Zillow (Z) 10-Q 4 May 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	Apr. 27, 2017
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1
Trading Symbol	ZG
Entity Registrant Name	Zillow Group, Inc.
Entity Central Index Key	1,617,640
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Class A Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		54,755,799
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		6,217,447
Class C Capital Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		123,029,399

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 261,524	$ 243,592
Short-term investments	297,520	262,870
Accounts receivable, net of allowance for doubtful accounts of $1,079 and $1,337 at March 31, 2017 and December 31, 2016, respectively	41,868	40,527
Prepaid expenses and other current assets	29,559	34,817
Total current assets	630,471	581,806
Restricted cash	1,053	1,053
Property and equipment, net	94,945	98,288
Goodwill	1,927,450	1,923,480
Intangible assets, net	525,771	527,464
Other assets	17,404	17,586
Total assets	3,197,094	3,149,677
Current liabilities:
Accounts payable	4,157	4,257
Accrued expenses and other current liabilities	43,742	38,427
Accrued compensation and benefits	26,596	24,057
Deferred revenue	30,875	29,154
Deferred rent, current portion	1,451	1,347
Total current liabilities	106,821	97,242
Deferred rent, net of current portion	15,384	15,298
Long-term debt	371,757	367,404
Deferred tax liabilities and other long-term liabilities	134,146	136,146
Total liabilities	628,108	616,090
Commitments and contingencies (Note 14)
Shareholders' equity:
Preferred stock, $0.0001 par value; 30,000,000 shares authorized as of March 31, 2017 and December 31, 2016; no shares issued and outstanding as of March 31, 2017 and December 31, 2016
Additional paid-in capital	3,071,664	3,030,854
Accumulated other comprehensive loss	(267)	(242)
Accumulated deficit	(502,429)	(497,043)
Total shareholders' equity	2,568,986	2,533,587
Total liabilities and shareholders' equity	3,197,094	3,149,677
Class A Common Stock
Shareholders' equity:
Common stock	5	5
Class B Common Stock
Shareholders' equity:
Common stock	1	1
Class C Capital Stock
Shareholders' equity:
Common stock	$ 12	$ 12

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Accounts receivable, allowance for doubtful accounts	$ 1,079	$ 1,337
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	30,000,000	30,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Class A Common Stock
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	1,245,000,000	1,245,000,000
Common stock, shares issued	54,709,306	54,402,809
Common stock, shares outstanding	54,709,306	54,402,809
Class B Common Stock
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	15,000,000	15,000,000
Common stock, shares issued	6,217,447	6,217,447
Common stock, shares outstanding	6,217,447	6,217,447
Class C Capital Stock
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	600,000,000	600,000,000
Common stock, shares issued	122,903,395	121,838,462
Common stock, shares outstanding	122,903,395	121,838,462

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Revenue		$ 245,775	$ 185,982
Costs and expenses:
Cost of revenue (exclusive of amortization)	[1]	20,232	16,203
Sales and marketing		105,940	99,101
Technology and development		72,868	60,371
General and administrative		45,466	57,791
Acquisition-related costs		105	593
Total costs and expenses		244,611	234,059
Income (loss) from operations		1,164	(48,077)
Other income		953	681
Interest expense		(6,723)	(1,573)
Loss before income taxes		(4,606)	(48,969)
Income tax benefit			1,364
Net loss		$ (4,606)	$ (47,605)
Net loss per share - basic and diluted		$ (0.03)	$ (0.27)
Weighted-average shares outstanding - basic and diluted		183,158	178,686
[1]	Amortization of website development costs and intangible assets included in technology and development

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Amortization of website development costs and intangible assets included in technology and development	$ 23,261	$ 20,059

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (4,606)	$ (47,605)
Other comprehensive income (loss):
Unrealized gains (losses) on investments	(25)	641
Reclassification adjustment for net gains from investments included in net loss		(1)
Net unrealized gains (losses) on investments	(25)	640
Total other comprehensive income (loss)	(25)	640
Comprehensive loss	$ (4,631)	$ (46,965)

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating activities
Net loss	$ (4,606)	$ (47,605)
Adjustments to reconcile net loss to net cash provided by operating activities, net of amounts assumed in connection with acquisitions:
Depreciation and amortization	27,135	23,807
Share-based compensation expense	26,395	25,551
Amortization of discount and issuance costs on 2021 Notes	4,353
Release of valuation allowance on certain deferred tax assets		1,364
Loss on disposal of property and equipment	999	1,436
Bad debt expense	718	313
Deferred rent	190	(7)
Amortization of bond premium	223	430
Changes in operating assets and liabilities:
Accounts receivable	(2,059)	(2,770)
Prepaid expenses and other assets	4,737	2,708
Accounts payable	53	1,594
Accrued expenses and other current liabilities	4,683	2,793
Accrued compensation and benefits	2,539	8,759
Deferred revenue	1,598	3,294
Other long-term liabilities		(2,749)
Net cash provided by operating activities	66,958	18,918
Investing activities
Proceeds from maturities of investments	49,107	44,108
Purchases of investments	(84,008)	(38,760)
Proceeds from sales of investments		4,795
Decrease in restricted cash		1,962
Purchases of property and equipment	(14,163)	(14,251)
Purchases of intangible assets	(5,308)	(2,675)
Proceeds from divestiture of business	579
Cash paid for acquisition, net	(6,002)	(12,357)
Net cash used in investing activities	(59,795)	(17,178)
Financing activities
Proceeds from exercise of stock options	11,006	1,682
Value of equity awards withheld for tax liability	(237)	(117)
Net cash provided by financing activities	10,769	1,565
Net increase in cash and cash equivalents during period	17,932	3,305
Cash and cash equivalents at beginning of period	243,592	229,138
Cash and cash equivalents at end of period	261,524	232,443
Noncash transactions:
Capitalized share-based compensation	2,868	2,250
Write-off of fully depreciated property and equipment	3,446	$ 6,834
Write-off of fully amortized intangible assets	$ 5,280

Organization and Description of

Organization and Description of Business	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Organization and Description of Business	Note 1. Organization and Description of Business Zillow Group, Inc. operates the leading real estate and home-related information marketplaces on mobile and the web, with a complementary portfolio of brands and products to help consumers find vital information about homes and connect with local professionals. Zillow Group’s brands focus on all stages of the home lifecycle: renting, buying, selling and financing. The Zillow Group portfolio of consumer brands includes real estate and rental marketplaces Zillow, Trulia, StreetEasy, HotPads, Naked Apartments and HREO. In addition, Zillow Group works with tens of thousands of real estate agents, lenders and rental professionals, helping maximize business opportunities and connect to millions of consumers. We also own and operate a number of brands for real estate, rental and mortgage professionals, including Mortech, dotloop and Bridge Interactive. Zillow, Inc. was incorporated as a Washington corporation in December 2004, and we launched the initial version of our website, Zillow.com, in February 2006. Zillow Group, Inc. was incorporated as a Washington corporation in July 2014 in connection with our acquisition of Trulia, Inc. (“Trulia”). Upon the closing of the Trulia acquisition in February 2015, each of Zillow, Inc. and Trulia became wholly owned subsidiaries of Zillow Group. Certain Significant Risks and Uncertainties We operate in a dynamic industry and, accordingly, can be affected by a variety of factors. For example, we believe that changes in any of the following areas could have a significant negative effect on us in terms of our future financial position, results of operations or cash flows: our ability to successfully integrate and realize the benefits of our past or future strategic acquisitions or investments; rates of revenue growth; engagement and usage of our products; competition in our market; outcomes of legal proceedings; changes in government regulation affecting our business; scaling and adaptation of existing technology and network infrastructure; management of our growth; our ability to attract and retain qualified employees and key personnel; protection of our brand and intellectual property; intellectual property infringement and other claims; and protection of customers’ information and other privacy concerns, among other things.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 2. Summary of Significant Accounting Policies Basis of Presentation The accompanying condensed consolidated financial statements include Zillow Group, Inc. and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. These condensed consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (“SEC”) regarding interim financial reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. Accordingly, these interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and accompanying notes included in Zillow Group, Inc.’s Annual Report on Form 10-K The unaudited condensed consolidated interim financial statements, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, necessary to present fairly our financial position as of March 31, 2017, our results of operations and comprehensive loss for the three month periods ended March 31, 2017 and 2016, and our cash flows for the three month periods ended March 31, 2017 and 2016. The results of the three month period ended March 31, 2017 are not necessarily indicative of the results to be expected for the year ending December 31, 2017 or for any interim period or for any other future year. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make certain estimates, judgments and assumptions that affect the reported amounts of assets and liabilities and the related disclosures at the date of the financial statements, as well as the reported amounts of revenue and expenses during the periods presented. On an ongoing basis, we evaluate our estimates, including those related to revenue recognition, website development costs, recoverability of long-lived assets and intangible assets with definite lives, share-based compensation, income taxes, business combinations and goodwill, among others. To the extent there are material differences between these estimates, judgments, or assumptions and actual results, our financial statements will be affected. Reclassifications Certain immaterial reclassifications have been made in the condensed consolidated statement of operations to conform data for prior periods to the current format. The Company reclassified certain technology-related costs and expenses between expense categories. Amounts previously reported in the condensed consolidated statement of operations for the three months ended March 31, 2016 were revised herein as shown below (in thousands): As Reported As Revised Effect of Change Cost of revenue (exclusive of amortization) $ 16,452 $ 16,203 $ (249 ) Sales and marketing 98,760 99,101 341 Technology and development 64,417 60,371 (4,046 ) General and administrative 53,837 57,791 3,954 Certain immaterial reclassifications have been made in the statement of cash flows to conform data for prior periods to the current format. Recently Adopted Accounting Standards In January 2017, the FASB issued guidance simplifying the test for goodwill impairment. This guidance eliminates Step 2 from the goodwill impairment test, instead requiring an entity to recognize a goodwill impairment charge for the amount by which the goodwill carrying amount exceeds the reporting unit’s fair value. This guidance is effective for interim and annual goodwill impairment tests in fiscal years beginning after December 15, 2019, and early adoption is permitted. This guidance must be applied on a prospective basis. We adopted this guidance for interim and annual goodwill impairment tests performed on testing dates after January 1, 2017. The adoption of this guidance did not have any impact on our financial position, results of operations or cash flows. In March 2016, the FASB issued guidance on contingent put and call options in debt instruments. This guidance clarifies that the assessment of whether an embedded contingent put or call option is clearly and closely related to the debt host only requires an analysis of the four-step decision sequence and does not require an entity to separately assess whether the contingency itself is indexed only to interest rates or the credit risk of the entity. This guidance is effective for interim and annual reporting periods beginning after December 15, 2016, and early adoption is permitted. The adoption of this guidance requires a modified retrospective transition method. We adopted this guidance on January 1, 2017. The adoption of this guidance did not have any impact on our financial position, results of operations or cash flows. In March 2016, the FASB issued guidance on several aspects of the accounting for share-based payment transactions, including the income tax consequences, impact of forfeitures, classification of awards as either equity or liabilities and classification on the statement of cash flows. This guidance is effective for interim and annual reporting periods beginning after December 15, 2016, and early adoption is permitted. We adopted this guidance on January 1, 2017 and elected to account for forfeitures as they occur using the modified retrospective approach through a cumulative-effect adjustment of approximately $0.8 million to beginning accumulated deficit. We also recognized our previously unrecognized excess tax benefits related to share-based payment awards using the modified retrospective approach, which resulted in no net impact to beginning accumulated deficit. The previously unrecognized excess tax benefits were recorded as a deferred tax asset, which was fully offset by a valuation allowance. Without the valuation allowance, our deferred tax asset would have increased by $128.3 million. The adoption of this guidance did not have a material impact on our financial position, results of operations or cash flows. Recently Issued Accounting Standards Not Yet Adopted In March 2017, the Financial Accounting Standards Board (“FASB”) issued guidance related to the premium amortization on purchased callable debt securities. This guidance shortens the amortization period for certain callable debt securities purchased at a premium by requiring that the premium be amortized to the earliest call date. This guidance is effective for interim and annual reporting periods beginning after December 15, 2018, and early adoption is permitted. This guidance must be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. We expect to adopt this guidance on January 1, 2019. We have not yet determined the impact the adoption of this guidance will have on our financial position, results of operations or cash flows. In December 2016, the FASB issued guidance to narrow the definition of a business. This guidance assists entities with evaluating when a set of transferred assets and activities is a business. This guidance is effective for interim and annual reporting periods beginning after December 15, 2017, and early adoption is permitted. This guidance must be applied prospectively to transactions occurring within the period of adoption. We expect to adopt this guidance on January 1, 2018. We do not expect the adoption of this guidance to have a material impact on our financial position, results of operations or cash flows. In November 2016, the FASB issued guidance on the classification and presentation of changes in restricted cash on the statement of cash flows. This guidance is effective for interim and annual reporting periods beginning after December 15, 2017, and early adoption is permitted. The adoption of this guidance requires a retrospective transition method to each period presented. We expect to adopt this guidance on January 1, 2018. We do not expect the adoption of this guidance to have a material impact on our statements of cash flows. In June 2016, the FASB issued guidance on the measurement of credit losses on financial instruments. This guidance requires the use of an expected loss impairment model for instruments measured at amortized cost. For available-for-sale In February 2016, the FASB issued guidance on leases. This guidance requires the recognition of a right-of-use In January 2016, the FASB issued guidance on the recognition and measurement of financial instruments. This guidance requires equity investments, except those accounted for under the equity method of accounting or those that result in consolidation of the investee, to be measured at fair value with changes in fair value recognized in net income. This guidance also requires the separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements. This guidance is effective for interim and annual reporting periods beginning after December 15, 2017, early adoption is permitted, and the guidance must be applied prospectively to equity investments that exist as of the adoption date. We expect to adopt this guidance on January 1, 2018. We have not yet determined our approach to adoption or the impact the adoption of this guidance will have on our financial position, results of operations or cash flows. In May 2014, the FASB issued guidance on revenue recognition. This guidance provides that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This guidance also requires more detailed disclosures to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The original effective date of this guidance was for interim and annual reporting periods beginning after December 15, 2016, early adoption is not permitted, and the guidance must be applied retrospectively or modified retrospectively. In July 2015, the FASB approved an optional one-year

