| **Segment Reporting - Table 2 (Details) - USD ($) $ in Millions**                                                                                                                                                                                                                                                                                                                       | Sep. 30, 2016 | Dec. 31, 2015 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------|---------------|
| **Segment Reporting, Asset Reconciling Item [Line Items]**                                                                                                                                                                                                                                                                                                                              |          |               |   |
| Total assets                                                                                                                                                                                                                                                                                                                                                                            | $ 4,631.3     | [1]           | $ 4,606.1 |
| Investments in and advances to nonconsolidated affiliates                                                                                                                                                                                                                                                                                                                               | 13.0          |               | 11.7 |
| Inpatient Rehabilitation Segment [Member]                                                                                                                                                                                                                                                                                                                                               |          |               |   |
| **Segment Reporting, Asset Reconciling Item [Line Items]**                                                                                                                                                                                                                                                                                                                              |          |               |   |
| Total assets                                                                                                                                                                                                                                                                                                                                                                            | 3,593.3       |               | 3,589.0 |
| Investments in and advances to nonconsolidated affiliates                                                                                                                                                                                                                                                                                                                               | 10.5          |               | 9.3 |
| Home Health and Hospice Segment [Member]                                                                                                                                                                                                                                                                                                                                                |          |               |   |
| **Segment Reporting, Asset Reconciling Item [Line Items]**                                                                                                                                                                                                                                                                                                                              |          |               |   |
| Total assets                                                                                                                                                                                                                                                                                                                                                                            | 1,109.3       |               | 1,088.4 |
| Investments in and advances to nonconsolidated affiliates                                                                                                                                                                                                                                                                                                                               | $ 2.5         |               | $ 2.4 |
|                                                                                                                                                                                                                                                                                                                                                                                         |
| [1]Our consolidated assets as of September 30, 2016 include total assets of variable interest entities of $258.0 million, which cannot be used by us to settle the obligations of other entities. Our consolidated liabilities as of September 30, 2016 include total liabilities of the variable interest entities of $51.1 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 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(12)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(11)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878
+ Details**Name:**us-gaap_Assets**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership.
+ 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 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682
+ Details**Name:**us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| 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_InpatientRehabilitationSegmentMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                   |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_StatementBusinessSegmentsAxis=hls_HomeHealthandHospiceSegmentMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |