Long-Term Debt (Details) (USD $)	12 Months Ended				0 Months Ended		12 Months Ended	0 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jul. 16, 2013	Jul. 01, 2018 Cash Convertible Notes [Member]	Jul. 16, 2013 Cash Convertible Notes [Member]	Dec. 31, 2013 Cash Convertible Notes [Member]	Oct. 01, 2019 CareFirst Convertible Note [Member]	Oct. 01, 2013 CareFirst Convertible Note [Member]	Dec. 31, 2013 CareFirst Convertible Note [Member]
Debt Instrument [Line Items]
Notes, Issuance Date						Jul. 16, 2013			Oct. 01, 2013
Date of Registration Rights Agreement									Oct. 01, 2013
Debt Instrument, Maturity Date					Jul. 01, 2018			Oct. 01, 2019
Debt Instrument, Interest Rate, Effective Percentage	5.66%
Amortization of debt discount	$ 3,140,000	$ 0	$ 0
Debt Instrument, Convertible, Conversion Ratio							51.38
Debt Instrument, Unamortized Discount	33,600,000					36,750,000
Deferred Finance Costs, Gross				3,939,543
Interest Rate for Notes				1.50%					4.75%
Aggregate Principal of convertible notes				150,000,000			150,000,000		20,000,000	20,000,000
Debt Instrument, Convertible, Conversion Price						$ 19.46			$ 22.41
Payments for Hedge, Financing Activities	36,750,000	0	0			36,750,000
Initial Conversion rate						$ 19.46			$ 22.41
Warrants Strike Price	$ 25.95
Minimum annual principal payments and repayments of the revolving advances [Abstract]
2014	12,500,000
2015	17,500,000
2016	20,000,000
2017	63,625,000
2018	150,000,000
2019 and thereafter	20,000,000
Total	283,625,000
Conversion price premium percentage	60.00%
Warrant Shares Initially Sold underlying Cash Convertible Notes Hedges				7,700,000
Debt Instrument, Carrying Amount							116,400,000
Debt Instrument, Unamortized Discount	$ 33,600,000					$ 36,750,000
CareFirst Warrant Shares Maximum									1,600,000
CareFirst Warrant Shares for one year period									400,000