Annual report pursuant to Section 13 and 15(d)

Summary of Potential Number of Units that Could Vest Under Restricted Stock Unit Awards (Parenthetical) (Detail)

v3.20.4
Summary of Potential Number of Units that Could Vest Under Restricted Stock Unit Awards (Parenthetical) (Detail) - Restricted Stock Units (RSUs) - $ / shares
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Schedule Of Restricted Stock Unit [Line Items]      
Weighted Average Grant Date Fair Value, Granted $ 32.12 $ 36.77  
Minimum      
Schedule Of Restricted Stock Unit [Line Items]      
Weighted Average Grant Date Fair Value, Granted     $ 37.55
Maximum      
Schedule Of Restricted Stock Unit [Line Items]      
Weighted Average Grant Date Fair Value, Granted     $ 39.03