| **Assets and Liabilities in and Results of Discontinued Operations** | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
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| **Discontinued Operations and Disposal Groups [Abstract]**           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
| Assets Held for Sale and Results of Discontinued Operations          | Assets and Liabilities in and Results of Discontinued Operations:In connection with the 2007 sale of our surgery centers division (now known as Surgical Care Affiliates, or “SCA”) to ASC Acquisition LLC, an affiliate of TPG Partners V, L.P. (“TPG”), a private investment partnership, we received an option, subject to terms and conditions set forth below, to purchase up to a 5% equity interest in SCA. The price of the option is equal to the original issuance price of the units subscribed for by TPG and certain other co-investors in connection with the acquisition plus a 15% premium, compounded annually. The option has a term of ten years and is exercisable upon certain liquidity events, including a public offering of SCA’s shares of common stock that results in 30% or more of SCA’s common stock being listed or traded on a national securities exchange. On November 4, 2013, SCA announced the closing of its initial public offering, which was not a qualifying liquidity event.During the second quarter of 2014, we entered into an amendment to the option agreement that requires us to settle the option net of our exercise price. The addition of this new feature resulted in the option becoming a derivative that must be recorded as an asset or liability on our consolidated balance sheet and marked to market each period. As of December 31, 2014, the fair value of this option was $9.9 million and is included in Other long-term assets in our consolidated balance sheet. Income from discontinued operations, net of tax for the year ended December 31, 2014 included a $9.9 million net gain resulting from the initial recording of this option as a derivative and its fair value adjustments during 2014.The fair value of the option and related adjustments were determined using a lattice model. Inputs into the model included the historical price volatility of SCA’s common stock, the risk free interest rate, and probability factors for the timing of when the option will be exercisable, or Level 3 inputs.Income from discontinued operations, net of tax, in 2012 primarily resulted from gains associated with the sale of the real estate of Dallas Medical Center and an investment we had in a cancer treatment center that was part of our former diagnostic division. |

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| - Definition
The entire disclosure for the facts and circumstances leading to the completed or expected disposal, manner and timing of disposal, the gain (loss) recognized in the income statement and the income statement caption that includes that gain (loss), amounts of revenues and pretax profit or loss reported in discontinued operations, the segment in which the disposal group was reported, and the classification (whether sold or classified as held for sale) and carrying value of the assets and liabilities comprising the disposal group. Includes all disposal groups, including those classified as components of the entity (discontinued operations).
+ References
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