CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands		Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Deficit)	Treasury Stock
Beginning Balances, (in shares) at Apr. 30, 2019			238,337,000				36,377,000
Beginning 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 loss		(150,247)				(150,247)
Other comprehensive income (loss)		(2,320)			(2,320)
Stock-based compensation		6,557		6,557
Stock-based awards exercised or vested		1,056		(13,789)		(2,786)	$ 17,631
Stock-based awards exercised or vested (in shares)							906,000
Acquisition of treasury shares (in shares)	[1]						(314,000)
Acquisition of treasury shares(1)	[1]	(9,185)					$ (9,185)
Repurchase and retirement of common shares (in shares)			(1,593,000)
Repurchase and retirement of common shares		(44,072)	$ (16)	(955)		(43,101)
Cash dividends declared - $0.26 per share		(52,512)				(52,512)
Ending Balances, (in shares) at Jul. 31, 2019			236,744,000				35,785,000
Ending Balances, Value at Jul. 31, 2019		$ 290,804	$ 2,367	759,449	(22,736)	250,740	$ (699,016)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (in usd per share)		$ 0.26
Beginning Balances, (in shares) at Apr. 30, 2019			238,337,000				36,377,000
Beginning 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 loss		(467,929)
Ending Balances, (in shares) at Jan. 31, 2020			228,207,000				35,733,000
Ending Balances, Value at Jan. 31, 2020		$ (318,379)	$ 2,282	769,990	(25,391)	(367,218)	$ (698,042)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (in usd per share)		$ 0.78
Beginning Balances, (in shares) at Jul. 31, 2019			236,744,000				35,785,000
Beginning Balances, Value at Jul. 31, 2019		$ 290,804	$ 2,367	759,449	(22,736)	250,740	$ (699,016)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss		(187,999)				(187,999)
Other comprehensive income (loss)		919			919
Stock-based compensation		9,331		9,331
Stock-based awards exercised or vested		(139)		(127)		(276)	$ 264
Stock-based awards exercised or vested (in shares)							13,000
Acquisition of treasury shares (in shares)	[1]						(6,000)
Acquisition of treasury shares(1)	[1]	(173)					$ (173)
Repurchase and retirement of common shares (in shares)			(5,720,000)
Repurchase and retirement of common shares		(136,939)	$ (57)	(3,433)		(133,449)
Cash dividends declared - $0.26 per share		(51,551)				(51,551)
Ending Balances, (in shares) at Oct. 31, 2019			231,024,000				35,778,000
Ending Balances, Value at Oct. 31, 2019		$ (75,747)	$ 2,310	765,220	(21,817)	(122,535)	$ (698,925)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (in usd per share)		$ 0.26
Net loss		$ (129,683)				(129,683)
Other comprehensive income (loss)		(3,574)			(3,574)
Stock-based compensation		6,529		6,529
Stock-based awards exercised or vested		690		(69)		(180)	$ 939
Stock-based awards exercised or vested (in shares)							47,000
Acquisition of treasury shares (in shares)							(2,000)
Acquisition of treasury shares(1)		(56)					$ (56)
Repurchase and retirement of common shares (in shares)			(2,817,000)
Repurchase and retirement of common shares		(65,774)	$ (28)	(1,690)		(64,056)
Cash dividends declared - $0.26 per share		(50,764)				(50,764)
Ending Balances, (in shares) at Jan. 31, 2020			228,207,000				35,733,000
Ending Balances, Value at Jan. 31, 2020		$ (318,379)	$ 2,282	769,990	(25,391)	(367,218)	$ (698,042)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (in usd per share)		$ 0.26
Beginning Balances, (in shares) at Apr. 30, 2020			228,207,000				35,731,000
Beginning 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 loss		91,259				91,259
Other comprehensive income (loss)		17,539			17,539
Stock-based compensation		7,422		7,422
Stock-based awards exercised or vested		973		(10,027)		(1,247)	$ 12,247
Stock-based awards exercised or vested (in shares)							627,000
Acquisition of treasury shares (in shares)	[1]						(204,000)
Acquisition of treasury shares(1)	[1]	(2,913)					$ (2,913)
Cash dividends declared - $0.26 per share		(50,044)				(50,044)
Ending Balances, (in shares) at Jul. 31, 2020			228,207,000				35,308,000
Ending Balances, Value at Jul. 31, 2020		$ 135,277	$ 2,282	772,782	(34,037)	82,933	$ (688,683)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (in usd per share)		$ 0.26
Beginning Balances, (in shares) at Apr. 30, 2020			228,207,000				35,731,000
Beginning 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 loss		(365,461)
Ending Balances, (in shares) at Jan. 31, 2021			218,719,000				35,226,000
Ending Balances, Value at Jan. 31, 2021		$ (534,580)	$ 2,187	778,495	(11,693)	(616,518)	$ (687,051)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (in usd per share)		$ 0.78
Beginning Balances, (in shares) at Jul. 31, 2020			228,207,000				35,308,000
Beginning Balances, Value at Jul. 31, 2020		$ 135,277	$ 2,282	772,782	(34,037)	82,933	$ (688,683)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss		(223,726)				(223,726)
Other comprehensive income (loss)		2,330			2,330
Stock-based compensation		6,768		6,768
Stock-based awards exercised or vested		(220)		(262)		(220)	$ 262
Stock-based awards exercised or vested (in shares)							13,000
Acquisition of treasury shares (in shares)	[1]						(6,000)
Acquisition of treasury shares(1)	[1]	(99)					$ (99)
Repurchase and retirement of common shares (in shares)			(9,488,000)
Repurchase and retirement of common shares		(150,142)	$ (95)	(5,597)		(144,450)
Cash dividends declared - $0.26 per share		(50,154)				(50,154)
Ending Balances, (in shares) at Oct. 31, 2020			218,719,000				35,301,000
Ending Balances, Value at Oct. 31, 2020		$ (279,966)	$ 2,187	773,691	(31,707)	(335,617)	$ (688,520)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (in usd per share)		$ 0.26
Net loss		$ (232,994)				(232,994)
Other comprehensive income (loss)		20,014			20,014
Stock-based compensation		5,265		5,265
Stock-based awards exercised or vested		794		(461)		(218)	$ 1,473
Stock-based awards exercised or vested (in shares)							76,000
Acquisition of treasury shares (in shares)							(1,000)
Acquisition of treasury shares(1)		(4)					$ (4)
Cash dividends declared - $0.26 per share		(47,689)				(47,689)
Ending Balances, (in shares) at Jan. 31, 2021			218,719,000				35,226,000
Ending Balances, Value at Jan. 31, 2021		$ (534,580)	$ 2,187	$ 778,495	$ (11,693)	$ (616,518)	$ (687,051)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (in usd per share)		$ 0.26

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