Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Exchangeable Shares	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Balance at Apr. 30, 2018	$ 579,451	$ 411	$ 0	$ 489,007	$ 89,592	$ 441
Balance (in shares) at Apr. 30, 2018		41,069
Increase (Decrease) in Stockholders' Equity
Net income	56,002				56,002
Issuance of Exchangeable Shares	29,639		29,639
Repurchase and retirement of common stock	(16,520)	$ (10)		(16,510)
Repurchase and retirement of common stock (in shares)		(978)
Foreign currency translation gain (loss)	(22,320)					(22,320)
Other comprehensive income (loss), net of tax	(4,695)					(4,695)
Equity-based compensation	3,726			3,726
Exercise of stock options	2,538	$ 2		2,536
Exercise of stock options (in shares)		205
Vesting of restricted stock units (in shares)		5
Tax withholding related to net share settlements of equity awards	(50)			(50)
Issuance of common stock pursuant to employee stock purchase plan	1,405	$ 1		1,404
Issuance of common stock pursuant to employee stock purchase plan (in shares)		74
Balance at Apr. 30, 2019	629,176	$ 404	29,639	480,113	145,594	(26,574)
Balance (in shares) at Apr. 30, 2019		40,375
Increase (Decrease) in Stockholders' Equity
Net income	23,381				23,381
Exercise of Exchangeable Shares	0	$ 11	(29,639)	29,628
Exercise of Exchangeable Shares (in shares)		1,129
Foreign currency translation gain (loss)	(18,257)					(18,257)
Other comprehensive income (loss), net of tax	(20,251)					(20,251)
Equity-based compensation	6,878			6,878
Exercise of stock options	11,793	$ 9		11,784
Exercise of stock options (in shares)		857
Vesting of restricted stock units	0	$ 1		(1)
Vesting of restricted stock units (in shares)		78
Tax withholding related to net share settlements of equity awards	(532)			(532)
Issuance of common stock pursuant to employee stock purchase plan	1,793	$ 1		1,792
Issuance of common stock pursuant to employee stock purchase plan (in shares)		115
Balance at Apr. 30, 2020	$ 633,981	$ 426	0	529,662	168,975	(65,082)
Balance (in shares) at Apr. 30, 2020	42,554	42,554
Increase (Decrease) in Stockholders' Equity
Net income	$ 105,560				105,560
Repurchase and retirement of common stock	(4,160)	$ (1)		(4,159)
Repurchase and retirement of common stock (in shares)		(134)
Foreign currency translation gain (loss)	61,341					61,341
Other comprehensive income (loss), net of tax	8,500					8,500
Equity-based compensation	8,412			8,412
Exercise of stock options	7,559	$ 4		7,555
Exercise of stock options (in shares)		483
Vesting of restricted stock units	0	$ 1		(1)
Vesting of restricted stock units (in shares)		75
Tax withholding related to net share settlements of equity awards	(807)			(807)
Issuance of common stock pursuant to employee stock purchase plan	2,076	$ 1		2,075
Issuance of common stock pursuant to employee stock purchase plan (in shares)		95
Balance at Apr. 30, 2021	$ 822,462	$ 431	$ 0	$ 542,737	$ 274,535	$ 4,759
Balance (in shares) at Apr. 30, 2021	43,073	43,073