Acquisitions and Transactions - Recognized Identifiable Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Oct. 14, 2015	Feb. 17, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Goodwill	$ 102,782			$ 63,864	$ 56,975
Pacific Cancer Institute Inc (PCI)
Business Acquisition [Line Items]
Equipment, net	1,921
Other assets	152
Goodwill	5,890
Identifiable intangible assets	8,800
Deferred tax liability	(3,748)
Other liabilities	(122)
Noncontrolling interest	(430)
Total consideration	$ 12,463
AHIP Florida LLC
Business Acquisition [Line Items]
Cash received		$ 264
Equipment, net		890
Other assets		1,184
Goodwill		7,806
Identifiable intangible assets		15,400
Other liabilities		(475)
Noncontrolling interest		(5,739)
Total consideration		$ 19,330
The Pain Center of Arizona
Business Acquisition [Line Items]
Cash received			$ 234
Accounts receivable, net			4,440
Equipment, net			3,346
Other assets			416
Goodwill			22,566
Identifiable intangible assets			24,600
Debt			(2,781)
Other liabilities			(3,030)
Noncontrolling interest			(20,598)
Total consideration			$ 29,193