Investments in Unconsolidated Affiliates (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) equity_method_investment	Mar. 31, 2015 USD ($) equity_method_investment	Dec. 31, 2015 USD ($)
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	$ 172,826		$ 169,170
Equity in earnings of unconsolidated affiliates	6,579	$ 2,651
Net loss on deconsolidation	$ 0	$ (223)
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	0	1
Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	$ 172,800		$ 169,200
Equity in earnings of unconsolidated affiliates	$ 6,600	$ 2,700
Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure [Member] | Joint Venture [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates		1,300
Deconsolidation [Member] | Ambulatory Services [Member]
Schedule of Equity Method Investments [Line Items]
Proceeds from Divestiture of Interest in Consolidated Subsidiaries		$ 600