| 
           Effects of Foreign Currency Forward Which Were Not Designated as Hedging Instruments (Detail) (Not Designated as Hedging Instrument, Foreign Exchange Forward, USD $) 
        In Thousands, unless otherwise specified  | 
        9 Months Ended | 
|---|---|
| 
           Sep. 30, 2013 
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      |
| 
           Not Designated as Hedging Instrument | Foreign Exchange Forward 
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        |
| Derivative Instruments, Gain (Loss) [Line Items] | |
| Gain recognized in other income (expense) | $ 20 | 
| X | ||||||||||
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- Definition 
          Amount of increase in the fair value of derivatives recognized in the income statement. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Details 
          
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