Business Combinations (Details) (USD $)	9 Months Ended		0 Months Ended		0 Months Ended			3 Months Ended	0 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Jul. 26, 2013 South Carolina Health Plan Community Healthy Solutions of America, Inc. Customer	Sep. 30, 2013 South Carolina Health Plan Community Healthy Solutions of America, Inc. member	Jul. 26, 2013 South Carolina Health Plan Number of Member Conversion Community Healthy Solutions of America, Inc.	Aug. 01, 2013 New Mexico Health Plan Lovelace Community Health Plan	Sep. 30, 2013 New Mexico Health Plan Lovelace Community Health Plan member	Sep. 30, 2013 New Mexico Health Plan Number of Member Conversion Lovelace Community Health Plan	Jun. 30, 2013 Florida Health Plan Statewid Medicaid Managed Care Long-Term Care Program
Business Acquisition [Line Items]
Payment made on the closing date	$ 57,684,000	$ 0	$ 7,500,000			$ 47,200,000
Expected members to be converted			130,000	130,000
Total estimated purchase price			65,000,000			53,500,000			3,300,000
Amount of purchase price that is contingent on members conversion					57,500,000			2,400,000
Minimum contingent consideration arrangement payment					7,500,000
Maximum contingent consideration arrangement payment					70,000,000
Goodwill recorded			42,100,000			35,200,000
Intangible assets recorded			22,900,000			18,300,000
Expected future amortization in the year 2014				1,900,000			1,800,000
Expected future amortization in the year 2015				1,900,000			1,800,000
Expected future amortization in the year 2016				1,900,000			1,800,000
Expected future amortization in the year 2017				1,900,000			1,800,000
Expected future amortization in the year 2018				$ 1,900,000			$ 1,800,000
Additional members expect to be added in coming months							80,000