| **Goodwill and Other Intangible Assets - Carrying Amounts of Goodwill (Details) - USD ($) $ in Millions** | 12 Months Ended |
|-----------------------------------------------------------------------------------------------------------|-----------------|
||
| **Schedule of Changes in the Carrying Amount of Goodwill**                                                |            |   |   |
| Goodwill, Beginning Balance                                                                               | $ 1,890.1       | $ 1,084.0 | $ 456.9 |
| Acquisitions                                                                                              | 51.4            | 806.1 | 593.1 |
| Consolidation of joint venture formerly accounted for under the equity method of accounting               |            |   | 34.0 |
| Divestiture of pediatric home health services                                                             | (14.3)          |   |   |
| Goodwill, Ending Balance                                                                                  | 1,927.2         | 1,890.1 | 1,084.0 |
| Inpatient Rehabilitation Segment [Member]                                                                 |            |   |   |
| **Schedule of Changes in the Carrying Amount of Goodwill**                                                |            |   |   |
| Goodwill, Beginning Balance                                                                               | 1,133.1         | 491.5 | 456.9 |
| Acquisitions                                                                                              | 8.9             | 641.6 | 0.6 |
| Consolidation of joint venture formerly accounted for under the equity method of accounting               |            |   | 34.0 |
| Divestiture of pediatric home health services                                                             | 0.0             |   |   |
| Goodwill, Ending Balance                                                                                  | 1,142.0         | 1,133.1 | 491.5 |
| Home Health and Hospice Segment [Member]                                                                  |            |   |   |
| **Schedule of Changes in the Carrying Amount of Goodwill**                                                |            |   |   |
| Goodwill, Beginning Balance                                                                               | 757.0           | 592.5 | 0.0 |
| Acquisitions                                                                                              | 42.5            | 164.5 | 592.5 |
| Consolidation of joint venture formerly accounted for under the equity method of accounting               |            |   | 0.0 |
| Divestiture of pediatric home health services                                                             | (14.3)          |   |   |
| Goodwill, Ending Balance                                                                                  | $ 785.2         | $ 757.0 | $ 592.5 |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=64834752&loc=SL49117168-202975
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267
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| X                                                                                                                                                                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of transfers into (out of) an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of divestiture of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267
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| X                                                                                                                                                                      |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                   |
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