Revenue Recognition - Disaggregation of Revenue (NET Services) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Total Service revenue, net	$ 282,256	$ 363,911	$ 649,547	$ 731,726
NET Services
Disaggregation of Revenue [Line Items]
Total Service revenue, net	282,256	363,911	649,547	731,726
NET Services | State Medicaid agency contracts
Disaggregation of Revenue [Line Items]
Total Service revenue, net	151,545	177,773	332,276	354,741
NET Services | Managed care organization contracts
Disaggregation of Revenue [Line Items]
Total Service revenue, net	130,711	186,138	317,271	376,985
NET Services | Capitated contracts
Disaggregation of Revenue [Line Items]
Total Service revenue, net	253,858	308,690	554,582	613,262
NET Services | Non-capitated contracts
Disaggregation of Revenue [Line Items]
Total Service revenue, net	$ 28,398	$ 55,221	$ 94,965	$ 118,464