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, 2018	$ 411		$ 489,007	$ 89,592	$ 441	$ 579,451
Balance (in shares) at Apr. 30, 2018	41,069
Increase (Decrease) in Stockholders' Equity
Net income				33,562		33,562
Issuance of Exchangeable Shares (in shares)		$ 33,194				33,194
Foreign currency translation adjustments					(8,693)	(8,693)
Change in other comprehensive income (loss), net of tax					490	490
Equity-based compensation			1,407			1,407
Tax withholding related to net share settlements of equity awards			(7)			(7)
Exercise of stock options	$ 1		972			973
Exercise of stock options (in shares)	53
Issuance of common stock pursuant to employee stock purchase plan			881			881
Issuance of common stock pursuant to employee stock purchase plan (in shares)	35
Balance at Oct. 31, 2018	$ 412	33,194	492,260	123,154	(7,762)	641,258
Balance (in shares) at Oct. 31, 2018	41,157
Balance at Apr. 30, 2019	$ 404	29,639	480,113	145,594	(26,574)	$ 629,176
Balance (in shares) at Apr. 30, 2019	40,375					40,375
Increase (Decrease) in Stockholders' Equity
Net income				53,958		$ 53,958
Exercise of Exchangeable Shares	$ 11	$ (29,639)	29,628
Exercise of Exchangeable Shares (in shares)	1,129
Foreign currency translation adjustments					11,451	11,451
Change in other comprehensive income (loss), net of tax					(9,667)	(9,667)
Equity-based compensation			3,620			3,620
Tax withholding related to net share settlements of equity awards			(282)			(282)
Exercise of stock options	$ 5		6,756			6,761
Exercise of stock options (in shares)	534
Vesting of restricted stock units	$ 1		(1)
Vesting of restricted stock units (in shares)	55
Issuance of common stock pursuant to employee stock purchase plan	$ 1		1,021			1,022
Issuance of common stock pursuant to employee stock purchase plan (in shares)	76
Balance at Oct. 31, 2019	$ 422		$ 520,855	$ 199,552	$ (24,790)	$ 696,039
Balance (in shares) at Oct. 31, 2019	42,169					42,169