State-Sponsored Health Plans Rate Settlement Agreement (Details) (USD $)		3 Months Ended
	Dec. 31, 2012	Mar. 31, 2013 Medicaid Premium Revenue [Member]
State-Sponsored Health Plans Rate Settlement Agreement [Line Items]
Settlement account balance, beginning	$ 0
Settlement account payment, maximum		264,000,000
Settlement account payment, current balance		$ 20,800,000