COVER - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Feb. 19, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	001-34063
Entity Registrant Name	LendingTree, Inc.
Entity Central Index Key	0001434621
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	26-2414818
Entity Address, Address Line One	1415 Vantage Park Dr., Suite 700
Entity Address, City or Town	Charlotte
Entity Address, State or Province	NC
Entity Address, Postal Zip Code	28203
City Area Code	704
Local Phone Number	541-5351
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
ICFR Auditor Attestation Flag	true
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	TREE
Security Exchange Name	NASDAQ
Entity Public Float			$ 2,298
Entity Common Stock, Shares Outstanding		13,128,360
Documents Incorporated by Reference	Portions of the Registrant's proxy statement for its 2021 Annual Meeting of Stockholders are incorporated by reference into Part III herein. Such proxy statement will be filed with the U.S. Securities and Exchange Commission within 120 days of the Registrant's fiscal year ended December 31, 2020.