Financing Arrangements Letters of Credit Outstanding (Details) - USD ($) $ in Thousands		Apr. 30, 2018	Apr. 30, 2017
Line of Credit Facility [Line Items]
Letters of Credit Outstanding, Amount	[1]	$ 514	$ 1,097
Wells Fargo Bank, N.A. [Member]
Line of Credit Facility [Line Items]
Letters of Credit Outstanding, Amount		$ 50	$ 50

[1] All of these LOC are outstanding under the Credit Agreement except one LOC for$50 that is outstanding with Wells Fargo. Any draws required under the LOC would be settled with available cash or borrowings under the Credit Agreement