| **Segment Reporting - Table 5 (Details) - USD ($) $ in Millions**         | 3 Months Ended | 9 Months Ended |
|---------------------------------------------------------------------------|----------------|----------------|
||
| **Segment Reporting, Revenue Reconciling Item [Line Items]**              |           |           |   |   |
| Net operating revenues                                                    | $ 926.8        | $ 778.6        | $ 2,757.3 | $ 2,283.6 |
| Inpatient Rehabilitation Segment [Member]                                 |           |           |   |   |
| **Segment Reporting, Revenue Reconciling Item [Line Items]**              |           |           |   |   |
| Net operating revenues                                                    | 751.7          | 651.6          | 2,253.5 | 1,927.2 |
| Inpatient Rehabilitation Segment [Member] | Inpatient [Member]            |           |           |   |   |
| **Segment Reporting, Revenue Reconciling Item [Line Items]**              |           |           |   |   |
| Net operating revenues                                                    | 724.1          | 625.1          | 2,164.6 | 1,850.4 |
| Inpatient Rehabilitation Segment [Member] | Outpatient and other [Member] |           |           |   |   |
| **Segment Reporting, Revenue Reconciling Item [Line Items]**              |           |           |   |   |
| Net operating revenues                                                    | 27.6           | 26.5           | 88.9 | 76.8 |
| Home Health and Hospice Segment [Member]                                  |           |           |   |   |
| **Segment Reporting, Revenue Reconciling Item [Line Items]**              |           |           |   |   |
| Net operating revenues                                                    | 175.1          | 127.0          | 503.8 | 356.4 |
| Home Health and Hospice Segment [Member] | Home health [Member]           |           |           |   |   |
| **Segment Reporting, Revenue Reconciling Item [Line Items]**              |           |           |   |   |
| Net operating revenues                                                    | 162.0          | 118.3          | 470.0 | 333.7 |
| Home Health and Hospice Segment [Member] | Hospice [Member]               |           |           |   |   |
| **Segment Reporting, Revenue Reconciling Item [Line Items]**              |           |           |   |   |
| Net operating revenues                                                    | $ 13.1         | $ 8.7          | $ 33.8 | $ 22.7 |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
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.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688
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| 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.
+ Details**Name:**us-gaap_SegmentReportingRevenueReconcilingItemLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                      |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                   |
|-------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_SubsegmentsAxis=hls_InpatientMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                            |
|----------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                   |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementBusinessSegmentsAxis=hls_HomeHealthandHospiceSegmentMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                    |
|--------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_SubsegmentsAxis=hls_HomehealthMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_SubsegmentsAxis=hls_HospiceMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |