Goodwill And Intangible Assets (Narrative) (Details) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) physician_practice center	Sep. 30, 2014 USD ($) center	Dec. 31, 2014 USD ($)
Segment Reporting Information [Line Items]
Goodwill		$ 3,589,317		$ 3,589,317		$ 3,381,149
Increase in goodwill				246,787
Goodwill deductible for tax purposes		126,200	$ 25,100	126,200	$ 25,100
Amortization of Intangible Assets		17,100	$ 13,700	50,500	$ 16,200
Estimated amortization of intangible assets, remainder of 2015		17,400		17,400
Estimated amortization of intangible assets, 2016		69,400		69,400
Estimated amortization of intangible assets, 2017		68,000		68,000
Estimated amortization of intangible assets, 2018		66,900		66,900
Estimated amortization of intangible assets, 2019		64,100		64,100
Estimated amortization of intangible assets, 2020		61,100		61,100
Estimated amortization of intangible assets, 2021 and thereafter		697,700		$ 697,700
Weighted average amortization period				17 years 182 days
Ambulatory Services [Member]
Segment Reporting Information [Line Items]
Goodwill		2,000,000		$ 2,000,000
Increase in goodwill				139,700
Physician Services [Member]
Segment Reporting Information [Line Items]
Goodwill		1,600,000		1,600,000
Increase in goodwill				68,500
Series of Individually Immaterial Business Acquisitions [Member]
Segment Reporting Information [Line Items]
Goodwill	[1]	255,251		255,251
Intangible assets	[1]	45,600		$ 45,600
Series of Individually Immaterial Business Acquisitions [Member] | Physician Services [Member]
Segment Reporting Information [Line Items]
Number of business acquisitions | physician_practice				6
Controlling Interest [Member] | Ambulatory Services [Member]
Segment Reporting Information [Line Items]
Number of business acquisitions | center				5	4
Controlling Interest [Member] | Joint Venture [Member] | Ambulatory Services [Member]
Segment Reporting Information [Line Items]
Number consolidated entities contributed to joint venture | center				3	4
Controlling Interest [Member] | Joint Venture [Member] | Physician Services [Member]
Segment Reporting Information [Line Items]
Number consolidated entities contributed to joint venture | center				2
Customer relationships with hospitals [Member]
Segment Reporting Information [Line Items]
Amount estimated to be amortized over weighted average period		$ 44,500		$ 44,500
Weighted average period of amortization		20 years

[1] Represents the preliminary allocation of fair value of acquired assets and liabilities associated with these acquisitions at September 30, 2015.