Income Taxes (Schedule Of Significant Components Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Apr. 30, 2016	Apr. 30, 2015
Deferred tax assets:
Pension benefits	$ 24,930	$ 23,074
Accounts receivable	5,981	5,523
Product liability	1,141	1,031
Employee benefits	7,101	7,429
Other	353	266
Gross deferred tax assets, before valuation allowance	44,373	37,323
Valuation allowance	(3,061)	0
Gross deferred tax assets, after valuation allowance	41,312	37,323
Deferred tax liabilities:
Inventory	440	451
Depreciation	8,298	3,485
Total	8,738	3,936
Net deferred tax asset	32,574	33,387
State [Member]
Deferred tax assets:
State tax credit carryforwards	$ 4,867	$ 0