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Net Income Per Common Share - Additional Information (Detail) - shares shares in Millions | 12 Months Ended
--- | ---
Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Net Income Loss Per Common Share |  |  |
Exercise of stock options | 0.2 | 0.3 | 0.4

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- Definition Net Income (Loss) Per Common Share [Line Items] + References No definition available. + Details
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- Definition Stock Issued During Period Shares Sale Of Stock And Exercise Of Stock Options + References No definition available. + Details
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Balance Type: | na
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