Fair Value Measurements - Additional Information (Details) - USD ($)	3 Months Ended			12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Mar. 31, 2020	Dec. 31, 2020		Dec. 31, 2019		Dec. 31, 2021
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total impairment loss				$ 199,500,000		$ 377,100,000
Term Loan B
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument net fair value								$ 394,000,000.0
Debt instrument net carrying amount								394,000,000.0
Revolving Credit Facility
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Line of credit								0
Carrying Value
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash and cash equivalents								$ 60,100,000
Nutrisystem, Inc.
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total impairment loss			$ 199,500,000	199,500,000	[1]	$ 377,100,000	[2]
Goodwill impairment loss				$ 90,200,000
Continuing Operations
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Goodwill impairment loss			0
Discontinued Operations | Nutrition
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Goodwill impairment loss	$ 24,000,000.0	$ 66,200,000
SilverSneakers | Continuing Operations | Tradename
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Impairment loss of intangibles			$ 0

[1] Results include the period from January 1, 2020 through December 8, 2020.

[2] Results include the period from March 8, 2019 (the date of acquisition) through December 31, 2019.