the weighted average cost of capital, using betas observed in its industry and published rates for industries relevant to our reporting units. The Company uses discount rates that are commensurate with the risks and uncertainty inherent in the respective business and its internally developed forecasts. Discount rates used in the Company's reporting unit valuations ranged from 11.0% to 12.0% . For purposes of the market approach, the Company uses a valuation technique in which values are derived based on market prices of comparable publicly traded companies. The Company also uses a market based valuation technique in which values are determined based on relevant observable information generated by market transactions involving comparable businesses. The Company assesses each valuation methodology based upon the relevance and availability of the data at the time it performs the valuation and weight the methodologies appropriately. The carrying values of the reporting units were determined through specific allocation of assets and liabilities to the reporting units, and an apportionment method relating to our debt, whereby debt that was incurred in order to finance the acquisition of assets or businesses of a reporting unit was allocated to that reporting unit. In prior years, the Company had only one reporting unit. Subsequent to the acquisition of Constant Contact, and as described in Note 20: Segment Information , the Company determined that there is a second reporting unit relating to email marketing. The Company has allocated the fair value of the goodwill acquired through its acquisitions to the applicable reporting unit, and allocated the fair value of the goodwill acquired through its acquisition of Constant Contact to its email marketing reporting unit. As of the Company's assessment date for 2016, the estimated fair values of its reporting units exceeded their carrying values and the Company concluded, based on the first step of the process, that no impairment existed as of that date in either of its reporting units. As of December 31, 2016, the carrying value of goodwill that was allocated to the email marketing reporting unit and the web presence reporting unit was $604.3 million and $1,255.6 million , respectively. As of December 31, 2016, the fair value of the web presence segment exceeded the carrying value of its net assets by 67% and the fair value of the email marketing segment exceeded the carrying value of its net assets by 35% . Go
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 impairment losses were identified for the years ended December 31, 2014 and December 31, 2015. During the year ended December 31, 2016, the Company determined that a portion of an internally developed software tool would not meet its needs following the acquisition of Constant Contact, resulting in an impairment charge of $2.0 million which was recorded in engineering and development expense in the consolidated statements of operations and comprehensive loss. Additionally, the Company recognized an impairment charge of $0.5 million relating to internally developed software relating to Webzai Ltd. (“Webzai”), and another impairment charge of $4.4 million relating to developed technology acquired in the Webzai acquisition, for a total impairment charge of $4.9 million , which was recorded in engineering and development expense in the consolidated statements of operations and comprehensive loss. Refer to Note 6: Property and Equipment and Capital Lease Obligations and Note 7: Goodwill and Other Intangible Assets for further details. Also during the year ended December 31, 2016, the Company incurred total impairment charges of IPR&D of $2.2 million , consisting of $1.4 million to impair certain acquired IPR&D projects from the Webzai acquisition that were abandoned during the three months ended March 31, 2016 and a charge of $0.8 million to impair certain acquired IPR&D projects from the AppMachine acquisition. Refer to Note 7: Goodwill and Other Intangible Assets , and Acquired In- Process Research and Development (IPR&D) below for further details. All of the impairments described above were recognized in the web presence segment. 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 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. Upon commercialization, the acquired fair value of the IPR&D will be reclassified to developed technology and amortized over its estimated useful life.
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 , whether the associated revenue is derived from a direct subscriber or through a reseller. Deferred revenue represents the liability to subscribers for advance billings for services not yet provided and the fair value of the assumed liability outstanding for subscriber relationships purchased in an acquisition. 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 and allocates revenue to each deliverable in a multiple-element service arrangement based on its respective relative selling price. 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 our 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.
Direct Costs of Revenue	Direct Costs of Revenue The Company’s direct costs of revenue include only those costs directly incurred in connection with the provision of its cloud-based products and services. The direct costs of registering domain names with registries are spread over the terms of the arrangement and the cost of reselling domains of other third-party registrars are expensed as incurred. Cost of revenue includes depreciation on data center equipment and support infrastructure and amortization expense related to the amortization of long-lived intangible assets.
Engineering and Development Costs	Engineering and Development Costs Engineering and development costs incurred in the development and maintenance of the Company’s technology infrastructure are expensed as incurred.
Sales and Marketing Costs	Sales and Marketing Costs The Company engages in sales and marketing through various online marketing channels, which include affiliate and search marketing as well as online partnerships.
Foreign Currency	Foreign Currency The Company has sales in a number of foreign currencies. In 2013, the Company commenced operations in foreign locations which report in the local currency. The assets and liabilities of the Company’s foreign locations are translated into U.S. dollars at current exchange rates as of the balance sheet date, and revenues and expenses are translated at average monthly exchange rates. The resulting translation adjustments are recorded as a separate component of stockholders’ equity and have not been material. Foreign currency transaction gains and losses relate to the settlement of assets or liabilities in another currency.
Income Taxes	Income Taxes Income taxes are accounted for in accordance with ASC 740, Accounting for Income Taxes , or ASC 740. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carry-forwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. In addition, 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 years ended December 31, 2014 , 2015 and 2016 . The Company records interest related to unrecognized tax benefits in interest expense and penalties in operating expenses.
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 , or ASC 718, which requires employee stock-based payments to be accounted for under the fair value method. Under this method, the Company is required to record compensation cost based on the estimated fair value for stock-based awards granted over the requisite service periods for the individual awards, which generally equals the vesting periods, net of estimated forfeitures. The Company uses the straight-line amortization method for recognizing stock-based compensation expense. In addition, for stock-based awards where vesting is dependent upon achieving certain performance goals, the Company estimates the likelihood of achieving the performance goals against established performance targets. 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. In March 2016, the FASB issued Accounting Standards Update No. 2016-09, Compensation-Stock Compensation: Improvements to Employee Share-Based Payment Accounting . The guidance simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification of excess tax benefits in the consolidated statements of cash flows. This amendment is effective for annual periods beginning after December 15, 2016, and early adoption is permitted. The Company elected to early adopt the new guidance in the fourth quarter of fiscal year 2016 which requires it to reflect any adjustments as of January 1, 2016, the beginning of the annual period that includes the interim period of adoption. The impact of the early adoption resulted in the following: • Due to the Company's net shortfall position upon the time of adoption, the new standard resulted in additional tax expense in our provision for income taxes rather than paid-in capital of $0.9 million for the year ended December 31, 2016. The Company's beginning retained earnings was not impacted by the early adoption as the Company had a full valuation allowance against the U.S. deferred tax assets as of December 31, 2015. • As a result of prior guidance that required excess tax benefits reduce taxes payable prior to recognition as an increase in paid in capital, the Company had not recognized certain deferred tax assets (loss carryforwards) that could be attributed to tax deductions related to equity compensation in excess of compensation recognized for financial reporting. As of January 1, 2016, the Company had generated federal and state net operating loss carryforwards due to excess tax benefits of $1.5 million and $0.7 million , respectively. • The Company elected to eliminate the forfeiture rate and adopted the new policy to account for forfeitures in the period that they are incurred, and applied this policy on a modified retrospective basis. The impact of eliminating the forfeiture rate increased the stock compensation recorded in 2016 by $0.9 million , which included an immaterial prior period adjustment that the Company recorded through the consolidated statement of operations and comprehensive loss for the year ended December 31, 2016.
Net Loss per Share	Net Loss per Share The Company considered ASC 260-10, Earnings per Share , or ASC 260-10, which requires the presentation of both basic and diluted earnings per share in the consolidated statements of operations and comprehensive loss. The Company’s basic net loss per share is computed by dividing net loss 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. The Company’s potentially dilutive shares of common stock are excluded from the diluted weighted-average number of shares of common stock outstanding as their inclusion in the computation would be anti-dilutive due to net losses.
Guarantees	Guarantees The Company has the following guarantees and indemnifications: In connection with its acquisitions of companies and assets from third parties, the Company may provide indemnification or guarantees to the sellers in the event of damages for breaches or other claims covered by such agreements. In connection with various vendor contracts, including those by which a product or service of a third party is offered to subscribers of the Company, the Company may guarantee the obligations of its subsidiaries or provide indemnification to the vendors in the event of damages for breaches or other claims covered by the contracts. As permitted under Delaware and other applicable law, the Company’s charter and by-laws and those of its subsidiary companies provide that the Company shall indemnify its officers and directors for certain liabilities, including those incurred by reason of the fact that the officer or director is, was, or has agreed to serve as an officer or director of the Company. The maximum potential amount of future payments the Company could be required to make under these indemnification provisions is unlimited. The Company leases office space and equipment under various operating leases. The Company has standard indemnification arrangements under these leases that require the Company to indemnify the lessor against losses, liabilities and claims incurred in connection with the premises or equipment covered by the Company’s lease agreements, the Company’s use of the premises, property damage or personal injury and breach of the agreement.
Recent Accounting Pronouncements	Recent Accounting Pronouncements - Recently Adopted The Company adopted ASU No. 2015-03, Simplifying the Presentation of Debt Issuance Costs, beginning on January 1, 2016, and retrospectively for all periods presented. ASU 2015-03 requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The unamortized value of deferred financing costs associated with our revolving credit facility were not affected by the ASU and continue to be presented as an asset on the Company’s consolidated balance sheets. In September 2015, the FASB issued ASU No. 2015-16, Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments . This new guidance requires an acquirer to recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined. The acquirer needs to record, in the same period’s financial statements, the effect on earnings of changes in depreciation, amortization or other income effects, if any, as a result of the provisional amounts, calculated as if the accounting had been completed as of the acquisition date. ASU 2015-16 is effective for annual reporting periods beginning after December 15, 2015. The Company adopted ASU 2015-16 which did not have a material effect on its accounting processes, adjustments made during the period were immaterial. In November 2015, the FASB issued ASU No. 2015-17, Income Taxes: Balance Sheet Classification of Deferred Taxes , or ASU 2015-17. This new guidance requires that deferred tax liabilities and assets be classified as noncurrent in the balance sheet, in order to simplify the presentation of deferred income taxes. ASU 2015-17 is effective for annual reporting periods beginning after December 15, 2016. The Company adopted ASU 2015-17 as of the fourth quarter in 2015, on a prospective basis, and it did not have a material impact 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 . The guidance simplifies several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification of excess tax benefits in the consolidated statements of cash flows. The Company elected to early adopt the new guidance in the fourth quarter of fiscal year 2016 which requires it to reflect any adjustments as of January 1, 2016, the beginning of the annual period that includes the interim period of adoption. Refer to Stock-Based Compensation above for further information. Recent Accounting Pronouncements - Recently Issued In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) , or ASU 2014-09, which supersedes nearly all existing revenue recognition guidance under U.S. GAAP. Since then, the FASB has also issued ASU 2016-08, Revenue from Contracts with Customers (Topic 606), Principals versus Agent Considerations and ASU 2016-10, Revenue from Contracts with Customers (Topic 606), Identifying Performance Obligations and Licensing, which further elaborate on the original ASU No. 2014-09. The core principle of these updates is to recognize revenue when promised goods or services are transferred to customers in an amount that reflects the consideration to which the entity expects to be entitled for those goods or services. ASU 2014-09 defines a five step process to achieve this core principle and, in doing so, more judgments and estimates may be required within the revenue recognition process than are required under existing U.S. GAAP. In July 2015, the FASB approved a one-year deferral of the effective date to January 1, 2018, with early adoption to be permitted as of the original effective date of January 1, 2017. Once this standard becomes effective, companies may use either of the following transition methods: (i) a full retrospective approach reflecting the application of the standard in each reporting period with the option to elect certain practical expedients, or (ii) a retrospective approach with the cumulative effect of initially adopting ASU 2014-09 recognized at the date of adoption (which includes additional footnote disclosures). The Company has performed an initial assessment of ASU 2014-09, and expects that this new guidance will impact the timing of when certain sales incentive payments, primarily external parties, are charged to expense as these costs must be deferred over the life of the related customer contract. The Company also expects that a considerable portion of its revenue recognition will not be materially impacted by this new guidance. The Company is currently calculating the impact of all expected changes from this guidance, and expects to have these calculations complete during the second half of fiscal 2017. After completing these calculations, the Company will then determine the transition method to be applied upon adoption. In January 2016, the FASB issued Accounting Standards Update No. 2016-01, Financial Instruments-Overall: Recognition and Measurement of Financial Assets and Financial Liabilities . This new standard enhances the reporting model for financial instruments to provide users of financial statements with more decision-useful information. This amendment is effective for annual periods beginning after December 15, 2017, 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, but does not believe that this will have a material effect. In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases . The new standard establishes a right-of-use (ROU) model that requires a lessee to record a ROU asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. The new standard is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. A modified retrospective transition approach is required for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. The Company is currently evaluating the impact of its pending adoption of the new standard on its consolidated financial statements, but expects that it will increase its assets and liabilities. 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 does not expect a material impact on its financial position or results of operations from adoption of this standard. In August 2016, the FASB issued Accounting Standards Update No. 2016-15, Statement of Cash Flows: Classification of Certain Cash Receipts and Cash Payments . This new standard clarifies certain statement of cash flow presentation issues. This amendment is effective for annual periods beginning after December 15, 2017, 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. In October 2016, the FASB issued Accounting Standards Update No. 2016-16, Income Taxes: Intra-Entity Transfers of Assets Other Than Inventory . This new standard improves the accounting for the income tax consequences of intra-entity transfers of assets other than inventory. This amendment is effective for annual periods beginning after December 15, 2018, and early adoption is permitted. The Company does not believe the adoption of this ASU will have a material impact on its consolidated Financial Statements. In November 2016, the FASB issued Accounting Standards Update No. 2016-18, Statement of Cash Flows: Restricted Cash . This new standard requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and restricted cash. This amendment is effective for annual periods beginning after December 15, 2017, and early adoption is permitted. The Company does not believe the adoption of this ASU will have a material impact on its consolidated Financial Statements. In January 2017, the FASB issued Accounting Standards Update No. 2017-04, Intangibles - Goodwill and Other: Simplifying the Test for Goodwill Impairment . This new standard eliminates Step 2, and instead an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. This amendment is effective for annual or interim goodwill impairment tests in fiscal years beginning after December 15, 2019, and should be applied on a prospective basis .The Company is currently evaluating the impact of its pending adoption of the new standard on its consolidated financial statements.

Summary of Significant Accoun34

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Summary of Estimated Useful Lives	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
Potentially Dilutive Shares of Common Stock Excluded from the Diluted Weighted-average Number of Shares of Common Stock Outstanding	For the years ended December 31, 2014 , 2015 and 2016 , all non-vested shares granted prior to the Company’s IPO in October 2013, stock options, restricted stock awards and restricted stock units were excluded from the calculation of diluted earnings per share as their inclusion would have been anti-dilutive as a result of the net losses for these periods. For the Year Ended December 31, 2014 2015 2016 (in thousands, except share amounts and per share data) Computation of basic and diluted net loss per share: Net loss attributable to Endurance International Group Holdings, Inc. $ (42,835 ) $ (25,770 ) $ (72,831 ) Net loss per share attributable to Endurance International Group Holdings, Inc.: Basic and diluted $ (0.34 ) $ (0.20 ) $ (0.55 ) Weighted average number of common shares used in computing net loss per share attributable to Endurance International Group Holdings, Inc.: Basic and diluted 127,512,346 131,340,557 133,415,732
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following number of weighted average potentially dilutive shares were excluded from the calculation of diluted loss per share because the effect of including such potentially dilutive shares would have been anti-dilutive: For the Year Ended December 31, 2014 2015 2016 Restricted Stock Awards 2,512,755 3,019,349 8,019,241 Options 5,436,298 6,723,589 10,380,991 Total 7,949,053 9,742,938 18,400,232

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 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, consisted of the following: Short- term Long- term (in thousands) Mojoness, Inc. (Acquired in 2012) $ 657 $ 813 Typepad (Acquired in 2013) 2,800 — Webzai (Acquired in 2014) 2,848 — BuyDomains (Acquired in 2014) 4,283 — Verio (Acquired in 2015) 2,474 — WWWH (Acquired in 2015) 4,600 — Ace (Acquired in 2015) 29,626 — Ecommerce (Acquired in 2015) 4,200 — Total $ 51,488 $ 813 Components of deferred consideration short-term and long-term as of December 31, 2016, consisted of the following: Short- term Long- term (in thousands) Mojoness, Inc. (Acquired in 2012) $ 818 $ — Verio (Acquired in 2015) 50 — Social Booster (Acquired in 2016) 40 25 AppMachine (Acquired in 2016) 4,365 7,419 Total $ 5,273 $ 7,444

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2016
Basis of Fair Value Measurements	The earn-out consideration in the table below is included in total deferred consideration in the Company’s consolidated balance sheets. 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 December 31, 2016 Financial assets: Interest rate cap (included in other assets) $ 979 — $ 979 $ — Total financial assets $ 979 $ — $ 979 $ — Financial liabilities: Contingent earn-out consideration $ 818 — — $ 818 Total financial liabilities $ 818 $ — $ — $ 818
Significant Unobservable Inputs (Level 3)
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 December 31, 2015 and 2016 : Amount (in thousands) Financial liabilities measured using Level 3 inputs at January 1, 2015 $ 10,887 Payment of contingent earn-out related to 2012 and 2014 acquisitions (10,592 ) Change in fair value of contingent earn-outs 1,174 Financial liabilities measured using Level 3 inputs at December 31, 2015 1,469 Payment of contingent earn-outs related to 2012 acquisitions (668 ) Change in fair value of contingent earn-outs 17 Financial liabilities measured using Level 3 inputs at December 31, 2016 $ 818

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Components of Property and Equipment	Components of property and equipment consisted of the following: As of December 31, 2015 2016 (in thousands) Land $ 713 $ 790 Building 5,091 5,517 Software 40,336 52,130 Computers and office equipment 97,332 143,091 Furniture and fixtures 5,914 10,892 Leasehold improvements 7,126 21,244 Construction in process 6,137 6,691 Property and equipment—at cost 162,649 240,355 Less accumulated depreciation (86,887 ) (145,083 ) Property and equipment—net $ 75,762 $ 95,272
Summary of Software Assets under Capital Lease	As of December 31, 2015 and 2016 , the Company’s software shown in the above table included the software assets under a capital lease as follows: As of December 31, 2015 2016 (in thousands) Software $ 21,499 $ 21,499 Less accumulated depreciation (8,412 ) (14,750 ) Assets under capital lease—net $ 13,087 $ 6,749
Summary of Future Minimum Lease Payments under Capital Lease	At December 31, 2016 , the expected future minimum lease payments under the capital lease discussed above were approximately as follows: Amount (in thousands) 2017 6,895 2018 575 Total minimum lease payments $ 7,470 Less amount representing interest (268 ) Present value of minimum lease payments (capital lease obligation) $ 7,202 Current portion $ 6,690 Long-term portion $ 512

Goodwill and Other Intangible38

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in Goodwill Balances	The following table summarizes the changes in the Company’s goodwill balances as of December 31, 2015 and 2016 : Web Presence Unit Email Marketing Unit Total Amount Amount Amount (in thousands) (in thousands) (in thousands) Goodwill balance at January 1, 2015 $ 1,105,023 $ — $ 1,105,023 Goodwill related to 2015 acquisitions 103,444 — 103,444 Foreign translation impact (1,212 ) — (1,212 ) Goodwill balance at December 31, 2015 1,207,255 — 1,207,255 Goodwill related to 2015 acquisitions 5,978 — 5,978 Goodwill related to 2016 acquisitions 43,019 604,305 647,324 Foreign translation impact (648 ) — (648 ) Goodwill balance at December 31, 2016 $ 1,255,604 $ 604,305 $ 1,859,909
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 year In-process research and development 1,438 — 1,438 — Total December 31, 2015 $ 749,139 $ 389,353 $ 359,786 At December 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 $ 284,005 $ 111,348 $ 172,657 7 years Subscriber relationships 659,662 345,070 314,592 7 years Trade-names 133,805 57,789 76,016 8 years Intellectual property 34,084 10,270 23,814 13 years Domain names available for sale 29,954 4,976 24,978 Indefinite Leasehold interests 314 314 — 1 year Total December 31, 2016 $ 1,141,824 $ 529,767 $ 612,057
Summary of Expected Future Amortization of Other Intangible Assets	At December 31, 2016 , the expected future amortization of the other intangible assets, excluding indefinite life and in-process research and development intangibles, was approximately as follows: Year Ending December 31, Amount (in thousands) 2017 $ 137,000 2018 103,000 2019 86,000 2020 72,000 2021 62,000 Thereafter 127,000 Total $ 587,000

