Annual report pursuant to Section 13 and 15(d)

Stock-based Expense - Summary of Time-Based Restricted Share Awards' Activity (Detail)

v3.6.0.2
Stock-based Expense - Summary of Time-Based Restricted Share Awards' Activity (Detail) - Restricted Stock - $ / shares
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Number of Shares      
Beginning Balance (in shares) 1,068,706 1,624,519 2,090,803
Granted (in shares) 1,793,257 913,077 1,238,226
Vested (in shares) (841,983) (1,077,102) (1,101,143)
Forfeited/cancelled (in shares) (386,479) (391,788) (603,367)
Ending Balance (in shares) 1,633,501 1,068,706 1,624,519
Weighted-Average price      
Beginning of Period (in dollars per share) $ 20.05 $ 20.01 $ 22.10
Granted (in dollars per share) 20.79 19.84 17.69
Vested (in dollars per share) 20.14 19.78 21.18
Forfeited/cancelled (in dollars per share) 20.21 18.65 20.36
Ending of Period (in dollars per share) $ 20.78 $ 20.05 $ 20.01