Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity (Details Textual)

v3.7.0.1
Stockholders' Equity (Details Textual)
 1 Months Ended 3 Months Ended 12 Months Ended
Feb. 28, 2017
USD ($)
class_of_stock
shares
Apr. 30, 2017
$ / shares
Feb. 28, 2017
USD ($)
class_of_stock
shares
Feb. 28, 2017
USD ($)
class_of_stock
$ / shares
shares
Feb. 29, 2016
USD ($)
$ / shares
Feb. 28, 2015
$ / shares
Nov. 30, 2016
USD ($)
Apr. 30, 2012
USD ($)
Class of Stock [Line Items]                
Number of classes of outstanding common stock | class_of_stock 2   2 2        
Dollar value of shares repurchased | $       $ 1,122,700,000 $ 33,800,000      
Class B Convertible Common Stock [Member]                
Class of Stock [Line Items]                
Common stock, conversion features       convertible into shares of Class A Common Stock on a one-to-one basis        
Common stock, voting rights       ten votes per share        
Cash dividends declared per common share | $ / shares       $ 1.44 $ 1.12 $ 0.00    
Class B Convertible Common Stock [Member] | Subsequent Event [Member]                
Class of Stock [Line Items]                
Cash dividends declared per common share | $ / shares   $ 0.47            
Class A Common Stock [Member]                
Class of Stock [Line Items]                
Common stock, voting rights       one vote per share        
Common stock, dividend rights       10.00%        
Cash dividends declared per common share | $ / shares       $ 1.60 $ 1.24 $ 0.00    
Class A Common Stock [Member] | Subsequent Event [Member]                
Class of Stock [Line Items]                
Cash dividends declared per common share | $ / shares   0.52            
Class A Common Stock [Member] | 2013 Authorization [Member]                
Class of Stock [Line Items]                
Share repurchases | shares 18,670,632     4,400,504        
Dollar value of shares repurchased | $ $ 1,000,000,000     $ 669,600,000        
Class A Common Stock [Member] | 2017 Authorization [Member]                
Class of Stock [Line Items]                
Share repurchases | shares 3,006,547   3,006,547          
Dollar value of shares repurchased | $ $ 453,100,000   $ 453,100,000          
Class 1 Common Stock [Member]                
Class of Stock [Line Items]                
Common stock, conversion features       convertible into shares of Class A Common Stock on a one-to-one basis        
Common stock, voting rights       generally have no voting rights        
Class 1 Common Stock [Member] | Subsequent Event [Member]                
Class of Stock [Line Items]                
Cash dividends declared per common share | $ / shares   $ 0.47            
Class A and Class B [Member] | 2013 Authorization [Member]                
Class of Stock [Line Items]                
Maximum authorized repurchase of common stock | $               $ 1,000,000,000.0
Class A and Class B [Member] | 2017 Authorization [Member]                
Class of Stock [Line Items]                
Maximum authorized repurchase of common stock | $             $ 1,000,000,000