Revenue Recognition - Summary of Revenue Disaggregated by Source (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation Of Revenue [Line Items]
Revenue	[1]	$ 254,909	$ 303,897	$ 855,162	$ 858,369
Other
Disaggregation Of Revenue [Line Items]
Revenue				6,800
Nutrition
Disaggregation Of Revenue [Line Items]
Revenue		159,428	143,918	518,066	384,382
Nutrition | Nutrisystem Direct to Consumer
Disaggregation Of Revenue [Line Items]
Revenue		147,317	122,419	467,826	326,397
Nutrition | South Beach Diet Direct to Consumer
Disaggregation Of Revenue [Line Items]
Revenue		6,314	12,162	27,728	31,280
Nutrition | Retail
Disaggregation Of Revenue [Line Items]
Revenue		4,069	6,311	13,419	19,343
Nutrition | QVC
Disaggregation Of Revenue [Line Items]
Revenue		1,282	2,882	8,370	6,926
Nutrition | Other
Disaggregation Of Revenue [Line Items]
Revenue		$ 446	$ 144	$ 723	$ 436

[1] The figure for total segments equals the consolidated figure for such item.