Zillow (Z) 10-Q 7 Aug 19 2019 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2019	Jul. 31, 2019
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Jun. 30, 2019
Entity File Number	001-36853
Entity Registrant Name	ZILLOW GROUP, INC.
Entity Central Index Key	0001617640
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Incorporation, State or Country Code	WA
Entity Tax Identification Number	47-1645716
Entity Address, Address Line One	1301 Second Avenue
Entity Address, Address Line Two	Floor 31
Entity Address, City or Town	Seattle
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98101
City Area Code	206
Local Phone Number	470-7000
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Class A Common Stock
Entity Information [Line Items]
Title of 12(b) Security	Class A Common Stock, par value $0.0001 per share
Trading Symbol	ZG
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		58,486,480
Class B Common Stock
Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		6,217,447
Class C Capital Stock
Entity Information [Line Items]
Title of 12(b) Security	Class C Capital Stock, par value $0.0001 per share
Trading Symbol	Z
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		141,903,904

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 766,698	$ 651,058
Short-term investments	673,029	903,867
Accounts receivable, net of allowance for doubtful accounts of $4,809 and $4,838 at June 30, 2019 and December 31, 2018, respectively	82,261	66,083
Mortgage loans held for sale	38,653	35,409
Inventory	552,823	162,829
Prepaid expenses and other current assets	62,062	61,067
Restricted cash	43,882	12,385
Total current assets	2,219,408	1,892,698
Contract cost assets	46,271	45,819
Property and equipment, net	145,932	135,172
Right of use assets	210,080
Goodwill	1,984,907	1,984,907
Intangible assets, net	202,824	215,904
Other assets	16,498	16,616
Total assets	4,825,920	4,291,116
Current liabilities:
Accounts payable	8,028	7,471
Accrued expenses and other current liabilities	68,520	63,101
Accrued compensation and benefits	32,001	31,388
Revolving credit facilities	409,799	116,700
Warehouse lines of credit	30,057	33,018
Deferred revenue	37,080	34,080
Deferred rent, current portion		1,740
Lease liabilities, current portion	18,794
Total current liabilities	604,279	287,498
Deferred rent, net of current portion		19,945
Lease liabilities, net of current portion	211,593
Long-term debt	716,819	699,020
Deferred tax liabilities and other long-term liabilities	15,123	17,474
Total liabilities	1,547,814	1,023,937
Commitments and contingencies (Note 17)
Shareholders’ equity:
Preferred stock, $0.0001 par value; 30,000,000 shares authorized; no shares issued and outstanding	0	0
Additional paid-in capital	4,088,470	3,939,842
Accumulated other comprehensive income (loss)	896	(905)
Accumulated deficit	(811,281)	(671,779)
Total shareholders’ equity	3,278,106	3,267,179
Total liabilities and shareholders’ equity	4,825,920	4,291,116
Class A Common Stock
Shareholders’ equity:
Common stock/capital stock	6	6
Class B Common Stock
Shareholders’ equity:
Common stock/capital stock	1	1
Class C Capital Stock
Shareholders’ equity:
Common stock/capital stock	$ 14	$ 14

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Allowance for doubtful accounts	$ 4,809	$ 4,838
Preferred stock, par value (usd per share)	$ 0.0001	$ 0.0001
Preferred stock, authorized (in shares)	30,000,000	30,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Class A Common Stock
Common stock, par value (usd per share)	$ 0.0001	$ 0.0001
Common stock, authorized (in shares)	1,245,000,000	1,245,000,000
Common stock, issued (in shares)	58,474,815	58,051,448
Common stock, outstanding (in shares)	58,474,815	58,051,448
Class B Common Stock
Common stock, par value (usd per share)	$ 0.0001	$ 0.0001
Common stock, authorized (in shares)	15,000,000	15,000,000
Common stock, issued (in shares)	6,217,447	6,217,447
Common stock, outstanding (in shares)	6,217,447	6,217,447
Class C Capital Stock
Common stock, par value (usd per share)	$ 0.0001	$ 0.0001
Common stock, authorized (in shares)	600,000,000	600,000,000
Common stock, issued (in shares)	141,821,374	139,635,370
Common stock, outstanding (in shares)	141,821,374	139,635,370

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenue:
Revenue		$ 599,578	$ 325,246	$ 1,053,682	$ 625,125
Cost of revenue (exclusive of amortization)
Cost of revenue		271,221	25,527	422,569	49,446
Sales and marketing		187,433	147,727	349,020	285,018
Technology and development		120,330	100,376	228,100	194,309
General and administrative		82,839	60,579	178,613	116,652
Acquisition-related costs		0	632	0	659
Integration costs		293	0	645	0
Total costs and expenses		662,116	334,841	1,178,947	646,084
Loss from operations		(62,538)	(9,595)	(125,265)	(20,959)
Other income		9,458	3,089	18,626	5,535
Interest expense		(18,897)	(7,187)	(35,363)	(14,260)
Loss before income taxes		(71,977)	(13,693)	(142,002)	(29,684)
Income tax benefit		0	10,600	2,500	8,000
Net loss		$ (71,977)	$ (3,093)	$ (139,502)	$ (21,684)
Net loss per share - basic and diluted (usd per share)		$ (0.35)	$ (0.02)	$ (0.68)	$ (0.11)
Weighted-average shares outstanding - basic and diluted (in shares)		205,754	194,155	205,137	192,807
Amortization of website development costs and intangible assets included in technology and development		$ 11,000	$ 12,600	$ 22,000	$ 25,600
Technology and Development
Cost of revenue (exclusive of amortization)
Amortization of website development costs and intangible assets included in technology and development		14,656	21,020	29,056	43,569
IMT
Revenue:
Revenue		323,669	305,941	621,941	586,797
Cost of revenue (exclusive of amortization)
Cost of revenue	[1]	26,059	24,290	50,310	46,884
Sales and marketing		135,440	137,972	262,094	266,719
Technology and development		94,261	91,131	182,230	177,048
General and administrative		54,671	52,438	125,521	102,625
Acquisition-related costs		0	0	0	27
Integration costs		0	0	0	0
Total costs and expenses		310,431	305,831	620,155	593,303
Loss from operations		13,238	110	1,786	(6,506)
Other income		0	0	0	0
Interest expense		0	0	0	0
Loss before income taxes		13,238	110	1,786	(6,506)
Homes
Revenue:
Revenue		248,924	0	377,396	0
Cost of revenue (exclusive of amortization)
Cost of revenue	[1]	240,732	0	363,151	86
Sales and marketing		37,409	2,095	58,271	2,385
Technology and development		18,198	3,790	30,479	6,026
General and administrative		17,808	4,176	32,165	5,954
Acquisition-related costs		0	0	0	0
Integration costs		0	0	0	0
Total costs and expenses		314,147	10,061	484,066	14,451
Loss from operations		(65,223)	(10,061)	(106,670)	(14,451)
Other income		0	0	0	0
Interest expense		(5,899)	0	(9,657)	0
Loss before income taxes		(71,122)	(10,061)	(116,327)	(14,451)
Mortgages
Revenue:
Revenue		26,985	19,305	54,345	38,328
Cost of revenue (exclusive of amortization)
Cost of revenue	[1]	4,430	1,237	9,108	2,476
Sales and marketing		14,584	7,660	28,655	15,914
Technology and development		7,871	5,455	15,391	11,235
General and administrative		10,360	3,965	20,927	8,073
Acquisition-related costs		0	632	0	632
Integration costs		293	0	645	0
Total costs and expenses		37,538	18,949	74,726	38,330
Loss from operations		(10,553)	356	(20,381)	(2)
Other income		402	0	715	0
Interest expense		(287)	0	(388)	0
Loss before income taxes		$ (10,438)	$ 356	$ (20,054)	$ (2)
[1]	Amortization of website development costs and intangible assets included in technology and development of $14,656 and $21,020 for the three months ended June 30, 2019 and 2018, respectively and $29,056 and $43,569 for the six months ended June 30, 2019 and 2018, respectively.

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (71,977)	$ (3,093)	$ (139,502)	$ (21,684)
Other comprehensive income (loss):
Unrealized gains (losses) on investments	751	223	1,895	(109)
Currency translation adjustments	(52)	(44)	(94)	(66)
Total other comprehensive income (loss)	699	179	1,801	(175)
Comprehensive loss	$ (71,278)	$ (2,914)	$ (137,701)	$ (21,859)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Class A Common Stock, Class B Common Stock and Class C Capital Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Dec. 31, 2017	$ 2,660,823	$ 20	$ 3,254,146	$ (592,243)	$ (1,100)
Beginning Balance (in shares) at Dec. 31, 2017		190,115,148,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common and capital stock upon exercise of stock options	99,653		99,653
Issuance of common and capital stock upon exercise of stock options (in shares)		4,479,759,000
Vesting of restricted stock units	0
Vesting of restricted stock units (in shares)		834,788,000
Shares and value of restricted stock units withheld for tax liability	(65)		(65)
Shares and value of restricted stock units withheld for tax liability (in shares)		(1,318,000)
Share-based compensation expense	74,307		74,307
Portion of conversion recorded in additional paid-in-capital in connection with partial conversion of convertible notes maturing in 2020	500		500
Portion of conversion recorded in additional paid-in-capital in connection with partial conversion of convertible notes maturing in 2020 (in shares)		20,727,000
Net loss	(21,684)			(21,684)
Other comprehensive income (loss)	(175)				(175)
Ending Balance at Jun. 30, 2018	2,853,681	$ 20	3,428,541	(573,605)	(1,275)
Ending Balance (in shares) at Jun. 30, 2018		195,449,104,000
Beginning Balance at Mar. 31, 2018	2,768,441	$ 20	3,340,387	(570,512)	(1,454)
Beginning Balance (in shares) at Mar. 31, 2018		192,944,326,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common and capital stock upon exercise of stock options	46,747		46,747
Issuance of common and capital stock upon exercise of stock options (in shares)		2,065,545,000
Vesting of restricted stock units	0
Vesting of restricted stock units (in shares)		439,944,000
Shares and value of restricted stock units withheld for tax liability	(37)		(37)
Shares and value of restricted stock units withheld for tax liability (in shares)		(711,000)
Share-based compensation expense	41,444		41,444
Net loss	(3,093)			(3,093)
Other comprehensive income (loss)	179				179
Ending Balance at Jun. 30, 2018	2,853,681	$ 20	3,428,541	(573,605)	(1,275)
Ending Balance (in shares) at Jun. 30, 2018		195,449,104,000
Beginning Balance at Dec. 31, 2018	3,267,179	$ 21	3,939,842	(671,779)	(905)
Beginning Balance (in shares) at Dec. 31, 2018		203,904,265,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common and capital stock upon exercise of stock options	$ 32,997		32,997
Issuance of common and capital stock upon exercise of stock options (in shares)	1,543,850	1,543,850,000
Vesting of restricted stock units	$ 0
Vesting of restricted stock units (in shares)		1,065,607,000
Shares and value of restricted stock units withheld for tax liability	(3)		(3)
Shares and value of restricted stock units withheld for tax liability (in shares)		(86,000)
Share-based compensation expense	115,634		115,634
Net loss	(139,502)			(139,502)
Other comprehensive income (loss)	1,801				1,801
Ending Balance at Jun. 30, 2019	3,278,106	$ 21	4,088,470	(811,281)	896
Ending Balance (in shares) at Jun. 30, 2019		206,513,636,000
Beginning Balance at Mar. 31, 2019	3,283,132	$ 21	4,022,218	(739,304)	197
Beginning Balance (in shares) at Mar. 31, 2019		205,130,332,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common and capital stock upon exercise of stock options	19,433		19,433
Issuance of common and capital stock upon exercise of stock options (in shares)		814,062,000
Vesting of restricted stock units	0
Vesting of restricted stock units (in shares)		569,260,000
Shares and value of restricted stock units withheld for tax liability	(1)		(1)
Shares and value of restricted stock units withheld for tax liability (in shares)		(18,000)
Share-based compensation expense	46,820		46,820
Net loss	(71,977)			(71,977)
Other comprehensive income (loss)	699				699
Ending Balance at Jun. 30, 2019	$ 3,278,106	$ 21	$ 4,088,470	$ (811,281)	$ 896
Ending Balance (in shares) at Jun. 30, 2019		206,513,636,000

