Reserves for Claims and performance-Based Arrangements - Claims Reserves (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) claim	Mar. 31, 2019 USD ($) claim
Liability for Unpaid Claims and Claims Adjustment Expense, Period Increase (Decrease) [Abstract]
Beginning balance	$ 61,150	$ 27,595
Incurred costs related to current year	136,316	65,275
Incurred costs related to prior year	(527)	13,138
Paid costs related to current year	92,234	40,366
Paid costs related to prior year	15,522	14,027
Change during the year	28,033	24,020
Other adjustments	(173)	(21,596)
Ending balance	89,010	30,019
Services
Liability for Unpaid Claims and Claims Adjustment Expense, Period Increase (Decrease) [Abstract]
Beginning balance	54,510	17,715
Incurred costs related to current year	112,760	33,777
Incurred costs related to prior year	(638)	6,879
Paid costs related to current year	77,351	28,684
Paid costs related to prior year	9,820	6,871
Change during the year	24,951	5,101
Other adjustments	(173)	(438)
Ending balance	79,288	22,378
True Health
Liability for Unpaid Claims and Claims Adjustment Expense, Period Increase (Decrease) [Abstract]
Beginning balance	6,640	9,880
Incurred costs related to current year	23,556	31,498
Incurred costs related to prior year	111	6,259
Paid costs related to current year	14,883	11,682
Paid costs related to prior year	5,702	7,156
Change during the year	3,082	18,919
Other adjustments	0	(21,158)
Ending balance	$ 9,722	$ 7,641
Number of claims processed, including denied claims | claim	112,032	86,368