Equity-Based Compensation - Restricted Stock Units (Details) - Restricted Stock Units $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Jul. 31, 2018 USD ($) $ / shares shares
Unrecognized compensation cost | $	$ 0.6
Weighted-average period for recognition of unrecognized compensation expense (in years)	2 years 4 months 24 days
Number of Restricted Stock Units
Outstanding, beginning of the period (in shares) | shares	21,766
Vested (in shares) | shares	(655)
Outstanding, end of the period (in shares) | shares	21,111
Weighted Average Exercise Price
Outstanding, beginning of period (in dollars per share) | $ / shares	$ 37.49
Vested (in dollars per share) | $ / shares	37.49
Outstanding, end of the period (in dollars per share) | $ / shares	$ 37.49