Property and Equipment - Additional Information (Detail) - USD ($) $ in Millions  | 
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016  | 
Dec. 31, 2015  | 
Dec. 31, 2014  | 
|
| Property Plant And Equipment [Abstract] | |||
| Interest capitalized in conjunction with construction projects and software development | $ 2.8 | $ 1.9 | $ 1.9 | 
| Commitments for facility construction projects | $ 56.5 | ||
| X | ||||||||||
- Definition Commitments for facility construction projects. No definition available. 
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| X | ||||||||||
- Definition Amount of interest capitalized during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
  | 
| X | ||||||||||
- References No definition available. 
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