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Stock-Based Compensation - Summary of Market Condition Grants of Restricted Shares (Detail) - Inducement Grant of Restricted Stock [Member] - $ / shares
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Stock based compensation, Shares Outstanding, beginning balance 40,500 94,500 113,000
Stock based compensation, Shares, Granted 97,000 2,500  
Stock based compensation, Shares, Vested   (56,500) (18,500)
Stock based compensation, Shares Outstanding, ending balance 137,500 40,500 94,500
Stock based compensation, Weighted Average Fair Value Per Share, beginning balance $ 15.55 $ 17.33 $ 18.40
Stock based compensation, Weighted Average Fair Value, Granted 36.85 38.97  
Stock based compensation, Weighted Average Fair Value, Vested   19.56 23.89
Stock based compensation, Weighted Average Fair Value Per Share, ending balance $ 30.58 $ 15.55 $ 17.33