Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Apr. 30, 2013	Apr. 30, 2012
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 50,399	$ 44,589
Allowance for loan losses	14,314	26,540
Accumulated depreciation and amortization	$ 420,318	$ 529,841
Common stock, no par value	$ 0	$ 0
Common stock, stated value per share	$ 0.01	$ 0.01
Common stock, shares authorized	800,000,000	800,000,000
Common stock, shares issued	316,628,110	397,886,599
Convertible preferred stock, stated value per share	$ 0.01	$ 0.01
Convertible preferred stock, shares authorized	500,000	500,000