v3.3.1.900
Share-Based Compensation - Summary of Status of Nonvested Shares (Detail) - $ / shares
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]      
Nonvested Shares, Beginning Balance 1,122,410 699,231 753,079
Nonvested Shares, Granted 1,278,329 992,919 377,379
Nonvested Shares, Vested (419,222) (400,429) (299,110)
Nonvested Shares, Canceled (246,261) (169,311) (132,117)
Nonvested Shares, Ending Balance 1,735,256 1,122,410 699,231
Weighted Average Grant-Date Fair Value, Nonvested, Beginning Balance $ 16.52 $ 23.70 $ 22.35
Weighted Average Grant-Date Fair Value, Nonvested, Granted 4.87 14.48 22.77
Weighted Average Grant-Date Fair Value, Nonvested, Vested 15.26 20.18 18.79
Weighted Average Grant-Date Fair Value, Nonvested, Canceled 14.30 25.57 24.47
Weighted Average Grant-Date Fair Value, Nonvested, Ending Balance $ 8.60 $ 16.52 $ 23.70