XML 69 R58.htm IDEA: XBRL DOCUMENT v3.10.0.1
Stock-Based Compensation Plans - Summary of Transactions of the Company's Stock Option Plans (Detail) - Stock Options Plan [Member]
9 Months Ended
Sep. 30, 2018
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Outstanding, Number of Options, Beginning balance | shares 357,666
Exercised, Number of Options | shares (91,362)
Forfeited, Number of Options | shares (14,443)
Outstanding, Number of Options, Ending balance | shares 551,177
Outstanding, Weighted Average Exercise Price, Beginning balance $ 13.74
Exercised, Weighted Average Exercise Price 12.47
Forfeited, Weighted Average Exercise Price 21.05
Outstanding, Weighted Average Exercise Price, Ending balance 32.25
Outstanding, Weighted Average Grant-Date Fair Value 35.69
Exercised 27.04
Forfeited, Weighted Average Grant-Date Fair Value 25.34
Outstanding, Weighted Average Grant-Date Fair Value $ 36.14
Discount [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Granted, Number of Options | shares 280,466
Granted, Weighted Average Exercise Price $ 46.42
Granted, Weighted Average Grant-Date Fair Value $ 34.54
Market Value [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Granted, Number of Options | shares 18,850
Granted, Weighted Average Exercise Price $ 68.20
Granted, Weighted Average Grant-Date Fair Value $ 16.23