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 3. Fair Value Measurements Accounting standards define fair value as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market in an orderly transaction between market participants on the measurement date. The standards also establish a fair value hierarchy, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. There are three levels of inputs that may be used to measure fair value: • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Assets and liabilities valued based on observable market data for similar instruments, such as quoted prices for similar assets or liabilities. • Level 3—Unobservable inputs that are supported by little or no market activity; instruments valued based on the best available data, some of which is internally developed, and considers risk premiums that a market participant would require. We applied the following methods and assumptions in estimating our fair value measurements: Cash equivalents Investments The following tables present the balances of assets measured at fair value on a recurring basis, by level within the fair value hierarchy, as of the dates presented (in thousands): March 31, 2017 Total Level 1 Level 2 Cash equivalents: Money market funds $ 182,978 $ 182,978 $ — Commercial paper 3,991 — 3,991 Certificates of deposit 748 — 748 Short-term investments: U.S. government agency securities 202,933 — 202,933 Corporate notes and bonds 59,762 — 59,762 Municipal securities 14,384 — 14,384 Commercial paper 8,972 — 8,972 Foreign government securities 5,990 — 5,990 Certificates of deposit 5,479 — 5,479 Restricted cash 1,053 — 1,053 Total $ 486,290 $ 182,978 $ 303,312 December 31, 2016 Total Level 1 Level 2 Cash equivalents: Money market funds $ 166,527 $ 166,527 $ — Certificates of deposit 460 — 460 Short-term investments: U.S. government agency securities 162,312 — 162,312 Corporate notes and bonds 61,483 — 61,483 Commercial paper 14,952 — 14,952 Municipal securities 11,912 — 11,912 Certificates of deposit 6,226 — 6,226 Foreign government securities 5,985 — 5,985 Restricted cash 1,053 — 1,053 Total $ 430,910 $ 166,527 $ 264,383 See Note 9 for the carrying amount and estimated fair value of the Company’s Convertible Senior Notes due in 2021 and Trulia’s Convertible Senior Notes due in 2020. We did not have any Level 3 assets as of March 31, 2017 or December 31, 2016. There were no liabilities measured at fair value on a recurring basis as of March 31, 2017 or December 31, 2016.

Cash, Cash Equivalents, Investm

Cash, Cash Equivalents, Investments and Restricted Cash	3 Months Ended
	Mar. 31, 2017
Text Block [Abstract]
Cash, Cash Equivalents, Investments and Restricted Cash	Note 4. Cash, Cash Equivalents, Investments and Restricted Cash Our investments are classified as available-for-sale The following tables present the amortized cost, gross unrealized gains and losses, and estimated fair market value of our cash and cash equivalents, available-for-sale March 31, 2017 Gross Gross Estimated Amortized Unrealized Unrealized Fair Market Cost Gains Losses Value Cash $ 73,807 $ — $ — $ 73,807 Cash equivalents: Money market funds 182,978 — — 182,978 Commercial paper 3,991 — — 3,991 Certificates of deposit 748 — — 748 Short-term investments: U.S. government agency securities 203,102 14 (183 ) 202,933 Corporate notes and bonds 59,795 2 (35 ) 59,762 Municipal securities 14,399 — (15 ) 14,384 Commercial paper 8,972 — — 8,972 Foreign government securities 5,996 — (6 ) 5,990 Certificates of deposit 5,479 — — 5,479 Restricted cash 1,053 — — 1,053 Total $ 560,320 $ 16 $ (239 ) $ 560,097 December 31, 2016 Amortized Gross Gross Estimated Cash $ 76,605 $ — $ — $ 76,605 Cash equivalents: Money market funds 166,527 — — 166,527 Certificates of deposit 460 — — 460 Short-term investments: U.S. government agency securities 162,438 31 (157 ) 162,312 Corporate notes and bonds 61,530 3 (50 ) 61,483 Commercial paper 14,952 — — 14,952 Municipal securities 11,925 — (13 ) 11,912 Certificates of deposit 6,226 — — 6,226 Foreign government securities 5,995 — (10 ) 5,985 Restricted cash 1,053 — — 1,053 Total $ 507,711 $ 34 $ (230 ) $ 507,515 The following table presents available-for-sale Amortized Cost Estimated Fair Market Value Due in one year or less $ 196,481 $ 196,376 Due after one year through two years 101,262 101,144 Total $ 297,743 $ 297,520

Property and Equipment, Net

Property and Equipment, Net	3 Months Ended
	Mar. 31, 2017
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	Note 5. Property and Equipment, net The following table presents the detail of property and equipment as of the dates presented (in thousands): March 31, 2017 December 31, 2016 Website development costs $ 107,866 $ 102,130 Computer equipment 28,049 28,175 Leasehold improvements 38,346 37,923 Construction-in-progress 19,009 19,470 Office equipment, furniture and fixtures 19,583 19,254 Property and equipment 212,853 206,952 Less: accumulated amortization and depreciation (117,908 ) (108,664 ) Property and equipment, net $ 94,945 $ 98,288 We recorded depreciation expense related to property and equipment (other than website development costs) of $3.9 million and $3.7 million, respectively, during the three months ended March 31, 2017 and 2016. We capitalized $12.5 million and $11.5 million, respectively, in website development costs during the three months ended March 31, 2017 and 2016. Amortization expense for website development costs included in technology and development expenses was $10.1 million and $9.1 million, respectively, during the three months ended March 31, 2017 and 2016. Construction-in-progress

Acquisition and Equity Investme

Acquisition and Equity Investment	3 Months Ended
	Mar. 31, 2017
Text Block [Abstract]
Acquisition and Equity Investment	Note 6. Acquisition and Equity Investment Acquisition On January 11, 2017, Zillow, Inc. acquired substantially all of the operating assets of RealNet Solutions, Inc., a New York corporation, RealNetDB, LLC, a New York limited liability company, Hamptons Real Estate Online, Inc., a New York corporation, and HREO.com, LLC, a New York limited liability company (collectively, “HREO”), pursuant to an Asset Purchase Agreement entered into by Zillow, Inc., HREO, each of the equity owners of HREO, and an individual acting as representative of the HREO equity holders. HREO is a Hamptons-focused real estate portal which provides buyers and renters with a specialized search experience and access to the area’s most comprehensive for-sale, for-rent, Acquisition-related costs incurred related to the acquisition of HREO, which primarily included legal and accounting fees and other external costs directly related to the acquisition, were expensed as incurred and were not material. The results of operations related to the acquisition of HREO have been included in our condensed consolidated financial statements since the date of acquisition, and are not significant. Pro forma financial information for the acquisition accounted for as a business combination has not been presented, as the effects were not material to our condensed consolidated financial statements. Equity Investment In October 2016, we purchased a 10% equity interest in a variable interest entity within the real estate industry for $10.0 million, which is accounted for as a cost method investment and classified within other assets in the consolidated balance sheet. In October 2016, we also entered into an immaterial commercial agreement with this entity. The entity is financed through its business operations. We are not the primary beneficiary of the entity, as we do not direct the activities that most significantly impact the entity’s economic performance. Therefore, we do not consolidate the entity. Our maximum exposure to loss is $10.0 million, the carrying amount of the investment as of March 31, 2017. As there were no identified events or changes in circumstances that may have a significant adverse effect on the fair value of the investment as of March 31, 2017, and it is not practicable to estimate the fair value of the investment given the investment’s fair value is not readily determinable, an estimate of the fair value of the cost method investment was not performed.

Goodwill

Goodwill	3 Months Ended
	Mar. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Note 7. Goodwill The following table presents the change in goodwill from December 31, 2016 through March 31, 2017 (in thousands): Balance as of December 31, 2016 $ 1,923,480 Goodwill recorded in connection with the acquisition of HREO 3,970 Balance as of March 31, 2017 $ 1,927,450 The goodwill recorded in connection with the acquisition of HREO, which includes intangible assets that do not qualify for separate recognition, is deductible for tax purposes.

Intangible Assets, Net

Intangible Assets, Net	3 Months Ended
	Mar. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets, Net	Note 8. Intangible Assets, net The following tables present the detail of intangible assets subject to amortization as of the dates presented (in thousands): March 31, 2017 Cost Accumulated Net Purchased content $ 31,510 $ (12,984 ) $ 18,526 Software 11,347 (5,631 ) 5,716 Customer relationships 103,900 (34,829 ) 69,071 Developed technology 111,480 (41,205 ) 70,275 Trade names and trademarks 4,900 (3,145 ) 1,755 Advertising relationships 9,000 (6,348 ) 2,652 MLS home data feeds 1,100 (776 ) 324 Intangibles-in-progress 6,452 — 6,452 Total $ 279,689 $ (104,918 ) $ 174,771 December 31, 2016 Cost Accumulated Net Purchased content $ 35,205 $ (15,508 ) $ 19,697 Software 9,712 (4,773 ) 4,939 Customer relationships 103,200 (30,952 ) 72,248 Developed technology 110,080 (36,341 ) 73,739 Trade names and trademarks 4,900 (2,877 ) 2,023 Advertising relationships 9,000 (5,598 ) 3,402 MLS home data feeds 1,100 (684 ) 416 Total $ 273,197 $ (96,733 ) $ 176,464 Amortization expense recorded for intangible assets for the three months ended March 31, 2017 and 2016 was $13.1 million and $11.5 million, respectively. These amounts are included in technology and development expenses. As of March 31, 2017 and December 31, 2016, we have an indefinite-lived intangible asset for $351.0 million that we recorded in connection with our February 2015 acquisition of Trulia for Trulia’s trade names and trademarks that is not subject to amortization. Intangibles-in-progress

