Stock-Based Compensation Restricted Stock Awards (Details) - Restricted stock awards shares in Thousands	12 Months Ended
	Apr. 30, 2020 $ / shares shares
Shares
Unvested stock at beginning of year (in shares) | shares	226,159
Stock granted (in shares) | shares	131,991
Stock vested (in shares) | shares	(143,962)
Stock canceled (in shares) | shares	(12,541)
Unvested stock at end of year (in shares) | shares	201,647
Weighted Average Grant Date Fair Value
Unvested stock at beginning of year (in dollars per share) | $ / shares	$ 43.35
Stock granted (in dollars per shares) | $ / shares	52.71
Stock vested (in dollars per shares) | $ / shares	34.03
Stock canceled (in dollars per shares) | $ / shares	47.86
Unvested stock at end of year (in dollars per share) | $ / shares	$ 55.84