Goodwill And Intangible Assets (Narrative) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) physician_practice center	Jun. 30, 2015 USD ($) physician_practice center	Dec. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Goodwill	$ 4,175,008		$ 4,175,008		$ 3,970,210
Increase in goodwill			207,333
Goodwill deductible for tax purposes	100,900	$ 107,600	100,900	$ 107,600
Amortization of Intangible Assets	21,100	$ 14,700	41,500	$ 29,200
Estimated amortization of intangible assets, remainder of 2016	44,900		44,900
Estimated amortization of intangible assets, 2017	88,600		88,600
Estimated amortization of intangible assets, 2018	87,400		87,400
Estimated amortization of intangible assets, 2019	84,700		84,700
Estimated amortization of intangible assets, 2020	82,400		82,400
Estimated amortization of intangible assets, 2021	78,000		78,000
Estimated amortization of intangible assets, 2022 and thereafter	976,300		$ 976,300
Weighted average amortization period			17 years 328 days
Series of Individually Immaterial Business Acquisitions [Member]
Segment Reporting Information [Line Items]
Goodwill	209,194		$ 209,194
Ambulatory Services [Member]
Segment Reporting Information [Line Items]
Goodwill	2,100,000		2,100,000
Increase in goodwill			$ 38,400
Number of business acquisitions | center			4	4
Physician Services [Member]
Segment Reporting Information [Line Items]
Goodwill	$ 2,100,000		$ 2,100,000
Increase in goodwill			$ 166,400
Physician Services [Member] | Series of Individually Immaterial Business Acquisitions [Member]
Segment Reporting Information [Line Items]
Number of business acquisitions | physician_practice			6	4
Joint Venture [Member] | Ambulatory Services [Member]
Segment Reporting Information [Line Items]
Number Of Consolidated Entities Contributed To Joint Venture | center			1