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Deferred Compensation Plans - Additional Information (Detail) - USD ($)
$ in Millions
 6 Months Ended 12 Months Ended
Jun. 30, 2016
Dec. 31, 2015
Jan. 31, 2016
Compensation And Retirement Disclosure [Abstract]      
Initial deferrals occurred     $ 1.2
Non-qualified deferred cash incentive plan maximum eligibility percentage of employees   100.00%  
Mutual fund investments, at fair value $ 1.3    
Trading gain and compensation expense $ 0.1