Basis of Presentation, Business and Summary of Significant Accounting Policies - Revision of Condensed Consolidated Statement of Operations (Details) - USD ($) $ / shares in Units, $ 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
Provision for income taxes	$ 710	$ 2,623	$ 6,869	$ 5,478
Net income	$ 17,224	$ 2,825	$ 26,387	$ 5,836	$ 12,564
Net income per share:
Basic (in dollars per share)	$ 0.42	$ 0.09	$ 0.67	$ 0.18
Diluted (in dollars per share)	$ 0.42	$ 0.09	$ 0.66	$ 0.18
As previously reported
Effect of the revision
Provision for income taxes				$ 5,928
Net income				$ 5,386
Net income per share:
Basic (in dollars per share)				$ 0.16
Diluted (in dollars per share)				$ 0.16
Adjustment | Correction to statutory tax rate used in purchase accounting for April 1, 2014 Acquisition
Effect of the revision
Provision for income taxes				$ (450)
Net income				$ 450
Net income per share:
Basic (in dollars per share)				$ 0.02
Diluted (in dollars per share)				$ 0.02