| **Self-Insured Risks Self-Insured Risks (Tables)** | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
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| **Self-Insured Risks [Abstract]**                  |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
| Self-Insurance Reserves                            | The following table presents the changes in our self-insurance reserves for the years ended December 31, 2014, 2013, and 2012 (in millions): 2014 2013 2012Balance at beginning of period, gross$140.3 $148.3 $153.3Less: Reinsurance receivables(32.6) (29.4) (34.4)Balance at beginning of period, net107.7 118.9 118.9Increase for the provision of current year claims34.7 34.4 33.8Decrease for the provision of prior year claims(3.5) (5.9) (6.4)Decrease related to change in statistical confidence level— (6.7) —Expenses related to discontinued operations(0.3) (1.8) (1.9)Payments related to current year claims(4.4) (3.9) (4.2)Payments related to prior year claims(25.9) (27.3) (21.3)Acquisition of Encompass0.3 — —Balance at end of period, net108.6 107.7 118.9Add: Reinsurance receivables26.0 32.6 29.4Balance at end of period, gross$134.6 $140.3 $148.3 |

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| - Definition
Schedule of activity in our self-insurance reserves.
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No definition available.
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| - Details**Name:**hls_SelfInsuredRisksAbstract**Namespace Prefix:**hls_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |