Employee Benefit And Retirement Plans (Schedule Of Pension Assets By Major Category Of Plan Assets And Type Of Fair Value Measurements)(Details) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2013		Apr. 30, 2012		Apr. 30, 2011
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 95,733		$ 85,717		$ 83,334
Fair Value Measurements Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	315		273
Fair Value Measurements Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	95,418		85,444
Fair Value Measurements Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	315		273
Cash and Cash Equivalents [Member] | Fair Value Measurements Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	315		273
Cash and Cash Equivalents [Member] | Fair Value Measurements Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
Cash and Cash Equivalents [Member] | Fair Value Measurements Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0		0
Equity Index Value Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	19,202	[1]	16,850	[1]
Equity Index Value Fund [Member] | Fair Value Measurements Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Equity Index Value Fund [Member] | Fair Value Measurements Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	19,202	[1]	16,850	[1]
Equity Index Value Fund [Member] | Fair Value Measurements Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Equity Index Growth Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	19,245	[1]	17,094	[1]
Equity Index Growth Fund [Member] | Fair Value Measurements Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Equity Index Growth Fund [Member] | Fair Value Measurements Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	19,245	[1]	17,094	[1]
Equity Index Growth Fund [Member] | Fair Value Measurements Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Small Cap Index Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	5,632	[1]	5,002	[1]
Small Cap Index Fund [Member] | Fair Value Measurements Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Small Cap Index Fund [Member] | Fair Value Measurements Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	5,632	[1]	5,002	[1]
Small Cap Index Fund [Member] | Fair Value Measurements Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
International Equity Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	3,932	[1]	3,315	[1]
International Equity Fund [Member] | Fair Value Measurements Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
International Equity Fund [Member] | Fair Value Measurements Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	3,932	[1]	3,315	[1]
International Equity Fund [Member] | Fair Value Measurements Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Core Fixed Income Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	17,407	[1]	25,824	[1]
Core Fixed Income Fund [Member] | Fair Value Measurements Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Core Fixed Income Fund [Member] | Fair Value Measurements Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	17,407	[1]	25,824	[1]
Core Fixed Income Fund [Member] | Fair Value Measurements Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Captial Preservation Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	30,000	[1]	17,359	[1]
Captial Preservation Fund [Member] | Fair Value Measurements Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	0	[1]	0	[1]
Captial Preservation Fund [Member] | Fair Value Measurements Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	30,000	[1]	17,359	[1]
Captial Preservation Fund [Member] | Fair Value Measurements Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	$ 0	[1]	$ 0	[1]

[1] The Collective Trust Funds are valued by applying each plan's ownership percentage in the fund to the fund's net assets at fair value at the valuation date.