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	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	$ 156,463	$ 123,920
Plan investment assets, at fair value	156,463	137,141	$ 106,965
QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	156,463	123,920
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	448	295
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	448	295
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	37,421	78,335
Mutual Fund Equity [Member] | QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	37,421	78,335
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	25,135
International Equity [Member] | QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	25,135
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	93,459	45,290
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	93,459	45,290
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
Capital Preservation Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan investment assets, at fair value		$ 13,221