| Fair Value Measurements and Derivatives - Effects of Foreign Currency Collar Designated as Cash Flow Hedges (Details 7) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
| Sep. 30, 2017 | Sep. 30, 2016 | Sep. 30, 2017 | Sep. 30, 2016 | |
| Cash Flow Hedging | Designated as Hedging Instrument | Foreign Currency Collar | ||||
| Derivative Instruments, Gain (Loss) [Line Items] | ||||
| Amount reclassified from accumulated other comprehensive income (loss) into depreciation and amortization expense | $ (91) | $ (91) | $ (273) | $ (273) | 
| X | ||||||||||
| 
- 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. 
 | 
| X | ||||||||||
| 
- 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 
 | 
| X | ||||||||||
| 
- Details 
 | 
| X | ||||||||||
| 
- Details 
 | 
| X | ||||||||||
| 
- Details 
 |