Convertible Senior Notes

Convertible Senior Notes	3 Months Ended
	Mar. 31, 2017
Debt Disclosure [Abstract]
Convertible Senior Notes	Note 9. Convertible Senior Notes Convertible Senior Notes due in 2021 On December 12, 2016, Zillow Group issued $460.0 million aggregate principal amount of 2.00% Convertible Senior Notes due 2021 (the “2021 Notes”), which amount includes the exercise in full of the $60.0 million over-allotment option, to Citigroup Global Markets Inc. as the initial purchaser of the 2021 Notes in a private offering to the initial purchaser in reliance on the exemption from the registration requirements provided by Section 4(a)(2) of the Securities Act of 1933, as amended (the “Securities Act”) for resale to qualified institutional buyers as defined in, and pursuant to, Rule 144A under the Securities Act. The 2021 Notes bear interest at a fixed rate of 2.00% per year, payable semiannually in arrears on June 1 and December 1 of each year, beginning on June 1, 2017. The 2021 Notes are convertible into cash, shares of our Class C capital stock or a combination thereof, at the Company’s election. The 2021 Notes will mature on December 1, 2021, unless earlier repurchased, redeemed, or converted in accordance with their terms. The net proceeds from the issuance of the 2021 Notes were approximately $447.8 million, after deducting fees and expenses. The Company used approximately $370.2 million of the net proceeds from the issuance of the 2021 Notes to repurchase a portion of the outstanding 2020 Notes (see additional information below under “Trulia’s Convertible Senior Notes due 2020”) in privately negotiated transactions. In addition, the Company used approximately $36.6 million of the net proceeds from the issuance of the 2021 Notes to pay the cost of the capped call transactions with the initial purchaser of the 2021 Notes and two additional financial institutions (“Capped Call Confirmations”) as discussed further below. The Company used the remainder of the net proceeds for general corporate purposes. Prior to the close of business on the business day immediately preceding September 1, 2021, the 2021 Notes are convertible at the option of the holders of the 2021 Notes only under certain conditions, none of which conditions have been satisfied as of March 31, 2017. On or after September 1, 2021, until the close of business on the second scheduled trading day immediately preceding the maturity date, holders of the 2021 Notes may convert their 2021 Notes at their option at the conversion rate then in effect, irrespective of these conditions. The Company will settle conversions of the 2021 Notes by paying or delivering, as the case may be, cash, shares of Class C capital stock, or a combination of cash and shares of Class C capital stock, at its election. The conversion rate will initially be 19.0985 shares of Class C capital stock per $1,000 principal amount of 2021 Notes (equivalent to an initial conversion price of approximately $52.36 per share of Class C capital stock). The conversion rate is subject to customary adjustments upon the occurrence of certain events. The Company may redeem for cash all or part of the 2021 Notes, at its option, on or after December 6, 2019, under certain circumstances at a redemption price equal to 100% of the principal amount of the 2021 Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date (as defined in the indenture governing the 2021 Notes). The conversion option does not meet the criteria for separate accounting as a derivative as it is indexed to our own stock. If the Company undergoes a fundamental change (as defined in the indenture governing the 2021 Notes), holders of the 2021 Notes may require the Company to repurchase for cash all or part of their 2021 Notes at a repurchase price equal to 100% of the principal amount of the 2021 Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date (as defined in the indenture governing the 2021 Notes). In addition, if certain fundamental changes occur, the Company may be required in certain circumstances to increase the conversion rate for any 2021 Notes converted in connection with such fundamental changes by a specified number of shares of its Class C capital stock. Certain events are also considered “Events of Default,” which may result in the acceleration of the maturity of the 2021 Notes, as described in the indenture governing the notes. There are no financial covenants associated with the 2021 Notes. We may not redeem the 2021 Notes prior to December 6, 2019. We may redeem the 2021 Notes for cash, at our option, in whole or in part on or after December 6, 2019, if the last reported sale price per share of our Class C capital stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period. In accounting for the issuance of the 2021 Notes, the Company separated the 2021 Notes into liability and equity components. The carrying amount of the liability component was calculated by measuring the fair value of a similar liability that does not have an associated convertible feature. The carrying amount of the equity component, representing the conversion option, was determined by deducting the fair value of the liability component from the par value of the 2021 Notes. The difference between the principal amount of the 2021 Notes and the liability component represents the debt discount, which is recorded as a direct deduction from the related debt liability in the consolidated balance sheet and amortized to interest expense using the effective interest method over the term of the 2021 Notes. The equity component of the 2021 Notes of approximately $91.4 million is included in additional paid-in The Company incurred transaction costs of approximately $12.2 million related to the issuance of the 2021 Notes, including approximately $11.5 million in fees to the initial purchaser, which amount was paid out of the gross proceeds from the note offering. In accounting for the transaction costs, the Company allocated the total amount incurred to the liability and equity components using the same proportions as the proceeds from the 2021 Notes. Transaction costs attributable to the liability component were recorded as a direct deduction from the related debt liability in the condensed consolidated balance sheet and amortized to interest expense over the term of the 2021 Notes, and transaction costs attributable to the equity component were netted with the equity component in shareholders’ equity. Interest expense related to the 2021 Notes for the three months ended March 31, 2017 was $6.7 million, which is comprised of approximately $4.4 million related to the amortization of debt discount and debt issuance costs and $2.3 million for the contractual coupon interest. The effective interest rate on the liability component of the 2021 Notes for the three months ended March 31, 2017 is 7.44%. Accrued interest related to the 2021 Notes as of March 31, 2017 and December 31, 2016 was $2.8 million and $0.5 million, respectively, and is recorded in accrued expenses and other current liabilities in the condensed consolidated balance sheet. The following table presents the outstanding principal amount and carrying value of the 2021 Notes as of the dates presented (in thousands): Outstanding Unamortized Carrying March 31, 2017 $ 460,000 $ (98,380 ) $ 361,620 December 31, 2016 $ 460,000 $ (102,733 ) $ 357,267 As of March 31, 2017, the unamortized debt discount and debt issuance costs for the 2020 Notes will be amortized to interest expense over a remaining period of approximately 56 months. The estimated fair value of the 2021 Notes was $455.3 million and $474.2 million, respectively, as of March 31, 2017 and December 31, 2016. The estimated fair value of the 2021 Notes was determined through consideration of quoted market prices. The fair value is classified as Level 3 due to the limited trading activity for the 2021 Notes. The Capped Call Confirmations are expected generally to reduce the potential dilution of our Class C capital stock upon any conversion of 2021 Notes and/or offset the cash payments the Company is required to make in excess of the principal amount of the 2021 Notes in the event that the market price of the Class C capital stock is greater than the strike price of the Capped Call Confirmations (which initially corresponds to the initial conversion price of the 2021 Notes and is subject to certain adjustments under the terms of the Capped Call Confirmations), with such reduction and/or offset subject to a cap based on the cap price of the Capped Call Confirmations. The Capped Call Confirmations have an initial cap price of $69.19 per share, which represents a premium of approximately 85% over the closing price of the Company’s Class C capital stock on The NASDAQ Global Select Market on December 6, 2016, and is subject to certain adjustments under the terms of the Capped Call Confirmations. The Capped Call Confirmations will cover, subject to anti-dilution adjustments substantially similar to those applicable to the 2021 Notes, the number of shares of Class C capital stock that will underlie the 2021 Notes. In addition, the Capped Call Confirmations provide for the Company to elect, subject to certain conditions, for the Capped Call Confirmations to remain outstanding (with certain modifications) following its election to redeem the 2021 Notes, notwithstanding any conversions of 2021 Notes in connection with such redemption. The Capped Call Confirmations do not meet the criteria for separate accounting as a derivative as they are indexed to our own stock. The premiums paid for the Capped Call Confirmations have been included as a net reduction to additional paid-in Trulia’s Convertible Senior Notes due in 2020 In connection with the February 2015 acquisition of Trulia, a portion of the total purchase price was allocated to Trulia’s Convertible Senior Notes due in 2020 (the “2020 Notes”), which are unsecured senior obligations. Pursuant to and in accordance with the Merger Agreement, Zillow Group entered into a supplemental indenture in respect of the 2020 Notes in the aggregate principal amount of $230.0 million, which supplemental indenture provides, among other things, that, at the effective time of the Trulia Merger, (i) each outstanding 2020 Note is no longer convertible into shares of Trulia common stock and is convertible solely into shares of Zillow Group Class A common stock, pursuant to, and in accordance with, the terms of the indenture governing the 2020 Notes, and (ii) Zillow Group guaranteed all of the obligations of Trulia under the 2020 Notes and related indenture. The aggregate principal amount of the 2020 Notes is due on December 15, 2020 if not earlier converted or redeemed. Interest is payable on the 2020 Notes at the rate of 2.75% semi-annually on June 15 and December 15 of each year. In December 2016, the Company used approximately $370.2 million of the net proceeds from the issuance of the 2021 Notes discussed above to repurchase $219.9 million aggregate principal of the 2020 Notes in privately negotiated transactions. The repurchase of the 2020 Notes was accounted for as a debt extinguishment, and the consideration transferred was allocated between the liability and equity components by determining the intrinsic value of the conversion option immediately prior to the debt extinguishment and allocating that portion of the repurchase price to additional paid-in Holders of the 2020 Notes may convert all or any portion of their notes, in multiples of $1,000 principal amount, at their option at any time prior to the close of business on the business day immediately preceding the maturity date. In connection with the supplemental indenture in respect of the 2020 Notes, the conversion ratio immediately prior to the effective time of the Trulia Merger of 27.8303 shares of Trulia common stock per $1,000 principal amount of notes was adjusted to 12.3567 shares of our Class A common stock per $1,000 principal amount of notes based on the exchange ratio of 0.444 per the Merger Agreement. This was equivalent to an initial conversion price of approximately $80.93 per share of our Class A common stock. In connection with the August 2015 distribution of shares of our Class C capital stock as a dividend to our Class A and Class B common shareholders, the conversion ratio has been further adjusted to 41.4550 shares of Class A common stock per $1,000 principal amount of notes, which is equivalent to a conversion price of approximately $24.12 per share of our Class A common stock. The conversion ratio will be adjusted for certain dilutive events and will be increased in the case of corporate events that constitute a “Make-Whole Fundamental Change” (as defined in the indenture governing the notes). The conversion option of the 2020 Notes has no cash settlement provisions. The conversion option does not meet the criteria for separate accounting as a derivative as it is indexed to our own stock. The holders of the 2020 Notes will have the ability to require us to repurchase the notes in whole or in part upon the occurrence of an event that constitutes a “Fundamental Change” (as defined in the indenture governing the notes, including such events as a “change in control” or “termination of trading”, subject to certain exceptions). In such case, the repurchase price would be 100% of the principal amount of the 2020 Notes plus accrued and unpaid interest, if any, to, but excluding, the Fundamental Change repurchase date. Certain events are also considered “Events of Default,” which may result in the acceleration of the maturity of the 2020 Notes, as described in the indenture governing the notes. There are no financial covenants associated with the 2020 Notes. The 2020 Notes are redeemable, at our option, in whole or in part on or after December 20, 2018, if the last reported sale price per share of our Class A common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period. Interest expense related to the 2020 Notes for the three months ended March 31, 2017 and 2016 was $0.1 million and $1.6 million, respectively. Accrued interest related to the 2020 Notes as of March 31, 2017 and December 31, 2016 was not material. The carrying value of the 2020 Notes was $10.1 million as of March 31, 2017 and December 31, 2016. The estimated fair value of the 2020 Notes was $16.5 million and $17.3 million, respectively, as of March 31, 2017 and December 31, 2016. The estimated fair value of the 2020 Notes was determined through consideration of quoted market prices. The fair value is classified as Level 3 due to the limited trading activity for the 2020 Notes.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Note 10. Income Taxes We are subject to federal and state income taxes in the United States and in Canada. During the three months ended March 31, 2017 and 2016, we did not have a material amount of current taxable income, and we are not projecting a material amount of current taxable income for the year ending December 31, 2017. We have provided a full valuation allowance against our net deferred tax assets as of March 31, 2017 and December 31, 2016 because, based on the weight of available evidence, it is more likely than not (a likelihood of more than 50%) that some or all of the deferred tax assets will not be realized. Therefore, no current tax liability or expense has been recorded in the condensed consolidated financial statements. We have accumulated federal tax losses of approximately $893.3 million as of December 31, 2016, which are available to reduce future taxable income. We have accumulated state tax losses of approximately $13.5 million (tax effected) as of December 31, 2016. We recorded an income tax benefit of $1.4 million for the three months ended March 31, 2016 primarily due to a deferred tax liability generated in connection with Zillow Group’s February 22, 2016 acquisition of Naked Apartments that can be used to realize certain deferred tax assets for which we had previously provided a full allowance.

Shareholders' Equity

Shareholders' Equity	3 Months Ended
	Mar. 31, 2017
Equity [Abstract]
Shareholders' Equity	Note 11. Shareholders’ Equity Preferred Stock Our board of directors has the authority to fix and determine and to amend the number of shares of any series of preferred stock that is wholly unissued or to be established and to fix and determine and to amend the designation, preferences, voting powers and limitations, and the relative, participating, optional or other rights, of any series of shares of preferred stock that is wholly unissued or to be established, subject in each case to certain approval rights of holders of our outstanding Class B common stock. There was no preferred stock issued and outstanding as of March 31, 2017 or December 31, 2016. Common and Capital Stock Our Class A common stock has no preferences or privileges and is not redeemable. Holders of Class A common stock are entitled to one vote for each share. Our Class B common stock has no preferences or privileges and is not redeemable. At any time after the date of issuance, each share of Class B common stock, at the option of the holder, may be converted into one share of Class A common stock, or automatically converted into Class A common stock upon the affirmative vote by or written consent of holders of a majority of the shares of the Class B common stock. During the three months ended March 31, 2017 and the year ended December 31, 2016, no shares of Class B common stock were converted into Class A common stock at the option of the holders. Holders of Class B common stock are entitled to 10 votes for each share. Our Class C capital stock has no preferences or privileges, is not redeemable and, except in limited circumstances, is non-voting.

