Consolidated Statements Of Income And Comprehensive Income (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014	Jan. 31, 2013
Income Statement [Abstract]
Tax effect of unrealized holding gains (losses) arising during the year	$ (1,869)	$ (405)	$ (6,206)	$ (122)
Tax effect of reclassification adjustment for gains included in income	$ 0	$ 0	$ 0	$ 71

Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 9

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e640-108580

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