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Summary of Statement of Operations and Comprehensive Loss for Equity Method Investment	The following table presents a summary of the statement of operations and comprehensive loss for WZ UK Ltd. for the years ended December 31, 2014 and 2015: For the years ended December 31, 2014 2015 (in thousands) Revenue $ 1 $ 4,053 Gross profit (loss) $ (96 ) $ 1,095 Operating loss $ (694 ) $ (28,439 ) Net loss $ (694 ) $ (28,439 )

Notes Payable (Tables)

Notes Payable (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	At December 31, 2015 and 2016, notes payable, net of original issuance discount and deferred financing costs, consisted of the following: For the Year Ended December 31, 2015 2016 (in thousands) First Lien Term Loan $ 1,025,385 $ 985,640 Incremental First Lien Term Loan — 674,860 Senior Notes — 326,480 Revolving Credit Facilities 67,000 — Total Notes Payable 1,092,385 1,986,980 Current portion of Notes Payable 77,500 35,700 Notes Payable - long-term $ 1,014,885 $ 1,951,280 As of December 31, 2016, the First Lien had an outstanding balance of: For the Year Ended December 31, 2016 Incremental First Lien Term Loan $ 720,300 Unamortized deferred financing costs (25,869 ) Unamortized original issue discounts (19,571 ) Net Incremental First Lien Term Loan 674,860 Current portion of Incremental First Lien Term Loan 14,700 Incremental First Lien Term Loan - long term $ 660,160 The Company has a first lien term loan (“First Lien”), which originated in November 2013, had an original balance of $1,050.0 million and a maturity date of November 9, 2019. As of December 31, 2015 and 2016, the First Lien had an outstanding balance of: For the Year Ended December 31, 2015 2016 First Lien Term Loan $ 1,026,375 $ 985,875 Unamortized deferred financing costs (990 ) (235 ) Net First Lien Term Loan 1,025,385 985,640 Current portion of First Lien Term Loan 10,500 21,000 First Lien Term Loan - long term $ 1,014,885 $ 964,640 As of December 31, 2016, the Senior Notes had an outstanding balance of: For the Year Ended December 31, 2016 Senior Notes $ 350,000 Unamortized deferred financing costs (17,238 ) Unamortized original issue discounts (6,282 ) Net Senior Notes 326,480 Current portion of Senior Notes — Senior Notes - long term $ 326,480
Summary of Maturity of the Notes Payable	The maturity of the notes payable at December 31, 2016 is as follows: First Lien, Incremental First Lien, and Notes (in thousands) 2017 $ 35,700 2018 35,700 2019 958,575 2020 14,700 2021 14,700 Thereafter 996,800 Total $ 2,056,175
Summary of Interest Rates and Interest Expense	The following table provides a summary of loan interest rates incurred and interest expense for the years ended December 31, 2014 , 2015 and 2016 : For the Year Ended December 31, 2014 2015 2016 (dollars in thousands) Interest rate—LIBOR 5.00%-7.75% 5.00%-7.75% 4.49%-7.75% Interest rate—reference 8.50 % 8.50 % 6.75%-8.75% Interest rate—Notes — % — % 10.875 % Non-refundable fee—unused facility 0.50 % 0.50 % 0.50 % Interest expense and service fees $ 56,247 $ 56,760 $ 140,470 Amortization of deferred financing fees $ 83 $ 82 $ 6,073 Amortization of original issue discounts $ — $ — $ 2,970 Amortization of net present value of deferred consideration $ 183 $ 1,264 $ 2,617 Other interest expense $ 901 $ 722 $ 758 Total interest expense $ 57,414 $ 58,828 $ 152,888

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2016
Summary of 2012 Restricted Stock Awards Activity for Restricted Stock Awards that were Granted Prior to Company's IPO	The following tables present a summary of the 2012 restricted stock awards activity for the year ended December 31, 2016 for restricted stock awards that were granted prior to the Company’s IPO: 2012 Restricted Stock Awards Non-Vested at December 31, 2015 46,645 Forfeitures — Vested (46,645 ) Non-Vested at December 31, 2016 —
Summary of Restricted Stock Units that were Granted in Connection with IPO and the Non-Vested Balance	The following table provides a summary of the restricted stock units that were granted in connection with the IPO under this plan and the non-vested balance as of December 31, 2016 : Restricted Stock Units Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 22,158 $ 12.00 Vested (22,158 ) $ 12.00 Non-vested at December 31, 2016 — $ —
Stock Incentive Plan	The weighted-average assumptions used to compute stock-based compensation expense for awards granted under the 2013 Stock Incentive Plan during the years ended December 31, 2014, 2015 and 2016 are as follows: 2014 2015 2016 Risk-free interest rate 2.1 % 1.8 % 1.6 % Expected volatility 58.3 % 56.1 % 53.1 % Expected life (in years) 6.25 6.25 6.25 Expected dividend yield — — —
Summary of Stock Options	The following table provides a summary of the Company’s stock options as of December 31, 2016 and the stock option activity for all stock options granted under the 2013 Plan during the year ended December 31, 2016 (dollars in thousands except exercise price): 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 3,575,851 $ 10.96 Exercised — $ — Forfeited (595,364 ) $ 13.56 Canceled (323,914 ) $ 13.41 Outstanding at December 31, 2016 9,607,431 $ 12.79 8.0 $ 205 Exercisable as of December 31, 2016 4,435,261 $ 13.15 7.1 $ — Expected to vest after December 31, 2016(1) 5,172,170 $ 12.49 8.7 $ 205 Exercisable as of December 31, 2016 and expected to vest thereafter(2) 9,607,431 $ 12.79 8.0 $ 205 (1) This represents the number of unvested options outstanding as of December 31, 2016 that are expected to vest in the future. (2) This represents the number of vested options as of December 31, 2016 plus the number of unvested options outstanding as of December 31, 2016 that are expected to vest in the future. (3) The aggregate intrinsic value was calculated based on the positive difference between the estimated fair value of the Company’s common stock on December 31, 2016 of $9.30 per share, or the date of exercise, as appropriate, and the exercise price of the underlying options. The following table provides a summary of the Company’s stock options as of December 31, 2016 and the stock option activity for all stock options granted under the 2011 Plan during the year ended December 31, 2016 : Stock Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Term (In years) Aggregate Intrinsic Value(3) (In thousands) Outstanding at December 31, 2015 — $ — Granted/Exchanged 3,002,887 $ 8.28 Exercised (396,486 ) $ 6.47 Canceled (674,571 ) $ 8.07 Outstanding at December 31, 2016 1,931,830 $ 8.73 5.1 2,606 Exercisable as of December 31, 2016 529,472 $ 7.12 3.7 1,316 Expected to vest after December 31, 2016(1) 1,123,921 $ 9.28 5.6 1,099 Exercisable as of December 31, 2016 and expected to vest thereafter(2) 1,653,393 $ 8.59 5.0 2,415 (1) This represents the number of unvested options outstanding as of December 31, 2016 that are expected to vest in the future. (2) This represents the number of vested options as of December 31, 2016 plus the number of unvested options outstanding as of December 31, 2016 that are expected to vest in the future. (3) The aggregate intrinsic value was calculated based on the positive difference between the estimated fair value of the Company’s common stock on December 31, 2016 of $9.30 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 year ended December 31, 2016: Restricted Stock Units Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 — — Granted 3,154,897 $ 8.49 Vested (1,266,771 ) $ 7.69 Canceled (414,471 ) $ 8.26 Non-vested at December 31, 2016 1,473,655 $ 9.25
Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions	The weighted-average assumptions used to compute stock-based compensation expense for awards granted under the 2011 Stock Incentive Plan during the year ended December 31, 2016 are as follows: 2016 Risk-free interest rate 1.27 % Expected volatility 53.1 % Expected life (in years) 4.75 Expected dividend yield —
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 loss for all 2012 restricted stock awards and units issued prior to the Company’s IPO in October 2013 and all awards granted under the 2013 Plan in connection with or subsequent to the IPO: For the Year Ended December 31, 2014 2015 2016 (in thousands) Cost of revenue $ 547 $ 1,975 $ 5,855 Sales and marketing 1,585 3,285 8,702 Engineering and development 883 1,988 5,989 General and administrative 13,028 22,677 37,721 Total operating expense $ 16,043 $ 29,925 $ 58,267
Restricted Stock Awards
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 year ended December 31, 2016 : Restricted Stock Awards Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 4,849,290 $ 15.24 Granted 3,355,341 $ 10.36 Vested (613,751 ) $ 13.84 Canceled (258,343 ) $ 12.75 Non-vested at December 31, 2016 7,332,537 $ 13.21
Restricted Stock Units
Summary of Restricted Stock Awards and Restricted Stock Units	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 year ended December 31, 2016 : Restricted Stock Units Weighted Average Grant Date Fair Value Non-vested at December 31, 2015 220,765 $ 12.00 Vested and unissued (120,396 ) $ 12.00 Non-vested at December 31, 2016 100,369 $ 12.00

Accumulated Other Comprehensi42

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Components of Accumulated Other Comprehensive Loss, Net of Tax	The components of accumulated other comprehensive loss, net of tax were as follows: Foreign Currency Translation Adjustments Unrealized Gains (Losses) on Cash Flow Hedges Total (in thousands) Balance at December 31, 2014 (517 ) — (517 ) Other comprehensive income (loss) (1,281 ) 80 (1,201 ) Balance at December 31, 2015 $ (1,798 ) $ 80 $ (1,718 ) Other comprehensive income (loss) (597 ) (1,351 ) (1,948 ) Balance at December 31, 2016 $ (2,395 ) $ (1,271 ) $ (3,666 )

Redeemable Non-Controlling In43

Redeemable Non-Controlling Interest (Tables)	12 Months Ended
	Dec. 31, 2016
Noncontrolling Interest [Abstract]
Redeemable Non-Controlling Interest	The following table presents changes in this redeemable non-controlling interest: Redeemable noncontrolling Interest (in thousands) Balance as of December 31, 2015 $ — Additions to non-controlling interest upon acquisition 12,790 Capital contribution from non-controlling interest 1,775 Accretion to redemption value 30,844 Accretion in excess of fair value 6,769 Adjustment to non-controlling interest (1,000 ) Redemption of non-controlling interest (33,425 ) Balance as of December 31, 2016 $ 17,753

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Components of Income (Loss) Before Income Taxes	The domestic and foreign components of income (loss) before income taxes for the periods presented: Year Ended December 31, 2014 2015 2016 (in thousands) United States $ (17,002 ) $ 1,258 $ (137,197 ) Foreign (27,603 ) (1,046 ) (52,593 ) Total income (loss) before income taxes $ (44,605 ) $ 212 $ (189,790 )
Components of Income Taxes Benefit and Expenses	The components of the provision (benefit) for income taxes consisted of the following: Year Ended December 31, 2014 2015 2016 (in thousands) Current: U.S. federal $ 781 $ 1,827 $ 328 State 183 696 744 Foreign 1,582 1,699 2,312 Total current provision 2,546 4,222 3,384 Deferred: U.S. federal (581 ) (1,103 ) (44,447 ) State (3,983 ) 1,952 (6,225 ) Foreign (5,310 ) (818 ) (10,037 ) Change in valuation allowance 13,514 7,089 (52,533 ) Total deferred provision 3,640 7,120 (113,242 ) Total expense (benefit) $ 6,186 $ 11,342 $ (109,858 )
Reconciliation of Statutory Federal Rate	The following table presents a reconciliation of the statutory federal rate, and the Company’s effective tax rate, for the periods presented: Year Ended December 31, 2014 2015 2016 U.S. federal taxes at statutory rate 34.0 % 34.0 % 35.0 % State income taxes, net of federal benefit 5.9 685.0 0.9 Nondeductible stock-based compensation (2.5 ) 827.3 (1.5 ) Nondeductible transaction costs (1.0 ) 856.5 (2.9 ) Nontaxable gain on redemption of equity interest — (674.9 ) — Other foreign permanent differences (2.5 ) 187.8 (0.4 ) Credits 0.6 — 3.7 Foreign rate differential (11.7 ) 299.7 (4.6 ) Change in valuation allowance—U.S. (23.2 ) 3,398.6 31.2 Change in valuation allowance—foreign (7.0 ) (130.8 ) (4.1 ) Rate change (1.1 ) 216.5 0.4 Prior year true-up stock-based compensation—U.S. (2.0 ) (132.8 ) — Other (3.4 ) (217.5 ) (0.5 ) Total (13.9 )% 5,349.4 % 57.2 %
Components of the Company's Deferred Income Tax Assets and Liabilities	The significant components of the Company’s deferred income tax assets and liabilities are as follows: As of December 31, 2015 2016 Deferred income tax assets: Net operating loss carry forward $ 43,698 $ 76,060 Credit carryforward 2,190 28,271 Other 6,612 5,414 Deferred compensation 497 364 Deferred revenue 21,327 26,291 Other reserves 4,895 3,545 Stock-based compensation 13,221 25,424 Total deferred income tax assets 92,440 165,369 Deferred income tax liabilities: Purchased intangible assets (11,098 ) (119,719 ) Goodwill (26,062 ) (37,099 ) Property and equipment (8,361 ) (12,403 ) Total deferred income tax liabilities (45,521 ) (169,221 ) Valuation allowance (75,705 ) (36,091 ) Net deferred income tax liabilities $ (28,786 ) $ (39,943 )

Severance and Other Exit Costs

Severance and Other Exit Costs (Tables)	12 Months Ended
	Dec. 31, 2016
Summary of Severance Charges	The following table presents restructuring charges recorded in the consolidated statement of operations and comprehensive loss for the periods presented: For the Year Ended December 31, 2014 2015 2016 (in thousands) Cost of revenue $ 2,349 $ (45 ) $ 8,986 Sales and marketing 301 555 6,550 Engineering and development 960 636 4,288 General and administrative 850 343 4,400 Total severance charges $ 4,460 $ 1,489 $ 24,224
Employee Severance
Summary of Activity Related to Company's Facilities Exit Costs Accrual	The following table provides a summary of the aggregate activity for the year ended December 31, 2016 related to the Company’s combined Restructuring Plans facilities exit accrual for each reporting segment: Facility (in thousands) Web presence segment Email marketing segment Total Balance at December 31, 2015 $ 479 $ — $ 479 Facility charges, net of estimated sublease income 445 12,070 12,515 Sublease income received 596 — 596 Cash paid (1,247 ) (3,323 ) (4,570 ) Balance at December 31, 2016 $ 273 $ 8,747 $ 9,020 The following table provides a summary of the aggregate activity for the year ended December 31, 2016 related to the Company’s combined Restructuring Plans severance accrual for each reporting segment: (in thousands) Web presence segment Email marketing segment Total Balance at December 31, 2015 $ 1,201 $ — $ 1,201 Severance Charges 1,596 10,113 $ 11,709 Cash Paid (2,164 ) (9,187 ) $ (11,351 ) Balance at December 31, 2016 $ 633 $ 926 $ 1,559

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Summary of Future Minimum Annual Rental Payments Under these Leases	The Company has operating lease commitments for certain facilities and equipment that expire on various dates through 2026 . The following table outlines future minimum annual rental payments under these leases at December 31, 2016 : Year Ending December 31, Amount (in thousands) 2017 20,058 2018 18,367 2019 17,457 2020 17,120 2021 14,074 Thereafter 27,779 Total minimum lease payments $ 114,855

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2016
Immediate Family Member of Management or Principal Owner
Summary of Related Party Transactions	The following table includes the amounts of related party transactions recorded in the consolidated statements of operations and comprehensive loss for the years ended December 31, 2014 , 2015 and 2016 relating to services provided by Tregaron and its affiliates under these agreements: For the Year Ended December 31, 2014 2015 2016 (in thousands) Cost of revenue $ 7,300 $ 10,200 $ 12,200 Sales and marketing 500 700 500 Engineering and development 1,700 1,100 1,300 General and administrative 900 300 300 Total related party transaction expense $ 10,400 $ 12,300 $ 14,300
Director
Summary of Related Party Transactions	The following table includes the revised amounts of related party transactions recorded in the consolidated statements of operations and comprehensive loss for the years ended December 31, 2014 , 2015 and 2016 relating to services provided by IBS under these agreements: For the Year Ended December 31, 2014 2015 2016 (in thousands) Revenue $ (400 ) $ (1,300 ) $ (3,100 ) Revenue (contra) 600 7,000 7,500 Total related party transaction impact to revenue $ 200 $ 5,700 $ 4,400 Cost of revenue 4,600 600 700 Total related party transaction expense, net $ 4,800 $ 6,300 $ 5,100

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	The following tables contain financial information for each reportable segment for the year ended December 31, 2016: Web presence Email marketing Total (in thousands) Revenue $ 784,334 $ 326,808 $ 1,111,142 Gross profit $ 353,988 $ 173,163 $ 527,151 Adjusted EBITDA $ 172,135 $ 116,261 $ 288,396 Less: Interest expense, net (including impact of amortization of deferred financing costs and original issuance discount) 152,312 Income tax expense (benefit) (109,858 ) Depreciation 60,360 Amortization of other intangible assets 143,562 Stock-based compensation 58,267 Restructuring expenses 24,224 Transaction expenses and charges 32,284 Gain of unconsolidated entities (565 ) Impairment of other long lived assets 9,039 Net loss $ (81,229 ) Total assets $ 1,507,977 $ 1,248,297 $ 2,756,274 Depreciation expense $ 36,613 $ 23,747 $ 60,360 Amortization expense $ 78,883 $ 64,679 $ 143,562 Revenue, classified by the major geographic areas in which our customers are located, was as follows: Year Ended December 31, 2014 2015 2016 (in thousands) United States $ 409,765 $ 465,446 $ 787,915 International 220,080 275,869 323,227 Total $ 629,845 $ 741,315 $ 1,111,142

Geographic and Other Informat49

Geographic and Other Information (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Revenues Classified by Major Geographic Areas	The following tables contain financial information for each reportable segment for the year ended December 31, 2016: Web presence Email marketing Total (in thousands) Revenue $ 784,334 $ 326,808 $ 1,111,142 Gross profit $ 353,988 $ 173,163 $ 527,151 Adjusted EBITDA $ 172,135 $ 116,261 $ 288,396 Less: Interest expense, net (including impact of amortization of deferred financing costs and original issuance discount) 152,312 Income tax expense (benefit) (109,858 ) Depreciation 60,360 Amortization of other intangible assets 143,562 Stock-based compensation 58,267 Restructuring expenses 24,224 Transaction expenses and charges 32,284 Gain of unconsolidated entities (565 ) Impairment of other long lived assets 9,039 Net loss $ (81,229 ) Total assets $ 1,507,977 $ 1,248,297 $ 2,756,274 Depreciation expense $ 36,613 $ 23,747 $ 60,360 Amortization expense $ 78,883 $ 64,679 $ 143,562 Revenue, classified by the major geographic areas in which our customers are located, was as follows: Year Ended December 31, 2014 2015 2016 (in thousands) United States $ 409,765 $ 465,446 $ 787,915 International 220,080 275,869 323,227 Total $ 629,845 $ 741,315 $ 1,111,142
Schedule of Tangible Long-Lived Assets	The following table presents the amount of tangible long-lived assets by geographic area: 2015 2016 (in thousands) United States $ 72,025 $ 89,147 International 3,737 6,125 Total $ 75,762 $ 95,272

