Organization (Details) medical_member in Millions	Dec. 31, 2016 medical_member counties county states
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of medical membership members | medical_member	39.9
Number of counties in the Kansas City area the Company does not serve | counties	30
Number of counties in the New York City metropolitan area the Company serves as an independent licensee | county	10
Number of states in which the Company is licensed to conduct insurance operations | states	50