Fair Value Measurements and Derivatives - Effects of Foreign Currency Collar Designated as Cash Flow Hedges (Details 9) - Cash Flow Hedging - Designated as Hedging Instrument - Foreign Currency Collar - USD ($) $ in Thousands  | 
3 Months Ended | 9 Months Ended | ||
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Sep. 30, 2015  | 
Sep. 30, 2014  | 
Sep. 30, 2015  | 
Sep. 30, 2014  | 
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| Derivative Instruments, Gain (Loss) [Line Items] | ||||
| Loss recognized in other comprehensive income (loss) - effective portion | $ (1,588) | |||
| Amount reclassified from accumulated other comprehensive income (loss) into depreciation and amortization expense | $ (91) | $ (91) | $ (273) | $ (242) | 
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
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- Definition The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition The effective portion of loss reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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