Summary of Significant Accounting Policies (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			12 Months Ended
	Mar. 31, 2015		Mar. 31, 2014	Dec. 31, 2014
Reconciliation of valuation and qualifying accounts
Estimated liability for appeals	$ 36,986			$ 36,799
Goodwill
Impairment of goodwill	0		0
Estimated liability for appeals and estimated allowance for appeals
Reconciliation of valuation and qualifying accounts
Balance at the beginning of the period	41,623	[1]	55,791	55,791
Provision	2,321			16,822
Appeals found in providers' favor	(1,485)	[2]	16,700	(30,990)	[2]
Balance at the end of the period	42,459	[1]		41,623	[1]
Estimated liability for appeals	5,473			4,824
Allowance for doubtful accounts
Reconciliation of valuation and qualifying accounts
Balance at the beginning of the period	1,898		916	916
Provision				6,085
Recoveries				(17)
Charge-offs				(5,086)
Charge-offs and other	(420)
Balance at the end of the period	1,478			1,898
CMS | Estimated liability for appeals and estimated allowance for appeals
Reconciliation of valuation and qualifying accounts
Appeals found in providers' favor	$ 400		$ 13,500

[1] Includes $5,473 and $4,824 related to estimated allowance for appeals that apply to uncollected accounts receivable as of March 31, 2015 and December 31, 2014, respectively.

[2] Includes appeals, closures or other adjustments.