Quarterly Financial Data (una50

Quarterly Financial Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Schedule of Condensed Income Statement	The following table presents the Company’s unaudited quarterly financial data: For the three months ended March 31, June 30, Sept. 30, Dec. 31, March 31, June 30, Sept. 30, Dec. 31, (in thousands, except per share data) Revenue $ 177,318 $ 182,431 $ 188,523 $ 193,043 $ 237,113 $ 290,713 $ 291,193 $ 292,123 Gross profit $ 76,344 $ 77,494 $ 77,750 $ 84,692 $ 100,637 $ 137,636 $ 141,766 $ 147,112 Income (loss) from operations $ 17,199 $ 12,548 $ 9,113 $ 14,326 $ (66,311 ) $ (6,168 ) $ 8,879 $ 24,260 Net income (loss) attributable to Endurance International Group Holdings, Inc. $ 884 $ (2,071 ) $ (15,351 ) $ (9,232 ) $ 21,811 $ (28,040 ) $ (31,737 ) $ (34,865 ) Basic net income (loss) per share attributable to Endurance International Group Holdings, Inc. $ 0.01 $ (0.02 ) $ (0.12 ) $ (0.07 ) $ 0.17 $ (0.21 ) $ (0.24 ) $ (0.26 ) Diluted net income (loss) per share attributable to Endurance International Group Holdings, Inc. $ 0.01 $ (0.02 ) $ (0.12 ) $ (0.07 ) $ 0.16 $ (0.21 ) $ (0.24 ) $ (0.26 )

Supplemental Guarantor Financ51

Supplemental Guarantor Financial Information (Tables)	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Consolidated Balance Sheets	The following tables present supplemental condensed consolidating balance sheet information of the Company (“Parent”), the Issuer, the Subsidiary Guarantors and the Non-Guarantor Subsidiaries as of December 31, 2015 and December 31, 2016, and supplemental condensed consolidating results of operations and cash flow information for the years ended December 31, 2014, 2015 and 2016: Condensed Consolidating Balance Sheets December 31, 2015 (in thousands) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Assets: Current assets: Cash and cash equivalents $ 12 $ 67 $ 21,286 $ 11,665 — $ 33,030 Restricted cash — — 973 75 — 1,048 Accounts receivable — — 7,120 4,920 — 12,040 Prepaid domain name registry fees — — 29,250 26,878 (335 ) 55,793 Prepaid expenses & other current assets — 62 9,722 8,263 (2,372 ) 15,675 Total current assets 12 129 68,351 51,801 (2,707 ) 117,586 Intercompany receivables, net 29,092 (10,324 ) 91,938 (110,706 ) — — Property and equipment, net — — 66,011 9,751 — 75,762 Goodwill — — 1,072,838 134,417 — 1,207,255 Other intangible assets, net — — 328,922 30,864 — 359,786 Investment in subsidiaries 150,164 1,260,399 38,819 — (1,449,382 ) — Other assets — 3,130 34,151 4,830 — 42,111 Total assets $ 179,268 $ 1,253,334 $ 1,701,030 $ 120,957 $ (1,452,089 ) $ 1,802,500 Liabilities, redeemable non-controlling interest and stockholders' equity Current liabilities: Accounts payable $ — $ 3,769 $ 7,269 $ 1,242 — $ 12,280 Accrued expenses and other current liabilities — 7,016 38,092 12,106 (2,372 ) 54,842 Deferred revenue — — 230,396 56,290 (741 ) 285,945 Current portion of notes payable — 77,500 — — — 77,500 Current portion of capital lease obligations — — 5,866 — — 5,866 Deferred consideration, short-term — — 50,840 648 — 51,488 Total current liabilities — 88,285 332,463 70,286 (3,113 ) 487,921 Deferred revenue, long-term — — 71,982 7,700 — 79,682 Notes payable — 1,014,885 — — — 1,014,885 Capital lease obligations — — 7,215 — — 7,215 Deferred consideration — — — 813 — 813 Other long-term liabilities — — 28,970 3,340 — 32,310 Total liabilities — 1,103,170 440,630 82,139 (3,113 ) 1,622,826 Redeemable non-controlling interest — — — — — — Equity 179,268 150,164 1,260,400 38,818 (1,448,976 ) 179,674 Total liabilities and equity $ 179,268 $ 1,253,334 $ 1,701,030 $ 120,957 $ (1,452,089 ) $ 1,802,500 Condensed Consolidating Balance Sheets December 31, 2016 (in thousands) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Assets: Current assets: Cash and cash equivalents $ 3 $ 4 $ 39,034 $ 14,555 $ — $ 53,596 Restricted cash — — 2,620 682 — 3,302 Accounts receivable — — 10,148 2,940 — 13,088 Prepaid domain name registry fees — — 31,044 24,697 (297 ) 55,444 Prepaid expenses & other current assets — 81 17,996 10,601 — 28,678 Total current assets 3 85 100,842 53,475 (297 ) 154,108 Intercompany receivables, net 31,665 799,953 (690,761 ) (140,857 ) — — Property and equipment, net — — 82,901 12,371 — 95,272 Goodwill — — 1,683,121 176,788 — 1,859,909 Other intangible assets, net — — 592,095 19,962 — 612,057 Investment in subsidiaries 92,068 1,299,562 40,651 — (1,432,281 ) — Other assets — 5,911 23,153 5,864 — 34,928 Total assets $ 123,736 $ 2,105,511 $ 1,832,002 $ 127,603 $ (1,432,578 ) $ 2,756,274 Liabilities, redeemable non-controlling interest and stockholders' equity: Current liabilities: Accounts payable $ — $ — $ 13,801 $ 2,273 $ — $ 16,074 Accrued expenses and other current liabilities — 27,208 60,760 9,890 — 97,858 Deferred revenue — — 295,208 60,925 (943 ) 355,190 Current portion of notes payable — 35,700 — — — 35,700 Current portion of capital lease obligations — — 6,690 — — 6,690 Deferred consideration, short-term — — 4,415 858 — 5,273 Total current liabilities — 62,908 380,874 73,946 (943 ) 516,785 Deferred revenue, long-term — — 77,649 11,551 — 89,200 Notes payable — 1,951,280 — — — 1,951,280 Capital lease obligations — — 512 — — 512 Deferred consideration — — 7,419 25 — 7,444 Other long-term liabilities — (745 ) 48,233 1,429 — 48,917 Total liabilities — 2,013,443 514,687 86,951 (943 ) 2,614,138 Redeemable non-controlling interest — — 17,753 — — 17,753 Equity 123,736 92,068 1,299,562 40,652 (1,431,635 ) 124,383 Total liabilities and equity $ 123,736 $ 2,105,511 $ 1,832,002 $ 127,603 $ (1,432,578 ) $ 2,756,274
Condensed Consolidated Statements of Operations and Comprehensive Loss	Condensed Consolidating Statements of Operations and Comprehensive Loss Year Ended December 31, 2014 (in thousands) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Revenue $ — $ — $ 559,434 $ 70,990 $ (579 ) $ 629,845 Cost of revenue — — 327,225 54,500 (237 ) 381,488 Gross profit — — 232,209 16,490 (342 ) 248,357 Operating expense: Sales & marketing — — 114,367 32,607 (177 ) 146,797 Engineering and development — — 16,805 2,744 — 19,549 General and administrative — 232 61,291 8,010 — 69,533 Total operating expense — 232 192,463 43,361 (177 ) 235,879 Income (loss) from operations — (232 ) 39,746 (26,871 ) (165 ) 12,478 Interest expense, net — 56,330 829 (76 ) — 57,083 Income (loss) before income taxes and equity earnings of unconsolidated entities — (56,562 ) 38,917 (26,795 ) (165 ) (44,605 ) Income tax expense (benefit) — 6,163 613 (590 ) — 6,186 Loss before equity earnings of unconsolidated entities — (62,725 ) 38,304 (26,205 ) (165 ) (50,791 ) Equity loss of unconsolidated entities, net of tax 42,835 (19,890 ) 26,500 — (49,384 ) 61 Net loss (42,835 ) (42,835 ) 11,804 (26,205 ) 49,219 (50,852 ) Net loss attributable to non-controlling interest — — (8,017 ) — — (8,017 ) Net loss attributable to Endurance $ (42,835 ) $ (42,835 ) $ 19,821 $ (26,205 ) $ 49,219 $ (42,835 ) Comprehensive loss Foreign currency translation adjustments — — — (462 ) — (462 ) Total comprehensive loss $ (42,835 ) $ (42,835 ) $ 19,821 $ (26,667 ) $ 49,219 $ (43,297 ) Condensed Consolidating Statements of Operations and Comprehensive Loss Year Ended December 31, 2015 (in thousands) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Revenue $ — $ — $ 628,266 $ 113,766 $ (717 ) $ 741,315 Cost of revenue — — 349,059 77,177 (1,201 ) 425,035 Gross profit — — 279,207 36,589 484 316,280 Operating expense: Sales & marketing — — 120,637 24,815 (33 ) 145,419 Engineering and development — — 23,019 3,688 — 26,707 General and administrative — 177 80,548 10,132 111 90,968 Total operating expense — 177 224,204 38,635 78 263,094 Income (loss) from operations — (177 ) 55,003 (2,046 ) 406 53,186 Interest expense and other income, net — 56,843 (3,554 ) (315 ) — 52,974 Income (loss) before income taxes and equity earnings of unconsolidated entities — (57,020 ) 58,557 (1,731 ) 406 212 Income tax expense (benefit) — 10,320 331 691 — 11,342 Loss before equity earnings of unconsolidated entities — (67,340 ) 58,226 (2,422 ) 406 (11,130 ) Equity loss of unconsolidated entities, net of tax 26,176 (41,164 ) 17,063 — 12,565 14,640 Net loss (26,176 ) (26,176 ) 41,163 (2,422 ) (12,159 ) (25,770 ) Net loss attributable to non-controlling interest — — — — — — Net loss attributable to Endurance $ (26,176 ) $ (26,176 ) $ 41,163 $ (2,422 ) $ (12,159 ) $ (25,770 ) Comprehensive loss — Foreign currency translation adjustments — — — (1,281 ) — (1,281 ) Unrealized gain on cash flow hedge — 80 — — — 80 Total comprehensive loss $ (26,176 ) $ (26,096 ) $ 41,163 $ (3,703 ) $ (12,159 ) $ (26,971 ) Condensed Consolidating Statements of Operations and Comprehensive Loss Year Ended December 31, 2016 (in thousands) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Revenue $ — $ — $ 978,690 $ 133,274 $ (822 ) $ 1,111,142 Cost of revenue — — 496,267 88,753 (1,029 ) 583,991 Gross profit — — 482,423 44,521 207 527,151 Operating expense: Sales and marketing — — 235,988 67,556 (33 ) 303,511 Engineering and development — — 72,922 14,679 — 87,601 General and administrative — 242 128,337 14,516 — 143,095 Transaction expenses — — 32,284 — — 32,284 Total operating expense — 242 469,531 96,751 (33 ) 566,491 Income (loss) from operations — (242 ) 12,892 (52,230 ) 240 (39,340 ) Interest expense and other income —net — 149,512 (3,606 ) 4,544 — 150,450 Income (loss) before income taxes and equity earnings of unconsolidated entities — (149,754 ) 16,498 (56,774 ) 240 (189,790 ) Income tax expense (benefit) — (53,847 ) (55,953 ) (58 ) — (109,858 ) Loss before equity earnings of unconsolidated entities — (95,907 ) 72,451 (56,716 ) 240 (79,932 ) Equity loss of unconsolidated entities, net of tax 73,071 (22,837 ) 58,014 297 (107,248 ) 1,297 Net loss $ (73,071 ) $ (73,070 ) $ 14,437 $ (57,013 ) $ 107,488 $ (81,229 ) Net loss attributable to non-controlling interest — — (8,398 ) — — (8,398 ) Net loss attributable to Endurance International Group Holdings, Inc. (73,071 ) (73,070 ) 22,835 (57,013 ) 107,488 (72,831 ) Comprehensive loss: — Foreign currency translation adjustments — — — (597 ) — (597 ) Unrealized gain (loss) on cash flow hedge (1,351 ) — — — (1,351 ) Total comprehensive loss $ (73,071 ) $ (74,421 ) $ 22,835 $ (57,610 ) $ 107,488 $ (74,779 )
Condensed Consolidated Statements of Cash Flows	Condensed Consolidating Statements of Cash Flows Year Ended December 31, 2014 (in thousands) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided by (used in) operating activities $ (1 ) $ (63,853 ) $ 215,212 $ (8,465 ) — $ 142,893 Cash flows from investing activities: Businesses acquired in purchase transaction, net of cash acquired — — (69,578 ) (24,120 ) — (93,698 ) Purchases of property and equipment — — (22,850 ) (1,054 ) — (23,904 ) Cash paid for minority investments — — (34,140 ) — — (34,140 ) Proceeds from sale of property and equipment — — 39 55 — 94 Proceeds from sale of assets — — 100 — — 100 Purchases of intangible assets — — (200 ) — — (200 ) Net (deposits) and withdrawals of principal balances in restricted cash accounts — — 191 242 — 433 Net cash used in investing activities — — (126,438 ) (24,877 ) — (151,315 ) Cash flows from financing activities: Proceeds from issuance of notes payable and draws on revolver — 150,000 — — — 150,000 Repayment of notes payable and revolver — (110,500 ) — — — (110,500 ) Payment of financing costs — (53 ) — — — (53 ) Payment of deferred consideration — — (41,244 ) (57,074 ) — (98,318 ) Payment of redeemable non-controlling interest liability — — (4,190 ) — — (4,190 ) Principal payments on capital lease obligations — — (3,608 ) — — (3,608 ) Proceeds from exercise of stock options 137 — — — — 137 Proceeds from issuance of common stock 43,500 — — — — 43,500 Issuance costs of common stock (2,904 ) — — — — (2,904 ) Intercompany loans and investments (40,731 ) (7,126 ) (46,073 ) 93,930 — — Net cash provided by (used in) financing activities 2 32,321 (95,115 ) 36,856 — (25,936 ) Net effect of exchange rate on cash and cash equivalents — — — (78 ) — (78 ) Net increase (decrease) in cash and cash equivalents 1 (31,532 ) (6,341 ) 3,436 — (34,436 ) Cash and cash equivalents: Beginning of period — 35,879 25,043 5,893 — $ 66,815 End of period $ 1 $ 4,347 $ 18,702 $ 9,329 $ — $ 32,379 Condensed Consolidating Statements of Cash Flows Year Ended December 31, 2015 (in thousands) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided by (used in) operating activities $ 2 $ (50,147 ) $ 220,468 6,905 — $ 177,228 Cash flows from investing activities: Businesses acquired in purchase transaction, net of cash acquired — — (92,376 ) (5,419 ) — (97,795 ) Purchases of property and equipment — — (28,058 ) (3,185 ) — (31,243 ) Cash paid for minority investments — — (8,475 ) — — (8,475 ) Proceeds from sale of property and equipment — — 51 42 — 93 Proceeds from note receivable — — 3,454 — — 3,454 Proceeds from sale of assets — — 191 — — 191 Purchases of intangible assets — — (76 ) — — (76 ) Net (deposits) and withdrawals of principal balances in restricted cash accounts — — (296 ) 346 — 50 Net cash used in investing activities — — (125,585 ) (8,216 ) — (133,801 ) Cash flows from financing activities: Proceeds from issuance of notes payable and draws on revolver — 147,000 — — — 147,000 Repayment of notes payable and revolver — (140,500 ) — — — (140,500 ) Payment of financing costs — — — — — — Payment of deferred consideration — — (14,503 ) (488 ) — (14,991 ) Payment of redeemable non-controlling interest liability — — (30,543 ) — — (30,543 ) Principal payments on capital lease obligations — — (4,822 ) — — (4,822 ) Proceeds from exercise of stock options 2,224 — — — — 2,224 Intercompany loans and investments (2,215 ) 39,367 (42,431 ) 5,279 — — Net cash provided by (used in) financing activities 9 45,867 (92,299 ) 4,791 — (41,632 ) Net effect of exchange rate on cash and cash equivalents — — — (1,144 ) — (1,144 ) Net increase (decrease) in cash and cash equivalents 11 (4,280 ) 2,584 2,336 — 651 Cash and cash equivalents: Beginning of period 1 4,347 18,702 9,329 — 32,379 End of period $ 12 $ 67 $ 21,286 $ 11,665 $ — $ 33,030 Condensed Consolidating Statements of Cash Flows Year Ended December 31, 2016 (in thousands) Parent Issuer Guarantor Subsidiaries Non-Guarantor Subsidiaries Eliminations Consolidated Net cash provided by (used in) operating activities $ (71,204 ) $ 256,461 (30,296 ) $ 154,961 Cash flows from investing activities: — — — — — Businesses acquired in purchase transaction, net of cash acquired — — (889,634 ) — — (889,634 ) Purchases of property and equipment — — (32,528 ) (4,731 ) — (37,259 ) Cash paid for minority investments — — (5,600 ) — — (5,600 ) Proceeds from sale of property and equipment — — 674 2 — 676 Proceeds from note receivable — — — — — — Proceeds from sale of assets — — — — — — Purchases of intangible assets — — (7 ) (20 ) — (27 ) Net (deposits) and withdrawals of principal balances in restricted cash accounts — — (347 ) (210 ) — (557 ) Net cash used in investing activities — — (927,442 ) (4,959 ) — (932,401 ) Cash flows from financing activities: Proceeds from issuance of notes payable and draws on revolver — 1,110,678 — — — 1,110,678 Repayment of notes payable and revolver — (176,700 ) — — — (176,700 ) Payment of financing costs — (52,561 ) — — — (52,561 ) Payment of deferred consideration — — (50,375 ) (669 ) — (51,044 ) Payment of redeemable non-controlling interest liability — — (33,425 ) — — (33,425 ) Principal payments on capital lease obligations — — (5,892 ) — — (5,892 ) Proceeds from exercise of stock options 2,564 — — — — 2,564 Capital investments from minority partner — — — 2,776 — 2,776 Intercompany loans and investments (2,573 ) (810,276 ) 778,421 34,428 — — Net cash provided by (used in) financing activities (9 ) 71,141 688,729 36,535 — 796,396 Net effect of exchange rate on cash and cash equivalents — — — 1,610 — 1,610 Net increase (decrease) in cash and cash equivalents (9 ) (63 ) 17,748 2,890 — 20,566 Cash and cash equivalents: Beginning of period 12 67 21,286 11,665 33,030 End of period $ 3 $ 4 $ 39,034 $ 14,555 $ — $ 53,596

Nature of Business - Additional

Nature of Business - Additional Information (Detail) - USD ($)	Mar. 11, 2015	Nov. 26, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Nov. 20, 2014
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Common stock, shares issued (in shares)			134,793,857	132,024,558
Net proceeds from issuance of common stock			$ 0	$ 0	$ 43,500,000
Stock issuance cost					$ 2,405,176
Follow-On Public Offering
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Common stock, shares issued (in shares)		3,000,000				13,000,000
Common stock, (in USD per share)	$ 19	$ 14.50
Number of shares sold by the selling stockholders (in shares)	12,000,000	10,000,000
Gross proceeds from issuance of common stock		$ 43,500,000
Net proceeds from issuance of common stock		41,100,000
Underwriting discounts and commissions		1,700,000
Stock issuance cost		$ 700,000
Over-Allotment Option
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of shares sold by the selling stockholders (in shares)	1,800,000	1,950,000
Selling Stockholders
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Stock issuance cost	$ 700,000	$ 300,000

