Quarterly report pursuant to Section 13 or 15(d)

Per Share Data and Stockholders' Equity - Additional Information (Detail)

v3.2.0.727
Per Share Data and Stockholders' Equity - Additional Information (Detail) - shares
shares in Millions
6 Months Ended
Jun. 30, 2015
Jun. 30, 2014
Common Class A [Member]    
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]    
Antidilutive stock options excluded in computation of diluted earnings per share 0.4 0.4