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				8,650		8,650
Exercise of Exchangeable Shares		$ 33,194				33,194
Foreign currency translation adjustments					(3,791)	(3,791)
Change in other comprehensive income (loss), net of tax					113	113
Equity-based compensation			358			358
Tax withholding related to net share settlements of equity awards			(7)			(7)
Exercise of stock options			431			431
Exercise of stock options (in shares)	35
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 Jul. 31, 2018	$ 411	33,194	490,670	98,242	(3,237)	619,280
Balance (in shares) at Jul. 31, 2018	41,139
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				24,820		$ 24,820
Exercise of Exchangeable Shares	$ 11	$ (29,639)	29,628
Exercise of Exchangeable Shares (in shares)	1,129
Foreign currency translation adjustments					11,860	11,860
Change in other comprehensive income (loss), net of tax					(6,065)	(6,065)
Equity-based compensation			1,349			1,349
Exercise of stock options			133			133
Exercise of stock options (in shares)	9
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 Jul. 31, 2019	$ 416		$ 512,244	$ 170,414	$ (20,779)	$ 662,295
Balance (in shares) at Jul. 31, 2019	41,589					41,589