Summary of Significant Accoun53

Summary of Significant Accounting Policies - Additional Information (Details)	1 Months Ended	12 Months Ended
	Feb. 29, 2016Segment	Dec. 31, 2016USD ($)Segment	Dec. 31, 2015USD ($)Segment	Dec. 31, 2014USD ($)	Jul. 27, 2016USD ($)	Apr. 08, 2016	Feb. 09, 2016USD ($)
Accounting Policies [Line Items]
Number of reportable segments | Segment	2	2	1
Software development cost capitalized		$ 11,800,000	$ 5,500,000	$ 5,400,000
Voting interest		20.00%
Impairment		$ 0	0
Goodwill		1,859,909,000	1,207,255,000	1,105,023,000
Impairment charges		0	0
Impairment of other long lived assets		$ 9,039,000	0	0
Contract service period		36 months
Reserves for refunds and chargebacks		$ 600,000	500,000
Deferred revenue expected to be refunded		$ 2,100,000	1,800,000
Percentage of deferred revenue refunded within same fiscal month		81.00%
Percentage of deferred revenue refunded within 45 days		94.00%
Sales and marketing costs		$ 303,511,000	145,419,000	146,797,000
Foreign currency transaction gains (losses)		1,800,000	1,900,000	800,000
Unrecognized tax benefits		0	0	0
Penalties and interest expense		0	0	$ 0
Amount of net operating loss carry-forwards available to offset future U.S. federal taxable income		40,600,000
Indemnification obligations claims outstanding		0
Indemnification obligations			$ 0
Fortifico Limited
Accounting Policies [Line Items]
Impairment charges on investments		$ 4,700,000
Ownership interest		33.00%				33.00%
Minimum
Accounting Policies [Line Items]
Percentage of voting interest		20.00%
Voting interest		20.00%
Fair value inputs, discount rate		11.00%
Maximum
Accounting Policies [Line Items]
Percentage of voting interest		50.00%
Voting interest		50.00%
Fair value inputs, discount rate		12.00%
Developed technology
Accounting Policies [Line Items]
Estimated useful life		7 years	7 years
In-process research and development
Accounting Policies [Line Items]
Impairment of other long lived assets		$ 2,200,000
Sales Revenue, Net | Customer Concentration Risk
Accounting Policies [Line Items]
Percentage of total revenue		10.00%	10.00%	10.00%
Constant Contact, Inc.
Accounting Policies [Line Items]
Goodwill		$ 604,305,000	$ 0	$ 0
Impairment of other long lived assets		2,000,000
Constant Contact, Inc. | Developed technology
Accounting Policies [Line Items]
In-process research and development capitalized							$ 83,000,000
Webzai Ltd
Accounting Policies [Line Items]
Impairment of other long lived assets		4,900,000
Webzai Ltd | Software Development
Accounting Policies [Line Items]
Impairment of other long lived assets		500,000
Webzai Ltd | Developed technology
Accounting Policies [Line Items]
Impairment of other long lived assets		4,400,000
Impairment of intangible assets (excluding goodwill)		4,400,000
Webzai Ltd | In-process research and development
Accounting Policies [Line Items]
Impairment of other long lived assets		1,400,000
Impairment of intangible assets (excluding goodwill)		$ 1,400,000
In-process research and development capitalized			3,200,000	$ 4,600,000
Estimated useful life		4 years
AppMachine
Accounting Policies [Line Items]
Ownership interest				40.00%
Goodwill					$ 21,500,000
AppMachine | Developed technology
Accounting Policies [Line Items]
In-process research and development capitalized		$ 900,000			1,700,000
Estimated useful life		4 years
AppMachine | In-process research and development
Accounting Policies [Line Items]
Impairment of other long lived assets		$ 800,000
Impairment of intangible assets (excluding goodwill)		800,000
In-process research and development capitalized		$ 1,700,000			$ 1,700,000
Email marketing
Accounting Policies [Line Items]
Percentage of fair value in excess of carrying amount of goodwill		35.00%
Web-presence
Accounting Policies [Line Items]
Percentage of fair value in excess of carrying amount of goodwill		67.00%
Accounting Standards Update 2016-09, Excess Tax Benefit Component [Member] | ASU 2016-09
Accounting Policies [Line Items]
Excess tax benefit amount		$ 900,000
Aggregate stock-based compensation expense		$ 900,000
Amount of net operating loss carry-forwards available to offset future U.S. federal taxable income			1,500,000
Amount of net operating loss carry-forwards available to offset future state taxable income			$ 700,000

Summary of Significant Accoun54

Summary of Significant Accounting Policies - Summary of Estimated Useful Lives (Details)	12 Months Ended
	Dec. 31, 2016
Building
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	35 years
Software | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	2 years
Software | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	3 years
Computers and office equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	3 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment useful life	5 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Leasehold improvements	Shorter of useful life or remaining term of the lease

Summary of Significant Accoun55

Summary of Significant Accounting Policies - Computation of Basic and Diluted Net Loss per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net income (loss) attributable to Endurance International Group Holdings, Inc.	$ (34,865)	$ (31,737)	$ (28,040)	$ 21,811	$ (9,232)	$ (15,351)	$ (2,071)	$ 884	$ (72,831)	$ (25,770)	$ (42,835)
Net loss per share attributable to Endurance International Group Holdings, Inc.—basic and diluted (in usd per share)									$ (0.55)	$ (0.20)	$ (0.34)
Weighted average number of common shares used in computing net loss per share attributable to Endurance International Group Holdings, Inc: Basic and diluted (in shares)									133,415,732	131,340,557	127,512,346
Accumulated Deficit
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Net income (loss) attributable to Endurance International Group Holdings, Inc.									$ (72,831)	$ (25,770)	$ (42,835)

Summary of Significant Accoun56

Summary of Significant Accounting Policies - Antidilutive Securities (Details) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	18,400,232	9,742,938	7,949,053
Restricted Stock Awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	8,019,241	3,019,349	2,512,755
Options Held
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	10,380,991	6,723,589	5,436,298

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail) - USD ($)	Jul. 27, 2016	Jul. 13, 2016	May 16, 2016	Feb. 09, 2016	Jan. 06, 2016	Dec. 02, 2015	Nov. 02, 2015	Oct. 30, 2015	Sep. 21, 2015	Jun. 25, 2015	May 26, 2015	Jul. 31, 2016	Dec. 31, 2014	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jul. 14, 2016	Aug. 31, 2014
Business Acquisition [Line Items]
Goodwill													$ 1,105,023,000	$ 1,859,909,000				$ 1,207,255,000				$ 1,859,909,000	$ 1,207,255,000	$ 1,105,023,000
Interest expense, net (including impact of amortization of deferred financing costs and original issuance discount)																						152,888,000	58,828,000	57,414,000
Investments														15,857,000				27,905,000				15,857,000	27,905,000
Loss of unconsolidated entities																						(1,297,000)	(14,640,000)	(61,000)
Goodwill acquired in year of purchase																						647,324,000	103,444,000
Revenue														292,123,000	$ 291,193,000	$ 290,713,000	$ 237,113,000	193,043,000	$ 188,523,000	$ 182,431,000	$ 177,318,000	1,111,142,000	741,315,000	629,845,000
Net loss																						(81,229,000)	(25,770,000)	(50,852,000)
Net loss attributable to Endurance International Group Holdings, Inc.														(34,865,000)	$ (31,737,000)	$ (28,040,000)	21,811,000	(9,232,000)	$ (15,351,000)	$ (2,071,000)	$ 884,000	(72,831,000)	(25,770,000)	(42,835,000)
Transaction expenses																						$ 32,284,000	9,582,000	4,787,000
Subscriber relationships
Business Acquisition [Line Items]
Weighted average useful life (in years)																						4 years 4 months 24 days
Trade-names
Business Acquisition [Line Items]
Weighted average useful life (in years)																						4 years 8 months 12 days
Developed technology
Business Acquisition [Line Items]
Weighted average useful life (in years)																						4 years 1 month 6 days
Verio
Business Acquisition [Line Items]
Business acquisition, estimated aggregate purchase price											$ 13,000,000
Business acquisition, cash paid											10,500,000											$ 2,400,000
Remaining consideration											2,500,000			50,000								50,000
Goodwill											1,200,000
Deferred revenue											1,400,000
Verio | Subscriber relationships
Business Acquisition [Line Items]
Long-lived intangible assets											13,100,000
Verio | Trade-names
Business Acquisition [Line Items]
Long-lived intangible assets											$ 100,000
World Wide Web Hosting, LLC
Business Acquisition [Line Items]
Business acquisition, estimated aggregate purchase price										$ 34,900,000
Business acquisition, cash paid										18,400,000												4,600,000
Remaining consideration										4,600,000
Goodwill										23,300,000
Deferred revenue										2,500,000
Cash payable										23,000,000
Contribution of investment interest										$ 11,900,000
Ownership interest										40.00%
Gain of unconsolidated entities										$ 5,400,000
Prepaid expense and other current assets										1,200,000
World Wide Web Hosting, LLC | Subscriber relationships
Business Acquisition [Line Items]
Long-lived intangible assets										11,000,000
World Wide Web Hosting, LLC | Trade-names
Business Acquisition [Line Items]
Long-lived intangible assets										$ 1,900,000
Ace Data Centers Inc
Business Acquisition [Line Items]
Business acquisition, estimated aggregate purchase price									$ 74,000,000
Business acquisition, cash paid									44,400,000													$ 31,400,000
Remaining consideration									31,500,000
Goodwill									62,200,000
Prepaid expense and other current assets									200,000
Working capital adjustment determination period from closing date of acquisition																						75 days
Additional consideration														700,000								$ 700,000
Interest expense, net (including impact of amortization of deferred financing costs and original issuance discount)																							700,000
Net present value of remaining consideration						$ 28,900,000																	29,600,000
Property and equipment									12,100,000
Other liabilities									600,000
Ace Data Centers Inc | Developed technology
Business Acquisition [Line Items]
Long-lived intangible assets									$ 100,000
Ecommerce, LLC
Business Acquisition [Line Items]
Business acquisition, estimated aggregate purchase price							$ 28,000,000
Business acquisition, cash paid							23,800,000
Remaining consideration							4,200,000
Goodwill							16,700,000
Deferred revenue							2,600,000
Ecommerce, LLC | Subscriber relationships
Business Acquisition [Line Items]
Long-lived intangible assets							9,400,000
Ecommerce, LLC | Trade-names
Business Acquisition [Line Items]
Long-lived intangible assets							100,000
Ecommerce, LLC | Intellectual property
Business Acquisition [Line Items]
Long-lived intangible assets							$ 4,400,000
WZ (UK) Ltd.
Business Acquisition [Line Items]
Business acquisition, estimated aggregate purchase price		$ 18,000,000	$ 15,400,000		$ 22,200,000							$ 25,000,000
Goodwill					21,600,000
Deferred revenue					$ 3,300,000
Ownership interest			77.50%		57.50%																				86.40%	49.00%
Property and equipment					$ 300,000
Investments																										$ 3,900,000
Redeemable noncontrolling interest, equity, fair value					10,800,000
Loss of unconsolidated entities					11,400,000
Negative net working capital					1,300,000
Exercised call option					30,000,000
Percentage of additional stake acquired		76.40%	20.00%																						10.00%
Noncontrolling interest, ownership percentage																									13.60%
WZ (UK) Ltd. | Subscriber relationships
Business Acquisition [Line Items]
Long-lived intangible assets					$ 4,900,000
Constant Contact, Inc.
Business Acquisition [Line Items]
Business acquisition, estimated aggregate purchase price				$ 1,100,000,000				$ 1,100,000,000
Goodwill													$ 0	604,305,000				$ 0				604,305,000	0	$ 0
Deferred revenue				25,200,000
Property and equipment				39,600,000
Issuance of common stock (in USD per share)								$ 32
Working capital				184,200,000
Goodwill acquired in year of purchase				604,300,000																		604,305,000	0
Deferred tax liabilities				125,100,000
Unaudited pro forma revenue																						1,200,000,000	1,100,000,000
Unaudited pro forma net loss																						59,100,000	$ 107,800,000
Acquisition related costs																	$ 31,100,000
Equity, fair value adjustment																						16,800,000
Constant Contact, Inc. | Subscriber relationships
Business Acquisition [Line Items]
Long-lived intangible assets				263,000,000
Constant Contact, Inc. | Trade-names
Business Acquisition [Line Items]
Long-lived intangible assets				52,000,000
Constant Contact, Inc. | Developed technology
Business Acquisition [Line Items]
Long-lived intangible assets				$ 83,000,000
AppMachine
Business Acquisition [Line Items]
Business acquisition, estimated aggregate purchase price	$ 22,500,000
Business acquisition, cash paid	5,500,000
Goodwill	21,500,000
Deferred revenue	200,000
Ownership interest													40.00%											40.00%
Interest expense, net (including impact of amortization of deferred financing costs and original issuance discount)	1,500,000
Net present value of remaining consideration	11,500,000
Property and equipment	600,000
Other liabilities	$ 100,000
Investments													$ 15,200,000											$ 15,200,000
Percentage of additional stake acquired	60.00%												60.00%											60.00%
Percentage of stock ownership	100.00%
Working capital	$ 400,000
Periodic payment on equity method investment, percentage													20.00%
Deferred consideration	17,000,000
Acquisition related costs	$ 4,000,000
Acquisition payment period	4 years
Recognized loss due to fair value of investment	$ 4,900,000
Business Combination, Consideration Transferred, Including Equity Interest in Acquiree Held Prior to Combination	25,700,000
Deferred consideration payable	13,000,000
Carrying value of investment	13,600,000
AppMachine | Subscriber relationships
Business Acquisition [Line Items]
Long-lived intangible assets	100,000
AppMachine | Developed technology
Business Acquisition [Line Items]
Long-lived intangible assets	1,700,000													900,000								900,000
AppMachine | In-process research and development
Business Acquisition [Line Items]
Long-lived intangible assets	$ 1,700,000													$ 1,700,000								1,700,000
2016 Acquisitions
Business Acquisition [Line Items]
Revenue																						340,900,000
Net loss attributable to Endurance International Group Holdings, Inc.																						(46,000,000)
Acquisition related costs																						15,500,000
Application of purchase accounting | Constant Contact, Inc.
Business Acquisition [Line Items]
Revenue																						15,200,000
Restructuring charges | Constant Contact, Inc.
Business Acquisition [Line Items]
Net loss																						$ 22,200,000

Acquisitions - Summary of Defer

Acquisitions - Summary of Deferred Consideration Related to Acquisition (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Deferred consideration short-term	$ 5,273	$ 51,488
Deferred consideration	7,444	813
Mojoness Inc
Business Acquisition [Line Items]
Deferred consideration short-term	818	657
Deferred consideration	0	813
Typepad Holdings LLC
Business Acquisition [Line Items]
Deferred consideration short-term		2,800
Deferred consideration		0
Webzai Ltd
Business Acquisition [Line Items]
Deferred consideration short-term		2,848
Deferred consideration		0
BuyDomains
Business Acquisition [Line Items]
Deferred consideration short-term		4,283
Deferred consideration		0
Verio
Business Acquisition [Line Items]
Deferred consideration short-term	50	2,474
Deferred consideration	0	0
World Wide Web Hosting, LLC
Business Acquisition [Line Items]
Deferred consideration short-term		4,600
Deferred consideration		0
Ace Data Centers Inc
Business Acquisition [Line Items]
Deferred consideration short-term		29,626
Deferred consideration		0
Ecommerce, LLC
Business Acquisition [Line Items]
Deferred consideration short-term		4,200
Deferred consideration		$ 0
Social Booster
Business Acquisition [Line Items]
Deferred consideration short-term	40
Deferred consideration	25
AppMachine
Business Acquisition [Line Items]
Deferred consideration short-term	4,365
Deferred consideration	$ 7,419

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred consideration short-term	$ 5,273	$ 51,488
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payment of contingent earn-out related to acquisition	668	10,592
Mojoness Inc
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred consideration short-term	818	657
Mojoness Inc | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payment of contingent earn-out related to acquisition	$ 700	500	$ 200
Domain Name Business
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Change in fair value of the earn-out consideration		1,200	400
Domain Name Business | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payment of contingent earn-out related to acquisition		$ 10,100	14,000
Deferred consideration short-term			$ 23,000

Fair Value Measurements - Basis

Fair Value Measurements - Basis of Fair Value Measurements (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financial assets:
Interest rate cap (included in other assets)	$ 979	$ 3,130
Total financial assets	979	3,130
Financial liabilities:
Contingent earn-out consideration	818	1,469
Total financial liabilities	818	1,469
Fair Value, Inputs, Level 1
Financial assets:
Interest rate cap (included in other assets)	0	0
Total financial assets	0	0
Financial liabilities:
Contingent earn-out consideration	0	0
Total financial liabilities	0	0
Significant Other Observable Inputs (Level 2)
Financial assets:
Interest rate cap (included in other assets)	979	3,130
Total financial assets	979	3,130
Financial liabilities:
Contingent earn-out consideration	0	0
Total financial liabilities	0	0
Significant Unobservable Inputs (Level 3)
Financial assets:
Interest rate cap (included in other assets)	0	0
Total financial assets	0	0
Financial liabilities:
Contingent earn-out consideration	818	1,469
Total financial liabilities	$ 818	$ 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) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Financial liabilities measured using Level 3 inputs , Opening balance	$ 1,469	$ 10,887
Payment of contingent earn-out related to 22012 and 2014 acquisitions	(668)	(10,592)
Change in fair value of contingent earn-outs	17	1,174
Financial liabilities measured using Level 3 inputs, Ending balance	$ 818	$ 1,469

Derivatives And Hedging Activ62

Derivatives And Hedging Activities - Additional Information (Detail)	Dec. 09, 2015	Dec. 31, 2016USD ($)agreement	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate cap agreement period	3 years
Gain on interest rate cash flow hedge ineffectiveness		$ 0
Unrealized gain (loss) on cash flow hedge, net of taxes of $0, $46, and ($792) for the years ended December 31, 2014, 2015 and 2016		1,351,000	$ (80,000)	$ 0
AOCI tax, attributable to parent		800,000
Reclassification out of Accumulated Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative gain to be reclassified as increase to interest expense in the next twelve months		600,000
Cash Flow Hedging | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Recognized gain		$ 100,000
Cash Flow Hedging | Interest Rate Cap
Derivative Instruments, Gain (Loss) [Line Items]
Number of interest rate cap agreements | agreement		1
Notional amount outstanding		$ 500,000,000
Fair Value, Measurements, Recurring
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate cap (included in other assets)		$ 979,000	$ 3,130,000

Property and Equipment - Compon

Property and Equipment - Components of Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property and equipment—at cost	$ 240,355	$ 162,649
Less accumulated depreciation	(145,083)	(86,887)
Property and equipment—net	95,272	75,762
Land
Property, Plant and Equipment [Line Items]
Property and equipment—at cost	790	713
Building
Property, Plant and Equipment [Line Items]
Property and equipment—at cost	5,517	5,091
Software
Property, Plant and Equipment [Line Items]
Property and equipment—at cost	52,130	40,336
Computers and office equipment
Property, Plant and Equipment [Line Items]
Property and equipment—at cost	143,091	97,332
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment—at cost	10,892	5,914
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment—at cost	21,244	7,126
Construction in process
Property, Plant and Equipment [Line Items]
Property and equipment—at cost	$ 6,691	$ 6,137

Property and Equipment - Additi

Property and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Depreciation	$ 60,360	$ 34,010	$ 30,956
Minimum
Property, Plant and Equipment [Line Items]
Term of lease	36 months
Maximum
Property, Plant and Equipment [Line Items]
Term of lease	39 months
Constant Contact, Inc. | Engineering And Development
Property, Plant and Equipment [Line Items]
Impaired software	$ 2,000
Webzai Ltd | Engineering And Development
Property, Plant and Equipment [Line Items]
Impaired software	$ 500

Property and Equipment - Summar

Property and Equipment - Summary of Software Assets under Capital Lease (Detail) - Software - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Software	$ 21,499	$ 21,499
Less accumulated depreciation	(14,750)	(8,412)
Assets under capital lease—net	$ 6,749	$ 13,087

Property and Equipment - Summ66

Property and Equipment - Summary of Future Minimum Lease Payments under Capital Lease (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
2,017	$ 6,895
2,018	575
Total minimum lease payments	7,470
Less amount representing interest	(268)
Present value of minimum lease payments (capital lease obligation)	7,202
Current portion	6,690	$ 5,866
Long-term portion	$ 512	$ 7,215

Goodwill and Other Intangible67

Goodwill and Other Intangible Assets - Changes in Goodwill Balances (Detail) - USD ($)	Feb. 09, 2016	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Goodwill, beginning balance		$ 1,207,255,000	$ 1,105,023,000
Goodwill adjustments related to prior period acquisition		5,978,000
Goodwill acquired in year of purchase		647,324,000	103,444,000
Foreign translation impact		(648,000)	(1,212,000)
Impairment		0	0
Goodwill, ending balance		1,859,909,000	1,207,255,000
Flagship Unit
Goodwill [Roll Forward]
Goodwill, beginning balance		1,207,255,000	1,105,023,000
Goodwill adjustments related to prior period acquisition		5,978,000
Goodwill acquired in year of purchase		43,019,000	103,444,000
Foreign translation impact		(648,000)	(1,212,000)
Goodwill, ending balance		1,255,604,000	1,207,255,000
Constant Contact, Inc.
Goodwill [Roll Forward]
Goodwill, beginning balance		0	0
Goodwill adjustments related to prior period acquisition		0
Goodwill acquired in year of purchase	$ 604,300,000	604,305,000	0
Foreign translation impact		0	0
Goodwill, ending balance		$ 604,305,000	$ 0

