CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS EQUITY - USD ($) $ in Thousands	Inc. Stockholders' Equity	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit	Treasury Stock	Total
Beginning Balance at Sep. 30, 2020	$ 1,213,614	$ 873	$ 1,942,850	$ 21,919	$ (551,072)	$ (200,956)	$ 1,213,614
Beginning Balance (in shares) at Sep. 30, 2020		87,293,710
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under restricted stock and purchase plans, net		$ 4	(4)
Shares issued under restricted stock and purchase plans, net (in shares)		378,422
Stock-based compensation	6,710		6,710				6,710
Common stock dividends declared	(7,424)				(7,424)		(7,424)
Net income	26,028				26,028		26,028
Foreign currency translation adjustments	13,264			13,264			13,264
Actuarial loss, net of tax effects	(38)			(38)			(38)
Ending Balance at Dec. 31, 2020	1,252,154	$ 877	1,949,556	35,145	(532,468)	(200,956)	1,252,154
Ending Balance (in shares) at Dec. 31, 2020		87,672,132
Beginning Balance at Sep. 30, 2021	1,325,334	$ 878	1,976,112	19,351	(470,051)	(200,956)	$ 1,325,334
Beginning Balance (in shares) at Sep. 30, 2021		87,808,922					74,347,053
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under restricted stock and purchase plans, net		$ 6	(6)
Shares issued under restricted stock and purchase plans, net (in shares)		566,488
Stock-based compensation	1,465		1,465				$ 1,465
Common stock dividends declared	(7,494)				(7,494)		(7,494)
Net income	43,320				43,320		43,320
Foreign currency translation adjustments	4,801			4,801			4,801
Actuarial loss, net of tax effects	(3)			(3)			(3)
Ending Balance at Dec. 31, 2021	$ 1,367,423	$ 884	$ 1,977,571	$ 24,149	$ (434,225)	$ (200,956)	$ 1,367,423
Ending Balance (in shares) at Dec. 31, 2021		88,375,410					74,913,541