Consolidated Statements Of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands		Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	[1]	Retained Earnings	Treasury Stock
Beginning Balances (in shares) at Apr. 30, 2018			246,199					36,945
Beginning Balances, Value at Apr. 30, 2018		$ 393,711	$ 2,462	$ 760,250	$ (14,303)		$ 362,980	$ (717,678)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		422,509					422,509
Other comprehensive income (loss)		(6,113)			(6,113)
Stock-based compensation		23,510		23,510
Stock-based awards exercised or vested (in shares)								787
Stock-based awards exercised or vested		2,333		(11,407)			(1,550)	$ 15,290
Acquisition of treasury shares (in shares)	[2]							(219)
Acquisition of treasury shares(3)	[2]	(5,074)						$ (5,074)
Repurchase and retirement of common shares (in shares)			(7,862)
Repurchase and retirement of common shares		(184,838)	$ (79)	(4,717)			(180,042)
Cash dividends declared		(205,461)					(205,461)
Ending Balances (in shares) at Apr. 30, 2019			238,337					36,377
Ending Balances, Value at Apr. 30, 2019		541,527	$ 2,383	767,636	(20,416)		499,386	$ (707,462)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(7,526)					(7,526)
Other comprehensive income (loss)		(31,160)			(31,160)
Stock-based compensation		27,848		27,848
Stock-based awards exercised or vested (in shares)								969
Stock-based awards exercised or vested		1,436		(14,019)			(3,419)	$ 18,874
Acquisition of treasury shares (in shares)	[2]							(323)
Acquisition of treasury shares(3)	[2]	(9,429)						$ (9,429)
Repurchase and retirement of common shares (in shares)			(10,130)
Repurchase and retirement of common shares		(246,785)	$ (101)	(6,078)			(240,606)
Cash dividends declared		(204,870)					(204,870)
Ending Balances (in shares) at Apr. 30, 2020			228,207					35,731
Ending Balances, Value at Apr. 30, 2020		71,041	$ 2,282	775,387	(51,576)		42,965	$ (698,017)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		583,791					583,791
Other comprehensive income (loss)		56,362			56,362
Stock-based compensation		26,138		26,138
Stock-based awards exercised or vested (in shares)								755
Stock-based awards exercised or vested		1,431		(11,417)			(1,900)	$ 14,748
Acquisition of treasury shares (in shares)	[2]							(214)
Acquisition of treasury shares(3)	[2]	(3,081)						$ (3,081)
Repurchase and retirement of common shares (in shares)			(11,551)
Repurchase and retirement of common shares		(188,213)	$ (115)	(6,816)			(181,282)
Cash dividends declared		(195,068)					(195,068)
Ending Balances (in shares) at Apr. 30, 2021			216,656					35,190
Ending Balances, Value at Apr. 30, 2021		$ 352,401	$ 2,167	$ 783,292	$ 4,786		$ 248,506	$ (686,350)

[1] The balance of our accumulated other comprehensive income (loss) consists of foreign currency translation adjustments.

[2] Represents shares swapped or surrendered to us in connection with the vesting or exercise of stock-based awards.