| 
           Future Minimum Lease Payments Under Non-Cancellable Operating Leases (Detail) (USD $) 
        In Thousands, unless otherwise specified  | 
        
           Dec. 31, 2012 
         | 
      
|---|---|
| 2012 | $ 2,068 | 
| 2013 | 1,955 | 
| 2014 | 1,945 | 
| 2015 | 1,974 | 
| 2016 | 1,934 | 
| Thereafter | 7,201 | 
| Operating Leases, Future Minimum Payments Due | $ 17,077 | 
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- Definition 
          Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of required minimum rental payments maturing in the next fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of required minimum rental payments maturing in the fifth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of required minimum rental payments maturing in the forth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of required minimum rental payments maturing in the third fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of required minimum rental payments maturing in the second fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of required minimum rental payments maturing after the fifth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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