Quarterly report pursuant to Section 13 or 15(d)

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

v2.4.0.8
Per Share Data and Stockholders' Equity - Additional Information (Detail) (Common Class A [Member])
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2014
Mar. 31, 2013
Common Class A [Member]
   
Capital Structure and Per Share Data [Line Items]    
Antidilutive stock options excluded in computation of diluted earnings per share 0.6 0.9