Acquisitions (Narrative) (Details)			1 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended
	Jul. 16, 2014 USD ($) shares	Jul. 02, 2014 shares	Dec. 31, 2015 USD ($) shares	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($) physician_practice	Dec. 31, 2015 USD ($) physician_practice center	Dec. 31, 2014 USD ($) center	Dec. 31, 2013 USD ($) center	Oct. 21, 2015 USD ($)
Business Acquisition [Line Items]
Acquisitions and related expenses, net						$ 962,689,000	$ 2,184,058,000	$ 73,594,000
Acquisition accounting, change in the contingent consideration						8,804,000	0	0
Proceeds from common stock offering						466,777,000	439,875,000	0
Proceeds from preferred stock offering						0	172,500,000	0
Payments of equity issuance costs						(19,058,000)	(24,494,000)	0
Transaction costs				$ 25,100,000		8,324,000	33,890,000	300,000
Debt extinguishment costs						0	(16,887,000)	$ 0
Contingent purchase price payable			$ 0		$ 8,470,000	0	8,470,000
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
Fees and expenses associated with acquisition					139,100,000		139,100,000
Deferred financing costs					$ 53,000,000		53,000,000
Goodwill, Purchase Accounting Adjustments						8,300,000
Transaction costs							31,900,000
Common Stock [Member]
Business Acquisition [Line Items]
Issuance of common stock (in shares) | shares		9,775,000	5,835,000
Proceeds from common stock offering	$ 421,300,000
Common Stock [Member] | Sheridan Healthcare [Member]
Business Acquisition [Line Items]
Shares of common stock issued for acquisition | shares	5,713,909
Mandatory Convertible Preferred Stock [Member]
Business Acquisition [Line Items]
Issuance of common stock (in shares) | shares		1,725,000
Proceeds from preferred stock offering	$ 166,600,000
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								$ 500,000,000
Debt extinguishment costs						4,500,000
Senior Notes [Member] | 2022 Senior Unsecured Notes [Member]
Business Acquisition [Line Items]
Face amount	$ 1,100,000,000.0
Interest rate	5.625%
Bridge Loan [Member] | Interest Expense [Member] | Sheridan Healthcare [Member]
Business Acquisition [Line Items]
Fees paid to obtain a commitment for financing							12,800,000
Ambulatory Services [Member]
Business Acquisition [Line Items]
Acquisitions and related expenses, net						$ 131,300,000	$ 50,900,000
Ambulatory Services [Member] | Controlling Interest [Member]
Business Acquisition [Line Items]
Number of business acquisitions | center						7	8
Ambulatory Services [Member] | Sheridan Healthcare [Member] | Controlling Interest [Member]
Business Acquisition [Line Items]
Number of business acquisitions | center							3
Ambulatory Services [Member] | Series of Individually Immaterial Business Acquisitions [Member] | Controlling Interest [Member]
Business Acquisition [Line Items]
Number of business acquisitions | center							5
Physician Services [Member]
Business Acquisition [Line Items]
Acquisition accounting, change in the contingent consideration						$ 10,000,000
Physician Services [Member] | Sheridan Healthcare [Member]
Business Acquisition [Line Items]
Acquisition accounting, change in the contingent consideration						$ 3,500,000
Physician Services [Member] | Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Number of business acquisitions | physician_practice					2	9
Cash paid to acquire business					$ 19,000,000	$ 831,400,000
Estimate of fair values of the contingent consideration			$ 5,500,000		$ 20,700,000	5,500,000	$ 20,700,000
Payments for contingent consideration						28,700,000
Payment to settle amount recorded at the acquisition date						15,700,000
Estimate contingent consideration payment, low			5,000,000			5,000,000
Estimate contingent consideration payment, high			$ 6,000,000			$ 6,000,000
Joint Venture [Member] | Ambulatory Services [Member] | Controlling Interest [Member]
Business Acquisition [Line Items]
Number Of Consolidated Entities Contributed To Joint Venture | center						9	4	1
Joint Venture [Member] | Physician Services [Member] | Controlling Interest [Member]
Business Acquisition [Line Items]
Number Of Consolidated Entities Contributed To Joint Venture | center						3