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating activities
Net loss	$ (139,502)	$ (21,684)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	41,728	52,926
Share-based compensation expense	109,756	69,684
Amortization of right of use assets	10,572
Amortization of contract cost assets	17,880	18,309
Amortization of discount and issuance costs on convertible notes maturing in 2023 and 2021	17,799	9,504
Deferred income taxes	(2,500)	(8,000)
Loss on disposal of property and equipment	3,878	2,106
Bad debt expense	706	(352)
Deferred rent	0	(2,845)
Accretion of bond discount	(3,695)	(504)
Changes in operating assets and liabilities:
Accounts receivable	(16,884)	(9,335)
Mortgage loans held for sale	(3,244)	0
Inventory	(389,994)	(5,666)
Prepaid expenses and other assets	(2,015)	(14,697)
Lease liabilities	(11,946)
Contract cost assets	(18,332)	(21,371)
Accounts payable	1,256	1,855
Accrued expenses and other current liabilities	6,952	(5,189)
Accrued compensation and benefits	613	4,309
Deferred revenue	3,000	4,002
Other long-term liabilities	149	0
Net cash provided by (used in) operating activities	(373,823)	73,052
Investing activities
Proceeds from maturities of investments	539,312	172,573
Purchases of investments	(302,891)	(230,276)
Purchases of property and equipment	(29,672)	(31,212)
Purchases of intangible assets	(8,927)	(4,777)
Net cash provided by (used in) investing activities	197,822	(93,692)
Financing activities
Proceeds from borrowing on revolving credit facilities	293,099	0
Net repayments on warehouse lines of credit	(2,961)	0
Proceeds from exercise of stock options	32,997	99,656
Value of equity awards withheld for tax liability	3	(66)
Net cash provided by financing activities	323,138	99,590
Net increase in cash, cash equivalents and restricted cash during period	147,137	78,950
Cash, cash equivalents and restricted cash at beginning of period	663,443	352,095
Cash, cash equivalents and restricted cash at end of period	810,580	431,045
Supplemental disclosures of cash flow information
Cash paid for interest	16,616	4,733
Noncash transactions:
Capitalized share-based compensation	5,878	4,623
Write-off of fully depreciated property and equipment	9,867	13,293
Write-off of fully amortized intangible assets	$ 3,311	$ 10,797

Organization and Description of

Organization and Description of Business	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Organization and Description of Business	Organization and Description of Business Zillow Group, Inc. houses one of the largest portfolios of real estate brands on mobile and the web. Zillow Group is committed to leveraging its proprietary data, technology and innovations to make home buying, selling, financing and renting a seamless, on-demand experience for consumers. As its flagship brand, Zillow now offers a fully integrated home shopping experience that includes access to for sale and rental listings, Zillow Offers, which provides a new, hassle-free way to buy and sell homes directly through Zillow, and Zillow Home Loans, Zillow’s affiliated lender that provides an easy way to receive mortgage pre-approvals and financing. Other consumer brands include Trulia, StreetEasy, HotPads, Naked Apartments, RealEstate.com and Out East. In addition, Zillow Group provides a comprehensive suite of marketing software and technology solutions to help real estate professionals maximize business opportunities and connect with millions of consumers. Zillow Group also operates a number of business brands for real estate, rental and mortgage professionals, including Mortech, dotloop, Bridge Interactive and New Home Feed. 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: rates of revenue growth; our ability to manage advertising inventory or pricing; engagement and usage of our products; our investment of resources to pursue strategies that may not prove effective; competition in our market; the stability of the residential real estate market and the impact of interest rate changes; changes in government regulation affecting our business; outcomes of legal proceedings; natural disasters and catastrophic events; scaling and adaptation of existing technology and network infrastructure; management of our growth; our ability to attract and retain qualified employees and key personnel; our ability to successfully integrate and realize the benefits of our past or future strategic acquisitions or investments; protection of customers’ information and other privacy concerns; protection of our brand and intellectual property; and intellectual property infringement and other claims, among other things.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	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 for the year ended December 31, 2018 , which was filed with the SEC on February 21, 2019. The condensed consolidated balance sheet as of December 31, 2018 , included herein, was derived from the audited financial statements of Zillow Group, Inc. as of that date. 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 June 30, 2019 , our results of operations, comprehensive loss and shareholders’ equity for the three and six month periods ended June 30, 2019 and 2018 , and our cash flows for the six month periods ended June 30, 2019 and 2018 . The results of the three and six month periods ended June 30, 2019 are not necessarily indicative of the results to be expected for the year ending December 31, 2019 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 the net realizable value of inventory, amortization period and recoverability of contract cost assets, website and software development costs, recoverability of long-lived assets and intangible assets with definite lives, share-based compensation, income taxes, business combinations, and the recoverability of goodwill and indefinite-lived intangible assets, among others. To the extent there are material differences between these estimates, judgments or assumptions and actual results, our financial statements will be affected. Recently Issued Accounting Standards Not Yet Adopted In August 2018, the Financial Accounting Standards Board (“FASB”) issued guidance related to a customer’s accounting for implementation costs incurred in hosting arrangements. The guidance aligns the requirements for capitalizing implementation costs incurred in cloud computing arrangements with the requirements for capitalizing costs to develop or obtain internal-use software. This guidance is effective for interim and annual reporting periods beginning after December 15, 2019, and early adoption is permitted. This guidance may be applied either retrospectively or prospectively. We expect to adopt this guidance on January 1, 2020. 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 August 2018, the FASB issued guidance related to disclosure requirements for fair value measurements. This guidance removes, modifies and adds disclosures related to fair value measurements. This guidance is effective for interim and annual periods beginning after December 15, 2019, and early adoption is permitted. The amendments on changes in unrealized gains and losses, the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements and the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim and annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. We expect to adopt this guidance on January 1, 2020. We have not yet determined the impact the adoption of this guidance will have on our financial statement disclosures. In June 2016, and subsequently amended in April 2019 and May 2019, the FASB issued guidance on the measurement of credit losses on financial instruments. This guidance will require an entity to measure credit losses for certain financial instruments and financial assets, including trade receivables. This guidance requires an entity to recognize an allowance that reflects the entity’s current estimate of credit losses expected to be incurred over the life of the financial instrument on initial recognition and at each reporting period. This guidance is effective for interim and annual reporting periods beginning after December 15, 2019, and early adoption is permitted for interim and annual reporting periods beginning after December 15, 2018. The adoption of this guidance requires a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. We expect to adopt this guidance on January 1, 2020. We have not yet determined the impact the adoption of this guidance will have on our financial position, results of operations or cash flows.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	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 — The fair value measurement of money market funds is based on quoted market prices in active markets. The fair value measurement of commercial paper is based on observable market-based inputs or inputs that are derived principally from or corroborated by observable market data by correlation or other means. Short-term investments — The fair value measurement of our short-term investments is based on observable market-based inputs or inputs that are derived principally from or corroborated by observable market data by correlation or other means. Restricted cash — Restricted cash consists of cash received from the resale of homes through Zillow Offers which may be used to repay amounts borrowed on our revolving credit facilities (see Note 13 ) and amounts held in escrow related to funding home purchases in our mortgage origination business. The carrying value of restricted cash approximates fair value due to the short period of time amounts borrowed on the revolving credit facilities are outstanding. Mortgage loans held for sale — The fair value of mortgage loans held for sale is generally calculated by reference to quoted prices in secondary markets for commitments to sell mortgage loans with similar characteristics. Interest rate lock commitments — The fair value of interest rate lock commitments (“IRLCs”) is calculated by reference to quoted prices in secondary markets for commitments to sell mortgage loans with similar characteristics. Expired commitments are excluded from the fair value measurement. We generally only issue IRLCs for products that meet specific purchaser guidelines. Since not all IRLCs will become closed loans, we adjust our fair value measurements for the estimated amount of IRLCs that will not close. Forward contracts — The fair value of mandatory loan sales commitments and derivative instruments such as forward sales of mortgage-backed securities that are utilized as hedging instruments are calculated by reference to quoted prices for similar assets. The following tables present the balances of assets and liabilities measured at fair value on a recurring basis, by level within the fair value hierarchy, as of the dates presented (in thousands): June 30, 2019 Total Level 1 Level 2 Cash equivalents: Money market funds $ 641,436 $ 641,436 $ — Short-term investments: U.S. government agency securities 446,736 — 446,736 Corporate notes and bonds 94,922 — 94,922 Commercial paper 87,062 — 87,062 Municipal securities 33,352 — 33,352 Foreign government securities 5,997 — 5,997 Certificates of deposit 1,481 — 1,481 Treasury bills 3,479 — 3,479 Mortgage origination-related: Mortgage loans held for sale 38,653 — 38,653 IRLCs 1,186 — 1,186 Forward contracts - other current assets 32 — 32 Forward contracts - other current liabilities (225 ) — (225 ) Total $ 1,354,111 $ 641,436 $ 712,675 December 31, 2018 Total Level 1 Level 2 Cash equivalents: Money market funds $ 541,575 $ 541,575 $ — Commercial paper 3,999 — 3,999 Short-term investments: U.S. government agency securities 646,496 — 646,496 Corporate notes and bonds 112,933 — 112,933 Commercial paper 85,506 — 85,506 Municipal securities 39,306 — 39,306 Foreign government securities 14,915 — 14,915 Certificates of deposit 4,711 — 4,711 Mortgage origination-related: Mortgage loans held for sale 35,409 — 35,409 IRLCs 847 — 847 Forward contracts - other current liabilities (125 ) — (125 ) Total $ 1,485,572 $ 541,575 $ 943,997 At June 30, 2019 , the notional amounts of the hedging instruments related to our mortgage loans held for sale were $45.7 million and $80.6 million for our IRLCs and forward contracts, respectively. At December 31, 2018 , the notional amounts of the hedging instruments related to our mortgage loans held for sale were $26.7 million and $28.8 million for our IRLCs and forward contracts, respectively. We do not have the right to offset our forward contract derivative positions. See Note 13 for the carrying amount and estimated fair value of the Company’s convertible senior notes. We did no t have material Level 3 assets or liabilities as of June 30, 2019 or December 31, 2018

Cash and Cash Equivalents, Shor

Cash and Cash Equivalents, Short-term Investments and Restricted Cash	6 Months Ended
	Jun. 30, 2019
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents, Short-term Investments and Restricted Cash	Cash and Cash Equivalents, Short-term 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 investments and restricted cash as of the dates presented (in thousands): June 30, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Market Value Cash $ 125,262 $ — $ — $ 125,262 Cash equivalents: Money market funds 641,436 — — 641,436 Short-term investments: U.S. government agency securities 446,098 668 (30 ) 446,736 Corporate notes and bonds 94,739 184 (1 ) 94,922 Commercial paper 87,062 — — 87,062 Municipal securities 33,253 99 — 33,352 Foreign government securities 5,996 1 — 5,997 Certificates of deposit 1,481 — — 1,481 Treasury bills 3,475 4 — 3,479 Restricted cash 43,882 — — 43,882 Total $ 1,482,684 $ 956 $ (31 ) $ 1,483,609 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Market Value Cash $ 105,484 $ — $ — $ 105,484 Cash equivalents: Money market funds 541,575 — — 541,575 Commercial paper 3,999 — — 3,999 Short-term investments: U.S. government agency securities 647,266 51 (821 ) 646,496 Corporate notes and bonds 113,109 1 (177 ) 112,933 Commercial paper 85,506 — — 85,506 Municipal securities 39,316 23 (33 ) 39,306 Foreign government securities 14,929 — (14 ) 14,915 Certificates of deposit 4,711 1 (1 ) 4,711 Restricted cash 12,385 — — 12,385 Total $ 1,568,280 $ 76 $ (1,046 ) $ 1,567,310 The following table presents available-for-sale investments by contractual maturity date as of June 30, 2019 (in thousands): Amortized Cost Estimated Fair Market Value Due in one year or less $ 651,437 $ 652,206 Due after one year through two years 20,667 20,823 Total $ 672,104 $ 673,029

Accounts Receivable, net

Accounts Receivable, net	6 Months Ended
	Jun. 30, 2019
Receivables [Abstract]
Accounts Receivable, net	Accounts Receivable, net The opening balance of accounts receivable, net was $66.1 million as of January 1, 2019. The following table presents the changes in the allowance for doubtful accounts (in thousands): Balance as of January 1, 2019 $ 4,838 Bad debt expense 706 Less: write-offs, net of recoveries and other adjustments (735 ) Balance as of June 30, 2019 $ 4,809

Inventory

Inventory	6 Months Ended
	Jun. 30, 2019
Inventory Disclosure [Abstract]
Inventory	Inventory The following table presents the components of inventory, net of applicable lower of cost or net realizable value adjustments, as of the dates presented (in thousands): June 30, December 31, Work-in-progress $ 174,272 $ 45,943 Finished goods 378,551 116,886 Inventory $ 552,823 $ 162,829

Contract Cost Assets

Contract Cost Assets	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Contract Cost Assets	Contract Cost Assets As of June 30, 2019 and December 31, 2018 , we had $46.3 million and $45.8 million , respectively, of contract cost assets. During the three and six month periods ended June 30, 2019 and 2018 , we recorded no impairment losses. We recorded amortization expense related to contract cost assets of $9.2 million and $9.0 million during the three months ended June 30, 2019 and 2018 , respectively, and $17.9 million and $18.3 million during the six months ended June 30, 2019 and 2018 , respectively. The following tables present the changes in deferred revenue for the periods presented (in thousands): Three Months Ended Balance as of April 1, 2019 $ 36,105 Deferral of revenue 259,132 Less: Revenue recognized (258,157 ) Balance as of June 30, 2019 $ 37,080 Six Months Ended Balance as of January 1, 2019 $ 34,080 Deferral of revenue 501,984 Less: Revenue recognized (498,984 ) Balance as of June 30, 2019 $ 37,080 During the three months ended June 30, 2019 we recognized as revenue a total of $33.0 million pertaining to amounts that were recorded in deferred revenue as of April 1, 2019. During the six months ended June 30, 2019 , we recognized as revenue a total of $30.9 million pertaining to amounts that were recorded in deferred revenue as of January 1, 2019.

