Loss Per Share and Stockholders' Equity (Details) (USD $)	3 Months Ended		9 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014	Apr. 30, 2014	Apr. 30, 2013
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss)			$ 3,334,000	$ 6,809,000
Gross gains (losses) arising during the year			(1,953,000)	(21,532,000)
Income taxes			4,472,000	(6,206,000)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			(6,425,000)
Gross amount reclassified			0
Income taxes			0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment from AOCI, Realized upon Sale or Liquidation, Net of Tax			0
Change in foreign currency translation adjustments	(9,987,000)	(3,313,000)	(13,342,000)	(5,823,000)
Accumulated Other Comprehensive Income (Loss)	(10,008,000)	986,000	(10,008,000)	986,000
Unrealized Gain (Loss) on AFS Securities
Accumulated Other Comprehensive Income (Loss)			1,843,000	3,741,000
Gross amount reclassified			(24,000)
Tax effect of reclassification adjustment for gains included in income			(9,000)
Reclassification adjustment for gains included in income	0	0	(15,000)	0
Net other comprehensive income (loss)			6,902,000	(9,503,000)
Accumulated Other Comprehensive Income (Loss)	8,745,000	(5,762,000)	8,745,000	(5,762,000)
Accumulated other comprehensive income (loss)	(1,263,000)	(4,776,000)	(1,263,000)	(4,776,000)	5,177,000	10,550,000
Other Comprehensive Income (Loss), Net of Tax			(6,440,000)	(15,326,000)
Net loss from continuing operations attributable to shareholders	(35,311,000)	(212,751,000)	(257,389,000)	(429,036,000)
Amounts allocated to participating securities	(105,000)	(88,000)	(291,000)	(242,000)
Net loss from continuing operations attributable to common shareholders	(35,416,000)	(212,839,000)	(257,680,000)	(429,278,000)
Basic weighted average common shares (in shares)	275,190,000	274,110,000	274,957,000	273,699,000
Potential dilutive shares (in shares)	0	0	0	0
Weighted Average Number of Shares Outstanding, Diluted	275,190,000	274,110,000	274,957,000	273,699,000
Basic (in usd per share)	$ (0.13)	$ (0.78)	$ (0.94)	$ (1.57)
Narrative Details [Abstract]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)			5,300,000	5,700,000
Shares repurchased during the period, (in shares)			300,000	200,000
Shares repurchased during the period, Value			10,400,000	6,000,000
Shares issued during period (in shares)			1,300,000	1,800,000
Nonvested units granted			1,000,000
Stock-based compensation	6,100,000	4,700,000	20,700,000	15,500,000
Unrecognized compensation costs, options	300,000		300,000
Unrecognized compensation costs, nonvested shares and units	37,200,000		37,200,000
Accumulated Translation Adjustment [Member]
Foreign Currency Translation Adjustments
Gross gains (losses) arising during the year			(13,342,000)	(5,823,000)
Income taxes			0	0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			(13,342,000)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Foreign Currency Translation Adjustments
Gross gains (losses) arising during the year			11,389,000	(15,709,000)
Income taxes			4,472,000	(6,206,000)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			$ 6,917,000