Organization and Basis of Presentation (Details) member in Millions	6 Months Ended
	Jun. 30, 2019 member State Segment
Basis Of Presentation [Line Items]
Number of reportable segments (in segment) | Segment	2
Health Plans
Basis Of Presentation [Line Items]
Number of states in which entity operates (in state) | State	14
Number of members eligible for the health care programs, approximately (in member) | member	3.4
Minimum contract terms	3 years
Maximum contract terms	5 years