Quarterly report pursuant to Section 13 or 15(d)

Earnings Per Share - Additional Information (Detail)

v3.7.0.1
Earnings Per Share - Additional Information (Detail) - shares
3 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Earnings Per Share [Line Items]    
Options excluded from the computation of diluted earnings 126,636 0
Class A Common Stock [Member]    
Earnings Per Share [Line Items]    
Common stock, voting rights One vote per share  
Class B Common Stock [Member]    
Earnings Per Share [Line Items]    
Common stock, voting rights Ten votes per share