| **Segment Reporting - Table 1 (Details) - USD ($) $ in Millions** | 3 Months Ended | 9 Months Ended |
|-------------------------------------------------------------------|----------------|----------------|
||
| **Segment Reporting Information [Line Items]**                    |           |           |   |   |
| Net operating revenues                                            | $ 926.8        | $ 778.6        | $ 2,757.3 | $ 2,283.6 |
| Less: Provision for doubtful accounts                             |           |           | (46.7) | (33.2) |
| Net operating revenues less provision for doubtful accounts       | 912.0          | 767.9          | 2,710.6 | 2,250.4 |
| **Costs and Expenses [Abstract]**                                 |           |           |   |   |
| Salaries and benefits                                             | 497.4          | 417.1          | 1,469.6 | 1,204.0 |
| Other operating expenses                                          | 126.3          | 106.7          | 367.0 | 314.1 |
| Supplies                                                          | 34.8           | 31.0           | 104.2 | 94.1 |
| Occupancy costs                                                   | 17.6           | 12.5           | 53.5 | 37.1 |
| Total operating expenses                                          | 749.9          | 632.0          | 2,221.6 | 1,855.6 |
| Other income                                                      | (0.8)          | (0.7)          | (2.1) | (4.2) |
| Equity in net income of nonconsolidated affiliates                | (2.5)          | (2.4)          | (7.3) | (6.3) |
| Net income attributable to noncontrolling interests               | 16.4           | 17.1           | 53.7 | 50.9 |
| Inpatient Rehabilitation Segment [Member]                         |           |           |   |   |
| **Segment Reporting Information [Line Items]**                    |           |           |   |   |
| Net operating revenues                                            | 751.7          | 651.6          | 2,253.5 | 1,927.2 |
| Less: Provision for doubtful accounts                             | (13.7)         | (10.2)         | (43.8) | (31.4) |
| Net operating revenues less provision for doubtful accounts       | 738.0          | 641.4          | 2,209.7 | 1,895.8 |
| **Costs and Expenses [Abstract]**                                 |           |           |   |   |
| Salaries and benefits                                             | 371.2          | 326.8          | 1,107.2 | 950.8 |
| Other operating expenses                                          | 110.1          | 95.8           | 321.7 | 284.5 |
| Supplies                                                          | 31.9           | 28.9           | 96.1 | 88.6 |
| Occupancy costs                                                   | 15.0           | 10.6           | 46.0 | 31.7 |
| Total operating expenses                                          | 528.2          | 462.1          | 1,571.0 | 1,355.6 |
| Other income                                                      | (0.8)          | (0.1)          | (2.1) | (1.0) |
| Equity in net income of nonconsolidated affiliates                | (2.3)          | (2.4)          | (6.7) | (6.3) |
| Net income attributable to noncontrolling interests               | 14.3           | 15.6           | 47.9 | 46.4 |
| Segment Adjusted EBITDA                                           | 198.6          | 166.2          | 599.6 | 501.1 |
| Capital Expenditures                                              | 42.7           | 43.8           | 128.9 | 103.2 |
| Home Health and Hospice Segment [Member]                          |           |           |   |   |
| **Segment Reporting Information [Line Items]**                    |           |           |   |   |
| Net operating revenues                                            | 175.1          | 127.0          | 503.8 | 356.4 |
| Less: Provision for doubtful accounts                             | (1.1)          | (0.5)          | (2.9) | (1.8) |
| Net operating revenues less provision for doubtful accounts       | 174.0          | 126.5          | 500.9 | 354.6 |
| **Costs and Expenses [Abstract]**                                 |           |           |   |   |
| Cost of services sold (excluding depreciation and amortization)   | 86.8           | 61.7           | 246.8 | 171.8 |
| Support and overhead costs                                        | 59.5           | 42.6           | 174.5 | 121.7 |
| Total operating expenses                                          | 146.3          | 104.3          | 421.3 | 293.5 |
| Other income                                                      | 0.0            | 0.0            | 0.0 | 0.0 |
| Equity in net income of nonconsolidated affiliates                | (0.2)          | 0.0            | (0.6) | 0.0 |
| Net income attributable to noncontrolling interests               | 2.1            | 1.5            | 5.8 | 4.5 |
| Segment Adjusted EBITDA                                           | 25.8           | 20.7           | 74.4 | 56.6 |
| Capital Expenditures                                              | $ 2.2          | $ 0.5          | $ 4.6 | $ 2.7 |

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Indirect expenses and cost incurred associated with services rendered by an entity during the reporting period.
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Amount of revenues recognized by the entity from providing services to in-patients, outpatients, residents in facilities owned or operated by the entity, from insurance premiums, or from goods provided or services performed.
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Amount of patient service revenue recognized, net of contractual allowances and discounts, less the provision for bad debts related to patient service revenue plus all other revenue.
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This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.
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Amount of Net Income (Loss) attributable to noncontrolling interest.
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Amount of income (expense) related to nonoperating activities, classified as other.
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The cash outflow for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets.
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Amount of expense related to write-down of receivables to the amount expected to be collected. Includes, but is not limited to, accounts receivable and notes receivable.
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