Annual report pursuant to Section 13 and 15(d)

Summary of Restricted Shares Activity (Detail)

v3.7.0.1
Summary of Restricted Shares Activity (Detail) - Restricted Stock - $ / shares
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares      
Number of Restricted Shares, Beginning Balance 134,633    
Number of Restricted Shares, Shares Granted 327,508 110,350 84,800
Number of Restricted Shares, Shares Vested (79,454)    
Number of Restricted Shares, Shares Forfeited (22,382)    
Number of Restricted Shares, Ending Balance 360,305 134,633  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value      
Weighted Average Grant Date Fair Value Per Share, Beginning Balance $ 19.36    
Weighted Average Grant Date Fair Value Per Share, Shares Granted 6.25 $ 13.30 $ 30.00
Weighted Average Grant Date Fair Value Per Share, Shares Vested 15.78    
Weighted Average Grant Date Fair Value Per Share, Shares Forfeited 18.91    
Weighted Average Grant Date Fair Value Per Share, Ending Balance $ 7.32 $ 19.36