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 (Deficit)	Treasury Stock
Beginning Balances (in shares) at Apr. 30, 2017		246,199					39,028
Beginning Balances, Value at Apr. 30, 2017	$ (60,883)	$ 2,462	$ 754,912	$ (15,299)		$ (48,206)	$ (754,752)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	613,149					613,149
Other comprehensive income (loss)	996			996
Stock-based compensation	21,713		21,713
Stock-based awards exercised or vested (in shares)							2,389
Stock-based awards exercised or vested	28,352		(16,375)			(1,494)	$ 46,221
Acquisition of treasury shares (in shares)							(306)
Acquisition of treasury shares	(9,147)						$ (9,147)
Cash dividends declared	(200,469)					(200,469)
Ending Balances (in shares) at Apr. 30, 2018		246,199					36,945
Ending 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)							(219)
Acquisition of treasury shares	(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)							(323)
Acquisition of treasury shares	(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)

[1] Substantially all of the balance of our accumulated comprehensive loss consists of foreign currency translation adjustments.