Stockholders' Equity Rollforward of OCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Foreign Currency Translation Adjustments, beginning balance	$ (6,789)	$ 3,334	$ 6,809
Unrealized Gains on AFS Securities, beginning balance	8,529	1,843	3,741
Accumulated other comprehensive income, beginning balance	1,740	5,177	10,550
Gross gains (losses) arising during the year	(10,198)	1,942	(822)
Tax expense (benefit)	(2,207)	5,420	846
Other comprehensive income before reclassifications:	(7,991)	(3,478)	(1,668)
Amount reclassified (1)	0	0	0
Amount reclassified (1)	(8,196)	68	(5,835)
Tax expense (benefit)	0	0	0
Tax effect of reclassification adjustment for gains included in income	(3,214)	27	(2,130)
Amounts reclassified to net income:	0	0	0
Amounts reclassified to net income:	(4,982)	41	(3,705)
Unrealized translation gain	(4,461)	(10,123)	(3,475)
Change in net unrealized gain on available-for-sale securities	(8,512)	6,686	(1,898)
Other comprehensive income (loss)	(12,973)	(3,437)	(5,373)
Realized gain on sale of residual interests in mortgage securities		18,300
Other-than-temporary impairments of AFS securities		12,400
Foreign Currency Translation Adjustments, ending balance	(11,250)	(6,789)	3,334
Unrealized Gains on AFS Securities, ending balance	17	8,529	1,843
Accumulated other comprehensive income, ending balance	(11,233)	1,740	5,177
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Gross gains (losses) arising during the year	(4,398)	(9,004)	(3,416)
Tax expense (benefit)	63	1,119	59
Other comprehensive income before reclassifications:	(4,461)	(10,123)	(3,475)
Unrealized Gains (Losses) on AFS Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Gross gains (losses) arising during the year	(5,800)	10,946	2,594
Tax expense (benefit)	(2,270)	4,301	787
Other comprehensive income before reclassifications:	$ (3,530)	$ 6,645	$ 1,807