Business Combinations - Table 1 (Details) - USD ($) $ in Millions	Jun. 30, 2016	Feb. 01, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill	$ 1,899.7		$ 1,890.1
Inpatient Rehabilitation Hospital [Member]
Business Acquisition [Line Items]
Property and equipment		$ 5.1
Goodwill		1.8
Total assets acquired		7.1
Inpatient Rehabilitation Hospital [Member] | Trade Names [Member]
Business Acquisition [Line Items]
Identifiable intangible assets		$ 0.2