Goodwill and Other Intangible68

Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,141,824,000	$ 749,139,000
Impairment	0	0
Amortization of other intangible assets	143,562,000	91,057,000	$ 102,723,000
In-process research and development
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		1,438,000
Developed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	284,005,000	$ 205,925,000
Webzai Ltd | In-process research and development
Finite-Lived Intangible Assets [Line Items]
Impairment of intangible assets (excluding goodwill)	1,400,000
Webzai Ltd | Developed technology
Finite-Lived Intangible Assets [Line Items]
Impairment of intangible assets (excluding goodwill)	4,400,000
AppMachine | In-process research and development
Finite-Lived Intangible Assets [Line Items]
Impairment of intangible assets (excluding goodwill)	$ 800,000

Goodwill and Other Intangible69

Goodwill and Other Intangible Assets - Summary of Other Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,141,824	$ 749,139
Accumulated Amortization	529,767	389,353
Net Carrying Amount	612,057	359,786
Developed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	284,005	205,925
Accumulated Amortization	111,348	80,795
Net Carrying Amount	$ 172,657	$ 125,130
Weighted Average Useful Life	7 years	7 years
Subscriber relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 659,662	$ 397,791
Accumulated Amortization	345,070	256,461
Net Carrying Amount	$ 314,592	$ 141,330
Weighted Average Useful Life	7 years	5 years
Trade-names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 133,805	$ 81,792
Accumulated Amortization	57,789	42,080
Net Carrying Amount	$ 76,016	$ 39,712
Weighted Average Useful Life	8 years	6 years
Intellectual property
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 34,084	$ 34,020
Accumulated Amortization	10,270	6,596
Net Carrying Amount	$ 23,814	$ 27,424
Weighted Average Useful Life	13 years	13 years
Leasehold interests
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 314	$ 314
Accumulated Amortization	314	314
Net Carrying Amount	$ 0	$ 0
Weighted Average Useful Life	1 year	1 year
In-process research and development
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount		$ 1,438
Accumulated Amortization		0
Net Carrying Amount		1,438
Domain names available for sale
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 29,954	27,859
Accumulated Amortization	4,976	3,107
Net Carrying Amount	$ 24,978	$ 24,752
Weighted Average Useful Life	Indefinite	Indefinite

Goodwill and Other Intangible70

Goodwill and Other Intangible Assets - Summary of Expected Future Amortization of Other Intangible Assets (Detail) $ in Thousands	Dec. 31, 2016USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2,017	$ 137,000
2,018	103,000
2,019	86,000
2,020	72,000
2,021	62,000
Thereafter	127,000
Total	$ 587,000

Investments - Additional Inform

Investments - Additional Information (Detail) - USD ($) $ in Thousands	Jun. 25, 2015	Jun. 24, 2015	Oct. 31, 2013	Dec. 31, 2014	May 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Apr. 08, 2016	Mar. 03, 2016	Jan. 06, 2016	Dec. 21, 2015	Jul. 02, 2015	Aug. 31, 2014	Jul. 31, 2012	Jan. 31, 2012
Schedule of Cost-method Investments [Line Items]
Investments						$ 15,857	$ 27,905
Accounts payable						16,074	12,280
Proceeds from note receivable						0	3,454	$ 0
Loss of unconsolidated entities						$ 1,297	$ 14,640	61
Voting interest						20.00%
Proportionate share exceed of the company's consolidated assets or income							10.00%
Bluezone Labs, LLC
Schedule of Cost-method Investments [Line Items]
Investments																$ 300
Ownership interest																25.00%
Purchase of products and services						$ 1,600	$ 1,100
Accounts payable						$ 100	100
World Wide Web Hosting, LLC
Schedule of Cost-method Investments [Line Items]
Investments															$ 10,000
Ownership interest	40.00%		40.00%												50.00%
Ownership interest percentage			20.00%
Percentage of companies capital stock sold			10.00%
Contribution of investment interest	$ 11,900
Gain of unconsolidated entities							$ 5,400
Proceeds from note receivable		$ 3,500
WZ UK Ltd.
Schedule of Cost-method Investments [Line Items]
Investments														$ 3,900
Ownership interest											57.50%			49.00%
Rate on royalty on billing							4.50%
Royalty revenue							$ 400	0
Loss of unconsolidated entities							13,900	200
Increase (decrease) in investment												$ 1,100	$ 7,400
Assets reported in equity method investment							2,100
Liabilities reported in equity method investment							$ 6,700
AppMachine
Schedule of Cost-method Investments [Line Items]
Investments				$ 15,200				$ 15,200
Ownership interest				40.00%				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				60.00%
Web and Money Management Solution
Schedule of Cost-method Investments [Line Items]
Interest note receivable										$ 600
Fortifico Limited
Schedule of Cost-method Investments [Line Items]
Investments									$ 5,000
Ownership interest						33.00%			33.00%
Impairment on the remaining investment						$ 4,700
Minimum
Schedule of Cost-method Investments [Line Items]
Voting interest						20.00%
Minimum | WZ UK Ltd.
Schedule of Cost-method Investments [Line Items]
Proportionate share of company's income from continuing operations						20.00%
Maximum
Schedule of Cost-method Investments [Line Items]
Voting interest						50.00%
Automattic
Schedule of Cost-method Investments [Line Items]
Investment made on asset					$ 15,000
Percentage of outstanding shares invested					5.00%

Investments - Summary of Statem

Investments - Summary of Statement of Operations and Comprehensive Loss for Equity Method Investment (Detail) - WZ UK Ltd. - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Revenue	$ 4,053	$ 1
Gross profit (loss)	1,095	(96)
Operating loss	(28,439)	(694)
Net loss	$ (28,439)	$ (694)

Notes Payable - Additional Info

Notes Payable - Additional Information (Detail) - USD ($)	Sep. 30, 2016	Feb. 28, 2016	Feb. 09, 2016	Nov. 30, 2013	Feb. 08, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jan. 30, 2017	Feb. 29, 2016
Long-Term Debt [Line Items]
Mandatory repayments on term loan						$ 55,200,000	$ 10,500,000	$ 10,500,000
Current portion of notes payable						$ 35,700,000	$ 77,500,000
Non-refundable fee-unused facility						0.50%	0.50%	0.50%
Interest expense, net (including impact of amortization of deferred financing costs and original issuance discount)						$ 152,888,000	$ 58,828,000	$ 57,414,000
Revolving Credit Facility
Long-Term Debt [Line Items]
Aggregate principal amount not to exceed			$ 165,000,000	$ 125,000,000		165,000,000				$ 165,000,000
Incremental First Lien Term Loan
Long-Term Debt [Line Items]
Mandatory repayments on term loan	$ 3,700,000
Notes payable amount outstanding			$ 735,000,000
Loan maturity period			7 years
Debt instrument issue price			97.00%
Financing fee			1.00%
Debt amortization rate			0.50%
Aggregate principal amount not to exceed										735,000,000
November 2013 First Lien
Long-Term Debt [Line Items]
First lien term loan outstanding				$ 1,050,000,000
Mandatory repayments on term loan						30,000,000	2,600,000
Current portion of notes payable						$ 10,500,000	$ 10,500,000
Bank Revolver Loans 7.75%
Long-Term Debt [Line Items]
Interest at LIBOR based rates							7.75%
Principal amount of term loan outstanding							$ 67,000,000
Bank Revolver Loans 8.50%
Long-Term Debt [Line Items]
Interest at LIBOR based rates							8.50%
Principal amount of term loan outstanding							$ 8,000,000
Senior Notes
Long-Term Debt [Line Items]
Interest at LIBOR based rates						10.875%	0.00%	0.00%
Debt instrument issue price			98.065%			101.00%
Senior notes			$ 350,000,000							$ 350,000,000
LIBOR Based Interest Rate Loan
Long-Term Debt [Line Items]
LIBOR based interest rate reduced					4.00%
Greater of the LIBOR rate					1.00%
LIBOR Based Interest Rate Loan | Revolving Credit Facility
Long-Term Debt [Line Items]
Greater of the LIBOR rate			4.00%
Basis spread on variable rate				6.25%
LIBOR Based Interest Rate Loan | First Lien
Long-Term Debt [Line Items]
Greater of the LIBOR rate		5.48%	5.23%
LIBOR Based Interest Rate Loan | Incremental First Lien Term Loan
Long-Term Debt [Line Items]
Greater of the LIBOR rate			5.00%
Mandatory repayments on term loan						$ 14,700,000
Reference Rate Loan | Revolving Credit Facility
Long-Term Debt [Line Items]
Greater of the LIBOR rate			3.00%
Reference Rate Loan | First Lien
Long-Term Debt [Line Items]
Greater of the LIBOR rate		4.48%	4.23%
Reference Rate Loan | November 2013 First Lien
Long-Term Debt [Line Items]
Debt instrument reference rate					3.00%
Percentage points added to federal funds effective rate				0.50%	0.50%
Adjusted LIBOR rate		2.00%			2.00%
Reference Rate Loan | Incremental First Lien Term Loan
Long-Term Debt [Line Items]
Adjusted LIBOR rate			4.00%
Alternate Base Rate Loan
Long-Term Debt [Line Items]
Non-refundable fee-unused facility				0.50%
Alternate Base Rate Loan | Revolving Credit Facility
Long-Term Debt [Line Items]
Debt instrument reference rate				5.25%
Adjusted LIBOR rate				2.25%
Debt instrument basis spread on LIBOR rate				1.50%
Revolving Credit Facility
Long-Term Debt [Line Items]
Line of credit facility, commitment fee percent			0.50%
London Interbank Offered Rate (LIBOR) | First Lien
Long-Term Debt [Line Items]
Interest at LIBOR based rates					5.00%
London Interbank Offered Rate (LIBOR) | Bank Revolver Loans 7.75%
Long-Term Debt [Line Items]
Principal amount of term loan outstanding							$ 59,000,000
Minimum | Revolving Credit Facility
Long-Term Debt [Line Items]
Debt extension period			91 days
Minimum | LIBOR Based Interest Rate Loan | Incremental First Lien Term Loan
Long-Term Debt [Line Items]
Basis spread on variable rate			1.00%
Minimum | Reference Rate Loan | November 2013 First Lien
Long-Term Debt [Line Items]
Adjusted LIBOR rate			2.00%
Minimum | Reference Rate Loan | Incremental First Lien Term Loan
Long-Term Debt [Line Items]
Adjusted LIBOR rate			2.00%
Minimum | London Interbank Offered Rate (LIBOR)
Long-Term Debt [Line Items]
Basis spread on variable rate		1.00%	1.00%
Subsequent Event | Senior Notes
Long-Term Debt [Line Items]
Senior notes									$ 350,000,000

Notes Payable - Schedule of Lon

Notes Payable - Schedule of Long Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Long-Term Debt [Line Items]
Notes Payable	$ 1,986,980	$ 1,092,385
Current portion of Notes Payable	35,700	77,500
Notes Payable - long-term	1,951,280	1,014,885
First Lien Term Loan
Long-Term Debt [Line Items]
Notes Payable	985,640	1,025,385
Current portion of Notes Payable	21,000	10,500
Notes Payable - long-term	964,640	1,014,885
Incremental First Lien Term Loan
Long-Term Debt [Line Items]
Notes Payable	674,860	0
Current portion of Notes Payable	14,700
Notes Payable - long-term	660,160
Senior Notes
Long-Term Debt [Line Items]
Notes Payable	326,480	0
Current portion of Notes Payable	0
Notes Payable - long-term	326,480
Revolving Credit Facilities
Long-Term Debt [Line Items]
Notes Payable	$ 0	$ 67,000

Notes Payable - Schedule of Fir

Notes Payable - Schedule of First Lien Term Loan (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Long-Term Debt [Line Items]
Notes payable, gross	$ 2,056,175
Unamortized deferred financing costs	(25,853)	$ 0
Net notes payable	1,986,980	1,092,385
Current portion of Notes Payable	35,700	77,500
Notes Payable - long-term	1,951,280	1,014,885
First Lien Term Loan
Long-Term Debt [Line Items]
Notes payable, gross	985,875	1,026,375
Unamortized deferred financing costs	(235)	(990)
Net notes payable	985,640	1,025,385
Current portion of Notes Payable	21,000	10,500
Notes Payable - long-term	$ 964,640	$ 1,014,885

Notes Payable - Schedule of Inc

Notes Payable - Schedule of Incremental First Lien Term Loan (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Long-Term Debt [Line Items]
Notes payable, gross	$ 2,056,175
Unamortized deferred financing costs	(25,853)	$ 0
Unamortized original issue discounts	(43,342)	(990)
Net notes payable	1,986,980	1,092,385
Current portion of Notes Payable	35,700	77,500
Notes Payable - long-term	1,951,280	1,014,885
Incremental First Lien Term Loan
Long-Term Debt [Line Items]
Notes payable, gross	720,300
Unamortized deferred financing costs	(25,869)
Unamortized original issue discounts	(19,571)
Net notes payable	674,860	$ 0
Current portion of Notes Payable	14,700
Notes Payable - long-term	$ 660,160

Notes Payable - Schedule of Sen

Notes Payable - Schedule of Senior Notes (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Long-Term Debt [Line Items]
Notes payable, gross	$ 2,056,175
Unamortized deferred financing costs	(25,853)	$ 0
Unamortized original issue discounts	(43,342)	(990)
Net notes payable	1,986,980	1,092,385
Current portion of Notes Payable	35,700	77,500
Notes Payable - long-term	1,951,280	1,014,885
Senior Notes
Long-Term Debt [Line Items]
Notes payable, gross	350,000
Unamortized deferred financing costs	(17,238)
Unamortized original issue discounts	(6,282)
Net notes payable	326,480	$ 0
Current portion of Notes Payable	0
Notes Payable - long-term	$ 326,480

Notes Payable - Summary of Matu

Notes Payable - Summary of Maturity of the Notes Payable (Detail) $ in Thousands	Dec. 31, 2016USD ($)
Debt Disclosure [Abstract]
2,017	$ 35,700
2,018	35,700
2,019	958,575
2,020	14,700
2,021	14,700
Thereafter	996,800
Total	$ 2,056,175

Notes Payable - Schedule of Int

Notes Payable - Schedule of Interest Rates and Interest Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Long-Term Debt [Line Items]
Interest rate-reference		8.50%	8.50%
Non-refundable fee-unused facility	0.50%	0.50%	0.50%
Interest expense and service fees	$ 140,470	$ 56,760	$ 56,247
Amortization of deferred financing fees	6,073	82	83
Amortization of original issuance discount	2,970	0	0
Amortization of net present value of deferred consideration	2,617	1,264	183
Other interest expense	758	722	901
Total interest expense	$ 152,888	$ 58,828	$ 57,414
Minimum
Long-Term Debt [Line Items]
Interest rate-LIBOR	4.49%	5.00%	5.00%
Interest rate-reference	6.75%
Maximum
Long-Term Debt [Line Items]
Interest rate-LIBOR	7.75%	7.75%	7.75%
Interest rate-reference	8.75%
Senior Notes
Long-Term Debt [Line Items]
Interest at LIBOR based rates	10.875%	0.00%	0.00%

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016vote$ / sharesshares	Dec. 31, 2015$ / sharesshares
Equity [Abstract]
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, par value (in usd per share) | $ / shares	$ 0.0001	$ 0.0001
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, par value (in usd per share) | $ / shares	$ 0.0001	$ 0.0001
Number of vote per share | vote	1

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail)	Feb. 16, 2016shares	Feb. 09, 2016USD ($)$ / sharesshares	Oct. 30, 2015USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2016USD ($)position$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2014USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cumulative effect of new accounting principle in period of adoption					$ 0		$ 0
Amount of net operating loss carry-forwards available to offset future U.S. federal taxable income						$ 40,600,000
Tax benefit from compensation expense						$ 19,200,000	$ 9,300,000	$ 4,600,000
Common stock, par value (in usd per share) | $ / shares					$ 0.0001	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares) | shares					500,000,000	500,000,000	500,000,000
2012 Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested period of award shares						4 years
Number of shares of common stock with accelerated vesting (in shares) | shares						2,167,870
Number of shares of common stock with modified vesting (in shares) | shares						3,574,637
Number of shares of common stock fully vested (in shares) | shares						2,580,271
Number of shares of common stock with modified vesting that vest as vesting schedule of time-based stock awards (in shares) | shares						994,366
2013 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares issued (in share) | shares						38,000,000
Shares available for grant (in shares) | shares						16,964,969
Stock options vesting period						4 years
Aggregate intrinsic value, outstanding						$ 205,000
2013 Stock Incentive Plan | Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options vesting period						4 years
Granted (in shares) | shares						3,355,341
Unrecognized stock-based compensation expense						$ 40,600,000
Weighted average period to be recognized						2 years
2013 Stock Incentive Plan | Performance-Based Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate stock-based compensation expense						$ 4,100,000
Percentage of weighted adjusted revenue required to earn share awards						50.00%
Percentage of weighted adjusted EBITDA required to earn share awards						25.00%
Percentage of weighted adjusted free cash flow required to earn share awards						25.00%
2013 Stock Incentive Plan | Stock Option Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized stock-based compensation expense						$ 29,500,000
Weighted average period to be recognized						2 years 4 months 24 days
2013 Stock Incentive Plan | Chief Financial Officer | Performance-Based Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares) | shares	223,214
Award shares granted for vesting, target (in shares) | shares	178,571
2013 Stock Incentive Plan | Chief Executive Officer | Performance-Based Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate stock-based compensation expense						$ 6,800,000
Vested period of award shares						3 years
Granted (in shares) | shares					184,115	1,003,600	3,693,754
2013 Stock Incentive Plan | Chief Operating Officer | Performance-Based Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares) | shares	260,416
Award shares granted for vesting, target (in shares) | shares	208,333
2013 Stock Incentive Plan | Chief Administrative Officer | Performance-Based Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares) | shares	148,810
Award shares granted for vesting, target (in shares) | shares	119,048
Constant Contact 2011 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares issued (in share) | shares		10,000,000
Common stock, shares authorized (in shares) | shares						9,278,088
Aggregate intrinsic value, outstanding		$ 22,300,000				$ 2,606,000
Business acquisition, estimated aggregate purchase price		$ 5,400,000
Constant Contact 2011 Stock Plan | Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested period of award shares						4 years
Granted (in shares) | shares						3,154,897
Options outstanding, period increase (decrease) | shares		2,202,846
Unrecognized stock-based compensation expense						$ 10,300,000
Weighted average period to be recognized						2 years 7 months 6 days
Constant Contact 2011 Stock Plan | Stock Option Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate stock-based compensation expense				$ 16,900,000
Options outstanding, period increase (decrease) | shares		2,143,987
Unrecognized stock-based compensation expense						$ 5,000,000
Weighted average period to be recognized						2 years 8 months 12 days
Combined 2016 Liability Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate stock-based compensation expense						$ 700,000
2016 Liability Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees awarded liability award | position						1,000
Sales and marketing | Combined 2016 Liability Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate stock-based compensation expense						$ 300,000
Engineering and development | Combined 2016 Liability Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate stock-based compensation expense						100,000
General and administrative | Combined 2016 Liability Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate stock-based compensation expense						300,000
Constant Contact, Inc.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, par value (in usd per share) | $ / shares		$ 0.01
Business acquisition, estimated aggregate purchase price		$ 1,100,000,000	$ 1,100,000,000
Accounting Standards Update 2016-09, Excess Tax Benefit Component [Member] | ASU 2016-09
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Excess tax benefit amount						900,000
Amount of net operating loss carry-forwards available to offset future U.S. federal taxable income					$ 1,500,000		$ 1,500,000
Amount of net operating loss carry-forwards available to offset future state taxable income					$ 700,000		$ 700,000
Aggregate stock-based compensation expense						$ 900,000