Share-Based Awards

Share-Based Awards	3 Months Ended
	Mar. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Awards	Note 12. Share-Based Awards In connection with our February 2015 acquisition of Trulia, we assumed the obligations of Zillow, Inc. and Trulia outstanding under pre-existing Zillow Group, Inc. Amended and Restated 2011 Incentive Plan On July 19, 2011, the 2011 Plan became effective and serves as the successor to Zillow, Inc.’s 2005 Equity Incentive Plan (the “2005 Plan”). Shareholders last approved the 2011 Plan on June 15, 2016. In addition to the share reserve of 18,400,000 shares, the number of shares available for issuance under the 2011 Plan automatically increases on the first day of each of our fiscal years by a number of shares equal to the least of (a) 3.5% of our outstanding Class A common stock, Class B common stock, and Class C capital stock on a fully diluted basis as of the end of our immediately preceding fiscal year, (b) 10,500,000 shares, and (c) a lesser amount determined by our board of directors; provided, however, that any shares from any increases in previous years that are not actually issued will continue to be available for issuance under the 2011 Plan. In addition, shares previously available for grant under the 2005 Plan, but not issued or subject to outstanding awards under the 2005 Plan as of July 19, 2011, and shares subject to outstanding awards under the 2005 Plan that subsequently cease to be subject to such awards (other than by reason of exercise of the awards) are available for grant under the 2011 Plan. The 2011 Plan is administered by the compensation committee of the board of directors. Under the terms of the 2011 Plan, the compensation committee may grant equity awards, including incentive stock options, nonqualified stock options, restricted stock, restricted stock units or restricted units to employees, officers, directors, consultants, agents, advisors and independent contractors. The board of directors has also authorized certain senior executive officers to grant equity awards under the 2011 Plan, within limits prescribed by our board of directors. The 2011 Plan provides that in the event of a stock dividend, stock split or similar event, the maximum number and kind of securities available for issuance under the plan will be proportionally adjusted. Options under the 2011 Plan are granted with an exercise price per share not less than 100% of the fair market value of our stock on the date of grant, with the exception of substituted option awards granted in connection with acquisitions, and are exercisable at such times and under such conditions as determined by the compensation committee. Under the 2011 Plan, the maximum term of an option is ten years from the date of grant. Any portion of an option that is not vested and exercisable on the date of a participant’s termination of service expires on such date. Employees generally forfeit their rights to exercise vested options after 3 months following their termination of employment or 12 months in the event of termination by reason of death, disability or retirement. Options granted under the 2011 Plan typically expire seven or 10 years from the grant date and typically vest either 25% after 12 months and ratably thereafter over the next 36 months or quarterly over a period of four years, though certain options have been granted with alternative vesting schedules. Restricted stock units granted under the 2011 Plan typically vest either 25% after 12 months and quarterly thereafter over the next three years or 12.5% after 6 months and quarterly thereafter for the next 3.5 years. Any portion of a restricted stock unit that is not vested on the date of a participant’s termination of service expires on such date. In March 2016, Zillow Group established an equity choice program pursuant to which Zillow Group grants restricted stock units and option awards to acquire shares of Class C capital stock to certain employees to retain and recognize their efforts on behalf of Zillow Group. Option Awards The following table summarizes option award activity for the three months ended March 31, 2017: Number Weighted- Weighted- Aggregate (in thousands) Outstanding at January 1, 2017 29,628,443 $ 24.11 5.97 $ 376,004 Granted 3,922,269 35.22 Exercised (1,038,560 ) 10.60 Forfeited or cancelled (264,111 ) 33.04 Outstanding at March 31, 2017 32,248,041 25.83 6.04 283,296 Vested and exercisable at March 31, 2017 15,047,317 21.76 4.34 191,603 The fair value of options granted is estimated at the date of grant using the Black-Scholes-Merton option-pricing model, assuming no dividends and with the following assumptions for the periods presented: Three Months Ended 2017 2016 Expected volatility 48%–49% 51% Expected dividend yields — — Risk-free interest rate 1.75%–1.84% 1.05%–1.12% Weighted-average expected life 4.25–4.75 years 3.75–4.25 years Weighted-average fair value of options granted $14.21 $8.71 As of March 31, 2017, there was a total of $205.6 million in unrecognized compensation cost related to unvested stock options. Restricted Stock Units The following table summarizes activity for restricted stock units for the three months ended March 31, 2017: Restricted Stock Units Weighted- Unvested outstanding at January 1, 2017 3,780,577 $ 28.54 Granted 1,636,649 35.31 Vested (351,710 ) 27.27 Forfeited or cancelled (190,168 ) 26.81 Unvested outstanding at March 31, 2017 4,875,348 30.97 The fair value of the outstanding restricted stock units will be recorded as share-based compensation expense over the vesting period. As of March 31, 2017, there was $141.1 million of total unrecognized compensation cost related to unvested restricted stock units. Share-Based Compensation Expense The following table presents the effects of share-based compensation in our condensed consolidated statements of operations during the periods presented (in thousands): Three Months Ended 2017 2016 Cost of revenue $ 903 $ 786 Sales and marketing 5,530 5,203 Technology and development 8,491 6,759 General and administrative 11,471 12,803 Total $ 26,395 $ 25,551

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Net Loss Per Share	Note 13. Net Loss Per Share Basic net loss per share is computed by dividing net loss by the weighted-average number of shares (including Class A common stock, Class B common stock and Class C capital stock) outstanding during the period. In the calculation of basic net loss per share, undistributed earnings are allocated assuming all earnings during the period were distributed. Diluted net loss per share is computed by dividing net loss by the weighted-average number of shares (including Class A common stock, Class B common stock and Class C capital stock) outstanding during the period and potentially dilutive Class A common stock and Class C capital stock equivalents, except in cases where the effect of the Class A common stock or Class C capital stock equivalent would be antidilutive. Potential Class A common stock and Class C capital stock equivalents consist of Class A common stock and Class C capital stock issuable upon exercise of stock options and Class A common stock and Class C capital stock underlying unvested restricted stock awards and unvested restricted stock units using the treasury stock method. Potential Class A common stock equivalents also include Class A common stock issuable upon conversion of the 2020 Notes using the if-converted For the periods presented, the following Class A common stock and Class C capital stock equivalents were excluded from the calculations of diluted net loss per share because their effect would have been antidilutive (in thousands): Three Months Ended 2017 2016 Weighted-average Class A common stock and Class C capital stock option awards and stock appreciation rights outstanding 27,994 9,994 Weighted-average Class A common stock and Class C capital stock unvested restricted stock awards and restricted stock units outstanding 4,042 2,718 Class A common stock issuable upon conversion of the 2020 Notes 444 9,535 Total Class A common stock and Class C capital stock equivalents 32,480 22,247 Since the Company expects to settle the principal amount of the outstanding 2021 Notes in cash, the Company uses the treasury stock method for calculating any potential dilutive effect of the conversion spread on diluted net income per share, if applicable. The conversion spread of approximately 8.8 million shares will have a dilutive impact on diluted net income per share when the market price of the Company’s Class C capital stock at the end of a period exceeds the conversion price of $52.36 per share for the 2021 Notes. In the event of liquidation, dissolution, distribution of assets or winding-up two-class

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 14. Commitments and Contingencies Lease Commitments We have entered into various non-cancelable Purchase Commitments We have entered into various non-cancelable We capitalize payments made to third parties for data licenses that we expect to provide future economic benefit through the recovery of the costs of these arrangements via the generation of our revenue and margins. For data license contracts that include uneven payment amounts, we capitalize the payments as they are made as an intangible asset and amortize the total contract value over the estimated useful life. For contracts in which we have perpetual rights to the data and expect to utilize the data beyond the life of the contract, the total contract value is amortized on a straight-line basis over the life of the contract plus two years, which is equivalent to the estimated useful life of the asset. For contracts in which we either do not have access to the data beyond the contractual term or do not expect to utilize the data beyond the life of the contract, the total contract value is amortized on a straight-line basis over the term of the contract. We evaluate data content contracts for potential capitalization at the inception of the arrangement as well as each time periodic payments to third parties are made. The amortization period for the capitalized purchased content is based on our best estimate of the useful life of the asset, which ranges from approximately five to nine years. The capitalized purchased data content is amortized on a straight-line basis as the pattern of delivery of the economic benefits of the data cannot reliably be determined because we do not have the ability to reliably predict future traffic to our mobile applications and websites. Under certain other data agreements, the underlying data is obtained on a subscription basis with consistent monthly or quarterly recurring payment terms over the contractual period. Upon the expiration of such arrangements, we no longer have the right to access the related data, and therefore, the costs incurred under such contracts are not capitalized and are expensed as payments are made. We would immediately lose rights to data under these arrangements if we were to cancel the subscription and/or cease making payments under the subscription arrangements. Letters of Credit As of March 31, 2017, we have outstanding letters of credit of approximately $5.2 million, $1.8 million, $1.1 million and $1.1 million, respectively, which secure our lease obligations in connection with the operating leases of our San Francisco, Seattle, New York and Denver office spaces. Certain of the letters of credit are unsecured obligations, and certain of the letters of credit are secured by certificates of deposit held as collateral in our name at a financial institution. The secured letters of credit are classified as restricted cash in our consolidated balance sheet. Surety Bonds In the course of business, we are required to provide financial commitments in the form of surety bonds to third parties as a guarantee of our performance on and our compliance with certain obligations. If we were to fail to perform or comply with these obligations, any draws upon surety bonds issued on our behalf would then trigger our payment obligation to the surety bond issuer. We have outstanding surety bonds issued for our benefit of approximately $3.5 million and $3.6 million as of March 31, 2017 and December 31, 2016, respectively. Legal Proceedings We are involved in a number of legal proceedings concerning matters arising in connection with the conduct of our business activities, some of which are at preliminary stages and some of which seek an indeterminate amount of damages. We regularly evaluate the status of legal proceedings in which we are involved to assess whether a loss is probable or there is a reasonable possibility that a loss or additional loss may have been incurred to determine if accruals are appropriate. We further evaluate each legal proceeding to assess whether an estimate of possible loss or range of loss can be made if accruals are not appropriate. For certain cases described below, management is unable to provide a meaningful estimate of the possible loss or range of possible loss because, among other reasons, (i) the proceedings are in preliminary stages; (ii) specific damages have not been sought; (iii) damages sought are, in our view, unsupported and/or exaggerated; (iv) there is uncertainty as to the outcome of pending appeals or motions; (v) there are significant factual issues to be resolved; and/or (vi) there are novel legal issues or unsettled legal theories presented. For these cases, however, management does not believe, based on currently available information, that the outcomes of these proceedings will have a material effect on our financial position, results of operations or cash flow. In March 2015, the Wage and Hour Division of the U.S. Department of Labor (“DOL”) notified the Company that it was initiating a compliance review to determine the Company’s compliance with one or more federal labor laws enforced by the DOL. As discussed below, on May 5, 2016, Zillow, Inc. agreed to settle a class action lawsuit which alleged, among other things, claims that we failed to provide meal and rest breaks, failed to pay overtime, and failed to keep accurate records of employees’ hours worked. The settlement of the class action lawsuit, which has not yet been approved by the court, was contingent on Zillow, Inc.’s complete resolution of the DOL compliance review. On November 28, 2016, Zillow, Inc. entered into a settlement agreement with the DOL that resolved the DOL’s compliance review. Under the terms of the settlement agreement, Zillow, Inc. agreed that it will make the voluntary payments contemplated by the class action lawsuit settlement and establish and maintain certain procedures to promote future compliance with the Fair Labor Standards Act. We expect to make the voluntary payments contemplated by the settlement agreement during 2017. The settlement agreement with the DOL does not require Zillow, Inc. to make any payments which are in addition to those contemplated by the class action lawsuit settlement. Zillow, Inc. has not admitted liability with respect to either the DOL settlement or the class action lawsuit settlement. In November 2014, a former employee filed a putative class action lawsuit against us in the United States District Court, Central District of California, with the caption Ian Freeman v. Zillow, Inc. The complaint alleged, among other things, claims that we failed to provide meal and rest breaks, failed to pay overtime, and failed to keep accurate records of employees’ hours worked. After the court granted our two motions to dismiss certain claims, plaintiff filed a second amended complaint that includes claims under the Fair Labor Standards Act. On November 20, 2015, plaintiff filed a motion for class certification. On February 26, 2016, the court granted the plaintiff’s motion for class certification. On May 5, 2016, the parties agreed to settle the lawsuit, which was later memorialized in a settlement agreement executed by the parties on December 2, 2016, with payment by Zillow, Inc. of up to $6.0 million. On June 9, 2016, the Ninth Circuit Court of Appeals granted our petition for permission to appeal the order granting class certification. The settlement does not contain any admission of liability, wrongdoing, or responsibility by any of the parties. On April 10, 2017, the parties executed an amendment to the settlement agreement providing that the settlement class includes all current and former inside sales consultants employed by Zillow, Inc. in (i) its California offices from November 19, 2010 through the date on which the court grants preliminary approval and (ii) its Washington offices from March 1, 2013 through the date on which the court grants preliminary approval. The settlement is subject to court approval. We have recorded a liability related to the settlement for $6.0 million as of March 31, 2017 and December 31, 2016. We do not believe there is a reasonable possibility that a material loss in excess of amounts accrued may be incurred. In July 2015, VHT, Inc. (“VHT”) filed a complaint against us in the U.S. District Court for the Western District of Washington alleging copyright infringement of VHT’s images on the Zillow Digs site. In January 2016, VHT filed an amended complaint alleging copyright infringement of VHT’s images on the Zillow Digs site as well as the Zillow listing site. In December 2016, the court granted a motion for partial summary judgment that dismissed VHT’s claims with respect to the Zillow listing site. A federal jury trial began on January 23, 2017, and on February 9, 2017, the jury returned a verdict finding that the Company had infringed VHT’s copyrights in images displayed or saved to the Digs site. The jury awarded VHT $79,875 in actual damages and approximately $8.2 million in statutory damages. In March 2017, the Company filed motions in the district court seeking judgment for the Company on certain claims that are the subject of the verdict, and for a new trial on others. We did not record an accrual related to this complaint as of December 31, 2016, as we did not believe a loss was probable. We did not record an accrual related to this complaint as of March 31, 2017, as the estimated range of loss is $0 to approximately $8.3 million, and no amount within the range is a better estimate than any other amount. There is a reasonable possibility that a loss may be incurred related to this complaint. In April 2017, we received a Civil Investigative Demand from the Consumer Financial Protection Bureau (“CFPB”) requesting information related to our March 2017 response to the CFPB’s February 2017 Notice and Opportunity to Respond and Advise (“NORA”) letter. The NORA letter notified us that the CFPB’s Office of Enforcement is considering whether to recommend that the CFPB take legal action against us, alleging that we violated Section 8 of the Real Estate Settlement Procedures Act (“RESPA”) and Section 1036 of the Consumer Financial Protection Act. The purpose of a NORA letter is to provide a party being investigated an opportunity to present its position to the CFPB before an enforcement action may be recommended or commenced. This notice stems from an inquiry that commenced in 2015 when we received and responded to an initial Civil Investigative Demand from the CFPB containing a broad request for information. We believe our response to the NORA letter addresses the CFPB’s concerns related to our co-marketing co-marketing In addition to the matters discussed above, from time to time, we are involved in litigation and claims that arise in the ordinary course of business. Although we cannot be certain of the outcome of any such litigation or claims, nor the amount of damages and exposure that we could incur, we currently believe that the final disposition of such matters will not have a material effect on our business, financial position, results of operations or cash flow. Regardless of the outcome, litigation can have an adverse impact on us because of defense and settlement costs, diversion of management resources and other factors. Indemnifications In the ordinary course of business, we enter into contractual arrangements under which we agree to provide indemnification of varying scope and terms to business partners and other parties with respect to certain matters, including, but not limited to, losses arising out of the breach of such agreements and out of intellectual property infringement claims made by third parties. In addition, we have agreements that indemnify certain issuers of surety bonds against losses that they may incur as a result of executing surety bonds on our behalf. For our indemnification arrangements, payment may be conditional on the other party making a claim pursuant to the procedures specified in the particular contract. Further, our obligations under these agreements may be limited in terms of time and/or amount, and in some instances, we may have recourse against third parties for certain payments. In addition, we have indemnification agreements with certain of our directors and executive officers that require us, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The terms of such obligations may vary.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2017
Related Party Transactions [Abstract]
Related Party Transactions	Note 15. Related Party Transactions In February 2016, we paid a total of approximately $0.2 million and $0.2 million, respectively, to Mr. Lloyd Frink, our Vice Chairman and President, and Mr. Richard Barton, our Executive Chairman, for reimbursement of costs incurred by Mr. Frink and Mr. Barton for use of private planes by certain of the Company’s employees and Mr. Frink and Mr. Barton for business travel in prior years. As of March 31, 2016, we recorded an accrual for approximately $0.1 million for an expected tax “gross-up”

