| **Accounts Receivable - Table 1 (Details) (USD $)In Millions, unless otherwise specified**                                     | Dec. 31, 2014                                                  | Dec. 31, 2013                                                  |
|--------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------|----------------------------------------------------------------|
| **Schedule of Accounts Receivable, Net, Current**                                                                              |                                                           |                                                           |
| Patient accounts receivable, net of allowance for doubtful accounts of $22.2 million in 2014; $23.1 million in 2013            | $ 309.3hls_PatientAccountsReceivableNetCurrent                 | $ 249.4hls_PatientAccountsReceivableNetCurrent                 |
| Other accounts receivable                                                                                                      | 13.9us-gaap_AccountsAndOtherReceivablesNetCurrent              | 12.4us-gaap_AccountsAndOtherReceivablesNetCurrent              |
| Accounts receivable, net, current                                                                                              | 323.2us-gaap_AccountsReceivableNetCurrent                      | 261.8us-gaap_AccountsReceivableNetCurrent                      |
| Noncurrent patient accounts receivable, net of allowance for doubtful accounts of $20.8 million in 2014; $10.0 million in 2013 | 51.4hls_PatientAccountsReceivableNetNoncurrent                 | 16.6hls_PatientAccountsReceivableNetNoncurrent                 |
| Accounts receivable, net                                                                                                       | 374.6hls_AccountsandOtherReceivableNet                         | 278.4hls_AccountsandOtherReceivableNet                         |
| **Allowance for Doubtful Accounts [Abstract]**                                                                                 |                                                           |                                                           |
| Allowance for doubtful accounts receivable, current                                                                            | 22.2us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent      | 23.1us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent      |
| Allowance for doubtful accounts receivable, noncurrent                                                                         | $ 20.8us-gaap_AllowanceForDoubtfulAccountsReceivableNoncurrent | $ 10.0us-gaap_AllowanceForDoubtfulAccountsReceivableNoncurrent |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount due from customers or clients, within one year or later of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.
+ References
No definition available.
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| X                                                                                                                                                                |
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Net amount, as of the balance sheet date, of accounts receivable at estimated net realizable amounts from services rendered from federal and state agencies (under the Medicare and Medicaid programs), managed care health plans, commercial insurance companies, workers' compensation programs, employers, and patients.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Net amount, as of the balance sheet date, of accounts receivable at estimated net realizable amounts from services rendered from federal and state agencies (under the Medicare and Medicaid programs), managed care health plans, commercial insurance companies, workers' compensation programs, employers, and patients.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount due from customers, clients, or other third-parties, or arising from transactions not separately disclosed, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), net of allowances established for the purpose of reducing such receivables to an amount that approximates their net realizable value.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
A valuation allowance for receivables due to an Entity for more than one year from the balance sheet date that are expected to be uncollectible.
+ References
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