Quarterly Financial Data (Schedule Of Share Price And Dividends Paid) (Details) - $ / shares	3 Months Ended								12 Months Ended
	Apr. 30, 2017	Jan. 31, 2017	Oct. 31, 2016	Jul. 31, 2016	Apr. 30, 2016	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2017	Apr. 30, 2016
Quarterly Financial Data [Line Items]
Dividends paid per share	$ 0.22	$ 0.22	$ 0.22	$ 0.22	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.88	$ 0.80
High
Quarterly Financial Data [Line Items]
Stock price range	24.82	24.06	24.95	24.53	35.14	37.53	37.50	34.62	24.95	37.53
Low
Quarterly Financial Data [Line Items]
Stock price range	$ 19.85	$ 20.91	$ 20.58	$ 19.18	$ 19.75	$ 31.00	$ 31.03	$ 29.15	$ 19.18	$ 19.75