Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income	Treasury Stock	Total
Balance at Apr. 30, 2015	$ 328	$ 329,884	$ (30,650)	$ 10		$ 299,572
Balance (in shares) at Apr. 30, 2015	32,757,905
Increase (Decrease) in Stockholders' Equity
Net income			12,564			12,564
Change in accounting | Change in accounting for liability equity-based awards			(3,208)			(3,208)
Decrease in fair value of financial instruments, net of tax				(1,158)		(1,158)
Equity-based compensation		2,699				2,699
Stock repurchases					$ (5,827)	(5,827)
Stock repurchases (in shares)					394,577
Exercise of stock options	$ 1	1,661	(971)		$ 5,827	6,518
Exercise of stock options (in shares)	135,000				(394,577)
Balance at Apr. 30, 2016	$ 329	334,244	(22,265)	(1,148)		311,160
Balance (in shares) at Apr. 30, 2016	32,892,905
Increase (Decrease) in Stockholders' Equity
Net income			9,163			9,163
Decrease in fair value of financial instruments, net of tax				(88)		(88)
Equity-based compensation		643				643
Issuance of common stock in initial public offering, net of underwriting discounts and offering costs	$ 80	151,607				151,687
Issuance of common stock in initial public offering (in shares)	8,050,000
Balance at Jul. 31, 2016	$ 409	$ 486,494	$ (13,102)	$ (1,236)		$ 472,565
Balance (in shares) at Jul. 31, 2016	40,942,905