Investments in Unconsolidated Affiliates (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) entity center	Jun. 30, 2014 USD ($) entity center	Dec. 31, 2014 USD ($)
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	$ 83,679		$ 83,679		$ 75,475
Equity in earnings of unconsolidated affiliates	3,989	$ 539	6,640	$ 1,303
Gain (loss) on deconsolidation	$ (3,035)	$ 1,366	(3,258)	3,411
Goodwill, Written off Related to Sale of Business Unit			3,324
Joint Venture [Member]
Schedule of Equity Method Investments [Line Items]
Increase in Equity Method Investments			$ 2,300	$ 6,500
Ambulatory Services [Member] | Controlling Interest [Member] | Joint Venture [Member]
Schedule of Equity Method Investments [Line Items]
Number consolidated entities contributed to joint venture | center			1	4
Ambulatory Services [Member] | Noncontrolling Interest In Centers [Member] | Joint Venture [Member]
Schedule of Equity Method Investments [Line Items]
Number of joint venture entities acquired | entity			1	3
Physician Services [Member] | Joint Venture [Member]
Schedule of Equity Method Investments [Line Items]
Goodwill, Written off Related to Sale of Business Unit			$ 5,200
Physician Services [Member] | Controlling Interest [Member] | Joint Venture [Member]
Schedule of Equity Method Investments [Line Items]
Number consolidated entities contributed to joint venture | center			1
Deconsolidation [Member] | Ambulatory Services [Member]
Schedule of Equity Method Investments [Line Items]
Proceeds from deconsolidation				$ 1,700