CONDENSED CONSOLIDATED STATEMENT OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	COMMON STOCK	CAPITAL IN EXCESS OF PAR VALUE	RETAINED EARNINGS	TREASURY SHARES	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	DEFERRED COMPENSATION
Balance (in shares) at Sep. 30, 2020		83,739			27,610
Balance at Sep. 30, 2020	$ 700,151	$ 20,935	$ 583,008	$ 607,518	$ (413,493)	$ (72,092)	$ (25,725)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	29,500			29,500
Dividend	(4,469)			(4,469)
Shares withheld on employee taxes on vested equity awards (in shares)					133
Shares withheld on employee taxes on vested equity awards	(2,909)				$ (2,909)
Amortization of deferred compensation	609						609
Equity awards granted, net (in shares)		494
Equity awards granted, net	0	$ 123	(123)
ESOP allocation of common stock	596		596
Stock-based compensation	3,428		3,428
Other comprehensive income, net of tax	13,141					13,141
Balance (in shares) at Dec. 31, 2020		84,233			27,743
Balance at Dec. 31, 2020	740,047	$ 21,058	586,909	632,549	$ (416,402)	(58,951)	(25,116)
Balance (in shares) at Sep. 30, 2020		83,739			27,610
Balance at Sep. 30, 2020	700,151	$ 20,935	583,008	607,518	$ (413,493)	(72,092)	(25,725)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	46,612
Other comprehensive income, net of tax	17,916
Balance (in shares) at Mar. 31, 2021		84,427			27,743
Balance at Mar. 31, 2021	764,431	$ 21,106	591,966	646,444	$ (416,402)	(54,176)	(24,507)
Balance (in shares) at Dec. 31, 2020		84,233			27,743
Balance at Dec. 31, 2020	740,047	$ 21,058	586,909	632,549	$ (416,402)	(58,951)	(25,116)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	17,112			17,112
Dividend	(3,217)			(3,217)
Amortization of deferred compensation	609						609
Equity awards granted, net (in shares)		194
Equity awards granted, net	0	$ 48	(48)
ESOP allocation of common stock	756		756
Stock-based compensation	4,349		4,349
Other comprehensive income, net of tax	4,775					4,775
Balance (in shares) at Mar. 31, 2021		84,427			27,743
Balance at Mar. 31, 2021	764,431	$ 21,106	591,966	646,444	$ (416,402)	(54,176)	(24,507)
Balance (in shares) at Sep. 30, 2021		84,375			27,762
Balance at Sep. 30, 2021	807,158	$ 21,094	602,181	669,998	$ (416,850)	(45,977)	(23,288)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	19,298			19,298
Dividend	(4,739)			(4,739)
Shares withheld on employee taxes on vested equity awards (in shares)					422
Shares withheld on employee taxes on vested equity awards	(10,886)				$ (10,886)
Amortization of deferred compensation	591						591
Equity awards granted, net (in shares)		113
Equity awards granted, net	0	$ 28	(28)
ESOP allocation of common stock	848		848
Stock-based compensation	2,866		2,866
Other comprehensive income, net of tax	(2,751)					(2,751)
Balance (in shares) at Dec. 31, 2021		84,488			28,184
Balance at Dec. 31, 2021	812,385	$ 21,122	605,867	684,557	$ (427,736)	(48,728)	(22,697)
Balance (in shares) at Sep. 30, 2021		84,375			27,762
Balance at Sep. 30, 2021	807,158	$ 21,094	602,181	669,998	$ (416,850)	(45,977)	(23,288)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	84,987
Other comprehensive income, net of tax	2,198
Balance (in shares) at Mar. 31, 2022		84,746			27,714
Balance at Mar. 31, 2022	883,214	$ 21,187	603,624	744,894	$ (420,606)	(43,779)	(22,106)
Balance (in shares) at Dec. 31, 2021		84,488			28,184
Balance at Dec. 31, 2021	812,385	$ 21,122	605,867	684,557	$ (427,736)	(48,728)	(22,697)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	65,689			65,689
Dividend	(5,352)			(5,352)
Amortization of deferred compensation	591						591
Equity awards granted, net (in shares)		258			(470)
Equity awards granted, net	0	$ 65	(7,195)		$ 7,130
ESOP allocation of common stock	638		638
Stock-based compensation	4,314		4,314
Other comprehensive income, net of tax	4,949					4,949
Balance (in shares) at Mar. 31, 2022		84,746			27,714
Balance at Mar. 31, 2022	$ 883,214	$ 21,187	$ 603,624	$ 744,894	$ (420,606)	$ (43,779)	$ (22,106)