Annual report pursuant to Section 13 and 15(d)

Summary of Potential Number of Shares Vesting under Restricted Stock Unit Awards (Parenthetical) (Detail)

v3.3.1.900
Summary of Potential Number of Shares Vesting under Restricted Stock Unit Awards (Parenthetical) (Detail) - $ / shares
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Restricted Stock Units (RSUs)      
Schedule of Restricted Stock Unit [Line Items]      
Weighted average grant date fair value per share $ 43.19 $ 28.54 $ 29.44