| **Business Combinations - Table 2 (Details) - USD ($) $ in Millions**                    | 3 Months Ended | 9 Months Ended |
|------------------------------------------------------------------------------------------|----------------|----------------|
||
| **Net Cash Paid For All Acquisitions During Each Period Presented**                      |           |           |   |   |
| Net cash paid for acquisition                                                            |           |           | $ 19.6 | $ 87.1 |
| Inpatient Rehabilitation Segment [Member] | Hot Springs, Bryan and Broken Arrow [Member] |           |           |   |   |
| **Net Cash Paid For All Acquisitions During Each Period Presented**                      |           |           |   |   |
| Fair value of assets acquired                                                            | $ 1.4          | $ 0.0          | 6.7 | 62.8 |
| Goodwill                                                                                 | 7.6            | 0.0            | 9.4 | 0.7 |
| Fair value of liabilities assumed                                                        | 0.0            | 0.0            | 0.0 | (2.7) |
| Fair value of noncontrolling interests owned by joint venture partner                    | (9.0)          | 0.0            | (16.1) | (4.2) |
| Net cash paid for acquisition                                                            | $ 0.0          | $ 0.0          | $ 0.0 | $ 56.6 |

| X                                                                                                                                                                                                                                                                                                                                                                                                     |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
This element represents the fair value of the noncontrolling interest in the acquiree at the acquisition date.
+ References
No definition available.
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The fair value of assets acquired in noncash investing or financing activities.
+ References
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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
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The total amount of [all] liabilities that an Entity assumes in acquiring a business or in consideration for an asset received in a noncash (or part noncash) acquisition. Noncash is defined as transactions during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.
+ References
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| - Definition
The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase.
+ References
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