Medical Claims and Benefits Payable (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Mar. 31, 2014 Minimum	Mar. 31, 2014 Maximum	Jan. 02, 2014 South Carolina member	Jan. 02, 2014 Medicaid Expansion member
Insurance Claims [Line Items]
Medical claims and benefits payable	$ 122,700,000		$ 151,300,000
Percentage of liability for unpaid claims not paid out				8.00%	10.00%
Policy holder benefits prior percentage	7.60%	11.80%	10.70%
Favorable prior period claims development	$ 50,904,000	$ 58,427,000	$ 52,779,000
Number of new members						126,000	133,000