Condensed Consolidated Statements of Shareholders' Equity Condensed Consolidated Statements of Shareholders' Equity - 9 months ended Jan. 31, 2019 - USD ($) $ in Thousands	Total	Common stock	Retained earnings
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	178,674		178,674
Dividends declared	(31,839)		(31,839)
Exercise of stock options (in shares)		37,692,000
Exercise of stock options	$ 1,168	$ 1,168
Repurchase of common stock (shares)	(352,592,000)
Repurchase of common stock	$ (35,247)		(35,247)
Stock based compensation (shares)		71,245,000
Stock based compensation	11,111	$ 11,111
Ending Balance (shares) at Jan. 31, 2019		36,630,667,000
Ending Balance at Jan. 31, 2019	$ 1,390,868	$ 12,279	$ 1,378,589