Property and Equipment, net

Property and Equipment, net	6 Months Ended
	Jun. 30, 2019
Property, Plant and Equipment [Abstract]
Property and Equipment, net	Property and Equipment, net The following table presents the detail of property and equipment as of the dates presented (in thousands): June 30, December 31, Website development costs $ 153,905 $ 149,891 Leasehold improvements 77,737 65,012 Office equipment, furniture and fixtures 43,484 39,510 Construction-in-progress 27,293 29,037 Computer equipment 23,024 22,477 Property and equipment 325,443 305,927 Less: accumulated amortization and depreciation (179,511 ) (170,755 ) Property and equipment, net $ 145,932 $ 135,172 We recorded depreciation expense related to property and equipment (other than website development costs) of $6.4 million and $4.9 million during the three months ended June 30, 2019 and 2018 , respectively, and $12.4 million and $9.1 million during the six months ended June 30, 2019 and 2018 , respectively. We capitalized $10.3 million and $10.0 million in website development costs during the three months ended June 30, 2019 and 2018 , respectively, and $20.3 million and $18.6 million during the six months ended June 30, 2019 and 2018 , respectively. Amortization expense for website development costs included in technology and development expenses was $3.6 million and $8.4 million during the three months ended June 30, 2019 and 2018 , respectively, and $7.0 million and $18.0 million during the six months ended June 30, 2019 and 2018 , respectively.

Equity Investment

Equity Investment	6 Months Ended
	Jun. 30, 2019
Equity Method Investments and Joint Ventures [Abstract]
Equity Investment	Equity Investment In October 2016, we purchased a 10% equity interest in a privately held variable interest entity within the real estate industry for $10.0 million . 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 June 30, 2019 . This investment is an equity security without a readily determinable fair value which we account for at cost minus any impairment, plus or minus changes resulting from observable price changes in orderly transactions for identical or similar investments of the same issuer. There has been no impairment or upward or downward adjustments to our equity investment as of June 30, 2019 that would impact the carrying amount of the investment. The equity investment is classified within other assets in the condensed consolidated balance sheet.

Intangible Assets, net

Intangible Assets, net	6 Months Ended
	Jun. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets, net	Intangible Assets, net The following tables present the detail of intangible assets subject to amortization as of the dates presented (in thousands): June 30, 2019 Cost Accumulated Amortization Net Purchased content $ 43,886 $ (35,555 ) $ 8,331 Software 28,807 (16,850 ) 11,957 Customer relationships 103,600 (67,257 ) 36,343 Developed technology 109,080 (76,869 ) 32,211 Trade names and trademarks 4,400 (4,400 ) — Lender licenses 400 (117 ) 283 Intangibles-in-progress 5,699 — 5,699 Total $ 295,872 $ (201,048 ) $ 94,824 December 31, 2018 Cost Accumulated Amortization Net Purchased content $ 42,110 $ (30,477 ) $ 11,633 Software 24,296 (13,925 ) 10,371 Customer relationships 103,900 (60,733 ) 43,167 Developed technology 111,980 (72,788 ) 39,192 Trade names and trademarks 4,900 (4,683 ) 217 Lender licenses 400 (17 ) 383 Intangibles-in-progress 2,941 — 2,941 Total $ 290,527 $ (182,623 ) $ 107,904 Amortization expense recorded for intangible assets for the three months ended June 30, 2019 and 2018 was $11.0 million and $12.6 million , respectively. Amortization expense recorded for intangible assets for the six months ended June 30, 2019 and 2018 was $22.0 million and $25.6 million , respectively. These amounts are included in technology and development expenses. We have an indefinite-lived intangible asset 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. The carrying value of the Trulia trade names and trademarks intangible asset was $108.0 million as of June 30, 2019 and December 31, 2018 . Intangibles-in-progress consists of software that is capitalizable but has not been placed in service.

Deferred Revenue

Deferred Revenue	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Deferred Revenue	Contract Cost Assets As of June 30, 2019 and December 31, 2018 , we had $46.3 million and $45.8 million , respectively, of contract cost assets. During the three and six month periods ended June 30, 2019 and 2018 , we recorded no impairment losses. We recorded amortization expense related to contract cost assets of $9.2 million and $9.0 million during the three months ended June 30, 2019 and 2018 , respectively, and $17.9 million and $18.3 million during the six months ended June 30, 2019 and 2018 , respectively. The following tables present the changes in deferred revenue for the periods presented (in thousands): Three Months Ended Balance as of April 1, 2019 $ 36,105 Deferral of revenue 259,132 Less: Revenue recognized (258,157 ) Balance as of June 30, 2019 $ 37,080 Six Months Ended Balance as of January 1, 2019 $ 34,080 Deferral of revenue 501,984 Less: Revenue recognized (498,984 ) Balance as of June 30, 2019 $ 37,080 During the three months ended June 30, 2019 we recognized as revenue a total of $33.0 million pertaining to amounts that were recorded in deferred revenue as of April 1, 2019. During the six months ended June 30, 2019 , we recognized as revenue a total of $30.9 million pertaining to amounts that were recorded in deferred revenue as of January 1, 2019.

Leases

Leases	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Leases	Leases Our lease portfolio is primarily composed of operating leases for our office space. We have lease agreements that include lease components (e.g., fixed rent) and non-lease components (e.g., common area maintenance), which are accounted for as a single component, as we have elected the practical expedient to group lease and non-lease components. We also elected the practical expedient to keep leases with an initial term of 12 months or less off the balance sheet and recognize the associated lease payments in the condensed consolidated statements of operations on a straight-line basis over the lease term. Our leases have remaining lease terms ranging from less than one year to twelve years , some of which include options to extend the lease term for up to an additional ten years . For example, our largest leases, which include our corporate headquarters in Seattle, Washington and office space in New York, New York and San Francisco, California, include options to renew the existing leases for either one or two periods of five years . When determining if a renewal option is reasonably certain of being exercised at lease commencement, we consider several factors, including but not limited to, contract-based, asset-based and entity-based factors. We reassess the term of existing leases if there is a significant event or change in circumstances within our control that affects whether we are reasonably certain to exercise an option to extend a lease. Examples of such events or changes include construction of significant leasehold improvements or other modifications or customizations to the underlying asset, relevant business decisions or subleases. In most cases, we have concluded that renewal options are not reasonably certain of being exercised, therefore, such renewals are not included in the right of use asset and lease liability. During the three months ended June 30, 2019 , it became reasonably certain that in a future period we would exercise the first of two five years renewal options related to the office space lease for our corporate headquarters in Seattle, Washington, due to the construction of significant leasehold improvements. Therefore, the payments associated with the renewal are now included in the measurement of the lease liability and right of use asset. As our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at the lease commencement date in determining the present value of the lease payments. For those leases that existed as of January 1, 2019, we used our incremental borrowing rate based on information available at that date. We apply a portfolio approach for determining the incremental borrowing rate based on the applicable lease terms and the current economic environment, and we utilize the assistance of third-party specialists to assist us in determining our yield curve. The components of our operating lease expense were as follows for the periods presented (in thousands): Three Months Ended Six Months Ended Operating lease cost $ 9,004 $ 15,527 Variable lease cost 4,965 9,746 Total lease cost $ 13,969 $ 25,273 Cash paid for amounts included in the measurement of lease liabilities for the three and six month periods ended June 30, 2019 was $7.2 million and $16.3 million , respectively. Right of use assets obtained in exchange for new operating lease obligations for the three and six month periods ended June 30, 2019 were $113.7 million . The weighted average remaining term for our leases as of June 30, 2019 was 9 years . The weighted average discount rate for our leases as of June 30, 2019 was 6.5% . Maturities of our operating lease liabilities by fiscal year were as follows as of June 30, 2019 (in thousands): Remainder of 2019 $ 15,106 2020 37,558 2021 41,089 2022 37,173 2023 34,990 All future years 164,992 Total lease payments 330,908 Less: Imputed interest (100,521 ) Present value of lease liabilities $ 230,387 Operating lease expense for the three and six month periods ended June 30, 2018 , was $5.6 million and $11.4 million , respectively. The following table presents our future minimum payments for all operating leases as of December 31, 2018, including future minimum payments for operating leases that had not yet commenced as of December 31, 2018 totaling $112.9 million (in thousands): 2019 $ 29,085 2020 38,060 2021 40,099 2022 37,721 2023 36,458 All future years 85,462 Total future minimum lease payments $ 266,885

Debt

Debt	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Debt	Debt Revolving Credit Facilities To provide capital for Zillow Offers, we utilize revolving credit facilities that are classified as current liabilities in our condensed consolidated balance sheets. The following table summarizes our revolving credit facilities as of the periods presented (in thousands, except interest rates): Effective Date Maximum Borrowing Capacity Outstanding Borrowings at June 30, 2019 Outstanding Borrowings at December 31, 2018 Weighted Average Interest Rate July 31, 2018 $ 500,000 $ 265,097 $ 116,700 5.97 % January 31, 2019 500,000 144,702 — 5.95 % Total $ 1,000,000 $ 409,799 $ 116,700 On January 31, 2019, certain wholly owned subsidiaries of Zillow Group entered into a revolving credit agreement with Citibank, N.A., as the directing lender, and certain other parties thereto. The credit agreement provides for a maximum borrowing capacity of $500.0 million (the “Maximum Amount”) with a current borrowing capacity of $145.0 million as of June 30, 2019 , which amount may be increased up to the Maximum Amount subject to the satisfaction of certain conditions, through a non-recourse credit facility secured by a pledge of the equity of certain Zillow Group subsidiaries that purchase and sell select residential properties through Zillow Offers. The credit agreement has an initial term of two years and may be extended for up to two additional periods of six months each, subject to agreement by the directing lender. Zillow Group formed certain special purpose entities to effectuate the transactions contemplated by the January 31, 2019 revolving credit facility. Each special purpose entity is a wholly owned subsidiary of Zillow Group and a separate legal entity, and neither the assets nor credit of any such entity are available to satisfy the debts and other obligations of any affiliate or other entity. The July 31, 2018 revolving credit facility has an initial term of one year and automatically renews on a monthly basis as of July 31, 2019 for up to 24 additional months, subject to agreement by the directing lender. The revolving credit facility has a current borrowing capacity of $275.1 million as of June 30, 2019 . Zillow Group formed certain special purpose entities to effectuate the transactions contemplated by the July 31, 2018 revolving credit facility. Each special purpose entity is a wholly owned subsidiary of Zillow Group and a separate legal entity, and neither the assets nor credit of any such entity are available to satisfy the debts and other obligations of any affiliate or other entity. The stated interest rate on our revolving credit facilities is one-month LIBOR plus an applicable margin as defined in the respective credit agreements. Our revolving credit facilities include customary representations and warranties, covenants (including financial covenants applicable to Zillow Group) and provisions regarding events of default. As of June 30, 2019 , Zillow Group was in compliance with all financial covenants and no event of default had occurred. In certain circumstances Zillow Group may be obligated to fund some or all of the payment obligations under the credit agreement. Further, borrowings against any eligible property are due upon its sale or at maturity of the applicable facility, or if the property’s ownership period exceeds the agreed aging criteria. Each of the credit facilities permits only a portion of the financed properties to be owned longer than 180 days, and no financed properties may be owned for longer than one year. Any financed property excluded by such aging criteria will drop out of the borrowing base, and the applicable borrower will be required to repay any resulting overadvance. Our revolving credit facilities also require that we establish, maintain and in certain circumstances fund, certain specified reserve accounts. These reserve accounts include, but are not limited to, interest reserves, insurance, tax reserves, renovation cost reserves and special reserves. Amounts funded to these reserve accounts and the collection accounts have been classified within our consolidated balance sheets as restricted cash. For additional details related to our revolving credit facilities, see Note 14 in the Notes to Consolidated Financial Statements included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2018 . Warehouse Lines of Credit To provide capital for Zillow Home Loans, we utilize warehouse lines of credit that are classified as current liabilities in our condensed consolidated balance sheets. The following table summarizes our warehouse lines of credit as of the periods presented (in thousands, except interest rates): Maturity Date Maximum Borrowing Capacity Outstanding Borrowings at June 30, 2019 Outstanding Borrowings at December 31, 2018 Weighted Average Interest Rate July 15, 2019 $ 50,000 $ 15,722 $ 14,125 4.95 % June 27, 2020 50,000 14,335 18,892 4.95 % Total $ 100,000 $ 30,057 $ 33,017 On June 28, 2019, Zillow Home Loans amended and restated its warehouse line of credit previously maturing on June 29, 2019. The amended and restated credit agreement extends the term of the original agreement for one year , through June 27, 2020, and continues to provide for a maximum borrowing capacity of $50.0 million with availability under the warehouse line of credit limited depending on the types of loans originated. Borrowings on the warehouse lines of credit bear interest at the one-month LIBOR plus an applicable margin, as defined in the credit agreements governing the warehouse lines of credit. The warehouse lines of credit include customary representations and warranties, covenants and provisions regarding events of default. As of June 30, 2019, Zillow Group was in compliance with all financial covenants and no event of default had occurred. Convertible Senior Notes The following table summarizes our outstanding convertible senior notes as of the periods presented (in thousands, except interest rates): Maturity Date Aggregate Principal Amount Fair Value at June 30, 2019 Fair Value at December 31, 2018 Stated Interest Rate Effective Interest Rate July 1, 2023 $ 373,750 $ 370,095 $ 321,855 1.50 % 6.99 % December 1, 2021 460,000 521,318 446,200 2.00 % 7.44 % December 15, 2020 9,637 16,842 16,744 2.75 % N/A Total $ 843,387 $ 908,255 $ 784,799 The convertible notes are senior unsecured obligations and are classified as long-term debt in our condensed consolidated balance sheets. Interest on the convertible notes is paid semi-annually. As of June 30, 2019 and December 31, 2018 , respectively, the total unamortized debt discount and debt issuance costs for our outstanding senior convertible notes were $126.6 million and $144.4 million . The convertible senior notes maturing in 2023 and 2021 are not redeemable or convertible as of June 30, 2019 . The convertible senior notes maturing in 2020 are convertible, at the option of the holder, and redeemable, at our option, as of June 30, 2019 . For additional details related to our convertible senior notes, see Note 14 in the Notes to Consolidated Financial Statements included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2018

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We are subject to federal and state income taxes in the United States and in Canada. As of June 30, 2019 and December 31, 2018 , we have provided a valuation allowance against our net deferred tax assets that we believe, based on the weight of available evidence, are not more likely than not to be realized. Therefore, no material current tax liability or expense has been recorded in the condensed consolidated financial statements. We have accumulated federal tax losses of approximately $1,081.7 million as of December 31, 2018 , which are available to reduce future taxable income. We have accumulated state tax losses of approximately $32.5 million (tax effected) as of December 31, 2018 .