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Restricted Stock Awards and Restricted Stock Units (Detail)	12 Months Ended
	Dec. 31, 2016$ / sharesshares
Restricted Stock Awards | 2012 Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Non-vested, beginning balance (in shares)	46,645
Vested (in shares)	(46,645)
Canceled (in shares)	0
Non-vested, ending balance (in shares)	0
Restricted Stock Awards | Constant Contact 2011 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Non-vested, beginning balance (in shares)	0
Granted (in shares)	3,154,897
Vested (in shares)	(1,266,771)
Canceled (in shares)	(414,471)
Non-vested, ending balance (in shares)	1,473,655
Weighted Average Grant Date Fair Value
Weighted average grant date fair value, non-vested, beginning balance (in usd per share) | $ / shares	$ 0
Weighted average grant date fair value, granted (in usd per share) | $ / shares	8.49
Weighted average grant date fair value, vested and unissued (in usd per share) | $ / shares	7.69
Weighted average grant date fair value, canceled (in usd per share) | $ / shares	8.26
Weighted average grant date fair value, non-vested, ending balance (in usd per share) | $ / shares	$ 9.25
Restricted Stock Awards | 2013 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Non-vested, beginning balance (in shares)	4,849,290
Granted (in shares)	3,355,341
Vested (in shares)	(613,751)
Canceled (in shares)	(258,343)
Non-vested, ending balance (in shares)	7,332,537
Weighted Average Grant Date Fair Value
Weighted average grant date fair value, non-vested, beginning balance (in usd per share) | $ / shares	$ 15.24
Weighted average grant date fair value, granted (in usd per share) | $ / shares	10.36
Weighted average grant date fair value, vested and unissued (in usd per share) | $ / shares	13.84
Weighted average grant date fair value, canceled (in usd per share) | $ / shares	12.75
Weighted average grant date fair value, non-vested, ending balance (in usd per share) | $ / shares	$ 13.21
Restricted Stock Units | Prior Equity Plan
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Non-vested, beginning balance (in shares)	22,158
Vested (in shares)	(22,158)
Non-vested, ending balance (in shares)	0
Weighted Average Grant Date Fair Value
Weighted average grant date fair value, non-vested, beginning balance (in usd per share) | $ / shares	$ 12
Weighted average grant date fair value, vested and unissued (in usd per share) | $ / shares	12
Weighted average grant date fair value, non-vested, ending balance (in usd per share) | $ / shares	$ 0
Restricted Stock Units | 2013 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Non-vested, beginning balance (in shares)	220,765
Vested (in shares)	(120,396)
Non-vested, ending balance (in shares)	100,369
Weighted Average Grant Date Fair Value
Weighted average grant date fair value, non-vested, beginning balance (in usd per share) | $ / shares	$ 12
Weighted average grant date fair value, vested and unissued (in usd per share) | $ / shares	12
Weighted average grant date fair value, non-vested, ending balance (in usd per share) | $ / shares	$ 12

Stock-Based Compensation - Weig

Stock-Based Compensation - Weighted Average Assumptions (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
2013 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.60%	1.80%	2.10%
Expected volatility	53.10%	56.10%	58.30%
Expected life (in years)	6 years 3 months	6 years 3 months	6 years 3 months
Expected dividend yield	0.00%	0.00%	0.00%
Constant Contact 2011 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.27%
Expected volatility	53.10%
Expected life (in years)	4 years 9 months
Expected dividend yield	0.00%

Stock-Based Compensation - Su84

Stock-Based Compensation - Summary of Stock Options (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Feb. 09, 2016
2013 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance, stock options, outstanding (in shares)	6,950,858
Stock options, granted (in shares)	3,575,851
Exercise of stock options, (in shares)	0
Stock options, forfeited (in shares)	(595,364)
Stock options, canceled (in shares)	(323,914)
Ending balance, stock options, outstanding (in shares)	9,607,431
Weighted- Average Exercise Price
Beginning balance, weighted - average exercise price, outstanding (in usd per share)	$ 13.83
Weighted - average exercise price, granted (in usd per share)	10.96
Weighted - average exercise price, exercised (in usd per share)	0
Weighted - average exercise price, forfeited (in usd per share)	13.56
Weighted - average exercise price, canceled (in usd per share)	13.41
Ending balance, weighted - average exercise price, outstanding (in usd per share)	$ 12.79
Stock Option Activity, Additional Disclosures
Weighted - average remaining contractual term, outstanding	8 years
Aggregate intrinsic value, outstanding	$ 205
Stock options, exercisable at December 31, 2016 (in shares)	4,435,261
Weighted - average exercise price, exercisable at December 31, 2016 (in usd per share)	$ 13.15
Weighted - average remaining contractual term, exercisable at December 31, 2016	7 years 1 month 6 days
Aggregate intrinsic value, exercisable at December 31, 2016	$ 0
Stock options, expected to vest after December 31, 2016 (in shares)	5,172,170
Weighted - average exercise price, expected to vest after December 31, 2016 (in usd per share)	$ 12.49
Weighted - average remaining contractual term, expected to vest after December 31, 2016	8 years 8 months 12 days
Aggregate intrinsic value, expected to vest after December 31, 2016	$ 205
Stock options, exercisable as of December 31, 2016 and expected to vest thereafter (in shares)	9,607,431
Weighted - average exercise price, exercisable as of December 31, 2016 and expected to vest thereafter (in usd per share)	$ 12.79
Weighted - average remaining contractual term, exercisable as of December 31, 2016 and expected to vest thereafter	8 years
Aggregate intrinsic value, exercisable as of December 31, 2016 and expected to vest thereafter	$ 205
Constant Contact 2011 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance, stock options, outstanding (in shares)	0
Stock options, granted (in shares)	3,002,887
Exercise of stock options, (in shares)	(396,486)
Stock options, canceled (in shares)	(674,571)
Ending balance, stock options, outstanding (in shares)	1,931,830
Weighted- Average Exercise Price
Beginning balance, weighted - average exercise price, outstanding (in usd per share)	$ 0
Weighted - average exercise price, granted (in usd per share)	8.28
Weighted - average exercise price, exercised (in usd per share)	6.47
Weighted - average exercise price, canceled (in usd per share)	8.07
Ending balance, weighted - average exercise price, outstanding (in usd per share)	$ 8.73
Stock Option Activity, Additional Disclosures
Weighted - average remaining contractual term, outstanding	5 years 1 month 6 days
Aggregate intrinsic value, outstanding	$ 2,606	$ 22,300
Stock options, exercisable at December 31, 2016 (in shares)	529,472
Weighted - average exercise price, exercisable at December 31, 2016 (in usd per share)	$ 7.12
Weighted - average remaining contractual term, exercisable at December 31, 2016	3 years 8 months 12 days
Aggregate intrinsic value, exercisable at December 31, 2016	$ 1,316
Stock options, expected to vest after December 31, 2016 (in shares)	1,123,921
Weighted - average exercise price, expected to vest after December 31, 2016 (in usd per share)	$ 9.28
Weighted - average remaining contractual term, expected to vest after December 31, 2016	5 years 7 months 6 days
Aggregate intrinsic value, expected to vest after December 31, 2016	$ 1,099
Stock options, exercisable as of December 31, 2016 and expected to vest thereafter (in shares)	1,653,393
Weighted - average exercise price, exercisable as of December 31, 2016 and expected to vest thereafter (in usd per share)	$ 8.59
Weighted - average remaining contractual term, exercisable as of December 31, 2016 and expected to vest thereafter	5 years
Aggregate intrinsic value, exercisable as of December 31, 2016 and expected to vest thereafter	$ 2,415

Stock-Based Compensation - Su85

Stock-Based Compensation - Summary of Stock Options (Narrative) (Detail)	12 Months Ended
	Dec. 31, 2016position$ / shares
2016 Liability Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees awarded liability award | position	1,000
2013 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated fair value of the Company's common stock	$ 9.30
Constant Contact 2011 Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated fair value of the Company's common stock	$ 9.30
Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tranche vesting period	1 year
Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tranche vesting period	2 years
Tranche Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tranche vesting period	3 years

Stock-Based Compensation - Su86

Stock-Based Compensation - Summary of Total Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]
Stock-based compensation expense	$ 58,267	$ 29,925	$ 16,043
Cost of revenue
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]
Stock-based compensation expense	5,855	1,975	547
Sales and marketing
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]
Stock-based compensation expense	8,702	3,285	1,585
Engineering and development
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]
Stock-based compensation expense	5,989	1,988	883
General and administrative
Common Stock Options Restricted Stock Warrants And Changes In Capitalization [Line Items]
Stock-based compensation expense	$ 37,721	$ 22,677	$ 13,028

Accumulated Other Comprehensi87

Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Loss, Net of Tax (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 179,674	$ 174,496
Ending balance	124,383	179,674
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(1,798)	(517)
Other comprehensive income (loss)	(597)	(1,281)
Ending balance	(2,395)	(1,798)
Unrealized Gains (Losses) on Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	80	0
Other comprehensive income (loss)	(1,351)	80
Ending balance	(1,271)	80
AOCI Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(1,718)	(517)
Other comprehensive income (loss)	(1,948)	(1,201)
Ending balance	$ (3,666)	$ (1,718)

Redeemable Non-Controlling In88

Redeemable Non-Controlling Interest - Additional Information (Detail) $ in Thousands	Aug. 14, 2016	Jul. 13, 2016USD ($)	May 16, 2016USD ($)	Jan. 06, 2016USD ($)	Jan. 13, 2015installment	Jul. 31, 2016USD ($)	Jan. 31, 2016USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Jul. 01, 2017USD ($)	Jul. 14, 2016	Aug. 31, 2014
Redeemable Noncontrolling Interest [Line Items]
Redeemable non-controlling interest								$ 17,753	$ 0	$ 20,800
Partial settlement of redeemable non-controlling interest liability								33,425	30,543	4,190
Number of installments | installment					3
Excess accretion of non-controlling interest								6,769	0	0
JDI Backup Ltd.
Redeemable Noncontrolling Interest [Line Items]
Partial settlement of redeemable non-controlling interest liability								$ 30,500		$ 4,200
Ownership percentage								100.00%
Resume Labs Limited
Redeemable Noncontrolling Interest [Line Items]
Cost of acquisition							$ 1,500
Pseudio Limited
Redeemable Noncontrolling Interest [Line Items]
Ownership percentage		100.00%
Cost of acquisition							$ 1,500
WZ (UK) Ltd.
Redeemable Noncontrolling Interest [Line Items]
Redeemable noncontrolling interest, equity, fair value				$ 10,800
Ownership interest			77.50%	57.50%								86.40%	49.00%
Exercised call option				$ 30,000
Accretion period	24 months
Cost of acquisition				2,100
Percentage of additional stake acquired		76.40%	20.00%									10.00%
Business acquisition, estimated aggregate purchase price		$ 18,000	$ 15,400	$ 22,200		$ 25,000
Maximum | JDI Backup Ltd.
Redeemable Noncontrolling Interest [Line Items]
Redeemable noncontrolling interest, equity, fair value									$ 30,500
Subsequent Event
Redeemable Noncontrolling Interest [Line Items]
Noncontrolling interest, change in redemption value											$ 14,200

Redeemable Non-Controlling In89

Redeemable Non-Controlling Interest - Schedule of Changes in Non-Controlling Interest (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Redeemable noncontrolling Interest
Beginning balance, redeemable noncontrolling interest	$ 0	$ 20,800
Additions to non-controlling interest upon acquisition	12,790
Capital contribution from non-controlling interest	1,775
Accretion to redemption value	30,844
Excess accretion of non-controlling interest	6,769	0	$ 0
Adjustment to non-controlling interest	(1,000)
Redemption of non-controlling interest	33,425
Ending balance, redeemable noncontrolling interest	$ 17,753	$ 0	$ 20,800

Income Taxes - Components of In

Income Taxes - Components of Income (Loss) Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
United States	$ (137,197)	$ 1,258	$ (17,002)
Foreign	(52,593)	(1,046)	(27,603)
Total income (loss) before income taxes	$ (189,790)	$ 212	$ (44,605)

Income Taxes - Components of 91

Income Taxes - Components of Income Taxes Benefit and Expenses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
U.S. federal	$ 328	$ 1,827	$ 781
State taxes	744	696	183
Foreign	2,312	1,699	1,582
Total current provision	3,384	4,222	2,546
U.S. federal	(44,447)	(1,103)	(581)
State	(6,225)	1,952	(3,983)
Foreign	(10,037)	(818)	(5,310)
Change in valuation allowance	(52,533)	7,089	13,514
Total deferred provision	(113,242)	7,120	3,640
Total expense (benefit)	$ (109,858)	$ 11,342	$ 6,186

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Statutory Federal Rate (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Benefit [Line Items]
State income taxes, net of federal benefit	0.90%	685.00%	5.90%
U.S. federal taxes at statutory rate	35.00%	34.00%	34.00%
Nondeductible stock-based compensation	(1.50%)	827.30%	(2.50%)
Nondeductible transaction costs	(2.90%)	856.50%	(1.00%)
Nontaxable gain on redemption of equity interest	0.00%	(674.90%)	0.00%
Credits	3.70%	(0.00%)	0.60%
Foreign rate differential	(4.60%)	299.70%	(11.70%)
Rate change	0.40%	216.50%	(1.10%)
Prior year true-up stock-based compensation-U.S.	0.00%	(132.80%)	(2.00%)
Other	(0.50%)	(217.50%)	(3.40%)
Total	57.20%	5349.40%	(13.90%)
Foreign Tax Authority
Income Tax Benefit [Line Items]
Other foreign permanent differences	(0.40%)	187.80%	(2.50%)
Change in valuation allowance-foreign	(4.10%)	(130.80%)	(7.00%)
Domestic Tax Authority
Income Tax Benefit [Line Items]
Change in valuation allowance-foreign	31.20%	3398.60%	(23.20%)

Income Taxes - Components of th

Income Taxes - Components of the Company's Deferred Income Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Net operating loss carry forward	$ 76,060	$ 43,698
Credit carryforward	28,271	2,190
Other	5,414	6,612
Deferred compensation	364	497
Deferred revenue	26,291	21,327
Other reserves	3,545	4,895
Stock-based compensation	25,424	13,221
Total deferred income tax assets	165,369	92,440
Purchased intangible assets	(119,719)	(11,098)
Goodwill	(37,099)	(26,062)
Property and equipment	(12,403)	(8,361)
Total deferred income tax liabilities	(169,221)	(45,521)
Valuation allowance	(36,091)	(75,705)
Net deferred income tax liabilities	$ (39,943)	$ (28,786)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	Mar. 11, 2015	Nov. 26, 2014	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Feb. 09, 2016	Dec. 02, 2015	Nov. 20, 2014
Operating Loss Carryforwards [Line Items]
Valuation allowance, deferred tax asset, increase (decrease)			$ 10,000,000		$ 7,100,000
Unrecognized tax positions			0	$ 0
Tax expense				(109,858,000)	11,342,000	$ 6,186,000
Federal and state current income taxes				1,100,000	2,500,000
Foreign current tax				2,312,000	1,699,000	1,582,000
Federal and state deferred tax expense				111,200,000	800,000
Accounting treatment for goodwill			2,000,000	2,000,000	800,000	5,800,000
Current foreign tax expense (benefit), including withholding						1,800,000
Current Federal Tax Expense (Benefit), Foreign Withholding Tax						200,000
U.S. alternative minimum taxes						500,000
State taxes				744,000	696,000	183,000
Deferred tax expense (benefit)				(113,242,000)	7,120,000	3,640,000
Loss carry-forwards available to future foreign taxable income			96,800,000	96,800,000
Credit carryforward			28,271,000	28,271,000	$ 2,190,000
Net operating loss carry-forwards annual limitations			$ 77,100,000	$ 77,100,000
Common stock, shares issued (in shares)			134,793,857	134,793,857	132,024,558
Undistributed earnings				$ 7,900,000
Cumulatively profitable foreign jurisdiction								$ 7,900,000
Amount of net operating loss carry-forwards available to offset future U.S. federal taxable income			$ 40,600,000	40,600,000
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount				70,600,000
Follow-On Public Offering
Operating Loss Carryforwards [Line Items]
Common stock, shares issued (in shares)		3,000,000							13,000,000
Number of shares sold by the selling stockholders (in shares)	12,000,000	10,000,000
Common stock, (in USD per share)	$ 19	$ 14.50
Over-Allotment Option
Operating Loss Carryforwards [Line Items]
Number of shares sold by the selling stockholders (in shares)	1,800,000	1,950,000
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Accounting treatment for goodwill						$ 2,200,000
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Federal NOL carry-forward			142,700,000	142,700,000
Deferred tax assets, capital loss carryforwards			3,400,000	3,400,000
Credit carryforward			20,300,000	20,300,000
Federal And State
Operating Loss Carryforwards [Line Items]
Valuation allowance, deferred tax asset, increase (decrease)				10,000,000
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Federal NOL carry-forward			125,600,000	125,600,000
Deferred tax assets, capital loss carryforwards			1,400,000	1,400,000
Credit carryforward			12,200,000	12,200,000
India
Operating Loss Carryforwards [Line Items]
Valuation allowance, deferred tax asset, increase (decrease)				800,000
Loss carry-forwards available to future foreign taxable income			2,500,000	2,500,000
CHINA
Operating Loss Carryforwards [Line Items]
Valuation allowance, deferred tax asset, increase (decrease)				100,000
Loss carry-forwards available to future foreign taxable income			300,000	300,000
NETHERLANDS
Operating Loss Carryforwards [Line Items]
Valuation allowance, deferred tax asset, increase (decrease)				2,500,000
Loss carry-forwards available to future foreign taxable income			10,700,000	10,700,000
United Kingdom
Operating Loss Carryforwards [Line Items]
Valuation allowance, deferred tax asset, increase (decrease)				13,100,000
Loss carry-forwards available to future foreign taxable income			81,100,000	81,100,000
ISRAEL
Operating Loss Carryforwards [Line Items]
Valuation allowance, deferred tax asset, increase (decrease)				500,000
Loss carry-forwards available to future foreign taxable income			1,900,000	1,900,000
SINGAPORE
Operating Loss Carryforwards [Line Items]
Loss carry-forwards available to future foreign taxable income			300,000	300,000
Constant Contact, Inc.
Operating Loss Carryforwards [Line Items]
Valuation allowance, deferred tax asset, increase (decrease)					$ 70,600,000
Constant Contact, Inc. | Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Federal NOL carry-forward							$ 60,200,000
Credit carryforward							10,900,000
Constant Contact, Inc. | State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Federal NOL carry-forward							32,400,000
Credit carryforward							$ 9,200,000
ASU 2016-09 | Accounting Standards Update 2016-09, Excess Tax Benefit Component [Member]
Operating Loss Carryforwards [Line Items]
Tax adjustments				900,000
Forfeitures				900,000
Amount of net operating loss carry-forwards available to offset future U.S. federal taxable income					1,500,000
Amount of net operating loss carry-forwards available to offset future state taxable income					$ 700,000
Research Tax Credit Carryforward | Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Valuation allowance, deferred tax asset, increase (decrease)				7,800,000
Capital Loss Carryforward | Federal And State
Operating Loss Carryforwards [Line Items]
Valuation allowance, deferred tax asset, increase (decrease)				1,200,000
Valuation Allowance, Operating Loss Carryforwards | State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Valuation allowance, deferred tax asset, increase (decrease)				1,000,000
Subsidiaries | Non-US
Operating Loss Carryforwards [Line Items]
Cash			$ 14,100,000	$ 14,100,000

Severance and Other Exit Cost95

Severance and Other Exit Costs - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)position	Dec. 31, 2015USD ($)position
Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	$ 1,559	$ 1,201
Severance costs paid	11,351
Facility closing
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	9,020	$ 479
Severance costs paid	4,570
Facilities charge	12,515
Sublease income	596
Integration And Consolidation Plan
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated | position		90
Severance cost incurred to date		$ 2,300
Integration And Consolidation Plan | Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	200
Integration And Consolidation Plan | Facility closing
Restructuring Cost and Reserve [Line Items]
Remaining lease obligations		3,000
Adjustments related to entering an agreement for an early buyout of the lease agreement		(600)
Severance costs paid	1,000
Facilities charge	600	$ 2,100
Restructuring and related cost, expected cost remaining	300
2015 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated | position		67
Severance cost incurred to date		$ 2,100
2015 Restructuring Plan | Employee Severance
Restructuring Cost and Reserve [Line Items]
Severance costs paid	1,200
Restructuring and related cost, expected cost remaining	$ 0
2016 Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated | position	265
Severance cost incurred to date	$ 11,700
2016 Restructuring Plan | Employee Severance
Restructuring Cost and Reserve [Line Items]
Severance costs paid	10,200
Restructuring and related cost, expected cost remaining	1,600
2016 Restructuring Plan | Facility closing
Restructuring Cost and Reserve [Line Items]
Remaining lease obligations	23,600
Severance costs paid	3,600
Facilities charge	700
Restructuring and related cost, expected cost remaining	8,700
Sublease income	$ 12,000

