| **Segment Reporting Segment Reporting - Table 2 (Details) (USD $)In Millions, unless otherwise specified** | Mar. 31, 2015                                                                                                                                              | Dec. 31, 2014                                                                                                                                              |
|------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------|
| **Segment Reporting, Asset Reconciling Item [Line Items]**                                                 |                                                                                                                                                       |                                                                                                                                                       |
| Total assets                                                                                               | $ 3,577.9us-gaap_Assets                                                                                                                                    | $ 3,408.8us-gaap_Assets                                                                                                                                    |
| Investments in and advances to nonconsolidated affiliates                                                  | 9.1us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures                                                                                   | 9.4us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures                                                                                   |
| Inpatient Rehabilitation Hospital [Member]                                                                 |                                                                                                                                                       |                                                                                                                                                       |
| **Segment Reporting, Asset Reconciling Item [Line Items]**                                                 |                                                                                                                                                       |                                                                                                                                                       |
| Total assets                                                                                               | 2,762.5us-gaap_Assets/ us-gaap_StatementBusinessSegmentsAxis= hls_InpatientRehabilitationHospitalMember                                                    | 2,596.8us-gaap_Assets/ us-gaap_StatementBusinessSegmentsAxis= hls_InpatientRehabilitationHospitalMember                                                    |
| Investments in and advances to nonconsolidated affiliates                                                  | 9.1us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures/ us-gaap_StatementBusinessSegmentsAxis= hls_InpatientRehabilitationHospitalMember | 9.4us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures/ us-gaap_StatementBusinessSegmentsAxis= hls_InpatientRehabilitationHospitalMember |
| Home Health and Hospice [Member]                                                                           |                                                                                                                                                       |                                                                                                                                                       |
| **Segment Reporting, Asset Reconciling Item [Line Items]**                                                 |                                                                                                                                                       |                                                                                                                                                       |
| Total assets                                                                                               | 879.7us-gaap_Assets/ us-gaap_StatementBusinessSegmentsAxis= sic_Z8082                                                                                      | 876.3us-gaap_Assets/ us-gaap_StatementBusinessSegmentsAxis= sic_Z8082                                                                                      |
| Investments in and advances to nonconsolidated affiliates                                                  | $ 0us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures/ us-gaap_StatementBusinessSegmentsAxis= sic_Z8082                                 | $ 0us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures/ us-gaap_StatementBusinessSegmentsAxis= sic_Z8082                                 |

| 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 7Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 18 -Article 5
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| 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
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| X                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                       |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------|
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