Share-Based Awards

Share-Based Awards	6 Months Ended
	Jun. 30, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Awards	Share-Based Awards Option Awards The following table summarizes option award activity for the six months ended June 30, 2019 : Number of Shares Subject to Existing Options Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Life (Years) Aggregate Intrinsic Value (in thousands) Outstanding at January 1, 2019 27,310,110 $ 34.04 6.23 $ 97,941 Granted 6,721,428 40.05 Exercised (1,543,850 ) 21.37 Forfeited or cancelled (1,419,750 ) 41.10 Outstanding at June 30, 2019 31,067,938 35.65 6.62 367,905 Vested and exercisable at June 30, 2019 17,363,786 31.63 4.87 266,575 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 Six Months Ended 2019 2018 2019 2018 Expected volatility 45% 43% 45%-47% 43%-45% Expected dividend yield — — — — Risk-free interest rate 2.00% 2.70% 2.00%-2.53% 2.52%-2.70% Weighted-average expected life 5.00 years 4.50 years 4.75-5.25 years 4.50-5.00 years Weighted-average fair value of options granted $16.96 $23.30 $16.79 $21.07 As of June 30, 2019 , there was a total of $210.7 million in unrecognized compensation cost related to unvested stock options. Restricted Stock Units The following table summarizes activity for restricted stock units for the six months ended June 30, 2019 : Restricted Stock Units Weighted- Average Grant- Date Fair Value Unvested outstanding at January 1, 2019 5,266,324 $ 42.19 Granted 3,638,550 39.32 Vested (1,065,607 ) 39.46 Forfeited or cancelled (601,829 ) 41.23 Unvested outstanding at June 30, 2019 7,237,438 41.23 As of June 30, 2019 , there was a total of $277.0 million in unrecognized compensation cost related to unvested restricted stock units. Share-Based Compensation Expense The following table presents the effects of share-based compensation expense in our condensed consolidated statements of operations during the periods presented (in thousands): Three Months Ended Six Months Ended 2019 2018 2019 2018 Cost of revenue $ 936 $ 1,256 $ 1,816 $ 2,211 Sales and marketing 6,801 6,340 12,451 11,502 Technology and development 18,399 14,347 33,908 25,889 General and administrative 17,496 17,000 61,581 30,082 Total $ 43,632 $ 38,943 $ 109,756 $ 69,684 On February 21, 2019, Zillow Group announced the appointment of Richard N. Barton as Zillow Group’s Chief Executive Officer, effective February 21, 2019. Mr. Barton succeeds Spencer Rascoff, who served as Zillow Group’s Chief Executive Officer since 2010 and who remains a member of Zillow Group’s board of directors. In connection with Mr. Rascoff’s resignation as Chief Executive Officer, Zillow Group entered into an Executive Departure Agreement and Release (the “Agreement”) with Mr. Rascoff. Pursuant to the Agreement, Mr. Rascoff remained a full-time employee of Zillow Group until March 22, 2019 (the “Departure Date”) in order to provide transition services until such date. Pursuant to the Agreement, Mr. Rascoff received, among other things, accelerated vesting of outstanding stock options held by Mr. Rascoff as of the Departure Date by an additional eighteen months from the Departure Date. Options not vested as of the Departure Date, taking into account the foregoing vesting acceleration, were terminated. Each of Mr. Rascoff’s vested stock options outstanding as of the Departure Date will remain exercisable until, except for any later date contemplated by the following proviso, the earlier of (x) the third anniversary of the Departure Date and (y) the latest day upon which the option would have expired by its original terms under any circumstances (the “Option Expiration Outside Date”); provided, however, that the options will remain exercisable for so long as Mr. Rascoff serves on Zillow Group’s board of directors (but not later than any applicable Option Expiration Outside Date), and if Mr. Rascoff ceases to serve on Zillow Group’s board of directors on or after the third anniversary of the Departure Date, each option will remain exercisable until the earlier of (i) ninety days from the final date of Mr. Rascoff’s service on Zillow Group’s board of directors and (ii) the applicable Option Expiration Outside Date. The change in the exercise period of the options as well as the vesting acceleration pursuant to the Agreement have been accounted for as equity modifications, and we recorded $26.4 million of share-based compensation expense associated with the modifications in the six months ended June 30, 2019. We measured the modification charge by calculating the incremental fair value of the modified award compared to the fair value of the original award immediately prior to the modification. The value of the modified awards as of the modification date was estimated using the Black-Scholes-Merton option-pricing model, assuming no dividends, expected volatility of 46% - 47% , a risk-free interest rate of 2.47% - 2.49% and a weighted-average expected life of 3.84-5.25 years.

Net Loss Per Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss 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 Six Months Ended 2019 2018 2019 2018 Weighted-average Class A common stock and Class C capital stock option awards outstanding 19,502 27,428 19,656 24,393 Weighted-average Class A common stock and Class C capital stock restricted stock units outstanding 7,230 5,246 6,548 4,799 Class A common stock issuable upon conversion of the convertible notes maturing in 2020 411 402 411 402 Class C capital stock issuable related to conversion spread on the convertible notes maturing in 2021 — 997 — 997 Total Class A common stock and Class C capital stock equivalents 27,143 34,073 26,615 30,591

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Lease Commitments We have entered into various non-cancelable operating lease agreements for certain of our office space and equipment with original lease periods expiring between 2019 and 2030 . For additional information regarding our lease agreements, see Note 12 . Purchase Commitments Purchase commitments primarily include various non-cancelable agreements to purchase content related to our mobile applications and websites as well as homes we are under contract to purchase through Zillow Offers but that have not closed as of the respective date. As of June 30, 2019 , the value of homes under contract that have not closed was $266.2 million . Letters of Credit As of June 30, 2019 , we have outstanding letters of credit of approximately $16.9 million , which secure our lease obligations in connection with certain of our office space operating leases. 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 $9.7 million and $8.9 million , respectively, as of June 30, 2019 and December 31, 2018 . 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 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. On June 20, 2017, the judge ruled and granted in part our motions, finding that VHT failed to present sufficient evidence to prove direct copyright infringement for a portion of the images, reducing the total damages to approximately $4.1 million . On March 15, 2019, after the Company had filed an appeal with the Ninth Circuit Court of Appeals seeking review of the final judgment and certain prior rulings entered by the district court, the Ninth Circuit Court of Appeals issued an opinion that, among other things, (i) affirmed the district court’s grant of summary judgment in favor of Zillow on direct infringement of images on Zillow’s listing site, (ii) affirmed the district court’s grant in favor of Zillow of judgment notwithstanding the verdict on certain images that were displayed on the Zillow Digs site, (iii) remanded consideration of the issue whether VHT’s images on the Zillow Digs site were part of a compilation or individual photos, and (iv) vacated the jury’s finding of willful infringement. On June 13, 2019, VHT filed a petition for writ of certiorari with the United States Supreme Court seeking review of certain rulings by the Ninth Circuit Court of Appeals. We have recorded an estimated liability for immaterial amounts related to this matter as of June 30, 2019 and December 31, 2018. We do not believe there is a reasonable possibility that a material loss in excess of amounts accrued may be incurred. In August and September 2017, two purported class action lawsuits were filed against us and certain of our executive officers, alleging, among other things, violations of federal securities laws on behalf of a class of those who purchased our common stock between February 12, 2016 and August 8, 2017. One of those purported class actions, captioned Vargosko v. Zillow Group, Inc. et al, was brought in the U.S. District Court for the Central District of California. The other purported class action lawsuit, captioned Shotwell v. Zillow Group, Inc. et al, was brought in the U.S. District Court for the Western District of Washington. The complaints allege, among other things, that during the period between February 12, 2016 and August 8, 2017, we issued materially false and misleading statements regarding our business practices. The complaints seek to recover, among other things, alleged damages sustained by the purported class members as a result of the alleged misconduct. In November 2017, an amended complaint was filed against us and certain of our executive officers in the Shotwell v. Zillow Group class action lawsuit, extending the beginning of the class period to November 17, 2014. In January 2018, the Vargosko v. Zillow Group purported class action lawsuit was transferred to the U.S. District Court for the Western District of Washington and consolidated with the Shotwell v. Zillow Group purported class action lawsuit. In February 2018, the plaintiffs filed a consolidated amended complaint, and in April 2018, we filed our motion to dismiss the consolidated amended complaint. In October 2018, our motion to dismiss was granted without prejudice, and the plaintiffs were given 45 days file a second consolidated amended complaint and attempt to cure the defects in their consolidated amended complaint. In November 2018, the plaintiffs filed a second consolidated amended complaint, which we moved to dismiss in December 2018. On April 19, 2019, our motion to dismiss the second consolidated amended complaint was denied, and we filed our answer to the second amended complaint on May 3, 2019. We have denied the allegations of wrongdoing and intend to vigorously defend the claims in this lawsuit. We have not recorded an accrual related to this lawsuit as of June 30, 2019 and December 31, 2018 , as we do not believe a loss is probable. In October and November 2017 and January and February 2018, four shareholder derivative lawsuits were filed in the U.S. District Court for the Western District of Washington and the Superior Court of the State of Washington, King County, against certain of our executive officers and directors seeking unspecified damages on behalf of the Company and certain other relief, such as reform to corporate governance practices. The plaintiffs in the derivative suits (in which the Company is a nominal defendant) allege, among other things, that the defendants breached their fiduciary duties in connection with oversight of the Company’s public statements and legal compliance, and as a result of the breach of such fiduciary duties, the Company was damaged, and defendants were unjustly enriched. Certain of the plaintiffs also allege, among other things, violations of Section 14(a) of the Securities Exchange Act of 1934 and waste of corporate assets. On February 5, 2018, the U.S. District Court for the Western District of Washington consolidated the two shareholder derivative lawsuits pending in that court. On February 16, 2018, the Superior Court of the State of Washington, King County, consolidated the two shareholder derivative lawsuits pending in that court. All four of the shareholder derivative lawsuits were stayed until our motion to dismiss the second consolidated amended complaint in the securities class action lawsuit discussed above was denied in April 2019. On July 8, 2019, the plaintiffs in the consolidated federal derivative lawsuit filed a consolidated shareholder derivative complaint, to which the defendants have 45 days to respond. The defendants intend to deny the allegations of wrongdoing and vigorously defend the claims in these lawsuits. We have not recorded an accrual related to these lawsuits as of June 30, 2019 and December 31, 2018 , as we do not believe a loss is probable. 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	6 Months Ended
	Jun. 30, 2019
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions On April 3, 2019, we entered into a Charter Service Agreement with Executive Jet Management, Inc. for the occasional use by us of an aircraft owned by an entity that is owned by Mr. Lloyd Frink, our Executive Chairman and President, for business travel. We recognized approximately $0.2 million in expenses pursuant to the Charter Service Agreement for the three and six month periods ended June 30, 2019 .

Self-Insurance

Self-Insurance	6 Months Ended
	Jun. 30, 2019
Insurance [Abstract]
Self-Insurance	Self-Insurance We are self-insured for medical benefits and dental benefits for all qualifying Zillow Group employees. The medical plan carries a stop-loss policy which provides protection when cumulative medical claims exceed 125% of expected claims for the plan year with a limit of $1.0 million and from individual claims during the plan year exceeding $500,000 . 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 claims is included within accrued compensation and benefits in our condensed consolidated balance sheets and was $3.6 million and $ 3.9 million , respectively, as of June 30, 2019 and December 31, 2018 .

Employee Benefit Plan

Employee Benefit Plan	6 Months Ended
	Jun. 30, 2019
Retirement Benefits [Abstract]
Employee Benefit Plan	Employee Benefit Plan We have a 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 $5.2 million and $4.0 million , respectively, for the three months ended June 30, 2019 and 2018 , and $10.1 million and $7.8 million , respectively, for the six months ended June 30, 2019 and 2018 .

