GOODWILL AND INTANGIBLE ASSETS - Goodwill and Intangible Assets (Details)			12 Months Ended
	Sep. 30, 2019 segment	Oct. 31, 2018 USD ($) segment	Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jan. 10, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jun. 11, 2018 USD ($)
Goodwill [Line Items]
Goodwill					$ 903,227,000	$ 903,227,000		$ 831,435,000
Accumulated impairment losses					(483,088,000)	(483,088,000)		(483,088,000)
Net Goodwill			$ 420,139,000	$ 348,347,000	420,139,000	420,139,000		$ 348,347,000
Goodwill [Roll Forward]
Net goodwill, beginning balance			420,139,000	348,347,000
Changes in goodwill			0
Net goodwill, ending balance			$ 420,139,000	420,139,000
Intangible Assets
Intangible assets with indefinite lives					10,142,000	10,142,000
Intangible assets with definite lives, net					118,360,000	171,438,000
Total intangible assets, net					128,502,000	$ 181,580,000
Number of reportable segments | segment	1	1	3
Impairment losses during period related to goodwill			$ 0
Impairment charges related to trade names and trademarks			$ 0
Ovation
Goodwill [Line Items]
Net Goodwill									$ 11,280,000
Goodwill [Roll Forward]
Acquisition of business				20,000
QuoteWizard
Goodwill [Line Items]
Net Goodwill		$ 182,896,000
Goodwill [Roll Forward]
Acquisition of business				33,000
Net goodwill, ending balance		$ 182,896,000
ValuePenguin
Goodwill [Line Items]
Net Goodwill							$ 71,739,000
Goodwill [Roll Forward]
Acquisition of business				$ 71,739,000
Home
Goodwill [Line Items]
Goodwill					59,300,000
Consumer
Goodwill [Line Items]
Goodwill					166,100,000
Insurance
Goodwill [Line Items]
Goodwill					$ 194,700,000