Investments in Unconsolidated Affiliates (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) equity_method_investment center	Jun. 30, 2015 USD ($) equity_method_investment center	Dec. 31, 2015 USD ($)
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	$ 179,056		$ 179,056		$ 169,170
Equity in earnings of unconsolidated affiliates	7,351	$ 3,989	13,930	$ 6,640
Net loss on deconsolidation	(700)	(3,000)	$ (700)	$ (3,300)
Joint Venture [Member] | Ambulatory Services [Member]
Schedule of Equity Method Investments [Line Items]
Number Of Consolidated Entities Contributed To Joint Venture | center			1
Joint Venture [Member] | Ambulatory Services [Member] | Noncontrolling Interest In Centers [Member]
Schedule of Equity Method Investments [Line Items]
Number of separate equity method investments | equity_method_investment			1	1
Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure [Member] | Joint Venture [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	$ 1,800	$ 2,300	$ 1,800	$ 2,300
Controlling Interest [Member] | Joint Venture [Member] | Physician Services [Member]
Schedule of Equity Method Investments [Line Items]
Number Of Consolidated Entities Contributed To Joint Venture | center			0	1