| **Long-term Debt**             | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
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| **Debt Disclosure [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| Long-term Debt                 | Long-term DebtOur long-term debt outstanding consists of the following (in millions): September 30, 2016 December 31, 2015Credit Agreement—   Advances under revolving credit facility$150.0 $130.0Term loan facilities426.8 443.3Bonds payable—   7.75% Senior Notes due 2022— 174.35.125% Senior Notes due 2023295.1 294.65.75% Senior Notes due 20241,193.1 1,192.65.75% Senior Notes due 2025343.7 343.42.00% Convertible Senior Subordinated Notes due 2043273.2 265.9Other notes payable47.1 39.2Capital lease obligations281.8 288.2 3,010.8 3,171.5Less: Current portion(36.8) (36.8)Long-term debt, net of current portion$2,974.0 $3,134.7The following chart shows scheduled principal payments due on long-term debt for the next five years and thereafter (in millions): Face Amount Net AmountOctober 1 through December 31, 2016$8.7 $8.7201737.3 37.3201837.8 37.8201940.4 40.42020834.2 786.1202110.7 10.7Thereafter2,108.0 2,089.8Total$3,077.1 $3,010.8On February 23, 2016, we gave notice of, and made an irrevocable commitment for, the redemption of$50 millionof the outstanding principal amount of ourexisting 7.75% Senior Notes due 2022 (the “2022 Notes”). On March 24, 2016, we completed this redemptionusing cash on hand and capacity under our revolving credit facility. Pursuant to the terms of the 2022 Notes, this optional redemption was made at a price of103.875%, which resulted in a total cash outlay of approximately$52 million. As a result of this redemption, we recorded a$2.4 millionLoss on early extinguishment of debtin the first quarter of 2016.On April 6, 2016, we gave notice of, and made an irrevocable commitment for, the redemption of an additional $50 million of the outstanding principal amount of the 2022 Notes. On May 6, 2016, we completed this redemption using cash on hand and capacity under our revolving credit facility. Pursuant to the terms of the 2022 Notes, this optional redemption was also made at a price of 103.875%, which resulted in a total cash outlay of approximately $52 million. As a result of this redemption, we recorded a$2.4 millionLoss on early extinguishment of debt in the second quarter of 2016. On July 28, 2016, we gave notice of, and made an irrevocable commitment for, theredemption of the remaining outstanding principal balance of$76.0 millionof the 2022 Notes. On September 15, 2016, we completed this redemption using cash on hand and capacity under our revolving credit facility.Pursuant to the terms of the 2022 Notes, this optional redemption was made at a price of102.583%,which resulted in a total cash outlay of approximately $78 million. As a result of this redemption, we recorded a$2.6 millionLoss on early extinguishment of debtin the third quarter of 2016.In February 2016, we entered into a development/lease agreement with CR HQ, LLC (the “Developer”) to construct our new corporate headquarters in Birmingham, Alabama. Under the terms of this agreement, the Developer is responsible for all costs of constructing the new facility ‘shell’ which will then be leased to us for an initial term of 15 years with four, five-year renewal options. The lease is expected to commence in the first half of 2018. We are responsible for the costs associated with improvements to the interior of the building. Due to the nature and extent of the tenant improvements we will be making to the new corporate headquarters and certain provisions of the development/lease agreement, we are deemed to be the accounting owner of the new corporate headquarters during the construction period. Construction commenced in the second quarter of 2016. Accordingly, we increased Property and equipment, net by $10.3 million, based on the construction costs incurred to date by the Developer, and recorded a corresponding noncurrent financing obligation liability of $10.3 million in Long-term debt, net of current portion within our condensed consolidated balance sheet as of September 30, 2016. The total financing obligation associated with the Developer’s costs to construct the new corporate headquarters is estimated at $56 million. The amounts recorded for construction costs and the corresponding liability are non-cash activities for purposes of our condensed consolidated statement of cash flows.For additional information regarding our indebtedness, see Note 8, Long-term Debt, to the consolidated financial statements accompanying the 2015 Form 10-K. |

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| - References
No definition available.
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| - Definition
The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19,20,22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682
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