CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit	Treasury Stock	Total
Beginning Balance at Sep. 30, 2019	$ 857	$ 1,921,954	$ 3,511	$ (586,412)	$ (200,956)	$ 1,138,954
Beginning Balance (in shares) at Sep. 30, 2019	85,759,700
Increase (Decrease) in Stockholders' Equity
Shares issued under restricted stock and purchase plans, net	$ 16	4,579				4,595
Shares issued under restricted stock and purchase plans, net (in shares)	1,534,010
Stock-based compensation		16,317				16,317
Common stock dividends declared				(29,513)		(29,513)
Net income				64,853		64,853
Foreign currency translation adjustments			18,877			18,877
Changes in unrealized gains on marketable securities, net of tax			7			7
Actuarial loss, net of tax effects			(476)			(476)
Ending Balance at Sep. 30, 2020	$ 873	1,942,850	21,919	(551,072)	(200,956)	1,213,614
Ending Balance (in shares) at Sep. 30, 2020	87,293,710
Increase (Decrease) in Stockholders' Equity
Shares issued under restricted stock and purchase plans, net	$ 5	5,806				5,811
Shares issued under restricted stock and purchase plans, net (in shares)	515,212
Stock-based compensation		27,456				27,456
Common stock dividends declared				(29,726)		(29,726)
Net income				110,747		110,747
Foreign currency translation adjustments			(2,922)			(2,922)
Actuarial loss, net of tax effects			354			354
Ending Balance at Sep. 30, 2021	$ 878	1,976,112	19,351	(470,051)	(200,956)	$ 1,325,334
Ending Balance (in shares) at Sep. 30, 2021	87,808,922					74,347,053
Increase (Decrease) in Stockholders' Equity
Shares issued under restricted stock and purchase plans, net	$ 7	5,239				$ 5,246
Shares issued under restricted stock and purchase plans, net (in shares)	673,203
Stock-based compensation		10,666				10,666
Common stock dividends declared				(7,494)		(7,494)
Net income				2,132,859		2,132,859
Unrealized gain on derivative asset, net of tax effects			93,020			93,020
Foreign currency translation reclassification adjustments included in income from discontinued operation (Note 2)			(16,567)			(16,567)
Foreign currency translation adjustments			(169,266)			(169,266)
Changes in unrealized gains on marketable securities, net of tax			(10,908)			(10,908)
Actuarial loss, net of tax effects			454			454
Other				42		42
Ending Balance at Sep. 30, 2022	$ 885	$ 1,992,017	$ (83,916)	$ 1,655,356	$ (200,956)	$ 3,363,386
Ending Balance (in shares) at Sep. 30, 2022	88,482,125					75,020,256