Self-Insurance

Self-Insurance	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Self-Insurance	Note 16. Self-Insurance Prior to January 1, 2016, we were self-insured for a portion of our medical and dental benefits for certain employees of Trulia since the date of our acquisition of Trulia in February 2015. Beginning on January 1, 2016, we are self-insured for medical benefits for all qualifying Zillow Group employees. The medical plan carries a stop-loss policy which will protect from individual claims during the plan year exceeding $150,000 or when cumulative medical claims exceed 125% of expected claims for the plan year. We record estimates of the total costs of claims incurred based on an analysis of historical data and independent estimates. Our liability for self-insured medical claims is included within accrued compensation and benefits in our consolidated balance sheet and was $1.8 million as of March 31, 2017 and $1.7 million as of December 31, 2016.

Employee Benefit Plan

Employee Benefit Plan	3 Months Ended
	Mar. 31, 2017
Postemployment Benefits [Abstract]
Employee Benefit Plan	Note 17. Employee Benefit Plan Prior to January 1, 2016, we maintained separate defined contribution 401(k) retirement plans for employees of Zillow, Inc. and Trulia. Effective January 1, 2016, we have a single defined contribution 401(k) retirement plan covering Zillow Group employees who have met certain eligibility requirements (“the Zillow Group 401(k) Plan”). Eligible employees may contribute pretax compensation up to a maximum amount allowable under the Internal Revenue Service limitations. Employee contributions and earnings thereon vest immediately. We currently match up to 4% of employee contributions under the Zillow Group 401(k) Plan. The total expense related to the Zillow Group 401(k) Plan was $2.9 million and $2.4 million, respectively, for the three months ended March 31, 2017 and 2016.

Segment Information and Revenue

Segment Information and Revenue	3 Months Ended
	Mar. 31, 2017
Segment Reporting [Abstract]
Segment Information and Revenue	Note 18. Segment Information and Revenue We have one operating and reportable segment which has been identified based on how our chief operating decision-maker manages our business, makes operating decisions and evaluates operating performance. The chief executive officer acts as the chief operating decision-maker and reviews financial and operational information on an entity-wide basis. We have one business activity and there are no segment managers who are held accountable for operations, operating results or plans for levels or components. The chief executive officer reviews information about revenue categories, including marketplace revenue and display revenue. The following table presents our revenue categories during the periods presented (in thousands): Three Months Ended 2017 2016 Marketplace revenue: Premier Agent $ 175,301 $ 134,529 Other real estate 34,755 17,978 Mortgages 20,270 16,454 Total Marketplace revenue 230,326 168,961 Display revenue 15,449 17,021 Total revenue $ 245,775 $ 185,982

Summary of Significant Accoun26

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements include Zillow Group, Inc. and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. These condensed consolidated financial statements have been prepared in conformity with U.S. generally accepted accounting principles (“GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (“SEC”) regarding interim financial reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. Accordingly, these interim condensed consolidated financial statements should be read in conjunction with the audited financial statements and accompanying notes included in Zillow Group, Inc.’s Annual Report on Form 10-K The unaudited condensed consolidated interim financial statements, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments, necessary to present fairly our financial position as of March 31, 2017, our results of operations and comprehensive loss for the three month periods ended March 31, 2017 and 2016, and our cash flows for the three month periods ended March 31, 2017 and 2016. The results of the three month period ended March 31, 2017 are not necessarily indicative of the results to be expected for the year ending December 31, 2017 or for any interim period or for any other future year.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make certain estimates, judgments and assumptions that affect the reported amounts of assets and liabilities and the related disclosures at the date of the financial statements, as well as the reported amounts of revenue and expenses during the periods presented. On an ongoing basis, we evaluate our estimates, including those related to revenue recognition, website development costs, recoverability of long-lived assets and intangible assets with definite lives, share-based compensation, income taxes, business combinations and goodwill, among others. To the extent there are material differences between these estimates, judgments, or assumptions and actual results, our financial statements will be affected.
Reclassifications	Reclassifications Certain immaterial reclassifications have been made in the condensed consolidated statement of operations to conform data for prior periods to the current format. The Company reclassified certain technology-related costs and expenses between expense categories. Amounts previously reported in the condensed consolidated statement of operations for the three months ended March 31, 2016 were revised herein as shown below (in thousands): As Reported As Revised Effect of Change Cost of revenue (exclusive of amortization) $ 16,452 $ 16,203 $ (249 ) Sales and marketing 98,760 99,101 341 Technology and development 64,417 60,371 (4,046 ) General and administrative 53,837 57,791 3,954 Certain immaterial reclassifications have been made in the statement of cash flows to conform data for prior periods to the current format.
Recently Adopted Accounting Standards and Recently Issued Accounting Standards Not Yet Adopted	Recently Adopted Accounting Standards In January 2017, the FASB issued guidance simplifying the test for goodwill impairment. This guidance eliminates Step 2 from the goodwill impairment test, instead requiring an entity to recognize a goodwill impairment charge for the amount by which the goodwill carrying amount exceeds the reporting unit’s fair value. This guidance is effective for interim and annual goodwill impairment tests in fiscal years beginning after December 15, 2019, and early adoption is permitted. This guidance must be applied on a prospective basis. We adopted this guidance for interim and annual goodwill impairment tests performed on testing dates after January 1, 2017. The adoption of this guidance did not have any impact on our financial position, results of operations or cash flows. In March 2016, the FASB issued guidance on contingent put and call options in debt instruments. This guidance clarifies that the assessment of whether an embedded contingent put or call option is clearly and closely related to the debt host only requires an analysis of the four-step decision sequence and does not require an entity to separately assess whether the contingency itself is indexed only to interest rates or the credit risk of the entity. This guidance is effective for interim and annual reporting periods beginning after December 15, 2016, and early adoption is permitted. The adoption of this guidance requires a modified retrospective transition method. We adopted this guidance on January 1, 2017. The adoption of this guidance did not have any impact on our financial position, results of operations or cash flows. In March 2016, the FASB issued guidance on several aspects of the accounting for share-based payment transactions, including the income tax consequences, impact of forfeitures, classification of awards as either equity or liabilities and classification on the statement of cash flows. This guidance is effective for interim and annual reporting periods beginning after December 15, 2016, and early adoption is permitted. We adopted this guidance on January 1, 2017 and elected to account for forfeitures as they occur using the modified retrospective approach through a cumulative-effect adjustment of approximately $0.8 million to beginning accumulated deficit. We also recognized our previously unrecognized excess tax benefits related to share-based payment awards using the modified retrospective approach, which resulted in no net impact to beginning accumulated deficit. The previously unrecognized excess tax benefits were recorded as a deferred tax asset, which was fully offset by a valuation allowance. Without the valuation allowance, our deferred tax asset would have increased by $128.3 million. The adoption of this guidance did not have a material impact on our financial position, results of operations or cash flows. Recently Issued Accounting Standards Not Yet Adopted In March 2017, the Financial Accounting Standards Board (“FASB”) issued guidance related to the premium amortization on purchased callable debt securities. This guidance shortens the amortization period for certain callable debt securities purchased at a premium by requiring that the premium be amortized to the earliest call date. This guidance is effective for interim and annual reporting periods beginning after December 15, 2018, and early adoption is permitted. This guidance must be applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. We expect to adopt this guidance on January 1, 2019. We have not yet determined the impact the adoption of this guidance will have on our financial position, results of operations or cash flows. In December 2016, the FASB issued guidance to narrow the definition of a business. This guidance assists entities with evaluating when a set of transferred assets and activities is a business. This guidance is effective for interim and annual reporting periods beginning after December 15, 2017, and early adoption is permitted. This guidance must be applied prospectively to transactions occurring within the period of adoption. We expect to adopt this guidance on January 1, 2018. We do not expect the adoption of this guidance to have a material impact on our financial position, results of operations or cash flows. In November 2016, the FASB issued guidance on the classification and presentation of changes in restricted cash on the statement of cash flows. This guidance is effective for interim and annual reporting periods beginning after December 15, 2017, and early adoption is permitted. The adoption of this guidance requires a retrospective transition method to each period presented. We expect to adopt this guidance on January 1, 2018. We do not expect the adoption of this guidance to have a material impact on our statements of cash flows. In June 2016, the FASB issued guidance on the measurement of credit losses on financial instruments. This guidance requires the use of an expected loss impairment model for instruments measured at amortized cost. For available-for-sale In February 2016, the FASB issued guidance on leases. This guidance requires the recognition of a right-of-use In January 2016, the FASB issued guidance on the recognition and measurement of financial instruments. This guidance requires equity investments, except those accounted for under the equity method of accounting or those that result in consolidation of the investee, to be measured at fair value with changes in fair value recognized in net income. This guidance also requires the separate presentation of financial assets and financial liabilities by measurement category and form of financial asset on the balance sheet or the accompanying notes to the financial statements. This guidance is effective for interim and annual reporting periods beginning after December 15, 2017, early adoption is permitted, and the guidance must be applied prospectively to equity investments that exist as of the adoption date. We expect to adopt this guidance on January 1, 2018. We have not yet determined our approach to adoption or the impact the adoption of this guidance will have on our financial position, results of operations or cash flows. In May 2014, the FASB issued guidance on revenue recognition. This guidance provides that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This guidance also requires more detailed disclosures to enable users of financial statements to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The original effective date of this guidance was for interim and annual reporting periods beginning after December 15, 2016, early adoption is not permitted, and the guidance must be applied retrospectively or modified retrospectively. In July 2015, the FASB approved an optional one-year
Fair Value	Accounting standards define fair value as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market in an orderly transaction between market participants on the measurement date. The standards also establish a fair value hierarchy, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. There are three levels of inputs that may be used to measure fair value: • Level 1—Quoted prices in active markets for identical assets or liabilities. • Level 2—Assets and liabilities valued based on observable market data for similar instruments, such as quoted prices for similar assets or liabilities. • Level 3—Unobservable inputs that are supported by little or no market activity; instruments valued based on the best available data, some of which is internally developed, and considers risk premiums that a market participant would require. We applied the following methods and assumptions in estimating our fair value measurements: Cash equivalents Investments
Net Loss Per Share	Basic net loss per share is computed by dividing net loss by the weighted-average number of shares (including Class A common stock, Class B common stock and Class C capital stock) outstanding during the period. In the calculation of basic net loss per share, undistributed earnings are allocated assuming all earnings during the period were distributed. Diluted net loss per share is computed by dividing net loss by the weighted-average number of shares (including Class A common stock, Class B common stock and Class C capital stock) outstanding during the period and potentially dilutive Class A common stock and Class C capital stock equivalents, except in cases where the effect of the Class A common stock or Class C capital stock equivalent would be antidilutive. Potential Class A common stock and Class C capital stock equivalents consist of Class A common stock and Class C capital stock issuable upon exercise of stock options and Class A common stock and Class C capital stock underlying unvested restricted stock awards and unvested restricted stock units using the treasury stock method. Potential Class A common stock equivalents also include Class A common stock issuable upon conversion of the 2020 Notes using the if-converted
Segment Information and Revenue	We have one operating and reportable segment which has been identified based on how our chief operating decision-maker manages our business, makes operating decisions and evaluates operating performance. The chief executive officer acts as the chief operating decision-maker and reviews financial and operational information on an entity-wide basis. We have one business activity and there are no segment managers who are held accountable for operations, operating results or plans for levels or components.

