Equity-Based Compensation - (Tables)

12 Months Ended

Apr. 30, 2018

Equity-Based Compensation

Summary of stock option activity

				Weighted
		Weighted		Average
		Average		Remaining	Aggregate
	Number of	Exercise		Contractual	Intrinsic
	Options	Price		Life (years)	Value
	(shares and dollars in thousands)
Outstanding as of April 30, 2017	2,088	$	13.49	7.23	$	47,336
Options granted	63		37.49
Options exercised	(199)		12.53
Options forfeited	—		—
Options expired	—		—
Outstanding as of April 30, 2018	1,952	$	14.37	6.52	$	33,209
Exercisable as of April 30, 2018	1,682	$	12.97	6.31	$	30,599
Vested and expected to vest as of April 30, 2018	1,946	$	14.33	6.52	$	33,173

Schedule of weighted average assumptions used in Black-Scholes option-pricing model

	Year Ended
	April 30,
	2018		2017
Volatility	30.86	%	40.68	%
Expected life (years)	6.0		6.0
Risk-free interest rate	2.18	%	1.55	%
Dividend yield	—	%	—	%