Condensed Consolidated Statements of Stockholders’ Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock	Exchangeable Shares	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Total
Balance at Apr. 30, 2017	$ 410		$ 488,459	$ 26,621	$ (884)	$ 514,606
Balance (in shares) at Apr. 30, 2017	40,971
Increase (Decrease) in Stockholders' Equity
Net income				53,052		53,052
Change in other comprehensive income (loss), net of tax					797	797
Equity-based compensation			1,141			1,141
Tax withholding related to net share settlements of equity awards / stock options			(1,441)			(1,441)
Exercise of stock options			130			130
Exercise of stock options (in shares)	70
Balance at Jan. 31, 2018	$ 410		488,289	79,673	(87)	568,285
Balance (in shares) at Jan. 31, 2018	41,041
Balance at Apr. 30, 2018	$ 411		489,007	89,592	441	$ 579,451
Balance (in shares) at Apr. 30, 2018	41,069					41,069
Increase (Decrease) in Stockholders' Equity
Net income				39,377		$ 39,377
Issuance of Exchangeable Shares						29,639
Issuance of Exchangeable Shares (in shares)		29,639
Repurchase and retirement of common stock	$ (7)		(11,507)			(11,514)
Repurchase and retirement of common stock (in shares)	(691)
Foreign currency translation adjustments					(8,821)	(8,821)
Change in other comprehensive income (loss), net of tax					491	491
Equity-based compensation			2,502			2,502
Tax withholding related to net share settlements of equity awards / stock options			(51)			(51)
Exercise of stock options	$ 1		1,280			1,281
Exercise of stock options (in shares)	103
Vesting of restricted stock units (in shares)	5
Issuance of common stock pursuant to employee stock purchase plan	$ 1		1,404			1,405
Issuance of common stock pursuant to employee stock purchase plan (in shares)	75
Balance at Jan. 31, 2019	$ 406		$ 482,635	$ 128,969	$ (7,889)	$ 633,760
Balance (in shares) at Jan. 31, 2019	40,561	29,639				40,561