Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Apr. 30, 2012	Apr. 30, 2011
Consolidated Balance Sheets [Abstract]
Allowance for doubtful accounts	$ 44,589	$ 47,943
Allowance for loan losses	26,540	92,087
Accumulated depreciation and amortization	$ 622,313	$ 578,655
Common stock, no par value
Common stock, stated value per share	$ 0.01	$ 0.01
Common stock, shares authorized	800,000,000	800,000,000
Common stock, shares issued	397,886,599	412,440,599
Convertible preferred stock, stated value per share	$ 0.01	$ 0.01
Convertible preferred stock, shares authorized	500,000	500,000