Segment Information and Revenue

Segment Information and Revenue	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Segment Information and Revenue	Segment Information and Revenue Beginning January 1, 2019, we have three operating and reportable segments, which have been identified based on the way in which 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 for the Internet, Media & Technology (“IMT”), Homes and Mortgages segments. The IMT segment includes the financial results for the Premier Agent, Rentals and new construction marketplaces, dotloop, and display, as well as revenue from the sale of various other marketing and business products and services to real estate professionals. The Homes segment includes the financial results from Zillow Group’s purchase and sale of homes directly. The Mortgages segment includes financial results for advertising sold to mortgage lenders and other mortgage professionals, mortgage originations through Zillow Home Loans and the sale of mortgages on the secondary market, as well as Mortech mortgage software solutions. Revenue and costs are directly attributed to our segments when possible. However, due to the integrated structure of our business, certain costs incurred by one segment may benefit the other segments. These costs primarily include headcount-related expenses, general and administrative expenses including executive, finance, accounting, legal, human resources, recruiting, and facilities costs, product development and data acquisition costs and marketing and advertising costs. These costs are allocated to each segment based on the estimated benefit each segment receives from such expenditures. The chief executive officer reviews information about our revenue categories as well as statement of operations data inclusive of loss before income taxes by segment. This information is included in the following tables for the periods presented (in thousands): Three Months Ended Three Months Ended IMT Homes Mortgages IMT Homes Mortgages Revenue: Premier Agent $ 231,961 $ — $ — $ 230,885 $ — $ — Rentals 42,670 — — 33,288 — — Other 49,038 — — 41,768 — — Homes — 248,924 — — — — Mortgages — — 26,985 — — 19,305 Total revenue 323,669 248,924 26,985 305,941 — 19,305 Costs and expenses: Cost of revenue 26,059 240,732 4,430 24,290 — 1,237 Sales and marketing 135,440 37,409 14,584 137,972 2,095 7,660 Technology and development 94,261 18,198 7,871 91,131 3,790 5,455 General and administrative 54,671 17,808 10,360 52,438 4,176 3,965 Acquisition-related costs — — — — — 632 Integration costs — — 293 — — — Total costs and expenses 310,431 314,147 37,538 305,831 10,061 18,949 Income (loss) from operations 13,238 (65,223 ) (10,553 ) 110 (10,061 ) 356 Segment other income — — 402 — — — Segment interest expense — (5,899 ) (287 ) — — — Income (loss) before income taxes (1) $ 13,238 $ (71,122 ) $ (10,438 ) $ 110 $ (10,061 ) $ 356 Six Months Ended Six Months Ended IMT Homes Mortgages IMT Homes Mortgages Revenue: Premier Agent $ 449,696 $ — $ — $ 444,617 $ — $ — Rentals 80,508 — — 62,351 — — Other 91,737 — — 79,829 — — Homes — 377,396 — — — — Mortgages — — 54,345 — — 38,328 Total revenue 621,941 377,396 54,345 586,797 — 38,328 Costs and expenses: Cost of revenue 50,310 363,151 9,108 46,884 86 2,476 Sales and marketing 262,094 58,271 28,655 266,719 2,385 15,914 Technology and development 182,230 30,479 15,391 177,048 6,026 11,235 General and administrative 125,521 32,165 20,927 102,625 5,954 8,073 Acquisition-related costs — — — 27 — 632 Integration costs — — 645 — — — Total costs and expenses 620,155 484,066 74,726 593,303 14,451 38,330 Income (loss) from operations 1,786 (106,670 ) (20,381 ) (6,506 ) (14,451 ) (2 ) Segment other income — — 715 — — — Segment interest expense — (9,657 ) (388 ) — — — Income (loss) before income taxes (1) $ 1,786 $ (116,327 ) $ (20,054 ) $ (6,506 ) $ (14,451 ) $ (2 ) (1) The following table presents the reconciliation of total segment loss before income taxes to consolidated loss before income taxes for the periods presented (in thousands): Three Months Ended Six Months Ended 2019 2018 2019 2018 Total segment loss before income taxes $ (68,322 ) $ (9,595 ) $ (134,595 ) $ (20,959 ) Corporate interest expense (12,711 ) (7,187 ) (25,318 ) (14,260 ) Corporate other income 9,056 3,089 17,911 5,535 Consolidated loss before income taxes $ (71,977 ) $ (13,693 ) $ (142,002 ) $ (29,684 ) Certain corporate items are not directly attributable to any of our segments, including interest income earned on our short-term investments included in Other income and interest costs on our convertible senior notes included in Interest expense.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On July 11, 2019, Zillow Home Loans extended the term of its $50.0 million

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2019
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 for the year ended December 31, 2018 , which was filed with the SEC on February 21, 2019. The condensed consolidated balance sheet as of December 31, 2018 , included herein, was derived from the audited financial statements of Zillow Group, Inc. as of that date. 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 June 30, 2019 , our results of operations, comprehensive loss and shareholders’ equity for the three and six month periods ended June 30, 2019 and 2018 , and our cash flows for the six month periods ended June 30, 2019 and 2018 . The results of the three and six month periods ended June 30, 2019 are not necessarily indicative of the results to be expected for the year ending December 31, 2019 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 the net realizable value of inventory, amortization period and recoverability of contract cost assets, website and software development costs, recoverability of long-lived assets and intangible assets with definite lives, share-based compensation, income taxes, business combinations, and the recoverability of goodwill and indefinite-lived intangible assets, among others. To the extent there are material differences between these estimates, judgments or assumptions and actual results, our financial statements will be affected.
Recently Issued Accounting Standards Not Yet Adopted	Recently Issued Accounting Standards Not Yet Adopted In August 2018, the Financial Accounting Standards Board (“FASB”) issued guidance related to a customer’s accounting for implementation costs incurred in hosting arrangements. The guidance aligns the requirements for capitalizing implementation costs incurred in cloud computing arrangements with the requirements for capitalizing costs to develop or obtain internal-use software. This guidance is effective for interim and annual reporting periods beginning after December 15, 2019, and early adoption is permitted. This guidance may be applied either retrospectively or prospectively. We expect to adopt this guidance on January 1, 2020. 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 August 2018, the FASB issued guidance related to disclosure requirements for fair value measurements. This guidance removes, modifies and adds disclosures related to fair value measurements. This guidance is effective for interim and annual periods beginning after December 15, 2019, and early adoption is permitted. The amendments on changes in unrealized gains and losses, the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements and the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim and annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. We expect to adopt this guidance on January 1, 2020. We have not yet determined the impact the adoption of this guidance will have on our financial statement disclosures. In June 2016, and subsequently amended in April 2019 and May 2019, the FASB issued guidance on the measurement of credit losses on financial instruments. This guidance will require an entity to measure credit losses for certain financial instruments and financial assets, including trade receivables. This guidance requires an entity to recognize an allowance that reflects the entity’s current estimate of credit losses expected to be incurred over the life of the financial instrument on initial recognition and at each reporting period. This guidance is effective for interim and annual reporting periods beginning after December 15, 2019, and early adoption is permitted for interim and annual reporting periods beginning after December 15, 2018. The adoption of this guidance requires a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. We expect to adopt this guidance on January 1, 2020. We have not yet determined the impact the adoption of this guidance will have on our financial position, results of operations or cash flows.
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 — The fair value measurement of money market funds is based on quoted market prices in active markets. The fair value measurement of commercial paper is based on observable market-based inputs or inputs that are derived principally from or corroborated by observable market data by correlation or other means. Short-term investments — The fair value measurement of our short-term investments is based on observable market-based inputs or inputs that are derived principally from or corroborated by observable market data by correlation or other means. Restricted cash — Restricted cash consists of cash received from the resale of homes through Zillow Offers which may be used to repay amounts borrowed on our revolving credit facilities (see Note 13 ) and amounts held in escrow related to funding home purchases in our mortgage origination business. The carrying value of restricted cash approximates fair value due to the short period of time amounts borrowed on the revolving credit facilities are outstanding. Mortgage loans held for sale — The fair value of mortgage loans held for sale is generally calculated by reference to quoted prices in secondary markets for commitments to sell mortgage loans with similar characteristics. Interest rate lock commitments — The fair value of interest rate lock commitments (“IRLCs”) is calculated by reference to quoted prices in secondary markets for commitments to sell mortgage loans with similar characteristics. Expired commitments are excluded from the fair value measurement. We generally only issue IRLCs for products that meet specific purchaser guidelines. Since not all IRLCs will become closed loans, we adjust our fair value measurements for the estimated amount of IRLCs that will not close. Forward contracts — The fair value of mandatory loan sales commitments and derivative instruments such as forward sales of mortgage-backed securities that are utilized as hedging instruments are calculated by reference to quoted prices for similar assets.
Segment Reporting	Beginning January 1, 2019, we have three operating and reportable segments, which have been identified based on the way in which 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 for the Internet, Media & Technology (“IMT”), Homes and Mortgages segments. The IMT segment includes the financial results for the Premier Agent, Rentals and new construction marketplaces, dotloop, and display, as well as revenue from the sale of various other marketing and business products and services to real estate professionals. The Homes segment includes the financial results from Zillow Group’s purchase and sale of homes directly. The Mortgages segment includes financial results for advertising sold to mortgage lenders and other mortgage professionals, mortgage originations through Zillow Home Loans and the sale of mortgages on the secondary market, as well as Mortech mortgage software solutions. Revenue and costs are directly attributed to our segments when possible. However, due to the integrated structure of our business, certain costs incurred by one segment may benefit the other segments. These costs primarily include headcount-related expenses, general and administrative expenses including executive, finance, accounting, legal, human resources, recruiting, and facilities costs, product development and data acquisition costs and marketing and advertising costs. These costs are allocated to each segment based on the estimated benefit each segment receives from such expenditures.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Summary of Balances of Cash Equivalents and Investments	The following tables present the balances of assets and liabilities measured at fair value on a recurring basis, by level within the fair value hierarchy, as of the dates presented (in thousands): June 30, 2019 Total Level 1 Level 2 Cash equivalents: Money market funds $ 641,436 $ 641,436 $ — Short-term investments: U.S. government agency securities 446,736 — 446,736 Corporate notes and bonds 94,922 — 94,922 Commercial paper 87,062 — 87,062 Municipal securities 33,352 — 33,352 Foreign government securities 5,997 — 5,997 Certificates of deposit 1,481 — 1,481 Treasury bills 3,479 — 3,479 Mortgage origination-related: Mortgage loans held for sale 38,653 — 38,653 IRLCs 1,186 — 1,186 Forward contracts - other current assets 32 — 32 Forward contracts - other current liabilities (225 ) — (225 ) Total $ 1,354,111 $ 641,436 $ 712,675 December 31, 2018 Total Level 1 Level 2 Cash equivalents: Money market funds $ 541,575 $ 541,575 $ — Commercial paper 3,999 — 3,999 Short-term investments: U.S. government agency securities 646,496 — 646,496 Corporate notes and bonds 112,933 — 112,933 Commercial paper 85,506 — 85,506 Municipal securities 39,306 — 39,306 Foreign government securities 14,915 — 14,915 Certificates of deposit 4,711 — 4,711 Mortgage origination-related: Mortgage loans held for sale 35,409 — 35,409 IRLCs 847 — 847 Forward contracts - other current liabilities (125 ) — (125 ) Total $ 1,485,572 $ 541,575 $ 943,997

Cash and Cash Equivalents, Sh_2

Cash and Cash Equivalents, Short-term Investments and Restricted Cash (Tables)	6 Months Ended
	Jun. 30, 2019
Cash and Cash Equivalents [Abstract]
Amortized Cost, Gross Unrealized Gains and Losses, and Estimated Fair Market Value of Cash and Cash Equivalents and Available-for-Sale Investments	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 investments and restricted cash as of the dates presented (in thousands): June 30, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Market Value Cash $ 125,262 $ — $ — $ 125,262 Cash equivalents: Money market funds 641,436 — — 641,436 Short-term investments: U.S. government agency securities 446,098 668 (30 ) 446,736 Corporate notes and bonds 94,739 184 (1 ) 94,922 Commercial paper 87,062 — — 87,062 Municipal securities 33,253 99 — 33,352 Foreign government securities 5,996 1 — 5,997 Certificates of deposit 1,481 — — 1,481 Treasury bills 3,475 4 — 3,479 Restricted cash 43,882 — — 43,882 Total $ 1,482,684 $ 956 $ (31 ) $ 1,483,609 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Market Value Cash $ 105,484 $ — $ — $ 105,484 Cash equivalents: Money market funds 541,575 — — 541,575 Commercial paper 3,999 — — 3,999 Short-term investments: U.S. government agency securities 647,266 51 (821 ) 646,496 Corporate notes and bonds 113,109 1 (177 ) 112,933 Commercial paper 85,506 — — 85,506 Municipal securities 39,316 23 (33 ) 39,306 Foreign government securities 14,929 — (14 ) 14,915 Certificates of deposit 4,711 1 (1 ) 4,711 Restricted cash 12,385 — — 12,385 Total $ 1,568,280 $ 76 $ (1,046 ) $ 1,567,310
Available-for-Sale Investments by Contractual Maturity	The following table presents available-for-sale investments by contractual maturity date as of June 30, 2019 (in thousands): Amortized Cost Estimated Fair Market Value Due in one year or less $ 651,437 $ 652,206 Due after one year through two years 20,667 20,823 Total $ 672,104 $ 673,029

