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Fair Value Measurements Fair Value Measurements, Textual (Details) (USD $) In Millions, unless otherwise specified | 6 Months Ended |  |
--- | --- | --- | ---
Jun. 30, 2014 | Jun. 30, 2013 | Jun. 30, 2014 Minimum | Jun. 30, 2014 Maximum | Jun. 30, 2014 Derivative | Dec. 31, 2013 Derivative
Schedule of Available-for-sale Securities [Line Items] |  |  |  |  |  |
Fair Value, Net Asset (Liability) |  |  |  |  | $ 0.6 | $ (4.3)
Non-cash unrealized (gains) losses on derivative positions | $ 4.9 | $ (5.4) |  |  |  |
Short-term investment maturity period |  |  | 32 days | 9 months |  |

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- Definition Fair value of asset after deduction of liability. + References No definition available. + Details
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- Definition The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 + Details
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