Business Combinations Business Combinations - Table 10 (Details) - USD ($) $ in Millions	Dec. 31, 2015	Oct. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Acquisition [Line Items]
Cash and cash equivalents		$ 42.6
Accounts receivable, net		25.7
Prepaid expenses and other current assets		2.8
Property and equipment, net		220.6
Goodwill	$ 1,890.1		$ 1,084.0	$ 456.9	$ 437.3
Long-term debt	1.3		2.9
Redeemable noncontrolling interests	$ 121.1		84.7
Noncompete Agreements [Member]
Business Acquisition [Line Items]
Identifiable intangible assets, Finite life		9.7
Trade Names [Member]
Business Acquisition [Line Items]
Identifiable intangible assets, Finite life		8.9
License [Member]
Business Acquisition [Line Items]
Identifiable intangible assets, Finite life		$ 11.4
Encompass [Member]
Business Acquisition [Line Items]
Cash and cash equivalents			20.9
Accounts receivable, net			37.6
Prepaid expenses and other current assets			8.6
Property and equipment, net			9.6
Goodwill			592.5
Other long-term assets			2.1
Total assets acquired			873.5
Current portion of long-term debt			2.0
Accounts payable			0.9
Accrued payroll			25.8
Other current liabilities			18.5
Long-term debt			2.0
Deferred tax liabilities			64.3
Total liabilities assumed			113.5
Redeemable noncontrolling interests			64.5
Net assets acquired			695.5
Encompass [Member] | Noncompete Agreements [Member]
Business Acquisition [Line Items]
Identifiable intangible assets, Finite life			5.6
Encompass [Member] | License [Member]
Business Acquisition [Line Items]
Identifiable intangible assets, Finite life			58.2
Encompass [Member] | Software Development [Member]
Business Acquisition [Line Items]
Identifiable intangible assets, Finite life			3.2
Encompass [Member] | Trade Names [Member]
Business Acquisition [Line Items]
Indentifiable intangible assets, Indefinite life			$ 135.2