Accounts Receivable, net (Table

Accounts Receivable, net (Tables)	6 Months Ended
	Jun. 30, 2019
Receivables [Abstract]
Schedule of Accounts Receivable, Net	The following table presents the changes in the allowance for doubtful accounts (in thousands): Balance as of January 1, 2019 $ 4,838 Bad debt expense 706 Less: write-offs, net of recoveries and other adjustments (735 ) Balance as of June 30, 2019 $ 4,809

Inventory (Tables)

Inventory (Tables)	6 Months Ended
	Jun. 30, 2019
Inventory Disclosure [Abstract]
Components of Net Inventory	The following table presents the components of inventory, net of applicable lower of cost or net realizable value adjustments, as of the dates presented (in thousands): June 30, December 31, Work-in-progress $ 174,272 $ 45,943 Finished goods 378,551 116,886 Inventory $ 552,823 $ 162,829

Property and Equipment, net (Ta

Property and Equipment, net (Tables)	6 Months Ended
	Jun. 30, 2019
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): June 30, December 31, Website development costs $ 153,905 $ 149,891 Leasehold improvements 77,737 65,012 Office equipment, furniture and fixtures 43,484 39,510 Construction-in-progress 27,293 29,037 Computer equipment 23,024 22,477 Property and equipment 325,443 305,927 Less: accumulated amortization and depreciation (179,511 ) (170,755 ) Property and equipment, net $ 145,932 $ 135,172

Intangible Assets, net (Tables)

Intangible Assets, net (Tables)	6 Months Ended
	Jun. 30, 2019
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): June 30, 2019 Cost Accumulated Amortization Net Purchased content $ 43,886 $ (35,555 ) $ 8,331 Software 28,807 (16,850 ) 11,957 Customer relationships 103,600 (67,257 ) 36,343 Developed technology 109,080 (76,869 ) 32,211 Trade names and trademarks 4,400 (4,400 ) — Lender licenses 400 (117 ) 283 Intangibles-in-progress 5,699 — 5,699 Total $ 295,872 $ (201,048 ) $ 94,824 December 31, 2018 Cost Accumulated Amortization Net Purchased content $ 42,110 $ (30,477 ) $ 11,633 Software 24,296 (13,925 ) 10,371 Customer relationships 103,900 (60,733 ) 43,167 Developed technology 111,980 (72,788 ) 39,192 Trade names and trademarks 4,900 (4,683 ) 217 Lender licenses 400 (17 ) 383 Intangibles-in-progress 2,941 — 2,941 Total $ 290,527 $ (182,623 ) $ 107,904

Deferred Revenue (Tables)

Deferred Revenue (Tables)	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Schedule of Change in Deferred Revenue	The following tables present the changes in deferred revenue for the periods presented (in thousands): Three Months Ended Balance as of April 1, 2019 $ 36,105 Deferral of revenue 259,132 Less: Revenue recognized (258,157 ) Balance as of June 30, 2019 $ 37,080 Six Months Ended Balance as of January 1, 2019 $ 34,080 Deferral of revenue 501,984 Less: Revenue recognized (498,984 ) Balance as of June 30, 2019 $ 37,080

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Components of Lease Expense	The components of our operating lease expense were as follows for the periods presented (in thousands): Three Months Ended Six Months Ended Operating lease cost $ 9,004 $ 15,527 Variable lease cost 4,965 9,746 Total lease cost $ 13,969 $ 25,273
Schedule of Maturities for Operating Lease Liabilities	Maturities of our operating lease liabilities by fiscal year were as follows as of June 30, 2019 (in thousands): Remainder of 2019 $ 15,106 2020 37,558 2021 41,089 2022 37,173 2023 34,990 All future years 164,992 Total lease payments 330,908 Less: Imputed interest (100,521 ) Present value of lease liabilities $ 230,387
Schedule of Future Minimum Payments for Operating Leases	The following table presents our future minimum payments for all operating leases as of December 31, 2018, including future minimum payments for operating leases that had not yet commenced as of December 31, 2018 totaling $112.9 million (in thousands): 2019 $ 29,085 2020 38,060 2021 40,099 2022 37,721 2023 36,458 All future years 85,462 Total future minimum lease payments $ 266,885

Debt (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Schedule of Revolving Credit Facilities and Lines of Credit	The following table summarizes our revolving credit facilities as of the periods presented (in thousands, except interest rates): Effective Date Maximum Borrowing Capacity Outstanding Borrowings at June 30, 2019 Outstanding Borrowings at December 31, 2018 Weighted Average Interest Rate July 31, 2018 $ 500,000 $ 265,097 $ 116,700 5.97 % January 31, 2019 500,000 144,702 — 5.95 % Total $ 1,000,000 $ 409,799 $ 116,700 Maturity Date Maximum Borrowing Capacity Outstanding Borrowings at June 30, 2019 Outstanding Borrowings at December 31, 2018 Weighted Average Interest Rate July 15, 2019 $ 50,000 $ 15,722 $ 14,125 4.95 % June 27, 2020 50,000 14,335 18,892 4.95 % Total $ 100,000 $ 30,057 $ 33,017
Schedule of Convertible Senior Notes	The following table summarizes our outstanding convertible senior notes as of the periods presented (in thousands, except interest rates): Maturity Date Aggregate Principal Amount Fair Value at June 30, 2019 Fair Value at December 31, 2018 Stated Interest Rate Effective Interest Rate July 1, 2023 $ 373,750 $ 370,095 $ 321,855 1.50 % 6.99 % December 1, 2021 460,000 521,318 446,200 2.00 % 7.44 % December 15, 2020 9,637 16,842 16,744 2.75 % N/A Total $ 843,387 $ 908,255 $ 784,799

Share-Based Awards (Tables)

Share-Based Awards (Tables)	6 Months Ended
	Jun. 30, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Option Award Activity	The following table summarizes option award activity for the six months ended June 30, 2019 : Number of Shares Subject to Existing Options Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Life (Years) Aggregate Intrinsic Value (in thousands) Outstanding at January 1, 2019 27,310,110 $ 34.04 6.23 $ 97,941 Granted 6,721,428 40.05 Exercised (1,543,850 ) 21.37 Forfeited or cancelled (1,419,750 ) 41.10 Outstanding at June 30, 2019 31,067,938 35.65 6.62 367,905 Vested and exercisable at June 30, 2019 17,363,786 31.63 4.87 266,575
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 Six Months Ended 2019 2018 2019 2018 Expected volatility 45% 43% 45%-47% 43%-45% Expected dividend yield — — — — Risk-free interest rate 2.00% 2.70% 2.00%-2.53% 2.52%-2.70% Weighted-average expected life 5.00 years 4.50 years 4.75-5.25 years 4.50-5.00 years Weighted-average fair value of options granted $16.96 $23.30 $16.79 $21.07
Summary of Restricted Stock Units Activity	The following table summarizes activity for restricted stock units for the six months ended June 30, 2019 : Restricted Stock Units Weighted- Average Grant- Date Fair Value Unvested outstanding at January 1, 2019 5,266,324 $ 42.19 Granted 3,638,550 39.32 Vested (1,065,607 ) 39.46 Forfeited or cancelled (601,829 ) 41.23 Unvested outstanding at June 30, 2019 7,237,438 41.23
Effects of Share Based Compensation in Consolidated Statements of Operations	The following table presents the effects of share-based compensation expense in our condensed consolidated statements of operations during the periods presented (in thousands): Three Months Ended Six Months Ended 2019 2018 2019 2018 Cost of revenue $ 936 $ 1,256 $ 1,816 $ 2,211 Sales and marketing 6,801 6,340 12,451 11,502 Technology and development 18,399 14,347 33,908 25,889 General and administrative 17,496 17,000 61,581 30,082 Total $ 43,632 $ 38,943 $ 109,756 $ 69,684

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2019
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 Six Months Ended 2019 2018 2019 2018 Weighted-average Class A common stock and Class C capital stock option awards outstanding 19,502 27,428 19,656 24,393 Weighted-average Class A common stock and Class C capital stock restricted stock units outstanding 7,230 5,246 6,548 4,799 Class A common stock issuable upon conversion of the convertible notes maturing in 2020 411 402 411 402 Class C capital stock issuable related to conversion spread on the convertible notes maturing in 2021 — 997 — 997 Total Class A common stock and Class C capital stock equivalents 27,143 34,073 26,615 30,591

Segment Information and Reven_2

Segment Information and Revenue (Tables)	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Revenue Categories	This information is included in the following tables for the periods presented (in thousands): Three Months Ended Three Months Ended IMT Homes Mortgages IMT Homes Mortgages Revenue: Premier Agent $ 231,961 $ — $ — $ 230,885 $ — $ — Rentals 42,670 — — 33,288 — — Other 49,038 — — 41,768 — — Homes — 248,924 — — — — Mortgages — — 26,985 — — 19,305 Total revenue 323,669 248,924 26,985 305,941 — 19,305 Costs and expenses: Cost of revenue 26,059 240,732 4,430 24,290 — 1,237 Sales and marketing 135,440 37,409 14,584 137,972 2,095 7,660 Technology and development 94,261 18,198 7,871 91,131 3,790 5,455 General and administrative 54,671 17,808 10,360 52,438 4,176 3,965 Acquisition-related costs — — — — — 632 Integration costs — — 293 — — — Total costs and expenses 310,431 314,147 37,538 305,831 10,061 18,949 Income (loss) from operations 13,238 (65,223 ) (10,553 ) 110 (10,061 ) 356 Segment other income — — 402 — — — Segment interest expense — (5,899 ) (287 ) — — — Income (loss) before income taxes (1) $ 13,238 $ (71,122 ) $ (10,438 ) $ 110 $ (10,061 ) $ 356 Six Months Ended Six Months Ended IMT Homes Mortgages IMT Homes Mortgages Revenue: Premier Agent $ 449,696 $ — $ — $ 444,617 $ — $ — Rentals 80,508 — — 62,351 — — Other 91,737 — — 79,829 — — Homes — 377,396 — — — — Mortgages — — 54,345 — — 38,328 Total revenue 621,941 377,396 54,345 586,797 — 38,328 Costs and expenses: Cost of revenue 50,310 363,151 9,108 46,884 86 2,476 Sales and marketing 262,094 58,271 28,655 266,719 2,385 15,914 Technology and development 182,230 30,479 15,391 177,048 6,026 11,235 General and administrative 125,521 32,165 20,927 102,625 5,954 8,073 Acquisition-related costs — — — 27 — 632 Integration costs — — 645 — — — Total costs and expenses 620,155 484,066 74,726 593,303 14,451 38,330 Income (loss) from operations 1,786 (106,670 ) (20,381 ) (6,506 ) (14,451 ) (2 ) Segment other income — — 715 — — — Segment interest expense — (9,657 ) (388 ) — — — Income (loss) before income taxes (1) $ 1,786 $ (116,327 ) $ (20,054 ) $ (6,506 ) $ (14,451 ) $ (2 ) (1) The following table presents the reconciliation of total segment loss before income taxes to consolidated loss before income taxes for the periods presented (in thousands): Three Months Ended Six Months Ended 2019 2018 2019 2018 Total segment loss before income taxes $ (68,322 ) $ (9,595 ) $ (134,595 ) $ (20,959 ) Corporate interest expense (12,711 ) (7,187 ) (25,318 ) (14,260 ) Corporate other income 9,056 3,089 17,911 5,535 Consolidated loss before income taxes $ (71,977 ) $ (13,693 ) $ (142,002 ) $ (29,684 )
Reconciliation of Total Segment Loss	The following table presents the reconciliation of total segment loss before income taxes to consolidated loss before income taxes for the periods presented (in thousands): Three Months Ended Six Months Ended 2019 2018 2019 2018 Total segment loss before income taxes $ (68,322 ) $ (9,595 ) $ (134,595 ) $ (20,959 ) Corporate interest expense (12,711 ) (7,187 ) (25,318 ) (14,260 ) Corporate other income 9,056 3,089 17,911 5,535 Consolidated loss before income taxes $ (71,977 ) $ (13,693 ) $ (142,002 ) $ (29,684 )

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value of Cash Equivalents and Investments (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	$ 673,029
Mortgage loans held for sale	38,653	$ 35,409
Total	1,354,111	1,485,572
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held for sale	0	0
Total	641,436	541,575
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage loans held for sale	38,653	35,409
Total	712,675	943,997
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	641,436	541,575
Money market funds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	641,436	541,575
Money market funds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents		3,999
Short-term investments	87,062	85,506
Commercial paper | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents		0
Short-term investments	0	0
Commercial paper | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents		3,999
Short-term investments	87,062	85,506
U.S. government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	446,736	646,496
U.S. government agency securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
U.S. government agency securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	446,736	646,496
Corporate notes and bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	94,922	112,933
Corporate notes and bonds | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Corporate notes and bonds | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	94,922	112,933
Municipal securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	33,352	39,306
Municipal securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Municipal securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	33,352	39,306
Foreign government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	5,997	14,915
Foreign government securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Foreign government securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	5,997	14,915
Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	1,481	4,711
Certificates of deposit | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0	0
Certificates of deposit | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	1,481	4,711
Treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	3,479
Treasury bills | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	0
Treasury bills | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	3,479
IRLCs | Not Designated as Hedging Instrument
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1,186	847
IRLCs | Level 1 | Not Designated as Hedging Instrument
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
IRLCs | Level 2 | Not Designated as Hedging Instrument
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1,186	847
Forward contracts | Not Designated as Hedging Instrument
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	32	(125)
Derivative liability	(225)
Forward contracts | Level 1 | Not Designated as Hedging Instrument
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liability	0
Forward contracts | Level 2 | Not Designated as Hedging Instrument
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	32	$ (125)
Derivative liability	$ (225)

