Basis of Presentation, Business and Summary of Significant Accounting Policies - Revision of Condensed Consolidated Statement of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015	Apr. 30, 2016
Effect of the revision
Net income	$ 17,224	$ 2,825	$ 26,387	$ 5,836	$ 12,564
Adjustments to reconcile net income to net cash used in operating activities
Deferred income tax expense			(12,373)	(11,089)
Cash used in operating activities			$ 691	(2,327)
As previously reported
Effect of the revision
Net income				5,386
Adjustments to reconcile net income to net cash used in operating activities
Deferred income tax expense				(10,639)
Cash used in operating activities				(2,327)
Correction to statutory tax rate used in purchase accounting for April 1, 2014 Acquisition | Adjustment
Effect of the revision
Net income				450
Adjustments to reconcile net income to net cash used in operating activities
Deferred income tax expense				$ (450)