Summary of Significant Accoun27

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Schedule of Reclassifications	The Company reclassified certain technology-related costs and expenses between expense categories. Amounts previously reported in the condensed consolidated statement of operations for the three months ended March 31, 2016 were revised herein as shown below (in thousands): As Reported As Revised Effect of Change Cost of revenue (exclusive of amortization) $ 16,452 $ 16,203 $ (249 ) Sales and marketing 98,760 99,101 341 Technology and development 64,417 60,371 (4,046 ) General and administrative 53,837 57,791 3,954

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Summary of Balances of Cash Equivalents and Investments	The following tables present the balances of assets measured at fair value on a recurring basis, by level within the fair value hierarchy, as of the dates presented (in thousands): March 31, 2017 Total Level 1 Level 2 Cash equivalents: Money market funds $ 182,978 $ 182,978 $ — Commercial paper 3,991 — 3,991 Certificates of deposit 748 — 748 Short-term investments: U.S. government agency securities 202,933 — 202,933 Corporate notes and bonds 59,762 — 59,762 Municipal securities 14,384 — 14,384 Commercial paper 8,972 — 8,972 Foreign government securities 5,990 — 5,990 Certificates of deposit 5,479 — 5,479 Restricted cash 1,053 — 1,053 Total $ 486,290 $ 182,978 $ 303,312 December 31, 2016 Total Level 1 Level 2 Cash equivalents: Money market funds $ 166,527 $ 166,527 $ — Certificates of deposit 460 — 460 Short-term investments: U.S. government agency securities 162,312 — 162,312 Corporate notes and bonds 61,483 — 61,483 Commercial paper 14,952 — 14,952 Municipal securities 11,912 — 11,912 Certificates of deposit 6,226 — 6,226 Foreign government securities 5,985 — 5,985 Restricted cash 1,053 — 1,053 Total $ 430,910 $ 166,527 $ 264,383

Cash, Cash Equivalents, Inves29

Cash, Cash Equivalents, Investments and Restricted Cash (Tables)	3 Months Ended
	Mar. 31, 2017
Text Block [Abstract]
Amortized Cost, Gross Unrealized Gains and Losses, and Estimated Fair Market Value of Cash and Cash Equivalents, Available-for-Sale Investments and Restricted Cash	The following tables present the amortized cost, gross unrealized gains and losses, and estimated fair market value of our cash and cash equivalents, available-for-sale March 31, 2017 Gross Gross Estimated Amortized Unrealized Unrealized Fair Market Cost Gains Losses Value Cash $ 73,807 $ — $ — $ 73,807 Cash equivalents: Money market funds 182,978 — — 182,978 Commercial paper 3,991 — — 3,991 Certificates of deposit 748 — — 748 Short-term investments: U.S. government agency securities 203,102 14 (183 ) 202,933 Corporate notes and bonds 59,795 2 (35 ) 59,762 Municipal securities 14,399 — (15 ) 14,384 Commercial paper 8,972 — — 8,972 Foreign government securities 5,996 — (6 ) 5,990 Certificates of deposit 5,479 — — 5,479 Restricted cash 1,053 — — 1,053 Total $ 560,320 $ 16 $ (239 ) $ 560,097 December 31, 2016 Amortized Gross Gross Estimated Cash $ 76,605 $ — $ — $ 76,605 Cash equivalents: Money market funds 166,527 — — 166,527 Certificates of deposit 460 — — 460 Short-term investments: U.S. government agency securities 162,438 31 (157 ) 162,312 Corporate notes and bonds 61,530 3 (50 ) 61,483 Commercial paper 14,952 — — 14,952 Municipal securities 11,925 — (13 ) 11,912 Certificates of deposit 6,226 — — 6,226 Foreign government securities 5,995 — (10 ) 5,985 Restricted cash 1,053 — — 1,053 Total $ 507,711 $ 34 $ (230 ) $ 507,515
Available-for-Sale Investments by Contractual Maturity	The following table presents available-for-sale Amortized Cost Estimated Fair Market Value Due in one year or less $ 196,481 $ 196,376 Due after one year through two years 101,262 101,144 Total $ 297,743 $ 297,520

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	3 Months Ended
	Mar. 31, 2017
Property, Plant and Equipment [Abstract]
Detail of Property and Equipment	The following table presents the detail of property and equipment as of the dates presented (in thousands): March 31, 2017 December 31, 2016 Website development costs $ 107,866 $ 102,130 Computer equipment 28,049 28,175 Leasehold improvements 38,346 37,923 Construction-in-progress 19,009 19,470 Office equipment, furniture and fixtures 19,583 19,254 Property and equipment 212,853 206,952 Less: accumulated amortization and depreciation (117,908 ) (108,664 ) Property and equipment, net $ 94,945 $ 98,288

Goodwill (Tables)

Goodwill (Tables)	3 Months Ended
	Mar. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Change in Goodwill	The following table presents the change in goodwill from December 31, 2016 through March 31, 2017 (in thousands): Balance as of December 31, 2016 $ 1,923,480 Goodwill recorded in connection with the acquisition of HREO 3,970 Balance as of March 31, 2017 $ 1,927,450

Intangible Assets, Net (Tables)

Intangible Assets, Net (Tables)	3 Months Ended
	Mar. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	The following tables present the detail of intangible assets subject to amortization as of the dates presented (in thousands): March 31, 2017 Cost Accumulated Net Purchased content $ 31,510 $ (12,984 ) $ 18,526 Software 11,347 (5,631 ) 5,716 Customer relationships 103,900 (34,829 ) 69,071 Developed technology 111,480 (41,205 ) 70,275 Trade names and trademarks 4,900 (3,145 ) 1,755 Advertising relationships 9,000 (6,348 ) 2,652 MLS home data feeds 1,100 (776 ) 324 Intangibles-in-progress 6,452 — 6,452 Total $ 279,689 $ (104,918 ) $ 174,771 December 31, 2016 Cost Accumulated Net Purchased content $ 35,205 $ (15,508 ) $ 19,697 Software 9,712 (4,773 ) 4,939 Customer relationships 103,200 (30,952 ) 72,248 Developed technology 110,080 (36,341 ) 73,739 Trade names and trademarks 4,900 (2,877 ) 2,023 Advertising relationships 9,000 (5,598 ) 3,402 MLS home data feeds 1,100 (684 ) 416 Total $ 273,197 $ (96,733 ) $ 176,464

Convertible Senior Notes (Table

Convertible Senior Notes (Tables)	3 Months Ended
	Mar. 31, 2017
Debt Disclosure [Abstract]
Outstanding Principal Amount and Carrying Value	The following table presents the outstanding principal amount and carrying value of the 2021 Notes as of the dates presented (in thousands): Outstanding Unamortized Carrying March 31, 2017 $ 460,000 $ (98,380 ) $ 361,620 December 31, 2016 $ 460,000 $ (102,733 ) $ 357,267

Share-Based Awards (Tables)

Share-Based Awards (Tables)	3 Months Ended
	Mar. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Option Award	The following table summarizes option award activity for the three months ended March 31, 2017: Number Weighted- Weighted- Aggregate (in thousands) Outstanding at January 1, 2017 29,628,443 $ 24.11 5.97 $ 376,004 Granted 3,922,269 35.22 Exercised (1,038,560 ) 10.60 Forfeited or cancelled (264,111 ) 33.04 Outstanding at March 31, 2017 32,248,041 25.83 6.04 283,296 Vested and exercisable at March 31, 2017 15,047,317 21.76 4.34 191,603
Fair Value of Options Granted, Estimated at Date of Grant Using Black Scholes Merton Option Pricing Model	The fair value of options granted is estimated at the date of grant using the Black-Scholes-Merton option-pricing model, assuming no dividends and with the following assumptions for the periods presented: Three Months Ended 2017 2016 Expected volatility 48%–49% 51% Expected dividend yields — — Risk-free interest rate 1.75%–1.84% 1.05%–1.12% Weighted-average expected life 4.25–4.75 years 3.75–4.25 years Weighted-average fair value of options granted $14.21 $8.71
Summary of Restricted Stock Units Activity	The following table summarizes activity for restricted stock units for the three months ended March 31, 2017: Restricted Stock Units Weighted- Unvested outstanding at January 1, 2017 3,780,577 $ 28.54 Granted 1,636,649 35.31 Vested (351,710 ) 27.27 Forfeited or cancelled (190,168 ) 26.81 Unvested outstanding at March 31, 2017 4,875,348 30.97
Effects of Share Based Compensation in Consolidated Statements of Operations	The following table presents the effects of share-based compensation in our condensed consolidated statements of operations during the periods presented (in thousands): Three Months Ended 2017 2016 Cost of revenue $ 903 $ 786 Sales and marketing 5,530 5,203 Technology and development 8,491 6,759 General and administrative 11,471 12,803 Total $ 26,395 $ 25,551

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2017
Earnings Per Share [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share	For the periods presented, the following Class A common stock and Class C capital stock equivalents were excluded from the calculations of diluted net loss per share because their effect would have been antidilutive (in thousands): Three Months Ended 2017 2016 Weighted-average Class A common stock and Class C capital stock option awards and stock appreciation rights outstanding 27,994 9,994 Weighted-average Class A common stock and Class C capital stock unvested restricted stock awards and restricted stock units outstanding 4,042 2,718 Class A common stock issuable upon conversion of the 2020 Notes 444 9,535 Total Class A common stock and Class C capital stock equivalents 32,480 22,247

Segment Information and Reven36

Segment Information and Revenue (Tables)	3 Months Ended
	Mar. 31, 2017
Segment Reporting [Abstract]
Revenue Categories	The chief executive officer reviews information about revenue categories, including marketplace revenue and display revenue. The following table presents our revenue categories during the periods presented (in thousands): Three Months Ended 2017 2016 Marketplace revenue: Premier Agent $ 175,301 $ 134,529 Other real estate 34,755 17,978 Mortgages 20,270 16,454 Total Marketplace revenue 230,326 168,961 Display revenue 15,449 17,021 Total revenue $ 245,775 $ 185,982

