| **Earnings per Common Share - Textual (Details) (USD $)In Millions, except Per Share data, unless otherwise specified** | 3 Months Ended | 9 Months Ended | 1 Months Ended |
|-------------------------------------------------------------------------------------------------------------------------|----------------|----------------|----------------|
||
| **Earnings per Common Share (Textual) [Abstract]**                                                                      |           |           |           |   |   |   |   |   |
| Antidilutive Securities Excluded from Computation of Earnings Per Share                                                 |           |           | 0.1            | 1.8 |   |   |   |   |
| Stock Repurchase Program, Authorized Amount                                                                             |           |           |           |   |   | $ 350 | $ 125 | $ 200 |
| Repurchase of common stock, Shares                                                                                      |           |           |           |   |   | 9.1 |   |   |
| Treasury Stock Acquired, Average Cost Per Share                                                                         |           |           |           |   |   | $ 25.50 |   |   |
| Repurchase of common stock                                                                                              |           |           | $ (234.1)      |   |   | $ (234.1) |   |   |
| Cash dividends per common share                                                                                         | $ 0.18         | $ 0.00         | $ 0.18         | $ 0.00 | $ 0.18 |   |   | $ 0.18 |

| X                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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| X                                                                                                                                                                                                                                                                                           |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Cost of common stock repurchased during the period and currently held in treasury.
+ References
No definition available.
+ Details**Name:**hls_RepurchaseOfCommonStock**Namespace Prefix:**hls_**Data Type:**xbrli:monetaryItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Antidilution -URI http://asc.fasb.org/extlink&oid=6505113Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Diluted Earnings Per Share -URI http://asc.fasb.org/extlink&oid=6510752Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Contingent Stock Agreement -URI http://asc.fasb.org/extlink&oid=6508534
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Aggregate dividends declared during the period for each share of common stock outstanding.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3Reference 2: 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 a stock repurchase plan authorized by an entity's Board of Directors.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Total cost of shares repurchased divided by the total number of shares repurchased.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Number of shares that have been repurchased during the period and are being held in treasury.
+ References
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