CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Accumulated Deficit)	Treasury Stock	Total
Beginning Balance at Sep. 30, 2021	$ 878	$ 1,976,112	$ 19,351	$ (470,051)	$ (200,956)	$ 1,325,334
Beginning Balance (in shares) at Sep. 30, 2021	87,808,922
Increase (Decrease) in Stockholders' Equity
Shares issued under restricted stock and purchase plans, net	$ 7	3,455				3,462
Shares issued under restricted stock and purchase plans, net (in shares)	641,161
Stock-based compensation		7,229				7,229
Common stock dividends declared				(7,493)		(7,493)
Net investment hedge currency translation adjustment, net of tax effect			7,149			7,149
Foreign currency translation reclassification adjustments included in income from discontinued operations			(16,567)			(16,567)
Foreign currency translation adjustments			(14,980)			(14,980)
Changes in unrealized gains (losses) on marketable securities, net of tax			(2,432)			(2,432)
Actuarial loss, net of tax effects			81			81
Net income (loss)				2,163,193		2,163,193
Ending Balance at Mar. 31, 2022	$ 885	1,986,796	(7,398)	1,685,649	(200,956)	3,464,976
Ending Balance (in shares) at Mar. 31, 2022	88,450,083
Beginning Balance at Dec. 31, 2021	$ 884	1,977,571	24,149	(434,225)	(200,956)	1,367,423
Beginning Balance (in shares) at Dec. 31, 2021	88,375,410
Increase (Decrease) in Stockholders' Equity
Shares issued under restricted stock and purchase plans, net	$ 1	3,460				3,461
Shares issued under restricted stock and purchase plans, net (in shares)	74,673
Stock-based compensation		5,765				5,765
Net investment hedge currency translation adjustment, net of tax effect			7,149			7,149
Foreign currency translation reclassification adjustments included in income from discontinued operations			(16,567)			(16,567)
Foreign currency translation adjustments			(18,907)			(18,907)
Changes in unrealized gains (losses) on marketable securities, net of tax			(3,306)			(3,306)
Actuarial loss, net of tax effects			84			84
Net income (loss)				2,119,874		2,119,874
Ending Balance at Mar. 31, 2022	$ 885	1,986,796	(7,398)	1,685,649	(200,956)	3,464,976
Ending Balance (in shares) at Mar. 31, 2022	88,450,083
Beginning Balance at Sep. 30, 2022	$ 885	1,992,017	(83,916)	1,655,356	(200,956)	$ 3,363,386
Beginning Balance (in shares) at Sep. 30, 2022	88,482,125					75,020,256
Increase (Decrease) in Stockholders' Equity
Shares issued under restricted stock and purchase plans, net of shares withheld for employee taxes		1,573			(4,629)	$ (3,056)
Shares issued under restricted stock and purchase plans, net of shares withheld for employee taxes (in shares)	210,711
Accelerated share repurchase					(500,000)	(500,000)
Accelerated share repurchase (in shares)	(6,090,134)
Retirement of treasury shares	$ (59)	(504,568)			504,629	2
Stock-based compensation		6,096				6,096
Net investment hedge currency translation adjustment, net of tax effect			(70,260)			(70,260)
Foreign currency translation adjustments			111,264			111,264
Changes in unrealized gains (losses) on marketable securities, net of tax			4,042			4,042
Net income (loss)				(16,162)		(16,162)
Other				(85)		(85)
Ending Balance at Mar. 31, 2023	$ 826	1,495,118	(38,870)	1,639,109	(200,956)	$ 2,895,227
Ending Balance (in shares) at Mar. 31, 2023	82,602,702					69,147,387
Beginning Balance at Dec. 31, 2022	$ 824	1,489,554	(62,074)	1,644,041	(200,956)	$ 2,871,389
Beginning Balance (in shares) at Dec. 31, 2022	82,515,917
Increase (Decrease) in Stockholders' Equity
Shares issued under restricted stock and purchase plans, net of shares withheld for employee taxes		1,573				1,573
Shares issued under restricted stock and purchase plans, net of shares withheld for employee taxes (in shares)	86,785
Retirement of treasury shares	$ 2					2
Stock-based compensation		3,991				3,991
Net investment hedge currency translation adjustment, net of tax effect			(13,133)			(13,133)
Foreign currency translation adjustments			33,850			33,850
Changes in unrealized gains (losses) on marketable securities, net of tax			2,487			2,487
Net income (loss)				(4,927)		(4,927)
Other				(5)		(5)
Ending Balance at Mar. 31, 2023	$ 826	$ 1,495,118	$ (38,870)	$ 1,639,109	$ (200,956)	$ 2,895,227
Ending Balance (in shares) at Mar. 31, 2023	82,602,702					69,147,387