Quarterly report pursuant to Section 13 or 15(d)

Summary of Treasury Stock Activity (Parenthetical) (Detail)

v3.8.0.1
Summary of Treasury Stock Activity (Parenthetical) (Detail)
3 Months Ended
Mar. 31, 2018
$ / shares
Minimum  
Schedule of Treasury Stock [Line Items]  
Market Value of Restricted Shares $ 34.83
Maximum  
Schedule of Treasury Stock [Line Items]  
Market Value of Restricted Shares $ 39.03