Severance and Other Exit Cost96

Severance and Other Exit Costs - Summary of Activity Related to Company's Exit Costs Accrual (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restructuring Reserve [Roll Forward]
Severance charges	$ 24,224	$ 1,489	$ 4,460
Facility closing
Restructuring Reserve [Roll Forward]
Beginning Balance	479
Facilities charge	12,515
Sublease income	596
Cash paid	(4,570)
Ending Balance	9,020	479
Employee Severance
Restructuring Reserve [Roll Forward]
Beginning Balance	1,201
Severance charges	11,709
Cash paid	(11,351)
Ending Balance	1,559	1,201
Web-presence | Facility closing
Restructuring Reserve [Roll Forward]
Beginning Balance	479
Facilities charge	445
Sublease income	596
Cash paid	(1,247)
Ending Balance	273	479
Web-presence | Employee Severance
Restructuring Reserve [Roll Forward]
Beginning Balance	1,201
Severance charges	1,596
Cash paid	(2,164)
Ending Balance	633	1,201
Email marketing | Facility closing
Restructuring Reserve [Roll Forward]
Beginning Balance	0
Facilities charge	12,070
Sublease income	0
Cash paid	(3,323)
Ending Balance	8,747	0
Email marketing | Employee Severance
Restructuring Reserve [Roll Forward]
Beginning Balance	0
Severance charges	10,113
Cash paid	(9,187)
Ending Balance	$ 926	$ 0

Severance and Other Exit Cost97

Severance and Other Exit Costs - Summary of Severance Costs (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Total severance charges	$ (24,224)	$ (1,489)	$ (4,460)
Cost of revenue
Restructuring Cost and Reserve [Line Items]
Total severance charges	(8,986)	(45)	(2,349)
Sales and marketing
Restructuring Cost and Reserve [Line Items]
Total severance charges	(6,550)	(555)	(301)
Engineering and development
Restructuring Cost and Reserve [Line Items]
Total severance charges	(4,288)	(636)	(960)
General and administrative
Restructuring Cost and Reserve [Line Items]
Total severance charges	$ (4,400)	$ (343)	$ (850)

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	Aug. 07, 2015defendant	Aug. 31, 2012patentdefendant	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Feb. 29, 2016USD ($)
Loss Contingencies [Line Items]
Operating leases due date			2,026
Total net rent expense			$ 20,000,000	$ 8,200,000	$ 9,800,000
Total sublease income			$ 400,000	$ 200,000
Machado | Minimum
Loss Contingencies [Line Items]
Disclosure of customer payment threshold						$ 500
Constant Contact, Inc. | McGee vs Constant Contact
Loss Contingencies [Line Items]
Number of defendants | defendant	2
Constant Contact, Inc. | RPost Holdings
Loss Contingencies [Line Items]
Number of patents allegedly infringed | patent		5
Number of defendants | defendant		5

Commitments and Contingencies99

Commitments and Contingencies - Summary of Future Minimum Annual Rental Payments Under these Leases (Detail) $ in Thousands	Dec. 31, 2016USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,017	$ 20,058
2,018	18,367
2,019	17,457
2,020	17,120
2,021	14,074
Thereafter	27,779
Total minimum lease payments	$ 114,855

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
401(k) Plan
Defined Contribution Plan Disclosure [Line Items]
Maximum annual contributions per employee (in usd)	$ 18,000
Employers matching contribution, annual vesting percentage			100.00%
Cost recognized	$ 5,700,000	$ 2,500,000	$ 2,200,000
Dotster 401k Plan | Dotster, Inc.
Defined Contribution Plan Disclosure [Line Items]
Employers matching contribution, annual vesting percentage	100.00%
Dotster 401k Plan | Series of Individually Immaterial Business Acquisitions
Defined Contribution Plan Disclosure [Line Items]
Cost recognized			400,000
HostGator 401(k) Plan | Host Gator
Defined Contribution Plan Disclosure [Line Items]
Employers matching contribution, annual vesting percentage	100.00%
Vesting period (in years)	3 years
Cost recognized			$ 100,000
Defined Contribution | 401(k) Plan | Defined Contribution Plan, Tranche One
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution, percent of match			100.00%
Employer matching contribution, percent of employees' gross pay			3.00%
Defined Contribution | 401(k) Plan | Defined Contribution Plan, Tranche Two
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution, percent of match			50.00%
Employer matching contribution, percent of employees' gross pay			2.00%
Defined Contribution | Dotster 401k Plan | Defined Contribution Plan, Tranche One | Dotster, Inc.
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution, percent of match	100.00%
Employer matching contribution, percent of employees' gross pay	3.00%
Defined Contribution | Dotster 401k Plan | Defined Contribution Plan, Tranche Two | Dotster, Inc.
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution, percent of match	50.00%
Employer matching contribution, percent of employees' gross pay	2.00%
Defined Contribution | HostGator 401(k) Plan | Host Gator
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution, percent of match	25.00%
Employer matching contribution, percent of employees' gross pay	4.00%

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($)	Dec. 09, 2015	Feb. 29, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Feb. 09, 2016	Nov. 30, 2013
Related Party Transaction [Line Items]
Prepaid expenses and other current assets				$ 28,678,000	$ 15,675,000
Amount included in accounts receivable				13,088,000	12,040,000
Notes payable, gross				2,056,175,000
Immediate Family Member of Management or Principal Owner
Related Party Transaction [Line Items]
Amount included in accounts payable and accrued expense				1,300,000	1,900,000
Related party transaction expense				14,300,000	12,300,000	$ 10,400,000
Chief Executive Officer and a Director
Related Party Transaction [Line Items]
Prepaid expenses and other current assets				200,000	200,000
Amount included in accounts payable and accrued expense				1,100,000	1,100,000
Amount included in accounts receivable				600,000	300,000
Related party transaction expense				5,100,000	$ 6,300,000	$ 4,800,000
Goldman Sachs & Co.
Related Party Transaction [Line Items]
Payments of debt issuance costs			$ 800,000
Incremental First Lien Term Loan
Related Party Transaction [Line Items]
Aggregate principal amount not to exceed		$ 735,000,000
Revolving Credit Facility
Related Party Transaction [Line Items]
Aggregate principal amount not to exceed		165,000,000		165,000,000			$ 165,000,000	$ 125,000,000
Revolving Credit Facility | Goldman Sachs & Co.
Related Party Transaction [Line Items]
Loan commitment				57,600,000
Senior Notes
Related Party Transaction [Line Items]
Senior notes		350,000,000
Notes payable, gross				350,000,000
Related Party Transaction, Long-term Debt Sold | Senior Notes | Goldman Sachs & Co.
Related Party Transaction [Line Items]
Related party transaction amount		148,800,000
Interest Rate Cap Premium | Goldman Sachs & Co.
Related Party Transaction [Line Items]
Interest rate cap agreement period	3 years
Related party transaction amount				3,000,000
Constant Contact, Inc. | Goldman Sachs & Co.
Related Party Transaction [Line Items]
Related party transaction expense				$ 8,600,000
Constant Contact, Inc. | Incremental First Lien Term Loan | Goldman Sachs & Co.
Related Party Transaction [Line Items]
Notes payable, gross		$ 312,400,000

Related Party Transactions - Su

Related Party Transactions - Summary of Related Party Transactions (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Revenue	$ (292,123)	$ (291,193)	$ (290,713)	$ (237,113)	$ (193,043)	$ (188,523)	$ (182,431)	$ (177,318)	$ (1,111,142)	$ (741,315)	$ (629,845)
Sales and marketing									303,511	145,419	146,797
Engineering and development									87,601	26,707	19,549
General and administrative									143,095	81,386	64,746
Immediate Family Member of Management or Principal Owner
Related Party Transaction [Line Items]
Cost of revenue									12,200	10,200	7,300
Sales and marketing									500	700	500
Engineering and development									1,300	1,100	1,700
General and administrative									300	300	900
Total related party transaction expense, net									14,300	12,300	10,400
Chief Executive Officer and a Director
Related Party Transaction [Line Items]
Revenue									(3,100)	(1,300)	(400)
Revenue (contra)									7,500	7,000	600
Total related party transaction impact to revenue									4,400	5,700	200
Cost of revenue									700	600	4,600
Total related party transaction expense, net									$ 5,100	$ 6,300	$ 4,800

Segment Information (Details)

Segment Information (Details)	1 Months Ended	3 Months Ended								12 Months Ended
	Feb. 29, 2016Segment	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2016USD ($)Segment	Dec. 31, 2015USD ($)Segment	Dec. 31, 2014USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | Segment										2
Revenue		$ 292,123,000	$ 291,193,000	$ 290,713,000	$ 237,113,000	$ 193,043,000	$ 188,523,000	$ 182,431,000	$ 177,318,000	$ 1,111,142,000	$ 741,315,000	$ 629,845,000
Gross profit		147,112,000	$ 141,766,000	$ 137,636,000	$ 100,637,000	84,692,000	$ 77,750,000	$ 77,494,000	$ 76,344,000	527,151,000	316,280,000	248,357,000
Adjusted EBITDA										288,396,000
Interest expense, net (including impact of amortization of deferred financing costs and original issuance discount)										152,312,000
Income tax expense (benefit)										(109,858,000)	11,342,000	6,186,000
Depreciation										60,360,000	34,010,000	30,956,000
Amortization of other intangible assets										143,562,000	91,057,000	102,723,000
Stock-based compensation										58,267,000	29,925,000	16,043,000
Restructuring expenses										24,224,000
Transaction costs										32,284,000	9,582,000	4,787,000
Gain of unconsolidated entities										1,862,000	5,440,000	0
Net gain (loss) from unconsolidated entities										(565,000)
Impairment of other long lived assets										9,039,000	0	0
Net loss										(81,229,000)	(25,770,000)	$ (50,852,000)
Total assets		2,756,274,000				$ 1,802,500,000				$ 2,756,274,000	$ 1,802,500,000
Number of reportable segments | Segment	2									2	1
Web-presence
Segment Reporting Information [Line Items]
Revenue										$ 784,334,000
Gross profit										353,988,000
Adjusted EBITDA										172,135,000
Depreciation										36,613,000
Amortization of other intangible assets										78,883,000
Total assets		1,507,977,000								1,507,977,000
Email marketing
Segment Reporting Information [Line Items]
Revenue										326,808,000
Gross profit										173,163,000
Adjusted EBITDA										116,261,000
Depreciation										23,747,000
Amortization of other intangible assets										64,679,000
Total assets		$ 1,248,297,000								$ 1,248,297,000

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($) $ in Millions	Jan. 31, 2017	Jan. 30, 2017	Feb. 29, 2016	Feb. 09, 2016
Employee Severance | 2017 Restructuring Plan | Subsequent Event
Subsequent Event [Line Items]
Restructuring and related cost, expected cost remaining	$ 8
Senior Notes
Subsequent Event [Line Items]
Senior notes			$ 350	$ 350
Senior Notes | Subsequent Event
Subsequent Event [Line Items]
Senior notes		$ 350

Geographic and Other Informa105

Geographic and Other Information - Revenues Classified by Major Geographical Areas (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenue	$ 292,123	$ 291,193	$ 290,713	$ 237,113	$ 193,043	$ 188,523	$ 182,431	$ 177,318	$ 1,111,142	$ 741,315	$ 629,845
United States
Segment Reporting Information [Line Items]
Revenue									787,915	465,446	409,765
International
Segment Reporting Information [Line Items]
Revenue									$ 323,227	$ 275,869	$ 220,080

Geographic and Other Informa106

Geographic and Other Information - Schedule of Tangible Long-Lived Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Geographic Information [Line Items]
Long lived assets	$ 95,272	$ 75,762
United States
Geographic Information [Line Items]
Long lived assets	89,147	72,025
International
Geographic Information [Line Items]
Long lived assets	$ 6,125	$ 3,737

Geographic and Other Informa107

Geographic and Other Information - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenue	$ 292,123	$ 291,193	$ 290,713	$ 237,113	$ 193,043	$ 188,523	$ 182,431	$ 177,318	$ 1,111,142	$ 741,315	$ 629,845
Directi and BuyDomains
Segment Reporting Information [Line Items]
Revenue									$ 39,400	$ 52,500	$ 28,300
Percentage of revenue									4.00%	7.00%	4.00%

Quarterly Financial Data - Sche

Quarterly Financial Data - Schedule of Condensed Income Statement (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 292,123	$ 291,193	$ 290,713	$ 237,113	$ 193,043	$ 188,523	$ 182,431	$ 177,318	$ 1,111,142	$ 741,315	$ 629,845
Gross profit	147,112	141,766	137,636	100,637	84,692	77,750	77,494	76,344	527,151	316,280	248,357
Income (loss) from operations	24,260	8,879	(6,168)	(66,311)	14,326	9,113	12,548	17,199	(39,340)	53,186	12,478
Net income (loss) attributable to Endurance International Group Holdings, Inc.	$ (34,865)	$ (31,737)	$ (28,040)	$ 21,811	$ (9,232)	$ (15,351)	$ (2,071)	$ 884	$ (72,831)	$ (25,770)	$ (42,835)
Basic net income (loss) per share attributable to Endurance International Group Holdings, Inc. (in usd per share)	$ (0.26)	$ (0.24)	$ (0.21)	$ 0.17	$ (0.07)	$ (0.12)	$ (0.02)	$ 0.01
Diluted net income (loss) per share attributable to Endurance International Group Holdings, Inc. (in usd per share)	$ (0.26)	$ (0.24)	$ (0.21)	$ 0.16	$ (0.07)	$ (0.12)	$ (0.02)	$ 0.01

Quarterly Financial Data - Narr

Quarterly Financial Data - Narrative (Details) - USD ($) $ in Thousands	Feb. 09, 2016	Oct. 30, 2015	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounting Policies [Line Items]
Restructuring expenses					$ 24,224
Increase in interest expense					94,100
Income tax expense (benefit)					(109,858)	$ 11,342	$ 6,186
Valuation allowance, deferred tax asset, increase (decrease)			$ 10,000			7,100
Constant Contact, Inc.
Accounting Policies [Line Items]
Business acquisition, estimated aggregate purchase price	$ 1,100,000	$ 1,100,000
Transaction costs				$ 31,100
Restructuring expenses				$ 11,600	$ 22,400
Valuation allowance, deferred tax asset, increase (decrease)						$ 70,600

Supplemental Guarantor Finan110

Supplemental Guarantor Financial Information (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2016USD ($)guarantor	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Feb. 29, 2016USD ($)	Feb. 09, 2016USD ($)
Guarantor Obligations [Line Items]
Number of guarantors sold | guarantor	2
Proceeds from sale of assets		$ 0	$ 191	$ 100
Senior Notes
Guarantor Obligations [Line Items]
Senior notes					$ 350,000	$ 350,000
Interest rate					10.875%
CardStar | Guarantor Subsidiaries
Guarantor Obligations [Line Items]
Proceeds from sale of assets	$ 100

Supplemental Guarantor Finan111

Supplemental Guarantor Financial Information - Condensed Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 53,596	$ 33,030	$ 32,379	$ 66,815
Restricted cash	3,302	1,048
Accounts receivable	13,088	12,040
Prepaid domain name registry fees	55,444	55,793
Prepaid expenses and other current assets	28,678	15,675
Total current assets	154,108	117,586
Intercompany receivables, net	0	0
Property and equipment—net	95,272	75,762
Goodwill	1,859,909	1,207,255	1,105,023
Other intangible assets—net	612,057	359,786
Investment in subsidiaries	0	0
Other assets	34,928	42,111
Total assets	2,756,274	1,802,500
Current liabilities:
Accounts payable	16,074	12,280
Accrued expenses and other current liabilities	97,858	54,842
Deferred revenue	355,190	285,945
Current portion of notes payable	35,700	77,500
Current portion of capital lease obligations	6,690	5,866
Deferred consideration, short-term	5,273	51,488
Total current liabilities	516,785	487,921
Long-term deferred revenue	89,200	79,682
Notes payable	1,951,280	1,014,885
Capital lease obligations—long term	512	7,215
Deferred consideration	7,444	813
Other long-term liabilities	48,917	32,310
Total liabilities	2,614,138	1,622,826
Redeemable non-controlling interest	17,753	0	20,800
Equity	124,383	179,674
Total liabilities, redeemable non-controlling interest and stockholders’ equity	2,756,274	1,802,500
Eliminations
Current assets:
Cash and cash equivalents	0	0	0	0
Restricted cash	0	0
Accounts receivable	0	0
Prepaid domain name registry fees	(297)	(335)
Prepaid expenses and other current assets	0	(2,372)
Total current assets	(297)	(2,707)
Intercompany receivables, net	0	0
Property and equipment—net	0	0
Goodwill	0	0
Other intangible assets—net	0	0
Investment in subsidiaries	(1,432,281)	(1,449,382)
Other assets	0	0
Total assets	(1,432,578)	(1,452,089)
Current liabilities:
Accounts payable	0	0
Accrued expenses and other current liabilities	0	(2,372)
Deferred revenue	(943)	(741)
Current portion of notes payable	0	0
Current portion of capital lease obligations	0	0
Deferred consideration, short-term	0	0
Total current liabilities	(943)	(3,113)
Long-term deferred revenue	0	0
Notes payable	0	0
Capital lease obligations—long term	0	0
Deferred consideration	0	0
Other long-term liabilities	0	0
Total liabilities	(943)	(3,113)
Redeemable non-controlling interest	0	0
Equity	(1,431,635)	(1,448,976)
Total liabilities, redeemable non-controlling interest and stockholders’ equity	(1,432,578)	(1,452,089)
Parent | Reportable Legal Entities
Current assets:
Cash and cash equivalents	3	12	1	0
Restricted cash	0	0
Accounts receivable	0	0
Prepaid domain name registry fees	0	0
Prepaid expenses and other current assets	0	0
Total current assets	3	12
Intercompany receivables, net	31,665	29,092
Property and equipment—net	0	0
Goodwill	0	0
Other intangible assets—net	0	0
Investment in subsidiaries	92,068	150,164
Other assets	0	0
Total assets	123,736	179,268
Current liabilities:
Accounts payable	0	0
Accrued expenses and other current liabilities	0	0
Deferred revenue	0	0
Current portion of notes payable	0	0
Current portion of capital lease obligations	0	0
Deferred consideration, short-term	0	0
Total current liabilities	0	0
Long-term deferred revenue	0	0
Notes payable	0	0
Capital lease obligations—long term	0	0
Deferred consideration	0	0
Other long-term liabilities	0	0
Total liabilities	0	0
Redeemable non-controlling interest	0	0
Equity	123,736	179,268
Total liabilities, redeemable non-controlling interest and stockholders’ equity	123,736	179,268
Issuer | Reportable Legal Entities
Current assets:
Cash and cash equivalents	4	67	4,347	35,879
Restricted cash	0	0
Accounts receivable	0	0
Prepaid domain name registry fees	0	0
Prepaid expenses and other current assets	81	62
Total current assets	85	129
Intercompany receivables, net	799,953	(10,324)
Property and equipment—net	0	0
Goodwill	0	0
Other intangible assets—net	0	0
Investment in subsidiaries	1,299,562	1,260,399
Other assets	5,911	3,130
Total assets	2,105,511	1,253,334
Current liabilities:
Accounts payable	0	3,769
Accrued expenses and other current liabilities	27,208	7,016
Deferred revenue	0	0
Current portion of notes payable	35,700	77,500
Current portion of capital lease obligations	0	0
Deferred consideration, short-term	0	0
Total current liabilities	62,908	88,285
Long-term deferred revenue	0	0
Notes payable	1,951,280	1,014,885
Capital lease obligations—long term	0	0
Deferred consideration	0	0
Other long-term liabilities	(745)	0
Total liabilities	2,013,443	1,103,170
Redeemable non-controlling interest	0	0
Equity	92,068	150,164
Total liabilities, redeemable non-controlling interest and stockholders’ equity	2,105,511	1,253,334
Guarantor Subsidiaries | Reportable Legal Entities
Current assets:
Cash and cash equivalents	39,034	21,286	18,702	25,043
Restricted cash	2,620	973
Accounts receivable	10,148	7,120
Prepaid domain name registry fees	31,044	29,250
Prepaid expenses and other current assets	17,996	9,722
Total current assets	100,842	68,351
Intercompany receivables, net	(690,761)	91,938
Property and equipment—net	82,901	66,011
Goodwill	1,683,121	1,072,838
Other intangible assets—net	592,095	328,922
Investment in subsidiaries	40,651	38,819
Other assets	23,153	34,151
Total assets	1,832,002	1,701,030
Current liabilities:
Accounts payable	13,801	7,269
Accrued expenses and other current liabilities	60,760	38,092
Deferred revenue	295,208	230,396
Current portion of notes payable	0	0
Current portion of capital lease obligations	6,690	5,866
Deferred consideration, short-term	4,415	50,840
Total current liabilities	380,874	332,463
Long-term deferred revenue	77,649	71,982
Notes payable	0	0
Capital lease obligations—long term	512	7,215
Deferred consideration	7,419	0
Other long-term liabilities	48,233	28,970
Total liabilities	514,687	440,630
Redeemable non-controlling interest	17,753	0
Equity	1,299,562	1,260,400
Total liabilities, redeemable non-controlling interest and stockholders’ equity	1,832,002	1,701,030
Non-Guarantor Subsidiaries | Reportable Legal Entities
Current assets:
Cash and cash equivalents	14,555	11,665	$ 9,329	$ 5,893
Restricted cash	682	75
Accounts receivable	2,940	4,920
Prepaid domain name registry fees	24,697	26,878
Prepaid expenses and other current assets	10,601	8,263
Total current assets	53,475	51,801
Intercompany receivables, net	(140,857)	(110,706)
Property and equipment—net	12,371	9,751
Goodwill	176,788	134,417
Other intangible assets—net	19,962	30,864
Investment in subsidiaries	0	0
Other assets	5,864	4,830
Total assets	127,603	120,957
Current liabilities:
Accounts payable	2,273	1,242
Accrued expenses and other current liabilities	9,890	12,106
Deferred revenue	60,925	56,290
Current portion of notes payable	0	0
Current portion of capital lease obligations	0	0
Deferred consideration, short-term	858	648
Total current liabilities	73,946	70,286
Long-term deferred revenue	11,551	7,700
Notes payable	0	0
Capital lease obligations—long term	0	0
Deferred consideration	25	813
Other long-term liabilities	1,429	3,340
Total liabilities	86,951	82,139
Redeemable non-controlling interest	0	0
Equity	40,652	38,818
Total liabilities, redeemable non-controlling interest and stockholders’ equity	$ 127,603	$ 120,957

