Business Combinations - Additional Information (Details) $ / shares in Units, $ in Thousands			3 Months Ended
	Mar. 08, 2019 USD ($) $ / shares	Dec. 09, 2018	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)
Business Acquisition [Line Items]
Increase (decrease) in acquisition, integration, and restructuring costs			$ (33,400)	$ 38,700
Increase (decrease) in income tax expense			$ (2,700)	2,700
Increase in cost of revenue				$ 2,800
Nutrisystem, Inc.
Business Acquisition [Line Items]
Business acquisition, cash received in conversion | $ / shares	$ 38.75
Business acquisition, common stock exchange ratio	0.2141
Merger consideration	$ 1,286,108
Nutrisystem, Inc. | Merger Agreement
Business Acquisition [Line Items]
Business acquisition, agreement date		Dec. 09, 2018
Business acquisition, effective date of acquisition	Mar. 08, 2019
Business acquisition, cash received in conversion | $ / shares	$ 38.75
Business acquisition, common stock exchange ratio	0.2141