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
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	0	0
Mortgage Loans Held For Sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional amount	45,700,000	26,700,000
IRLCs
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional amount	$ 80,600,000	$ 28,800,000

Cash and Cash Equivalents, Sh_3

Cash and Cash Equivalents, Short-term Investments and Restricted Cash - Amortized Cost, Gross Unrealized Gains and Losses, and Estimated Fair Market Value of Cash and Cash Equivalents and Available-for-Sale Investments (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash and cash equivalents	$ 766,698	$ 651,058
Short-term investments:
Amortized Cost	672,104
Gross Unrealized Gains	956	76
Gross Unrealized Losses	(31)
Estimated Fair Market Value	673,029
Restricted cash	43,882	12,385
Cash, cash equivalents, short-term investments, and restricted cash, amortized cost	1,482,684	1,568,280
Cash, cash equivalents, short-term investments, and restricted cash, gross unrealized losses		(1,046)
Cash, cash equivalents, short-term investments, and restricted cash, estimated fair market value	1,483,609	1,567,310
U.S. government agency securities
Short-term investments:
Amortized Cost	446,098	647,266
Gross Unrealized Gains	668	51
Gross Unrealized Losses	(30)	(821)
Estimated Fair Market Value	446,736	646,496
Corporate notes and bonds
Short-term investments:
Amortized Cost	94,739	113,109
Gross Unrealized Gains	184	1
Gross Unrealized Losses	(1)	(177)
Estimated Fair Market Value	94,922	112,933
Commercial paper
Short-term investments:
Amortized Cost	87,062	85,506
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Market Value	87,062	85,506
Municipal securities
Short-term investments:
Amortized Cost	33,253	39,316
Gross Unrealized Gains	99	23
Gross Unrealized Losses	0	(33)
Estimated Fair Market Value	33,352	39,306
Foreign government securities
Short-term investments:
Amortized Cost	5,996	14,929
Gross Unrealized Gains	1	0
Gross Unrealized Losses	0	(14)
Estimated Fair Market Value	5,997	14,915
Certificates of deposit
Short-term investments:
Amortized Cost	1,481	4,711
Gross Unrealized Gains	0	1
Gross Unrealized Losses	0	(1)
Estimated Fair Market Value	1,481	4,711
Treasury bills
Short-term investments:
Amortized Cost	3,475
Gross Unrealized Gains	4
Gross Unrealized Losses	0
Estimated Fair Market Value	3,479
Cash
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash and cash equivalents	125,262	105,484
Money market funds
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash and cash equivalents	$ 641,436	541,575
Commercial paper
Cash and Cash Equivalents, at Carrying Value [Abstract]
Cash and cash equivalents		$ 3,999

Cash and Cash Equivalents, Sh_4

Cash and Cash Equivalents, Short-term Investments and Restricted Cash - Available-for-Sale Investments by Contractual Maturity (Detail) $ in Thousands	Jun. 30, 2019USD ($)
Cash and Cash Equivalents [Abstract]
Amortized Cost, Due in one year or less	$ 651,437
Amortized Cost, Due after one year through two years	20,667
Amortized Cost	672,104
Estimated Fair Market Value, Due in one year or less	652,206
Estimated Fair Market Value, Due after one year through two years	20,823
Total	$ 673,029

Accounts Receivable, net (Detai

Accounts Receivable, net (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Receivables [Abstract]
Accounts receivable, net	$ 82,261		$ 66,083
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning balance	4,838
Bad debt expense	706	$ (352)
Less: write-offs, net of recoveries and other adjustments	(735)
Ending balance	$ 4,809

Inventory (Details)

Inventory (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Work-in-progress	$ 174,272	$ 45,943
Finished goods	378,551	116,886
Inventory	$ 552,823	$ 162,829

Contract Cost Assets (Details)

Contract Cost Assets (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Revenue from Contract with Customer [Abstract]
Contract cost assets	$ 46,271,000		$ 46,271,000		$ 45,819,000
Impairment of contract cost assets	0	$ 0	0	$ 0
Amortization of contract cost assets	$ 9,200,000	$ 9,000,000	$ 17,880,000	$ 18,309,000

Property and Equipment, net - D

Property and Equipment, net - Detail of Property and Equipment (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and equipment	$ 325,443	$ 305,927
Less: accumulated amortization and depreciation	(179,511)	(170,755)
Property and equipment, net	145,932	135,172
Website development costs
Property, Plant and Equipment [Line Items]
Property and equipment	153,905	149,891
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	77,737	65,012
Office equipment, furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment	43,484	39,510
Construction-in-progress
Property, Plant and Equipment [Line Items]
Property and equipment	27,293	29,037
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment	$ 23,024	$ 22,477

Property and Equipment, net - A

Property and Equipment, net - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Property, Plant and Equipment [Line Items]
Amortization and depreciation expense related to property and equipment other than website development costs	$ 6.4	$ 4.9	$ 12.4	$ 9.1
Capitalization of website development costs	10.3	10	20.3	18.6
Amortization of website development costs and intangible assets included in technology and development	11	12.6	22	25.6
Technology and development | Software Development
Property, Plant and Equipment [Line Items]
Amortization of website development costs and intangible assets included in technology and development	$ 3.6	$ 8.4	$ 7	$ 18

Equity Investment - Additional

Equity Investment - Additional Information (Detail) - October 2016 Investment - USD ($)	1 Months Ended
	Oct. 31, 2016	Jun. 30, 2019
Schedule of Equity Method Investments [Line Items]
Cumulative impairment charge		$ 0
Upward adjustments		0
Downward adjustments		0
Variable Interest Entity, Not Primary Beneficiary
Schedule of Equity Method Investments [Line Items]
Percentage of equity interest held	10.00%
Equity investments	$ 10,000,000
Maximum exposure to loss		$ 10,000,000

Intangible Assets, net - Intang

Intangible Assets, net - Intangible Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Cost	$ 295,872	$ 290,527
Accumulated Amortization	(201,048)	(182,623)
Net	94,824	107,904
Purchased content
Finite-Lived Intangible Assets [Line Items]
Cost	43,886	42,110
Accumulated Amortization	(35,555)	(30,477)
Net	8,331	11,633
Software
Finite-Lived Intangible Assets [Line Items]
Cost	28,807	24,296
Accumulated Amortization	(16,850)	(13,925)
Net	11,957	10,371
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Cost	103,600	103,900
Accumulated Amortization	(67,257)	(60,733)
Net	36,343	43,167
Developed technology
Finite-Lived Intangible Assets [Line Items]
Cost	109,080	111,980
Accumulated Amortization	(76,869)	(72,788)
Net	32,211	39,192
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Cost	4,400	4,900
Accumulated Amortization	(4,400)	(4,683)
Net	0	217
Lender licenses
Finite-Lived Intangible Assets [Line Items]
Cost	400	400
Accumulated Amortization	(117)	(17)
Net	283	383
Intangibles-in-progress
Finite-Lived Intangible Assets [Line Items]
Cost	5,699	2,941
Accumulated Amortization	0	0
Net	$ 5,699	$ 2,941

Intangible Assets, net - Additi

Intangible Assets, net - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Indefinite-lived Intangible Assets [Line Items]
Amortization of website development costs and intangible assets included in technology and development	$ 11	$ 12.6	$ 22	$ 25.6
Trade names and trademarks | Trulia
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible asset	$ 108		$ 108		$ 108

Deferred Revenue (Details)

Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Change in Contract with Customer, Liability [Roll Forward]
Beginning balance	$ 36,105	$ 34,080
Deferral of revenue	259,132	501,984
Less: Revenue recognized	(258,157)	(498,984)
Ending balance	37,080	37,080
Revenue recognized, recorded in deferred revenue as of prior period	$ 33,000	$ 30,900

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019USD ($)renewal_option	Jun. 30, 2019USD ($)renewal_option	Dec. 31, 2018USD ($)
Lessee, Lease, Description [Line Items]
Option to extend lease	10 years	10 years
Number of periods | renewal_option	2
Option to extend existing lease	5 years	5 years
Cash paid for amounts included in measurement of lease liabilities	$ 7.2	$ 16.3
Right of use assets obtained in exchange for new operating lease obligations	$ 113.7	$ 113.7
Weighted average remaining lease term	9 years	9 years
Weighted average discount rate	6.50%	6.50%
Operating lease expense	$ 5.6	$ 11.4
Operating leases not yet commenced			$ 112.9
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term		1 year
Number of periods | renewal_option		1
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term		12 years
Number of periods | renewal_option		2

Leases - Components of Lease Ex

Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Leases [Abstract]
Operating lease cost	$ 9,004	$ 15,527
Variable lease cost	4,965	9,746
Total lease cost	$ 13,969	$ 25,273

Leases - Schedule of Maturities

Leases - Schedule of Maturities for Operating Lease Liabilities (Details) $ in Thousands	Jun. 30, 2019USD ($)
Leases [Abstract]
Remainder of 2019	$ 15,106
2020	37,558
2021	41,089
2022	37,173
2023	34,990
All future years	164,992
Total lease payments	330,908
Less: Imputed interest	(100,521)
Present value of lease liabilities	$ 230,387

Leases - Schedule of Future Min

Leases - Schedule of Future Minimum Payments for Operating Leases (Details) $ in Thousands	Dec. 31, 2018USD ($)
Leases [Abstract]
2019	$ 29,085
2020	38,060
2021	40,099
2022	37,721
2023	36,458
All future years	85,462
Total future minimum lease payments	$ 266,885

Debt - Schedule of Revolving Cr

Debt - Schedule of Revolving Credit Facilities (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Outstanding borrowings on revolving credit facility	$ 409,799,000	$ 116,700,000
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Maximum Borrowing Capacity	1,000,000,000
Outstanding borrowings on revolving credit facility	409,799,000	116,700,000
Line of Credit | Revolving Credit Facility | July 31, 2018
Debt Instrument [Line Items]
Maximum Borrowing Capacity	500,000,000
Outstanding borrowings on revolving credit facility	$ 265,097,000	116,700,000
Weighted Average Interest Rate	5.97%
Line of Credit | Revolving Credit Facility | January 31, 2019
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 500,000,000
Outstanding borrowings on revolving credit facility	$ 144,702,000	$ 0
Weighted Average Interest Rate	5.95%

Debt - Narrative (Detail)

Debt - Narrative (Detail) - USD ($)	Jun. 28, 2019	Jan. 31, 2019	Jul. 31, 2018	Jun. 30, 2019	Dec. 31, 2018
Convertible Debt
Debt Instrument [Line Items]
Unamortized debt discount and debt issuance costs				$ 126,600,000	$ 144,400,000
Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity				1,000,000,000
Extension of expiration period (up to)			2 years
Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity				100,000,000
Credit Agreement | Revolving Credit Facility | Citibank, N.A. | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 500,000,000
Current borrowing capacity				145,000,000
Revolving credit facility, initial term		2 years
July 31, 2018 | Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity				500,000,000
Current borrowing capacity				275,100,000
Revolving credit facility, initial term			1 year
Automatic renewal term			24 months
June 27, 2020 | Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 50,000,000			$ 50,000,000
Revolving credit facility, initial term	1 year

Debt - Schedule of Warehouse Li

Debt - Schedule of Warehouse Lines of Credit (Details) - USD ($)	Jun. 30, 2019	Jun. 28, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Warehouse lines of credit	$ 30,057,000		$ 33,018,000
Line of Credit
Debt Instrument [Line Items]
Maximum Borrowing Capacity	100,000,000
Warehouse lines of credit	30,057,000		33,017,000
Line of Credit | July 15, 2019
Debt Instrument [Line Items]
Maximum Borrowing Capacity	50,000,000
Warehouse lines of credit	$ 15,722,000		14,125,000
Weighted Average Interest Rate	4.95%
Line of Credit | June 27, 2020
Debt Instrument [Line Items]
Maximum Borrowing Capacity	$ 50,000,000	$ 50,000,000
Warehouse lines of credit	$ 14,335,000		$ 18,892,000
Weighted Average Interest Rate	4.95%

Debt - Schedule of Convertible

Debt - Schedule of Convertible Senior Notes (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Aggregate Principal Amount	$ 843,387
Fair Value	908,255	$ 784,799
Convertible Debt | July 1, 2023
Debt Instrument [Line Items]
Aggregate Principal Amount	373,750
Fair Value	$ 370,095	321,855
Stated Interest Rate	1.50%
Effective Interest Rate	6.99%
Convertible Debt | December 1, 2021
Debt Instrument [Line Items]
Aggregate Principal Amount	$ 460,000
Fair Value	$ 521,318	446,200
Stated Interest Rate	2.00%
Effective Interest Rate	7.44%
Convertible Debt | December 15, 2020
Debt Instrument [Line Items]
Aggregate Principal Amount	$ 9,637
Fair Value	$ 16,842	$ 16,744
Stated Interest Rate	2.75%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) $ in Millions	Dec. 31, 2018USD ($)
Federal
Schedule Of Income Tax [Line Items]
Net operating loss carryforwards	$ 1,081.7
State
Schedule Of Income Tax [Line Items]
Net operating loss carryforwards	$ 32.5

