Goodwill And Intangible Assets (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) physician_practice center	Sep. 30, 2015 USD ($) physician_practice center	Dec. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Goodwill	$ 4,300,102		$ 4,300,102		$ 3,970,210
Increase in goodwill			332,945
Goodwill deductible for tax purposes	159,100	$ 126,200	159,100	$ 126,200
Amortization of Intangible Assets	22,300	$ 15,000	63,700	$ 44,200
Estimated amortization of intangible assets, remainder of 2016	23,000		23,000
Estimated amortization of intangible assets, 2017	90,600		90,600
Estimated amortization of intangible assets, 2018	89,300		89,300
Estimated amortization of intangible assets, 2019	86,600		86,600
Estimated amortization of intangible assets, 2020	84,200		84,200
Estimated amortization of intangible assets, 2021	80,100		80,100
Estimated amortization of intangible assets, 2022 and thereafter	988,100		$ 988,100
Weighted average amortization period			17 years 219 days
Series of Individually Immaterial Business Acquisitions [Member]
Segment Reporting Information [Line Items]
Goodwill	296,791		$ 296,791
Ambulatory Services [Member]
Segment Reporting Information [Line Items]
Goodwill	2,100,000		2,100,000
Increase in goodwill			$ 61,200
Number of business acquisitions | center			7	5
Physician Services [Member]
Segment Reporting Information [Line Items]
Goodwill	$ 2,200,000		$ 2,200,000
Increase in goodwill			$ 268,700
Physician Services [Member] | Series of Individually Immaterial Business Acquisitions [Member]
Segment Reporting Information [Line Items]
Number of business acquisitions | physician_practice			8	6
Joint Venture [Member] | Ambulatory Services [Member]
Segment Reporting Information [Line Items]
Number Of Consolidated Entities Contributed To Joint Venture | center			1	3