ORGANIZATION - Narrative (Details) review in Millions	12 Months Ended
Dec. 31, 2018 operating_segment country review service_category
Noncontrolling Interest [Line Items]
Number of consumer reviews \| review	15
Period of consumer reviews collected	20 years
Number of countries in which entity operates \| country	8
Number of service categories \| service_category	700
Number of operating segments \| operating_segment	2
ANGI Homeservices \| Class B Common Stock \| IAC
Noncontrolling Interest [Line Items]
Ownership interest (as a percent)	83.90%
Voting interest (as a percent)	98.10%

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

No definition available.

Name:	us-gaap_NumberOfOperatingSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration