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Stock-based Compensation - Summary of Restricted Stock Units (Detail) - $ / shares
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Weighted-Average Grant Date Fair Value $ 3.40 $ 3.97 $ 3.31
Time-Based Restricted Stock Units [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Number of Shares, Outstanding, Beginning Balance 90,255    
Number of Shares, Granted 366,004    
Number of Shares, Vested (90,255)    
Number of Shares, Outstanding, Ending Balance 366,004    
Weighted-Average Grant Date Fair Value $ 6.63 6.66  
Weighted-Average Grant Date Fair Value, Granted 6.63    
Weighted-Average Grant Date Fair Value, Vested $ 7.04    
Performance-Based Restricted Stock Units [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Number of Shares, Outstanding, Beginning Balance 321,525    
Number of Shares, Granted 340,094    
Number of Shares, Vested (137,127)    
Number of Shares, Forfeited or expired (25,123)    
Number of Shares, Outstanding, Ending Balance 499,369    
Weighted-Average Grant Date Fair Value $ 6.66 $ 6.41  
Weighted-Average Grant Date Fair Value, Granted 6.64    
Weighted-Average Grant Date Fair Value, Vested 6.09    
Weighted-Average Grant Date Fair Value, Forfeited or expired $ 6.23