| **Redeemable Noncontrolling Interests - Table 1 (Details) (USD $)In Millions, unless otherwise specified** | 12 Months Ended                                                                                                                           |
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| **Redeemable Noncontrolling Interest [Line Items]**                                                        |                                                                                                                                      |   |   |
| Balance at beginning of period                                                                             | $ 13.5us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount                                                                        |   |   |
| Net Income attributable to noncontrolling interest                                                         | 6.6us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest                                                                    | 5.8us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest | 3.8us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest |
| Distributions declared                                                                                     | (44.9)us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders                                                    | (40.4)us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders | (45.4)us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders |
| Balance at end of period                                                                                   | 84.7us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount                                                                          | 13.5us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount |   |
| Altoona and Jonesboro [Member]                                                                             |                                                                                                                                      |   |   |
| **Redeemable Noncontrolling Interest [Line Items]**                                                        |                                                                                                                                      |   |   |
| Balance at beginning of period                                                                             | 13.5us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount/ dei_LegalEntityAxis= hls_AltoonaAndJonesboroMember                      |   |   |
| Net Income attributable to noncontrolling interest                                                         | 6.6us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest/ dei_LegalEntityAxis= hls_AltoonaAndJonesboroMember                | 5.8us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest/ dei_LegalEntityAxis= hls_AltoonaAndJonesboroMember |   |
| Distributions declared                                                                                     | (8.5)us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders/ dei_LegalEntityAxis= hls_AltoonaAndJonesboroMember | (4.9)us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders/ dei_LegalEntityAxis= hls_AltoonaAndJonesboroMember |   |
| Contribution to joint venture                                                                              | 4.3hls_ContributionToJointVenture/ dei_LegalEntityAxis= hls_AltoonaAndJonesboroMember                                                     | 7.1hls_ContributionToJointVenture/ dei_LegalEntityAxis= hls_AltoonaAndJonesboroMember |   |
| Change in fair value                                                                                       | 4.3hls_NoncontrollingInterestChangeinFairValue/ dei_LegalEntityAxis= hls_AltoonaAndJonesboroMember                                        | (1.7)hls_NoncontrollingInterestChangeinFairValue/ dei_LegalEntityAxis= hls_AltoonaAndJonesboroMember |   |
| Balance at end of period                                                                                   | 84.7us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount/ dei_LegalEntityAxis= hls_AltoonaAndJonesboroMember                      | 13.5us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount/ dei_LegalEntityAxis= hls_AltoonaAndJonesboroMember |   |
| Altoona [Member]                                                                                           |                                                                                                                                      |   |   |
| **Redeemable Noncontrolling Interest [Line Items]**                                                        |                                                                                                                                      |   |   |
| Balance at beginning of period                                                                             |                                                                                                                                      |   | 7.3us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount/ dei_LegalEntityAxis= hls_AltoonaMember |
| Net Income attributable to noncontrolling interest                                                         |                                                                                                                                      |   | 3.8us-gaap_NetIncomeLossAttributableToRedeemableNoncontrollingInterest/ dei_LegalEntityAxis= hls_AltoonaMember |
| Distributions declared                                                                                     |                                                                                                                                      |   | (3.9)us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders/ dei_LegalEntityAxis= hls_AltoonaMember |
| Contribution to joint venture                                                                              |                                                                                                                                      |   | 0hls_ContributionToJointVenture/ dei_LegalEntityAxis= hls_AltoonaMember |
| Change in fair value                                                                                       |                                                                                                                                      |   | 0hls_NoncontrollingInterestChangeinFairValue/ dei_LegalEntityAxis= hls_AltoonaMember |
| Balance at end of period                                                                                   |                                                                                                                                      |   | 7.2us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount/ dei_LegalEntityAxis= hls_AltoonaMember |
| Encompass [Member]                                                                                         |                                                                                                                                      |   |   |
| **Redeemable Noncontrolling Interest [Line Items]**                                                        |                                                                                                                                      |   |   |
| Redeemable noncontrolling interests, Increase from acquisition                                             | $ 64.5hls_RedeemablenoncontrollinginterestsIncreasefromacquisition/ dei_LegalEntityAxis= hls_EncompassMember                              | $ 0hls_RedeemablenoncontrollinginterestsIncreasefromacquisition/ dei_LegalEntityAxis= hls_EncompassMember | $ 0hls_RedeemablenoncontrollinginterestsIncreasefromacquisition/ dei_LegalEntityAxis= hls_EncompassMember |

| X                                                                                                                                                                                                                                                                                                  |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Contribution of primarily intangible assets relating to a joint venture agreement.
+ References
No definition available.
+ Details**Name:**hls_ContributionToJointVenture**Namespace Prefix:**hls_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Change in noncontrolling interest during the period as a result of a change in the fair value of redeemable noncontrolling interest.
+ References
No definition available.
+ Details**Name:**hls_NoncontrollingInterestChangeinFairValue**Namespace Prefix:**hls_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                      |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
An increase in redeemable noncontrolling interests due to an acquisition.
+ References
No definition available.
+ Details**Name:**hls_RedeemablenoncontrollinginterestsIncreasefromacquisition**Namespace Prefix:**hls_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Decrease in noncontrolling interest balance from payment of dividends or other distributions by the non-wholly owned subsidiary or partially owned entity, included in the consolidation of the parent entity, to the noncontrolling interest holders.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of Net Income (Loss) attributable to redeemable noncontrolling interest.
+ 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 210.5-03.19) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
As of the reporting date, the aggregate carrying amount of all noncontrolling interests which are redeemable by the (parent) entity (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the (parent) entity. This item includes noncontrolling interest holder's ownership (or holders' ownership) regardless of the type of equity interest (common, preferred, other) including all potential organizational (legal) forms of the investee entity.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 480 -SubTopic 10 -Section S99 -Paragraph 3A -Subparagraph 14 -URI http://asc.fasb.org/extlink&oid=27011957&loc=SL6540498-122764Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 480 -SubTopic 10 -Section S99 -Paragraph 3A -Subparagraph (16)(c) -URI http://asc.fasb.org/extlink&oid=27011957&loc=SL6540498-122764Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 480 -SubTopic 10 -Section S99 -Paragraph 3A -Subparagraph 15 -URI http://asc.fasb.org/extlink&oid=27011957&loc=SL6540498-122764Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 480 -SubTopic 10 -Section S99 -Paragraph 3A -Subparagraph (12)(c) -URI http://asc.fasb.org/extlink&oid=27011957&loc=SL6540498-122764
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| X                                                                                                                                                                             |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_RedeemableNoncontrollingInterestLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                         |
|-------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**dei_LegalEntityAxis=hls_AltoonaAndJonesboroMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
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| - Details**Name:**dei_LegalEntityAxis=hls_AltoonaMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                               |
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| - Details**Name:**dei_LegalEntityAxis=hls_EncompassMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |