Employee Benefit and Retirement Plans (Reconciliation Of Benefit Obligations, Plan Assets, And Funded Status) (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2016
Retirement Benefits [Abstract]
Projected benefit obligation at beginning of year	$ 165,173	$ 174,096
Interest cost	5,727	5,772	$ 7,014
Acturial (gains) and losses	(2,596)	(4,672)
Benefits paid	(4,881)	(10,023)
Projected benefit obligation at end of year	163,423	165,173	174,096
Fair value of plan assets at beginning of year	137,141	106,965
Actual return on plan assets	4,884	12,895
Company contributions	19,319	27,304
Benefits paid	(4,881)	(10,023)
Fair value of plan assets at end of year	156,463	137,141	$ 106,965
Funded status of the plan	$ (6,960)	$ (28,032)