Schedule of Reclassifications (

Schedule of Reclassifications (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cost of revenue (exclusive of amortization)	[1]	$ 20,232	$ 16,203
Sales and marketing		105,940	99,101
Technology and development		72,868	60,371
General and administrative		$ 45,466	57,791
As Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cost of revenue (exclusive of amortization)			16,452
Sales and marketing			98,760
Technology and development			64,417
General and administrative			53,837
Effect of Change
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Cost of revenue (exclusive of amortization)			(249)
Sales and marketing			341
Technology and development			(4,046)
General and administrative			$ 3,954
[1]	Amortization of website development costs and intangible assets included in technology and development

Summary of Significant Accoun38

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Millions	Mar. 31, 2017USD ($)
Summary Of Significant Accounting Policies [Line Items]
Cumulative-effect adjustment on accumulated deficit	$ 0.8
Accounting Standards Update 2016-09 [Member] | Deferred Tax Assets [Member]
Summary Of Significant Accounting Policies [Line Items]
Cumulative-effect adjustment on accumulated deficit	$ 128.3

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Original maturities date of money market funds	Three months or less
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value	$ 0	$ 0
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value on recurring basis	$ 0	$ 0

Fair Value of Cash Equivalents

Fair Value of Cash Equivalents and Investments (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash	$ 1,053	$ 1,053
Short-term investments	560,097	507,515
Total	486,290	430,910
Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	182,978	166,527
Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	748	460
Short-term investments	5,479	6,226
US Government Agencies Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	202,933	162,312
Corporate Notes and Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	59,762	61,483
Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	3,991
Short-term investments	8,972	14,952
Municipal Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	14,384	11,912
Foreign Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	5,990	5,985
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	182,978	166,527
Fair Value, Inputs, Level 1 | Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	182,978	166,527
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash	1,053	1,053
Total	303,312	264,383
Fair Value, Inputs, Level 2 | Certificates of Deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	748	460
Short-term investments	5,479	6,226
Fair Value, Inputs, Level 2 | US Government Agencies Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	202,933	162,312
Fair Value, Inputs, Level 2 | Corporate Notes and Bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	59,762	61,483
Fair Value, Inputs, Level 2 | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	3,991
Short-term investments	8,972	14,952
Fair Value, Inputs, Level 2 | Municipal Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	14,384	11,912
Fair Value, Inputs, Level 2 | Foreign Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	$ 5,990	$ 5,985

Amortized Cost, Gross Unrealize

Amortized Cost, Gross Unrealized Gains and Losses, and Estimated Fair Market Value of Cash and Cash Equivalents, Available-for-Sale Investments and Restricted Cash (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule of Investments [Line Items]
Amortized Cost	$ 560,320	$ 507,711
Gross Unrealized Gains	16	34
Gross Unrealized Losses	(239)	(230)
Estimated Fair Market Value	560,097	507,515
Cash
Schedule of Investments [Line Items]
Amortized Cost	73,807	76,605
Estimated Fair Market Value	73,807	76,605
Certificates of Deposit
Schedule of Investments [Line Items]
Estimated Fair Market Value	5,479	6,226
US Government Agencies Debt Securities
Schedule of Investments [Line Items]
Estimated Fair Market Value	202,933	162,312
Corporate Notes and Bonds
Schedule of Investments [Line Items]
Estimated Fair Market Value	59,762	61,483
Commercial Paper
Schedule of Investments [Line Items]
Estimated Fair Market Value	8,972	14,952
Municipal Securities
Schedule of Investments [Line Items]
Estimated Fair Market Value	14,384	11,912
Foreign Government Securities
Schedule of Investments [Line Items]
Estimated Fair Market Value	5,990	5,985
Restricted Cash
Schedule of Investments [Line Items]
Amortized Cost	1,053	1,053
Estimated Fair Market Value	1,053	1,053
Cash Equivalents | Money Market Funds
Schedule of Investments [Line Items]
Amortized Cost	182,978	166,527
Estimated Fair Market Value	182,978	166,527
Cash Equivalents | Certificates of Deposit
Schedule of Investments [Line Items]
Amortized Cost	748	460
Estimated Fair Market Value	748	460
Cash Equivalents | Commercial Paper
Schedule of Investments [Line Items]
Amortized Cost	3,991
Estimated Fair Market Value	3,991
Short-term Investments | Certificates of Deposit
Schedule of Investments [Line Items]
Amortized Cost	5,479	6,226
Estimated Fair Market Value	5,479	6,226
Short-term Investments | US Government Agencies Debt Securities
Schedule of Investments [Line Items]
Amortized Cost	203,102	162,438
Gross Unrealized Gains	14	31
Gross Unrealized Losses	(183)	(157)
Estimated Fair Market Value	202,933	162,312
Short-term Investments | Corporate Notes and Bonds
Schedule of Investments [Line Items]
Amortized Cost	59,795	61,530
Gross Unrealized Gains	2	3
Gross Unrealized Losses	(35)	(50)
Estimated Fair Market Value	59,762	61,483
Short-term Investments | Commercial Paper
Schedule of Investments [Line Items]
Amortized Cost	8,972	14,952
Estimated Fair Market Value	8,972	14,952
Short-term Investments | Municipal Securities
Schedule of Investments [Line Items]
Amortized Cost	14,399	11,925
Gross Unrealized Losses	(15)	(13)
Estimated Fair Market Value	14,384	11,912
Short-term Investments | Foreign Government Securities
Schedule of Investments [Line Items]
Amortized Cost	5,996	5,995
Gross Unrealized Losses	(6)	(10)
Estimated Fair Market Value	$ 5,990	$ 5,985

Available-for-Sale Investments

Available-for-Sale Investments by Contractual Maturity (Detail) $ in Thousands	Mar. 31, 2017USD ($)
Available-for-sale Securities, Debt Maturities [Abstract]
Amortized Cost, Due in one year or less	$ 196,481
Amortized Cost, Due after one year through two years	101,262
Total	297,743
Estimated Fair Market Value, Due in one year or less	196,376
Estimated Fair Market Value, Due after one year through two years	101,144
Total	$ 297,520

Detail of Property and Equipmen

Detail of Property and Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment	$ 212,853	$ 206,952
Less: accumulated amortization and depreciation	(117,908)	(108,664)
Property and equipment, net	94,945	98,288
Website development costs
Property, Plant and Equipment [Line Items]
Property and equipment	107,866	102,130
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment	28,049	28,175
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	38,346	37,923
Construction-in-progress
Property, Plant and Equipment [Line Items]
Property and equipment	19,009	19,470
Office equipment, furniture, and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment	$ 19,583	$ 19,254

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Property, Plant and Equipment [Line Items]
Amortization and depreciation expense related to property and equipment other than website development costs	$ 3,900	$ 3,700
Capitalization of website development costs	12,500	11,500
Amortization of website development costs and intangible assets included in technology and development	23,261	20,059
Technology and Development
Property, Plant and Equipment [Line Items]
Amortization of website development costs and intangible assets included in technology and development	13,100	11,500
Technology and Development | Software Development
Property, Plant and Equipment [Line Items]
Amortization of website development costs and intangible assets included in technology and development	$ 10,100	$ 9,100

Acquisition and Equity Invest45

Acquisition and Equity Investment - Acquisition - Additional Information (Detail) - HREO - USD ($) $ in Thousands	Jan. 11, 2017	Mar. 31, 2017
Business Acquisition [Line Items]
Goodwill acquired	$ 4,000	$ 3,970
Identifiable intangible assets acquired	2,100
Net liabilities acquired	$ 100

Acquisition and Equity Invest46

Acquisition and Equity Investment - Equity Investment - Additional Information (Detail) - Variable Interest Entity, Not Primary Beneficiary - USD ($)	1 Months Ended
	Oct. 31, 2016	Mar. 31, 2017
Schedule of Equity Method Investments [Line Items]
Percentage of equity interest in variable interest entity	10.00%
Maximum exposure to loss in variable interest entity		$ 10,000,000
Other Assets
Schedule of Equity Method Investments [Line Items]
Cost method investment	$ 10,000,000

Change in Goodwill (Detail)

Change in Goodwill (Detail) - USD ($) $ in Thousands	Jan. 11, 2017	Mar. 31, 2017
Goodwill [Line Items]
Balance as of December 31, 2016		$ 1,923,480
Balance as of March 31, 2017		1,927,450
HREO
Goodwill [Line Items]
Goodwill recorded in connection with the acquisition of HREO	$ 4,000	$ 3,970

Intangible Assets (Detail)

Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Cost	$ 279,689	$ 273,197
Accumulated Amortization	(104,918)	(96,733)
Net	174,771	176,464
Purchased Content
Finite-Lived Intangible Assets [Line Items]
Cost	31,510	35,205
Accumulated Amortization	(12,984)	(15,508)
Net	18,526	19,697
Software
Finite-Lived Intangible Assets [Line Items]
Cost	11,347	9,712
Accumulated Amortization	(5,631)	(4,773)
Net	5,716	4,939
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Cost	103,900	103,200
Accumulated Amortization	(34,829)	(30,952)
Net	69,071	72,248
Developed Technology
Finite-Lived Intangible Assets [Line Items]
Cost	111,480	110,080
Accumulated Amortization	(41,205)	(36,341)
Net	70,275	73,739
Trade Names and Trademarks
Finite-Lived Intangible Assets [Line Items]
Cost	4,900	4,900
Accumulated Amortization	(3,145)	(2,877)
Net	1,755	2,023
Advertising Relationships
Finite-Lived Intangible Assets [Line Items]
Cost	9,000	9,000
Accumulated Amortization	(6,348)	(5,598)
Net	2,652	3,402
MLS Home Data Feeds
Finite-Lived Intangible Assets [Line Items]
Cost	1,100	1,100
Accumulated Amortization	(776)	(684)
Net	324	$ 416
Intangibles-in-Progress
Finite-Lived Intangible Assets [Line Items]
Cost	6,452
Net	$ 6,452

Intangible Assets, Net - Additi

Intangible Assets, Net - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Amortization of website development costs and intangible assets included in technology and development	$ 23,261	$ 20,059
Trulia
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible asset	351,000		$ 351,000
Technology and Development
Finite-Lived Intangible Assets [Line Items]
Amortization of website development costs and intangible assets included in technology and development	$ 13,100	$ 11,500

Convertible Senior Notes - Addi

Convertible Senior Notes - Additional Information (Detail)	Dec. 12, 2016USD ($)	Mar. 31, 2017USD ($)d$ / shares	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)	Feb. 17, 2015USD ($)
Debt Instrument [Line Items]
Interest expense		$ 6,723,000	$ 1,573,000
Amortization of discount and issuance costs		$ 4,353,000
Class A Common Stock | Stock Split
Debt Instrument [Line Items]
Debt instrument, conversion rate shares		41.4550
Debt instrument, conversion rate principal amount		$ 1,000
Initial conversion price | $ / shares		$ 24.12
2.75% Convertible Senior Notes Due 2020
Debt Instrument [Line Items]
Debt instrument, interest rate stated percentage					2.75%
Debt instrument, frequency of period payment		Semi-annually on June 15 and December 15
Debt instrument, due date		Dec. 15, 2020
Debt instrument, conversion rate shares		27.8303
Debt instrument, conversion rate principal amount		$ 1,000
Debt instrument, redemption period start date		Dec. 20, 2018
Repurchase price percentage of principal amount		100.00%
Debt instrument, covenant description		There are no financial covenants associated with the 2020 Notes.
Interest expense		$ 100,000	$ 1,600,000
Debt instrument amortization period		56 months
Debt instrument carrying value		$ 10,100,000		$ 10,100,000	$ 230,000,000
Debt repurchase aggregate principal amount				219,900,000
Portion of repurchase price recorded in additional paid-in capital				127,600,000
Loss on debt extinguishment				22,800,000
2.75% Convertible Senior Notes Due 2020 | Class A Common Stock
Debt Instrument [Line Items]
Debt instrument, conversion rate shares		12.3567
Initial conversion price | $ / shares		$ 80.93
Debt instrument, convertible threshold percentage		130.00%
Debt instrument, convertible threshold trading days | d		20
Debt instrument, convertible threshold consecutive trading days		30 days
Common stock exchange ratio		0.444
2.00% Convertible Senior Notes Due 2021
Debt Instrument [Line Items]
Debt instrument, principal amount issued	$ 460,000,000
Debt instrument, interest rate stated percentage	2.00%
Debt instrument, frequency of period payment		Semiannually in arrears on June 1 and December 1
Debt instrument, date of first payment		Jun. 1, 2017
Debt instrument, due date		Dec. 1, 2021
Proceeds from issuance of 2021 Notes, net of issuance costs	$ 447,800,000
Partial repurchase of 2020 Notes	370,200,000			370,200,000
Premiums paid for Capped Call Confirmations	36,600,000
Debt instrument, earliest conversion date		Sep. 1, 2021
Debt instrument, redemption period start date		Dec. 6, 2019
Repurchase price percentage of principal amount		100.00%
Debt instrument, covenant description		There are no financial covenants associated with the 2021 Notes.
Equity component of issuance of 2021 Notes		$ 91,400,000
Issuance of Convertible Senior notes, transaction costs		12,200,000
Amount of fees paid		11,500,000
Interest expense		6,700,000
Amortization of discount and issuance costs		4,400,000
Contractual coupon interest		$ 2,300,000
Effective interest rate		7.44%
Accrued interest		$ 2,800,000		500,000
Initial cap price | $ / shares		$ 69.19
Capped call confirmation premium percentage		85.00%
Debt instrument carrying value		$ 361,620,000		357,267,000
2.00% Convertible Senior Notes Due 2021 | Class C Capital Stock
Debt Instrument [Line Items]
Debt instrument, conversion rate shares		19.0985
Debt instrument, conversion rate principal amount		$ 1,000
Initial conversion price | $ / shares		$ 52.36
Debt instrument, convertible threshold percentage		130.00%
Debt instrument, convertible threshold trading days | d		20
Debt instrument, convertible threshold consecutive trading days		30 days
2.00% Convertible Senior Notes Due 2021, Over-Allotment Option
Debt Instrument [Line Items]
Debt instrument, principal amount issued	$ 60,000,000
Fair Value, Inputs, Level 3 | 2.75% Convertible Senior Notes Due 2020
Debt Instrument [Line Items]
Fair value of convertible notes		$ 16,500,000		17,300,000
Fair Value, Inputs, Level 3 | 2.00% Convertible Senior Notes Due 2021
Debt Instrument [Line Items]
Fair value of convertible notes		$ 455,300,000		$ 474,200,000

