Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	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 (loss)			12,564			12,564
Change in accounting | Change in accounting for liability equity-based awards			(3,208)			(3,208)
Increase (decrease) in fair value of financial instrument, 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 (loss)			34,614			34,614
Increase (decrease) in fair value of financial instrument, net of tax				238		238
Equity-based compensation		1,860				1,860
Issuance of common stock in initial public offering, net of underwriting discounts and offering costs	$ 80	151,332				151,412
Issuance of common stock in initial public offering (in shares)	8,050,000
Balance at Jan. 31, 2017	$ 409	$ 487,436	$ 12,349	$ (910)		$ 499,284
Balance (in shares) at Jan. 31, 2017	40,942,905