Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jul. 31, 2015	Apr. 30, 2015	Jul. 31, 2014
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 53,771	$ 54,527	$ 51,400
Allowance for loan losses	7,659	7,886	10,561
Accumulated depreciation and amortization	$ 538,823	$ 518,797	$ 468,372
Common stock, no par value	$ 0	$ 0	$ 0
Common stock, stated value per share	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized	800,000,000	800,000,000	800,000,000
Common stock, shares issued	316,628,110	316,628,110	316,628,110