Revenue Recognition - Summary of Revenue Disaggregated by Program (Parenthetical) (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
Well-Being Program
Disaggregation Of Revenue [Line Items]
Revenue		$ 100		$ 2,200

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