Consolidated Statements of Shareholders' Equity Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common stock	Retained earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Implementation of ASU 2014-09	$ (4,140)		$ (4,140)
Beginning Balance (shares) at Apr. 30, 2018		36,874,322,000
Beginning Balance at Apr. 30, 2018	1,271,141	$ 0	1,271,141
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	70,224		70,224
Dividends declared	(10,601)		(10,601)
Exercise of stock options (in shares)		3,600,000
Exercise of stock options	$ 148	$ 148
Repurchase of common stock (shares)	(352,592,000)
Repurchase of common stock	$ (35,247)	$ 0	(35,247)
Stock based compensation (shares)		67,895,000
Stock based compensation	7,174	$ 7,174
Ending Balance (shares) at Jul. 31, 2018		36,593,225,000
Ending Balance at Jul. 31, 2018	$ 1,298,699	$ 7,322	$ 1,291,377