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Stock-Based Compensation (Stock Options) - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Options Outstanding, Weighted Average Exercise Price, and Additional Disclosures [Abstract]    
Total pre-tax intrinsic value of options exercised $ 0.4  
Number of Options, granted 0 0
Unvested Stock Options [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Unrecognized compensation expense related to stock options $ 6.3  
Recognition period of unvested compensation expense 2 years