| **Segment Reporting Segment Reporting - Table 4 (Details) - USD ($) $ in Millions**                                                                                                                                                                                                                                                                                            | 3 Months Ended | 12 Months Ended |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------|-----------------|
||
| **Segment Reporting, Asset Reconciling Item [Line Items]**                                                                                                                                                                                                                                                                                                                     |           |                 |   |
| Total assets for reportable segments                                                                                                                                                                                                                                                                                                                                           | $ 4,608.3      | [1]             | $ 4,606.1 |
| Reclassification of noncurrent deferred income tax liabilities to net noncurrent deferred income tax assets                                                                                                                                                                                                                                                                    | (71.3)         |                 | (71.3) |
| Total assets                                                                                                                                                                                                                                                                                                                                                                   | 4,608.3        | [1]             | 4,606.1 |
| Inpatient Rehabilitation Hospital and Home Health and Hospice [Member]                                                                                                                                                                                                                                                                                                         |           |                 |   |
| **Segment Reporting, Asset Reconciling Item [Line Items]**                                                                                                                                                                                                                                                                                                                     |           |                 |   |
| Total assets for reportable segments                                                                                                                                                                                                                                                                                                                                           | 4,679.6        |                 | 4,677.4 |
| Total assets                                                                                                                                                                                                                                                                                                                                                                   | $ 4,679.6      |                 | $ 4,677.4 |
|                                                                                                                                                                                                                                                                                                                                                                                |
| [1](1) Our consolidated assets as of March 31, 2016 include total assets of variable interest entities of $247.3 million, which cannot be used by us to settle the obligations of other entities. Our consolidated liabilities as of March 31, 2016 include total liabilities of the variable interest entities of $54.0 million. See Note 3, Variable Interest Entities. |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.18) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 12 -Article 7
+ Details**Name:**us-gaap_Assets**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of a reclassification adjustment made to prior period financial statement amounts.
+ References
No definition available.
+ Details**Name:**us-gaap_PriorPeriodReclassificationAdjustment**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| 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_SegmentReportingAssetReconcilingItemLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                              |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementBusinessSegmentsAxis=hls_InpatientRehabilitationHospitalandHomeHealthandHospiceMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |