Acquisitions (Narrative) (Details) (USD $)	3 Months Ended		0 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Jul. 16, 2014	Jul. 02, 2014	Jul. 15, 2014	Dec. 31, 2014
Business Acquisition [Line Items]
Transaction costs	$ 1,471,000	$ 0
Acquisitions and related expenses, net	126,578,000	5,038,000
Sheridan Healthcare [Member]
Business Acquisition [Line Items]
Cash paid to acquire business			2,100,000,000
Value of common stock issued for acquisition			272,000,000
Common Stock [Member]
Business Acquisition [Line Items]
Issuance of common stock (in shares)				9,775,000
Common Stock [Member] | Sheridan Healthcare [Member]
Business Acquisition [Line Items]
Shares of common stock issued for acquisition			5,713,909
Mandatory Convertible Preferred Stock [Member]
Business Acquisition [Line Items]
Issuance of common stock (in shares)				1,725,000
Senior Secured Credit Facility - Term Loan [Member]
Business Acquisition [Line Items]
Maximum borrowing capacity			870,000,000.0
Revolving Credit Facility [Member]
Business Acquisition [Line Items]
Maximum borrowing capacity			300,000,000.0		475,000,000.0
Senior Notes [Member] | 2022 Senior Unsecured Notes [Member]
Business Acquisition [Line Items]
Face amount			1,100,000,000.0
Interest rate			5.625%
Ambulatory Services [Member]
Business Acquisition [Line Items]
Acquisitions and related expenses, net	41,900,000	5,000,000
Ambulatory Services [Member] | Controlling Interest [Member]
Business Acquisition [Line Items]
Number of business acquisitions	1	1
Physician Services [Member] | Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Cash paid to acquire business	84,700,000
Business Combination, Contingent Consideration, Liability	24,600,000					20,700,000
Number of business acquisitions	3
Contingent consideration arrangements, low	21,000,000
Contingent consideration arrangements, high	$ 26,000,000