Significant Accounting Policies (Government Contracts) (Details) (USD $)	12 Months Ended				12 Months Ended				12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Mar. 31, 2011 Government Contracts [Member] options	Dec. 31, 2013 Government Contracts [Member] T-3 Contract [Member]	Dec. 31, 2012 Government Contracts [Member] T-3 Contract [Member]	Dec. 31, 2011 Government Contracts [Member] T-3 Contract [Member]	Apr. 02, 2011 Government Contracts [Member] T-3 Contract [Member]	Dec. 31, 2013 Government Contracts [Member] TRICARE Contract North Region [Member]	Dec. 31, 2011 Government Contracts [Member] TRICARE Contract North Region [Member]	Dec. 31, 2013 Government Contracts [Member] MFLC Contract [Member]	Dec. 31, 2012 Government Contracts [Member] MFLC Contract [Member]	Dec. 31, 2011 Government Contracts [Member] MFLC Contract [Member]
Significant Accounting Policies [Line Items]
Number of administrative services option periods				5
Deferred costs								$ 43,800,000
Effective date of contract											August 15, 2012
Administrative services option period											5 years
Deferred revenue								52,500,000
Costs paid and reimbursable					2,500,000,000	2,600,000,000	1,700,000,000
Percentage of reimbursed health care target costs and underwriting fees									80.00%
Percentage of unreimbursed health care target costs and underwriting fees									20.00%
Changes in estimate of target cost revenues										(42,000,000)
Changes in estimate of target costs										(52,000,000)
Contracts revenue	$ 572,266,000	$ 689,121,000	$ 1,416,619,000								$ 104,800,000	$ 221,300,000	$ 258,600,000