Employee Benefit and Retirement Plans (Schedule Of Pension Assets By Major Category Of Plan Assets And Type Of Fair Value Measurements) (Details) - USD ($)	Apr. 30, 2020	Apr. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	$ 190,743,000	$ 169,471,000
QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	190,743,000	169,471,000
SIGNIFICANT OBSERVABLE INPUTS (LEVEL 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	0	0
SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	0	0
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	490,000	469,000
Cash and Cash Equivalents [Member] | QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	490,000	469,000
Cash and Cash Equivalents [Member] | SIGNIFICANT OBSERVABLE INPUTS (LEVEL 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	0	0
Cash and Cash Equivalents [Member] | SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	0	0
Mutual Fund Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	37,569,000	31,143,000
Mutual Fund Equity [Member] | QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	37,569,000	31,143,000
Mutual Fund Equity [Member] | SIGNIFICANT OBSERVABLE INPUTS (LEVEL 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	0	0
Mutual Fund Equity [Member] | SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	0	0
International Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	24,578,000	20,553,000
International Equity [Member] | QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	24,578,000	20,553,000
International Equity [Member] | SIGNIFICANT OBSERVABLE INPUTS (LEVEL 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	0
International Equity [Member] | SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value
Mutual Fund Income Tax [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	128,106,000	117,306,000
Mutual Fund Income Tax [Member] | QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	128,106,000	117,306,000
Mutual Fund Income Tax [Member] | SIGNIFICANT OBSERVABLE INPUTS (LEVEL 2) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	0	0
Mutual Fund Income Tax [Member] | SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	$ 0	$ 0