Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity (Details Textual)

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Stockholders' Equity (Details Textual) - 2013 Authorization [Member] - USD ($)
 1 Months Ended 6 Months Ended
Oct. 05, 2016
Oct. 05, 2016
Aug. 31, 2016
Apr. 30, 2012
Class A and Class B [Member]        
Equity, Class of Treasury Stock [Line Items]        
Repurchase authorization       $ 1,000,000,000.0
Class A Common Stock [Member]        
Equity, Class of Treasury Stock [Line Items]        
Number of shares repurchased     34,500  
Dollar value of shares repurchased     $ 5,500,000  
Class A Common Stock [Member] | Subsequent Event [Member]        
Equity, Class of Treasury Stock [Line Items]        
Number of shares repurchased 14,437,939 133,311    
Dollar value of shares repurchased $ 357,900,000 $ 21,900,000