| **Business Combinations - Pro Forma Results of Operation (Details) - USD ($) $ in Millions**             | 12 Months Ended |
|----------------------------------------------------------------------------------------------------------|-----------------|
||
| 2014 Acquisitions [Member]                                                                               |            |   |   |   |
| **Business Acquisition [Line Items]**                                                                    |            |   |   |   |
| Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual          |            |   | $ 27.2 |   |
| Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual |            |   | 4.0 |   |
| Business Acquisition, Pro Forma Revenue                                                                  |            |   | 2,799.8 | $ 2,627.6 |
| Business Acquisition, Pro Forma Net Income (Loss)                                                        |            |   | 237.5 | $ 311.3 |
| 2016 Acquisitions [Member]                                                                               |            |   |   |   |
| **Business Acquisition [Line Items]**                                                                    |            |   |   |   |
| Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual          | $ 27.4          |   |   |   |
| Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual | (2.2)           |   |   |   |
| Business Acquisition, Pro Forma Revenue                                                                  | 3,745.6         | $ 3,217.1 |   |   |
| Business Acquisition, Pro Forma Net Income (Loss)                                                        | $ 252.2         | 187.3 |   |   |
| 2015 Acquisitions [Member]                                                                               |            |   |   |   |
| **Business Acquisition [Line Items]**                                                                    |            |   |   |   |
| Business Acquisition, Pro Forma Revenue                                                                  |            | 3,479.9 | 2,851.0 |   |
| Business Acquisition, Pro Forma Net Income (Loss)                                                        |            | 234.0 | $ 276.9 |   |
| Inpatient Rehabilitation Segment [Member] | All Other Acquisitions [Member]                              |            |   |   |   |
| **Business Acquisition [Line Items]**                                                                    |            |   |   |   |
| Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual          |            | 54.7 |   |   |
| Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual |            | 1.7 |   |   |
| Inpatient Rehabilitation Segment [Member] | Reliant [Member]                                             |            |   |   |   |
| **Business Acquisition [Line Items]**                                                                    |            |   |   |   |
| Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual          |            | 63.7 |   |   |
| Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual |            | 11.2 |   |   |
| Home Health and Hospice Segment [Member] | All Other Acquisitions [Member]                               |            |   |   |   |
| **Business Acquisition [Line Items]**                                                                    |            |   |   |   |
| Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual          |            | 17.8 |   |   |
| Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual |            | 1.2 |   |   |
| Home Health and Hospice Segment [Member] | CareSouth [Member]                                            |            |   |   |   |
| **Business Acquisition [Line Items]**                                                                    |            |   |   |   |
| Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual          |            | 19.2 |   |   |
| Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual |            | $ 2.5 |   |   |

| X                                                                                                                                                                                                                                                                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(2)-(3) -URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1392-128463
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
This element represents the amount of earnings or loss of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.
+ References
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| X                                                                                                                                           |
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