Loss Per Share and Stockholders' Equity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2015	Oct. 31, 2014	Oct. 31, 2015	Oct. 31, 2014	Sep. 01, 2015
Earnings Per Share [Abstract]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)			5,000	5,400
Net loss from continuing operations attributable to shareholders	$ (142,518)	$ (113,227)	$ (239,023)	$ (222,078)
Amounts allocated to participating securities	(102)	(97)	(204)	(186)
Net loss from continuing operations attributable to common shareholders	$ (142,620)	$ (113,324)	$ (239,227)	$ (222,264)
Basic weighted average common shares (in shares)	266,267	275,106	271,016	274,841
Potential dilutive shares (in shares)	0	0	0	0
Weighted Average Number of Shares Outstanding, Diluted	266,267	275,106	271,016	274,841
Basic (in usd per share)	$ (0.54)	$ (0.41)	$ (0.88)	$ (0.81)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of shares retired during current period			$ 1,500,000
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss)			1,740	$ 5,177
Gross losses arising during the period			(15,224)	4,128
Income taxes			(2,259)	2,713
Other comprehensive income (loss) before reclassifications, net of tax			(12,965)	1,415
Gross amount reclassified			(8,196)	(24)
Tax effect of reclassification adjustment for gains included in income			(3,213)	(9)
Reclassification adjustment for gains included in income			(4,983)	(15)
Net other comprehensive income (loss)			(17,948)	1,400
Accumulated other comprehensive income (loss)	$ (16,208)	$ 6,577	$ (16,208)	$ 6,577
Narrative Details [Abstract]
Stock Repurchase Program, Authorized Amount					$ 3,500,000
Stock Repurchased and Retired During Period, Shares			40,500
Accelerated Share Repurchases, Final Price Paid Per Share			$ 37.00
Shares repurchased during the period, (in shares)			600	300
Shares repurchased during the period, Value			$ 17,800	$ 10,200
Shares issued during period (in shares)			1,800	1,200
Nonvested units granted			1,000
Stock-based compensation	7,900	7,100	$ 13,900	$ 14,600
Unrecognized compensation costs, options	500		500
Unrecognized compensation costs, nonvested shares and units	43,700		43,700
Common Stock [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of shares retired during current period			405
Additional Paid-in Capital [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of shares retired during current period			24,325
Retained Earnings [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of shares retired during current period			1,475,270
Foreign Currency Translation Adjustments [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss)			(6,789)	3,334
Gross losses arising during the period			(9,455)	(3,355)
Income taxes			0	0
Other comprehensive income (loss) before reclassifications, net of tax			(9,455)	(3,355)
Gross amount reclassified			0	0
Tax effect of reclassification adjustment for gains included in income			0	0
Reclassification adjustment for gains included in income			0	0
Net other comprehensive income (loss)			(9,455)	(3,355)
Accumulated other comprehensive income (loss)	(16,244)	(21)	(16,244)	(21)
Unrealized Gain (Loss) on AFS Securities [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Accumulated other comprehensive income (loss)			8,529	1,843
Gross losses arising during the period			(5,769)	7,483
Income taxes			(2,259)	2,713
Other comprehensive income (loss) before reclassifications, net of tax			(3,510)	4,770
Gross amount reclassified			(8,196)	(24)
Tax effect of reclassification adjustment for gains included in income			(3,213)	(9)
Reclassification adjustment for gains included in income			(4,983)	(15)
Net other comprehensive income (loss)			(8,493)	4,755
Accumulated other comprehensive income (loss)	$ 36	$ 6,598	$ 36	$ 6,598