Convertible Senior Notes - Outs

Convertible Senior Notes - Outstanding Principal Amount and Carrying Value (Detail) - 2.00% Convertible Senior Notes Due 2021 - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Outstanding Principal Amount	$ 460,000	$ 460,000
Unamortized Debt Discount and Debt Issuance Costs	(98,380)	(102,733)
Carrying Value	$ 361,620	$ 357,267

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2017	Dec. 31, 2016
Schedule Of Income Tax [Line Items]
Current income tax liability		$ 0
Income tax benefit	$ (1,364,000)
Federal
Schedule Of Income Tax [Line Items]
Net operating loss carryforwards			$ 893,300,000
State
Schedule Of Income Tax [Line Items]
Net operating loss carryforwards			$ 13,500,000

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Mar. 31, 2017Voteshares	Dec. 31, 2016shares
Class of Stock [Line Items]
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Class A Common Stock
Class of Stock [Line Items]
Common stock holders voting right | Vote	1
Conversion of common stock conversion ratio	1
Number of common stock issued	0
Class B Common Stock
Class of Stock [Line Items]
Common stock holders voting right | Vote	10
Number of common stock converted	0	0
Class C Capital Stock
Class of Stock [Line Items]
Common stock holders voting right | Vote	0

Share-Based Awards - Zillow Gro

Share-Based Awards - Zillow Group, Inc. Incentive Plan - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2017shares
Amended and Restated 2011 Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	18,400,000
Increase in number of shares of common and capital stock available for issuance percentage	3.50%
Increase in number of shares of common and capital stock available for issuance	10,500,000
2011 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price per share fixed	100.00%
2011 Plan | Option Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment, award minimum exercisable period	3 months
Share based compensation arrangement by share based payment, award maximum exercisable period	12 months
Options vesting rights	Options granted under the 2011 Plan typically expire seven or 10 years from the grant date and typically vest either 25% after 12 months and ratably thereafter over the next 36 months or quarterly over a period of four years, though certain options have been granted with alternative vesting schedules.
2011 Plan | Option Awards | Vesting After 12 Months
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	25.00%
Vesting period	12 months
2011 Plan | Option Awards | Vesting After 36 Months
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	36 months
2011 Plan | Option Awards | Quarterly Vesting Over 4 Years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
2011 Plan | Option Awards | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	7 years
2011 Plan | Option Awards | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	10 years
2011 Plan | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options vesting rights	Vest either 25% after 12 months and quarterly thereafter over the next three years or 12.5% after 6 months and quarterly thereafter for the next 3.5 years.
2011 Plan | Restricted Stock Units | Vesting After 12 Months
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	25.00%
2011 Plan | Restricted Stock Units | Vesting After 36 Months
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	12.50%
2011 Plan | Restricted Stock Units | Minimum | Vesting After 12 Months
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	12 months
2011 Plan | Restricted Stock Units | Minimum | Vesting After 36 Months
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	6 months
2011 Plan | Restricted Stock Units | Maximum | Vesting After 12 Months
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
2011 Plan | Restricted Stock Units | Maximum | Vesting After 36 Months
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years 6 months

Summary of Option Award (Detail

Summary of Option Award (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Shares Subject to Existing Option Awards, Beginning Balance	29,628,443
Number of Shares Subject to Existing Option Awards, Granted	3,922,269
Number of Shares Subject to Existing Option Awards, Exercised	(1,038,560)
Number of Shares Subject to Existing Option Awards, Forfeited or cancelled	(264,111)
Number of Shares Subject to Existing Option Awards, Ending Balance	32,248,041	29,628,443
Number of Shares Subject to Existing Option Awards, Vested and exercisable, Ending balance	15,047,317
Weighted-Average Exercise Price Per Share, Beginning Balance	$ 24.11
Weighted-Average Exercise Price Per Share, Granted	35.22
Weighted-Average Exercise Price Per Share, Exercised	10.60
Weighted-Average Exercise Price Per Share, Forfeited or cancelled	33.04
Weighted-Average Exercise Price Per Share, Ending Balance	25.83	$ 24.11
Weighted-Average Exercise Price Per Share, Vested and exercisable	$ 21.76
Weighted-Average Remaining Contractual Life (Years)	6 years 15 days	5 years 11 months 19 days
Weighted-Average Remaining Contractual Life (Years), Vested and exercisable	4 years 4 months 2 days
Aggregate Intrinsic Value	$ 283,296	$ 376,004
Aggregate Intrinsic Value Vested, and exercisable	$ 191,603

Fair Value of Options Granted,

Fair Value of Options Granted, Estimated at Date of Grant Using Black Scholes Merton Option Pricing Model (Detail) - Option Awards - $ / shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility, minimum	48.00%	51.00%
Expected volatility, maximum	49.00%
Expected dividend yields	0.00%	0.00%
Risk-free interest rate, minimum	1.75%	1.05%
Risk-free interest rate, maximum	1.84%	1.12%
Weighted-average fair value of options granted	$ 14.21	$ 8.71
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average expected life	4 years 3 months	3 years 9 months
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average expected life	4 years 9 months	4 years 3 months

Share-Based Awards - Option Awa

Share-Based Awards - Option Awards - Additional Information (Detail) $ in Millions	Mar. 31, 2017USD ($)
Option Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized cost of unvested share-based compensation awards	$ 205.6

Summary of Restricted Stock Uni

Summary of Restricted Stock Units Activity (Detail) - Restricted Stock Units	3 Months Ended
	Mar. 31, 2017$ / sharesshares
Restricted Stock Units
Unvested outstanding, beginning balance | shares	3,780,577
Granted | shares	1,636,649
Vested | shares	(351,710)
Forfeited or cancelled | shares	(190,168)
Unvested outstanding, ending balance | shares	4,875,348
Weighted-Average Grant-Date Fair Value
Unvested outstanding, beginning balance | $ / shares	$ 28.54
Granted | $ / shares	35.31
Vested | $ / shares	27.27
Forfeited or cancelled | $ / shares	26.81
Unvested outstanding, ending balance | $ / shares	$ 30.97

Share-Based Awards - Restricted

Share-Based Awards - Restricted Stock Units - Additional Information (Detail) $ in Millions	Mar. 31, 2017USD ($)
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost	$ 141.1

Effects of Share Based Compensa

Effects of Share Based Compensation in Consolidated Statements of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation	$ 26,395	$ 25,551
Cost of Revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation	903	786
Sales and Marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation	5,530	5,203
Technology and Development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation	8,491	6,759
General and Administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation	$ 11,471	$ 12,803

Antidilutive Securities Exclude

Antidilutive Securities Excluded from Computation of Earnings Per Share (Detail) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Class A Common Stock and Class C Capital Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Class A common stock and Class C capital stock equivalents excluded from calculations of diluted net income (loss) per share	32,480	22,247
Class A Common Stock and Class C Capital Stock | Option Awards And Stock Appreciation Rights | Weighted Average
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Class A common stock and Class C capital stock equivalents excluded from calculations of diluted net income (loss) per share	27,994	9,994
Class A Common Stock and Class C Capital Stock | Restricted Stock Awards and Restricted Stock Units | Weighted Average
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Class A common stock and Class C capital stock equivalents excluded from calculations of diluted net income (loss) per share	4,042	2,718
Class A Common Stock | 2.75% Convertible Senior Notes Due 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Class A common stock and Class C capital stock equivalents excluded from calculations of diluted net income (loss) per share	444	9,535

Net Loss Per Share - Additional

Net Loss Per Share - Additional Information (Detail) - 2.00% Convertible Senior Notes Due 2021 shares in Millions	3 Months Ended
	Mar. 31, 2017$ / sharesshares
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Conversion spread, shares | shares	8.8
Class C Capital Stock
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Conversion price | $ / shares	$ 52.36

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	Feb. 09, 2017	May 05, 2016	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Other Commitments [Line Items]
Operating lease expense			$ 5,000,000	$ 3,900,000
Amortization periods description			For contracts in which we have perpetual rights to the data and expect to utilize the data beyond the life of the contract, the total contract value is amortized on a straight-line basis over the life of the contract plus two years, which is equivalent to the estimated useful life of the asset.
Outstanding surety bonds			$ 3,500,000		$ 3,600,000
Minimum
Other Commitments [Line Items]
Estimate useful life of the asset			5 years
Maximum
Other Commitments [Line Items]
Estimate useful life of the asset			9 years
Ian Freeman Vs Zillow Inc [Member]
Other Commitments [Line Items]
Loss contingency accrual			$ 6,000,000		6,000,000
Ian Freeman Vs Zillow Inc [Member] | Maximum
Other Commitments [Line Items]
Settlement of lawsuit		$ 6,000,000
VHT Vs Zillow Group Inc [Member]
Other Commitments [Line Items]
Jury awarded damages	$ 79,875
Estimated immaterial liability			0		$ 0
VHT Vs Zillow Group Inc [Member] | Statutory Damages
Other Commitments [Line Items]
Jury awarded damages	$ 8,200,000
VHT Vs Zillow Group Inc [Member] | Minimum
Other Commitments [Line Items]
Estimated range of loss			0
VHT Vs Zillow Group Inc [Member] | Maximum
Other Commitments [Line Items]
Estimated range of loss			8,300,000
San Francisco, California
Other Commitments [Line Items]
Outstanding letters of credit			5,200,000
Seattle, Washington
Other Commitments [Line Items]
Outstanding letters of credit			1,800,000
New York
Other Commitments [Line Items]
Outstanding letters of credit			1,100,000
Denver, Colorado
Other Commitments [Line Items]
Outstanding letters of credit			$ 1,100,000

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended
	Feb. 29, 2016	Mar. 31, 2016
Mr.Lloyd Frink
Related Party Transaction [Line Items]
Reimbursement of costs incurred	$ 0.2
Mr.Richard Barton
Related Party Transaction [Line Items]
Reimbursement of costs incurred	$ 0.2
Accrual gross-up payment		$ 0.1

Self-Insurance - Additional Inf

Self-Insurance - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Insurance [Line Items]
Minimum amount of individual claim under self insurance plan	$ 150,000
Liability for self-insured claims included in accrued compensation and benefits	$ 1,800,000	$ 1,700,000
Minimum
Insurance [Line Items]
Percentage of cumulative medical claim under self insurance plan	125.00%

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Detail) - Zillow Merger - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Defined Contribution Plan Disclosure [Line Items]
Company's expense related to its defined contribution 401(k) retirement plans	$ 2.9	$ 2.4
Maximum
Defined Contribution Plan Disclosure [Line Items]
Company's contribution based on employee contribution	4.00%

Segment Information and Reven67

Segment Information and Revenue - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2017Segment
Segment Reporting [Abstract]
Number of reportable segment	1

Revenue Categories (Detail)

Revenue Categories (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Revenues:
Total Marketplace revenue	$ 230,326	$ 168,961
Display revenue	15,449	17,021
Total revenue	245,775	185,982
Premier Agent
Revenues:
Total Marketplace revenue	175,301	134,529
Other Real Estate
Revenues:
Total Marketplace revenue	34,755	17,978
Mortgages Revenue
Revenues:
Total Marketplace revenue	$ 20,270	$ 16,454