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, 2017	Apr. 30, 2016	Apr. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	$ 123,920	$ 89,029
Plan investment assets, at fair value	137,141	106,965	$ 108,661
QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	123,920	89,029
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	295	10
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	295	10
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	78,335	61,338
Mutual Fund Equity [Member] | QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1) [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	78,335	61,338
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
Mutual Fund Income Tax [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets at net asset value	45,290	27,681
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	45,290	27,681
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	$ 17,936