Share-Based Awards - Summary of

Share-Based Awards - Summary of Option Award (Detail) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares
Number of Shares Subject to Existing Options
Beginning Balance (in shares) | shares	27,310,110
Granted (in shares) | shares	6,721,428
Exercised (in shares) | shares	(1,543,850)
Forfeited or cancelled (in shares) | shares	(1,419,750)
Ending Balance (in shares) | shares	31,067,938	27,310,110
Vested and exercisable ending balance (in shares) | shares	17,363,786
Weighted- Average Exercise Price Per Share
Beginning Balance (usd per share) | $ / shares	$ 34.04
Granted (usd per share) | $ / shares	40.05
Exercised (usd per share) | $ / shares	21.37
Forfeited or cancelled (usd per share) | $ / shares	41.10
Ending Balance (usd per share) | $ / shares	35.65	$ 34.04
Vested and exercisable (usd per share) | $ / shares	$ 31.63
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted-Average Remaining Contractual Life, Outstanding	6 years 7 months 13 days	6 years 2 months 23 days
Weighted-Average Remaining Contractual Life, Vested and exercisable	4 years 10 months 13 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract]
Aggregate Intrinsic Value, Outstanding | $	$ 367,905	$ 97,941
Aggregate Intrinsic Value Vested, and exercisable | $	$ 266,575

Share-Based Awards - Fair Value

Share-Based Awards - Fair Value of Options Granted, Estimated at Date of Grant Using Black Scholes Merton Option Pricing Model (Detail) - Option Awards - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	45.00%	43.00%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Weighted-average expected life	5 years	4 years 6 months
Weighted-average fair value of options granted (usd per share)	$ 16.96	$ 23.30	$ 16.79	$ 21.07
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility			45.00%	43.00%
Risk-free interest rate	2.00%	2.70%	2.00%	2.52%
Weighted-average expected life			4 years 9 months	4 years 6 months
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility			47.00%	45.00%
Risk-free interest rate			2.53%	2.70%
Weighted-average expected life			5 years 3 months	5 years

Share-Based Awards - Option Awa

Share-Based Awards - Option Awards - Additional Information (Detail) $ in Millions	Jun. 30, 2019USD ($)
Option Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized cost of unvested share-based compensation awards	$ 210.7

Share-Based Awards - Summary _2

Share-Based Awards - Summary of Restricted Stock Units Activity (Detail) - Restricted Stock Units	6 Months Ended
	Jun. 30, 2019$ / sharesshares
Restricted Stock Units
Beginning balance (in shares) | shares	5,266,324
Granted (in shares) | shares	3,638,550
Vested (in shares) | shares	(1,065,607)
Forfeited or cancelled (in shares) | shares	(601,829)
Ending balance (in shares) | shares	7,237,438
Weighted- Average Grant- Date Fair Value
Unvested outstanding, beginning balance (usd per share) | $ / shares	$ 42.19
Granted (usd per share) | $ / shares	39.32
Vested (usd per share) | $ / shares	39.46
Forfeited or cancelled (usd per share) | $ / shares	41.23
Unvested outstanding, ending balance (usd per share) | $ / shares	$ 41.23

Share-Based Awards - Restricted

Share-Based Awards - Restricted Stock Units - Additional Information (Detail) $ in Millions	Jun. 30, 2019USD ($)
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost	$ 277

Share-Based Awards - Effects of

Share-Based Awards - Effects of Share Based Compensation in Consolidated Statements of Operations (Detail) - USD ($) $ in Thousands	Feb. 21, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation		$ 43,632	$ 38,943	$ 109,756	$ 69,684
Chief Executive Officer
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation				26,400
Accelerated vesting period from departure date	18 months
Exercisable period from final date	90 days
Minimum | Chief Executive Officer
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Expected volatility	46.00%
Risk-free interest rate	2.47%
Weighted-average expected life	3 years 10 months 2 days
Maximum | Chief Executive Officer
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Expected volatility	47.00%
Risk-free interest rate	2.49%
Weighted-average expected life	5 years 3 months
Cost of revenue
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation		936	1,256	1,816	2,211
Sales and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation		6,801	6,340	12,451	11,502
Technology and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation		18,399	14,347	33,908	25,889
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation		$ 17,496	$ 17,000	$ 61,581	$ 30,082

Net Loss Per Share - Antidiluti

Net Loss Per Share - Antidilutive Securities Excluded from Computation of Earnings Per Share (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Class A Common Stock and Class C Capital Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total Class A common stock and Class C capital stock equivalents (in shares)	27,143	34,073	26,615	30,591
Class A Common Stock and Class C Capital Stock | Weighted Average | Option Awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total Class A common stock and Class C capital stock equivalents (in shares)	19,502	27,428	19,656	24,393
Class A Common Stock and Class C Capital Stock | Weighted Average | Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total Class A common stock and Class C capital stock equivalents (in shares)	7,230	5,246	6,548	4,799
Class A Common Stock | December 15, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total Class A common stock and Class C capital stock equivalents (in shares)	411	402	411	402
Class C Capital Stock | December 1, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total Class A common stock and Class C capital stock equivalents (in shares)	0	997	0	997

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	Jun. 20, 2017USD ($)	Feb. 09, 2017USD ($)	Jun. 30, 2019USD ($)	Dec. 31, 2018USD ($)	Feb. 28, 2018claim	Feb. 05, 2018claim	Sep. 30, 2017claim
Other Commitments [Line Items]
Outstanding letters of credit			$ 16,900,000
Outstanding surety bonds			9,700,000	$ 8,900,000
VHT Vs Zillow Group Inc.
Other Commitments [Line Items]
Jury awarded damages	$ 4,100,000
VHT Vs Zillow Group Inc. | Actual Damages
Other Commitments [Line Items]
Jury awarded damages		$ 79,875
VHT Vs Zillow Group Inc. | Statutory Damages
Other Commitments [Line Items]
Jury awarded damages		$ 8,200,000
Class Action Lawsuits
Other Commitments [Line Items]
Number of pending claims | claim							2
Shareholder Derivative Lawsuits
Other Commitments [Line Items]
Number of pending claims | claim					4	2
Homes under contract to purchase that have not closed
Other Commitments [Line Items]
Value of homes under contract that have not closed			$ 266,200,000

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Affiliated Entity | Charter Service Agreement
Related Party Transaction [Line Items]
Expense recognized pursuant to the Charter Service Agreement	$ 0.2	$ 0.2

Self-Insurance - Additional Inf

Self-Insurance - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Insurance [Abstract]
Percentage of cumulative medical claim under self insurance plan (percent exceeded)	125.00%
Limit of medical claim under self insurance plan (limit)	$ 1,000,000
Minimum amount of individual claim under self insurance plan	500,000
Liability for self-insured claims included in accrued compensation and benefits	$ 3,600,000	$ 3,900,000

Employee Benefit Plan - Additio

Employee Benefit Plan - Additional Information (Detail) - Zillow Merger - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Defined Contribution Plan Disclosure [Line Items]
Company's contribution based on employee contribution (up to)			4.00%
Company's expense related to its defined contribution 401(k) retirement plans	$ 5.2	$ 4	$ 10.1	$ 7.8

Segment Information and Reven_3

Segment Information and Revenue - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2019Segment
Segment Reporting [Abstract]
Number of reportable segments	3

Segment Information and Reven_4

Segment Information and Revenue - Revenue Categories (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenue:
Total revenue		$ 599,578	$ 325,246	$ 1,053,682	$ 625,125
Costs and expenses:
Cost of revenue		271,221	25,527	422,569	49,446
Sales and marketing		187,433	147,727	349,020	285,018
Technology and development		120,330	100,376	228,100	194,309
General and administrative		82,839	60,579	178,613	116,652
Acquisition-related costs		0	632	0	659
Integration costs		293	0	645	0
Total costs and expenses		662,116	334,841	1,178,947	646,084
Income (loss) from operations		(62,538)	(9,595)	(125,265)	(20,959)
Other income		9,458	3,089	18,626	5,535
Interest expense		(18,897)	(7,187)	(35,363)	(14,260)
Loss before income taxes		(71,977)	(13,693)	(142,002)	(29,684)
IMT
Revenue:
Total revenue		323,669	305,941	621,941	586,797
Costs and expenses:
Cost of revenue	[1]	26,059	24,290	50,310	46,884
Sales and marketing		135,440	137,972	262,094	266,719
Technology and development		94,261	91,131	182,230	177,048
General and administrative		54,671	52,438	125,521	102,625
Acquisition-related costs		0	0	0	27
Integration costs		0	0	0	0
Total costs and expenses		310,431	305,831	620,155	593,303
Income (loss) from operations		13,238	110	1,786	(6,506)
Other income		0	0	0	0
Interest expense		0	0	0	0
Loss before income taxes		13,238	110	1,786	(6,506)
IMT | Premier Agent
Revenue:
Total revenue		231,961	230,885	449,696	444,617
IMT | Rentals
Revenue:
Total revenue		42,670	33,288	80,508	62,351
IMT | Other
Revenue:
Total revenue		49,038	41,768	91,737	79,829
IMT | Homes
Revenue:
Total revenue		0	0	0	0
IMT | Mortgages
Revenue:
Total revenue		0	0	0	0
Homes
Revenue:
Total revenue		248,924	0	377,396	0
Costs and expenses:
Cost of revenue	[1]	240,732	0	363,151	86
Sales and marketing		37,409	2,095	58,271	2,385
Technology and development		18,198	3,790	30,479	6,026
General and administrative		17,808	4,176	32,165	5,954
Acquisition-related costs		0	0	0	0
Integration costs		0	0	0	0
Total costs and expenses		314,147	10,061	484,066	14,451
Income (loss) from operations		(65,223)	(10,061)	(106,670)	(14,451)
Other income		0	0	0	0
Interest expense		(5,899)	0	(9,657)	0
Loss before income taxes		(71,122)	(10,061)	(116,327)	(14,451)
Homes | Premier Agent
Revenue:
Total revenue		0	0	0	0
Homes | Rentals
Revenue:
Total revenue		0	0	0	0
Homes | Other
Revenue:
Total revenue		0	0	0	0
Homes | Homes
Revenue:
Total revenue		248,924	0	377,396	0
Homes | Mortgages
Revenue:
Total revenue		0	0	0	0
Mortgages
Revenue:
Total revenue		26,985	19,305	54,345	38,328
Costs and expenses:
Cost of revenue	[1]	4,430	1,237	9,108	2,476
Sales and marketing		14,584	7,660	28,655	15,914
Technology and development		7,871	5,455	15,391	11,235
General and administrative		10,360	3,965	20,927	8,073
Acquisition-related costs		0	632	0	632
Integration costs		293	0	645	0
Total costs and expenses		37,538	18,949	74,726	38,330
Income (loss) from operations		(10,553)	356	(20,381)	(2)
Other income		402	0	715	0
Interest expense		(287)	0	(388)	0
Loss before income taxes		(10,438)	356	(20,054)	(2)
Mortgages | Premier Agent
Revenue:
Total revenue		0	0	0	0
Mortgages | Rentals
Revenue:
Total revenue		0	0	0	0
Mortgages | Other
Revenue:
Total revenue		0	0	0	0
Mortgages | Homes
Revenue:
Total revenue		0	0	0	0
Mortgages | Mortgages
Revenue:
Total revenue		$ 26,985	$ 19,305	$ 54,345	$ 38,328
[1]	Amortization of website development costs and intangible assets included in technology and development of $14,656 and $21,020 for the three months ended June 30, 2019 and 2018, respectively and $29,056 and $43,569 for the six months ended June 30, 2019 and 2018, respectively.

Segment Information and Reven_5

Segment Information and Revenue - Reconciliation of Total Segment Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting, Revenue Reconciling Item [Line Items]
Loss before income taxes	$ (71,977)	$ (13,693)	$ (142,002)	$ (29,684)
Corporate interest expense	(18,897)	(7,187)	(35,363)	(14,260)
Corporate other income	9,458	3,089	18,626	5,535
Consolidated loss before income taxes	(71,977)	(13,693)	(142,002)	(29,684)
Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Loss before income taxes	(68,322)	(9,595)	(134,595)	(20,959)
Consolidated loss before income taxes	(68,322)	(9,595)	(134,595)	(20,959)
Corporate
Segment Reporting, Revenue Reconciling Item [Line Items]
Corporate interest expense	(12,711)	(7,187)	(25,318)	(14,260)
Corporate other income	$ 9,056	$ 3,089	$ 17,911	$ 5,535

Subsequent Event (Details)

Subsequent Event (Details) - Line of Credit - USD ($)	Jul. 11, 2019	Jun. 30, 2019
Subsequent Event [Line Items]
Maximum borrowing capacity		$ 100,000,000
Subsequent Event | June 27, 2020
Subsequent Event [Line Items]
Maximum borrowing capacity	$ 50,000,000

Uncategorized Items - q22019for

Label	Element	Value
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 40,322,000
Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 40,322,000