Organization (Details) medical_member in Millions	Jun. 30, 2018 medical_member county states
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of medical members | medical_member	39.5
Number of counties in the Kansas City area the Company does not serve | county	30
Number of states in which customers are served through subsidiaries	25
Number of states in which the Company is licensed to conduct insurance operations	50