Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation Plans - Changes in Company's Common Stock Price During Reporting Period (Detail)

v3.7.0.1
Stock-Based Compensation Plans - Changes in Company's Common Stock Price During Reporting Period (Detail) - Stock Based Compensation Expense [Member] - $ / shares
3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Common stock price at beginning of period $ 26.72 $ 29.14
Common stock price at end of period 24.58 25.39
Decrease in stock price $ (2.14) $ (3.75)