Supplemental Guarantor Finan112

Supplemental Guarantor Financial Information Consolidated Statements of Operations and Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Revenue	$ 292,123	$ 291,193	$ 290,713	$ 237,113	$ 193,043	$ 188,523	$ 182,431	$ 177,318	$ 1,111,142	$ 741,315	$ 629,845
Cost of revenue									583,991	425,035	381,488
Gross profit	147,112	141,766	137,636	100,637	84,692	77,750	77,494	76,344	527,151	316,280	248,357
Operating expense:
Sales and marketing									303,511	145,419	146,797
Engineering and development									87,601	26,707	19,549
General and administrative									143,095	81,386	64,746
General and administrative including transaction costs										90,968	69,533
Transaction expenses									32,284	9,582	4,787
Total operating expense									566,491	263,094	235,879
Income (loss) from operations	24,260	8,879	(6,168)	(66,311)	14,326	9,113	12,548	17,199	(39,340)	53,186	12,478
Interest expense, net									150,450	52,974	57,083
Income (loss) before income taxes and equity earnings of unconsolidated entities									(189,790)	212	(44,605)
Income tax expense (benefit)									(109,858)	11,342	6,186
Loss before equity earnings of unconsolidated entities									(79,932)	(11,130)	(50,791)
Equity loss of unconsolidated entities, net of tax									1,297	14,640	61
Net loss									(81,229)	(25,770)	(50,852)
Net loss attributable to non-controlling interest									(8,398)	0	(8,017)
Net loss attributable to Endurance International Group Holdings, Inc.	$ (34,865)	$ (31,737)	$ (28,040)	$ 21,811	$ (9,232)	$ (15,351)	$ (2,071)	$ 884	(72,831)	(25,770)	(42,835)
Comprehensive loss
Foreign currency translation adjustments									(597)	(1,281)	(462)
Unrealized gain (loss) on cash flow hedge									(1,351)	80	0
Total comprehensive loss									(74,779)	(26,971)	(43,297)
Eliminations
Income Statement [Abstract]
Revenue									(822)	(717)	(579)
Cost of revenue									(1,029)	(1,201)	(237)
Gross profit									207	484	(342)
Operating expense:
Sales and marketing									(33)	(33)	(177)
Engineering and development									0	0	0
General and administrative									0
General and administrative including transaction costs										111	0
Transaction expenses									0
Total operating expense									(33)	78	(177)
Income (loss) from operations									240	406	(165)
Interest expense, net									0	0	0
Income (loss) before income taxes and equity earnings of unconsolidated entities									240	406	(165)
Income tax expense (benefit)									0	0	0
Loss before equity earnings of unconsolidated entities									240	406	(165)
Equity loss of unconsolidated entities, net of tax									(107,248)	12,565	(49,384)
Net loss									107,488	(12,159)	49,219
Net loss attributable to non-controlling interest									0	0	0
Net loss attributable to Endurance International Group Holdings, Inc.									107,488	(12,159)	49,219
Comprehensive loss
Foreign currency translation adjustments									0	0	0
Unrealized gain (loss) on cash flow hedge									0	0
Total comprehensive loss									107,488	(12,159)	49,219
Parent | Reportable Legal Entities
Income Statement [Abstract]
Revenue									0	0	0
Cost of revenue									0	0	0
Gross profit									0	0	0
Operating expense:
Sales and marketing									0	0	0
Engineering and development									0	0	0
General and administrative									0
General and administrative including transaction costs										0	0
Transaction expenses									0
Total operating expense									0	0	0
Income (loss) from operations									0	0	0
Interest expense, net									0	0	0
Income (loss) before income taxes and equity earnings of unconsolidated entities									0	0	0
Income tax expense (benefit)									0	0	0
Loss before equity earnings of unconsolidated entities									0	0	0
Equity loss of unconsolidated entities, net of tax									73,071	26,176	42,835
Net loss									(73,071)	(26,176)	(42,835)
Net loss attributable to non-controlling interest									0	0	0
Net loss attributable to Endurance International Group Holdings, Inc.									(73,071)	(26,176)	(42,835)
Comprehensive loss
Foreign currency translation adjustments									0	0	0
Unrealized gain (loss) on cash flow hedge										0
Total comprehensive loss									(73,071)	(26,176)	(42,835)
Issuer | Reportable Legal Entities
Income Statement [Abstract]
Revenue									0	0	0
Cost of revenue									0	0	0
Gross profit									0	0	0
Operating expense:
Sales and marketing									0	0	0
Engineering and development									0	0	0
General and administrative									242
General and administrative including transaction costs										177	232
Transaction expenses									0
Total operating expense									242	177	232
Income (loss) from operations									(242)	(177)	(232)
Interest expense, net									149,512	56,843	56,330
Income (loss) before income taxes and equity earnings of unconsolidated entities									(149,754)	(57,020)	(56,562)
Income tax expense (benefit)									(53,847)	10,320	6,163
Loss before equity earnings of unconsolidated entities									(95,907)	(67,340)	(62,725)
Equity loss of unconsolidated entities, net of tax									(22,837)	(41,164)	(19,890)
Net loss									(73,070)	(26,176)	(42,835)
Net loss attributable to non-controlling interest									0	0	0
Net loss attributable to Endurance International Group Holdings, Inc.									(73,070)	(26,176)	(42,835)
Comprehensive loss
Foreign currency translation adjustments									0	0	0
Unrealized gain (loss) on cash flow hedge									(1,351)	80
Total comprehensive loss									(74,421)	(26,096)	(42,835)
Guarantor Subsidiaries | Reportable Legal Entities
Income Statement [Abstract]
Revenue									978,690	628,266	559,434
Cost of revenue									496,267	349,059	327,225
Gross profit									482,423	279,207	232,209
Operating expense:
Sales and marketing									235,988	120,637	114,367
Engineering and development									72,922	23,019	16,805
General and administrative									128,337
General and administrative including transaction costs										80,548	61,291
Transaction expenses									32,284
Total operating expense									469,531	224,204	192,463
Income (loss) from operations									12,892	55,003	39,746
Interest expense, net									(3,606)	(3,554)	829
Income (loss) before income taxes and equity earnings of unconsolidated entities									16,498	58,557	38,917
Income tax expense (benefit)									(55,953)	331	613
Loss before equity earnings of unconsolidated entities									72,451	58,226	38,304
Equity loss of unconsolidated entities, net of tax									58,014	17,063	26,500
Net loss									14,437	41,163	11,804
Net loss attributable to non-controlling interest									(8,398)	0	(8,017)
Net loss attributable to Endurance International Group Holdings, Inc.									22,835	41,163	19,821
Comprehensive loss
Foreign currency translation adjustments									0	0	0
Unrealized gain (loss) on cash flow hedge									0	0
Total comprehensive loss									22,835	41,163	19,821
Non-Guarantor Subsidiaries | Reportable Legal Entities
Income Statement [Abstract]
Revenue									133,274	113,766	70,990
Cost of revenue									88,753	77,177	54,500
Gross profit									44,521	36,589	16,490
Operating expense:
Sales and marketing									67,556	24,815	32,607
Engineering and development									14,679	3,688	2,744
General and administrative									14,516
General and administrative including transaction costs										10,132	8,010
Transaction expenses									0
Total operating expense									96,751	38,635	43,361
Income (loss) from operations									(52,230)	(2,046)	(26,871)
Interest expense, net									4,544	(315)	(76)
Income (loss) before income taxes and equity earnings of unconsolidated entities									(56,774)	(1,731)	(26,795)
Income tax expense (benefit)									(58)	691	(590)
Loss before equity earnings of unconsolidated entities									(56,716)	(2,422)	(26,205)
Equity loss of unconsolidated entities, net of tax									297	0	0
Net loss									(57,013)	(2,422)	(26,205)
Net loss attributable to non-controlling interest									0	0	0
Net loss attributable to Endurance International Group Holdings, Inc.									(57,013)	(2,422)	(26,205)
Comprehensive loss
Foreign currency translation adjustments									(597)	(1,281)	(462)
Unrealized gain (loss) on cash flow hedge									0	0
Total comprehensive loss									$ (57,610)	$ (3,703)	$ (26,667)

Supplemental Guarantor Finan113

Supplemental Guarantor Financial Information - Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 154,961	$ 177,228	$ 142,893
Cash flows from investing activities:
Businesses acquired in purchase transaction, net of cash acquired	(889,634)	(97,795)	(93,698)
Purchases of property and equipment	(37,259)	(31,243)	(23,904)
Cash paid for minority investment	(5,600)	(8,475)	(34,140)
Proceeds from sale of property and equipment	676	93	94
Proceeds from sale of assets	0	191	100
Proceeds from note receivable	0	3,454	0
Purchases of intangible assets	(27)	(76)	(200)
Net (deposits) and withdrawals of principal balances in restricted cash accounts	(557)	50	433
Net cash used in investing activities	(932,401)	(133,801)	(151,315)
Cash flows from financing activities:
Proceeds from issuance of notes payable and draws on revolver	1,110,678	147,000	150,000
Repayment of notes payable and revolver	(176,700)	140,500	(110,500)
Payment of financing costs	(52,561)	0	(53)
Payment of deferred consideration	(51,044)	(14,991)	(98,318)
Payment of redeemable non-controlling interest liability	(33,425)	(30,543)	(4,190)
Principal payments on capital lease obligations	(5,892)	(4,822)	(3,608)
Proceeds from exercise of stock options	2,564	2,224	137
Capital investments from minority partner	2,776
Proceeds from issuance of common stock	0	0	43,500
Issuance costs of common stock	0	0	(2,904)
Intercompany loans and investments	0	0	0
Net cash provided by (used in) financing activities	796,396	(41,632)	(25,936)
Net effect of exchange rate on cash and cash equivalents	1,610	(1,144)	(78)
Net increase (decrease) in cash and cash equivalents	20,566	651	(34,436)
Cash and cash equivalents:
Beginning of period	33,030	32,379	66,815
End of period	53,596	33,030	32,379
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities		0	0
Cash flows from investing activities:
Businesses acquired in purchase transaction, net of cash acquired	0	0	0
Purchases of property and equipment	0	0	0
Cash paid for minority investment	0	0	0
Proceeds from sale of property and equipment	0	0	0
Proceeds from sale of assets	0	0	0
Proceeds from note receivable	0	0
Purchases of intangible assets	0	0	0
Net (deposits) and withdrawals of principal balances in restricted cash accounts	0	0	0
Net cash used in investing activities	0	0	0
Cash flows from financing activities:
Proceeds from issuance of notes payable and draws on revolver	0	0	0
Repayment of notes payable and revolver	0	0	0
Payment of financing costs	0	0	0
Payment of deferred consideration	0	0	0
Payment of redeemable non-controlling interest liability	0	0	0
Principal payments on capital lease obligations	0	0	0
Proceeds from exercise of stock options	0	0	0
Capital investments from minority partner	0
Proceeds from issuance of common stock			0
Issuance costs of common stock			0
Intercompany loans and investments	0	0	0
Net cash provided by (used in) financing activities	0	0	0
Net effect of exchange rate on cash and cash equivalents	0	0	0
Net increase (decrease) in cash and cash equivalents	0	0	0
Cash and cash equivalents:
Beginning of period	0	0	0
End of period	0	0	0
Parent | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities		2	(1)
Cash flows from investing activities:
Businesses acquired in purchase transaction, net of cash acquired	0	0	0
Purchases of property and equipment	0	0	0
Cash paid for minority investment	0	0	0
Proceeds from sale of property and equipment	0	0	0
Proceeds from sale of assets	0	0	0
Proceeds from note receivable	0	0
Purchases of intangible assets	0	0	0
Net (deposits) and withdrawals of principal balances in restricted cash accounts	0	0	0
Net cash used in investing activities	0	0	0
Cash flows from financing activities:
Proceeds from issuance of notes payable and draws on revolver	0	0	0
Repayment of notes payable and revolver	0	0	0
Payment of financing costs	0	0	0
Payment of deferred consideration	0	0	0
Payment of redeemable non-controlling interest liability	0	0	0
Principal payments on capital lease obligations	0	0	0
Proceeds from exercise of stock options	2,564	2,224	137
Capital investments from minority partner	0
Proceeds from issuance of common stock			43,500
Issuance costs of common stock			(2,904)
Intercompany loans and investments	(2,573)	(2,215)	(40,731)
Net cash provided by (used in) financing activities	(9)	9	2
Net effect of exchange rate on cash and cash equivalents	0	0	0
Net increase (decrease) in cash and cash equivalents	(9)	11	1
Cash and cash equivalents:
Beginning of period	12	1	0
End of period	3	12	1
Issuer | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(71,204)	(50,147)	(63,853)
Cash flows from investing activities:
Businesses acquired in purchase transaction, net of cash acquired	0	0	0
Purchases of property and equipment	0	0	0
Cash paid for minority investment	0	0	0
Proceeds from sale of property and equipment	0	0	0
Proceeds from sale of assets	0	0	0
Proceeds from note receivable	0	0
Purchases of intangible assets	0	0	0
Net (deposits) and withdrawals of principal balances in restricted cash accounts	0	0	0
Net cash used in investing activities	0	0	0
Cash flows from financing activities:
Proceeds from issuance of notes payable and draws on revolver	1,110,678	147,000	150,000
Repayment of notes payable and revolver	(176,700)	140,500	(110,500)
Payment of financing costs	(52,561)	0	(53)
Payment of deferred consideration	0	0	0
Payment of redeemable non-controlling interest liability	0	0	0
Principal payments on capital lease obligations	0	0	0
Proceeds from exercise of stock options	0	0	0
Capital investments from minority partner	0
Proceeds from issuance of common stock			0
Issuance costs of common stock			0
Intercompany loans and investments	(810,276)	39,367	(7,126)
Net cash provided by (used in) financing activities	71,141	45,867	32,321
Net effect of exchange rate on cash and cash equivalents	0	0	0
Net increase (decrease) in cash and cash equivalents	(63)	(4,280)	(31,532)
Cash and cash equivalents:
Beginning of period	67	4,347	35,879
End of period	4	67	4,347
Guarantor Subsidiaries | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	256,461	220,468	215,212
Cash flows from investing activities:
Businesses acquired in purchase transaction, net of cash acquired	(889,634)	(92,376)	(69,578)
Purchases of property and equipment	(32,528)	(28,058)	(22,850)
Cash paid for minority investment	(5,600)	(8,475)	(34,140)
Proceeds from sale of property and equipment	674	51	39
Proceeds from sale of assets	0	191	100
Proceeds from note receivable	0	3,454
Purchases of intangible assets	(7)	(76)	(200)
Net (deposits) and withdrawals of principal balances in restricted cash accounts	(347)	(296)	191
Net cash used in investing activities	(927,442)	(125,585)	(126,438)
Cash flows from financing activities:
Proceeds from issuance of notes payable and draws on revolver	0	0	0
Repayment of notes payable and revolver	0	0	0
Payment of financing costs	0	0	0
Payment of deferred consideration	(50,375)	(14,503)	(41,244)
Payment of redeemable non-controlling interest liability	(33,425)	(30,543)	(4,190)
Principal payments on capital lease obligations	(5,892)	(4,822)	(3,608)
Proceeds from exercise of stock options	0	0	0
Capital investments from minority partner	0
Proceeds from issuance of common stock			0
Issuance costs of common stock			0
Intercompany loans and investments	778,421	(42,431)	(46,073)
Net cash provided by (used in) financing activities	688,729	(92,299)	(95,115)
Net effect of exchange rate on cash and cash equivalents	0	0	0
Net increase (decrease) in cash and cash equivalents	17,748	2,584	(6,341)
Cash and cash equivalents:
Beginning of period	21,286	18,702	25,043
End of period	39,034	21,286	18,702
Non-Guarantor Subsidiaries | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	(30,296)	6,905	(8,465)
Cash flows from investing activities:
Businesses acquired in purchase transaction, net of cash acquired	0	(5,419)	(24,120)
Purchases of property and equipment	(4,731)	(3,185)	(1,054)
Cash paid for minority investment	0	0	0
Proceeds from sale of property and equipment	2	42	55
Proceeds from sale of assets	0	0	0
Proceeds from note receivable	0	0
Purchases of intangible assets	(20)	0	0
Net (deposits) and withdrawals of principal balances in restricted cash accounts	(210)	346	242
Net cash used in investing activities	(4,959)	(8,216)	(24,877)
Cash flows from financing activities:
Proceeds from issuance of notes payable and draws on revolver	0	0	0
Repayment of notes payable and revolver	0	0	0
Payment of financing costs	0	0	0
Payment of deferred consideration	(669)	(488)	(57,074)
Payment of redeemable non-controlling interest liability	0	0	0
Principal payments on capital lease obligations	0	0	0
Proceeds from exercise of stock options	0	0	0
Capital investments from minority partner	2,776
Proceeds from issuance of common stock			0
Issuance costs of common stock			0
Intercompany loans and investments	34,428	5,279	93,930
Net cash provided by (used in) financing activities	36,535	4,791	36,856
Net effect of exchange rate on cash and cash equivalents	1,610	(1,144)	(78)
Net increase (decrease) in cash and cash equivalents	2,890	2,336	3,436
Cash and cash equivalents:
Beginning of period	11,665	9,329	5,893
End of period	$ 14,555	$ 11,665	$ 9,329