| 
           Financial Instruments (Narratives) (Details) (USD $) 
        In Millions, unless otherwise specified  | 
        
           Mar. 31, 2013 
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|---|---|
| 
           2021 Notes [Member] 
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        |
| Debt Instrument [Line Items] | |
| Long-term Debt | $ 325.0 | 
| Debt Instrument, Interest Rate, Stated Percentage | 6.75% | 
| 
           2019 Notes [Member] 
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        |
| Debt Instrument [Line Items] | |
| Long-term Debt | $ 425.0 | 
| Debt Instrument, Interest Rate, Stated Percentage | 8.63% | 
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- Definition 
          Interest rate stated in the contractual debt agreement. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Details 
          
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- Definition 
          Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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