Derivative Financial Instruments - Additional Information (Details)  | 
 Dec. 31, 2014  
DerivativeInstrument 
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| Derivative Instruments And Hedging Activities Disclosure [Abstract] | |
| Number of open derivative instruments | 0 | 
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- References No definition available. 
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- Definition The number of derivative instruments of a particular group held by the entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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